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I AM DELIGHTED TO INTRODUCE OUR
SPEAKERS TODAY.
DR. SWEE LAY THEIN AND DR. SAM
MBULAITEYE.
THEY WILL DELIVER A JOINT
PRESENTATION SO I WILL INTRODUCE
THEM BOTH AT THIS TIME.
OUR FIRST SPEAKER, DR. SWEE LAY
THEIN, IS SENIOR INVESTIGATOR
AND CHIEF OF THE SICKLE CELL
BRANCH AT THE NATIONAL HEART,
LUNG, BLOOD, INSTITUTE SINCE
MARCH 2015.
PRIOR TO THIS TIME, SHE WAS
PROFESSOR OF MOLECULAR
HEMATOLOGY AND A CONSULTANT
HEMATOLOGIST AT KINGS COLLEGE
LONDON HOSPITAL, WHERE SHE
SERVED AS CLINICAL DIRECTOR OF
THE RED CELL CENTER.
AT KCL, SHE WAS INVOLVED IN THE
CARE OF 800 ADULT PATIENTS WITH
SICKLE CELL DISEASE AND OTHER
RED BLOOD CELL DISORDERS.
SHE HAS PARTICIPATED AND
DIRECTED A WIDE RANGE OF
CLINICAL AND TRANSLATIONAL
HEMATOLOGY RESEARCH ON INHERITED
ANEMIAS, AND PARTICULARLY THE
BETA HEMOGLOBIN DISORDERS.
HER RESEARCH FOCUSES ON SICKLE
CELL DISEASE TO BETTER
UNDERSTAND HOW A SIMPLE MUTATION
IN A SINGLE GENE CAN CAUSE
DAMAGE IN MULTIPLE ORGANS AND
THE EXTREME VARIABILITY IN
SICKLE CELL DISEASE SEVERITY AND
ALSO TO ACCELERATE TRANSLATION
OF BASIC DISCOVERY TO THE
THERAPEUTIC APPLICATION AND
MANAGEMENT OF THESE DISEASES.
IN 2022, DR. THEIN'S WORK IN
SICKLE CELL DISEASE WAS CHOSEN
BY SCIENTISTS AND AMONG THE 10
BIGGEST SCIENCE STORIES AS
PUBLISHED IN THE GUARDIAN IN THE
U.K.
THE STORY TITLED INCLUSIVE
INRHODES FEATURES AN NIH STUDY
OF METABABAT -- KINASE ACTIVATOR
IN SICKLE CELL DISEASE AS PART
OF A BROADER STORY ON INCLUSIVE
SCIENCE WHERE GENDER, ETHNICITY
AND LOCATION NEITHER PRIVILEGE
NOR EXCLUDE.
TURNING TO OUR SECOND SPEAKER,
DR. SAM MBULAITEYE IS A SENIOR
INVESTIGATOR IN THE INFECTIONS
AND IMMUNOEPIDEMIOLOGY BRANCH AT
THE NATIONAL CANCER INSTITUTE.
HE CONDUCTS RESEARCH TO
UNDERSTAND THE ETIOLOGY OF
BURKITT LYMPHOMA, A CANCER THAT
OCCURS WORLDWIDE BUT HAS ITS
HIGHEST INCIDENCE RECORDED IN
POPULATIONS OF SUB-SAHARAN
AFRICA.
HE IS A PRINCIPAL INVESTIGATOR
OF A MULTI-COUNTRY CASE CONTROL
STUDY CALLED THE EPIDEMIOLOGY OF
BURKITT LYMPHOMA IN EAST AFRICAN
CHILDREN IN SIX RURAL REGIONS IN
AN UGANDA, TANZANIA AND KENYA.
TO IDENTIFY AND ELUCIDATE
INFECTIOUS, ET LOGICAL RISK
FACTORS OF BURKITT LYMPHOMA.
HIS STUDIES SHOW THE FEASIBILITY
OF CONDUCTING HIGH IMPACT
MOLECULAR STUDIES ON BURKITT
LYMPHOMA IN AFRICA, GENERATE NEW
DATA TO SUPPORT NEW DISCOVERIES
AND COLLABORATIONS TO IMPROVE
ITS DIAGNOSIS AND TREATMENT.
DR. MBULAITEYE RECEIVED HIS
PHYSICIAN TRAINING AT MAKERERE
UNIVERSITY IN UGANDA, ADVANCED
TRAINING IN EPIDEMIOLOGY AND
BIOSTATISTICS FROM THE
UNIVERSITY OF CAMBRIDGE U.K.,
AND SPECIALIST TRAINING IN
INTERNAL MEDICINE FROM MAKERERE
UNIVERSITY.
MEASURING THE IMPACT OF HIV IN
CANCER PATIENTS AND
INVESTIGATING POPULATION TRENDS
OF HIV IN EURL AND SOUTHWEST
UGANDA.
HE JOINED THE NCI IN
DECEMBER 2000 TO FOCUS HIS WORK
ON KAPOSI SARCOMA AND BURKITT
LYMPHOMA AS A RESEARCH FELLOW
AND THEN WENT ON TO OBTAIN
SCIENTIFIC TENURE AND
APPOINTMENT AS A SENIOR
INVESTIGATOR IN 2013.
IN 2022, HE WAS NAMED SCIENTIST
OF THE YEAR BY THE LYMPHOMA
FOUNDATION OF AMERICA.
SO PLEASE JOIN ME IN WELCOMING
OUR SPEAKERS FOR THEIR JOINT
PRESENTATION TITLED "EXPLORING
THE LINK BETWEEN SICKLE CELL,
ALPHA THALASSEMIA, P FALCIPARUM
MALARIA AND BURKITT LYMPHOMA IN
AFRICA.
I'LL TURN IT OVER TO YOU,
DR. THEIN.
SO THANK YOU, DR. CHUNG, AND
THANK YOU TO THE COMMITTEE FOR
GIVING SAM AND I THE OPPORTUNITY
TO PRESENT OUR COLLABORATIVE
WORK, WHICH IS ENTITLED
EXPLORING THE LINK BETWEEN
SICKLE CELL, ALPHA THALASSEMIA
AND BURKITT LYMPHOMA IN AFRICA.
SO THESE ARE OUR LEARNING
OBJECTIVES.
FIRST TO RECOGNIZE THAT MALARIA
INFECTION AND BURKITT LYMPHOMA
ARE CO-ENDEMIC, THAT MALARIA IS
A RISK FACTOR FOR BURKITT
LYMPHOMA.
SECOND, TO RECOGNIZE THE
INDEPENDENT PROTECTIVE EFFECTS
OF SICKLE CELL TRAIT AND ALPHA
THALASSEMIA AGAINST MALARIA AND
THEIR PHYSIOLOGICAL IMPACT IN
THE U.S. POPULATION.
AND THIRDLY, TO EVALUATE THE
INTERACTION OF ALPHA THALASSEMIA
AND SICKLE CELL TRAIT ON THE
PROTECTION AGAINST BURKITT
LYMPHOMA.
WE HAVE NOTHING TO DISCLOSE.
SO I WILL SET THE SCENE FOR
SAM'S PRESENTATION, STARTING
WITH AN OVERVIEW OF THE GLOBAL
DISTRIBUTION OF SICKLE CELL AND
ALPHA THALASSEMIA IN RELATION TO
MALARIA.
AND THEN I'LL COVER A LITTLE ON
THE PHYSIOLOGICAL IMPACT OF
SICKLE CELL TRAIT AND ALPHA
THALASSEMIA GENOTYPES IN THE
U.S. POPULATION.
AND FINALLY, TO COMPARE THE
FREQUENCY OF ALPHA THALASSEMIA
IN AFRICAN VERSUS THE U.S.
POPULATION AND HOW COINHERITANCE
OF ALPHA THALASSEMIA MODIFIES
THE PHENOTYPE OF SICKLE CELL
TRAIT.
SO FIRST THE INHERITED DISORDERS
OF HEMOGLOBIN LIKE ALPHA
THALASSEMIA AND SICKLE CELL
DISEASE, THEY ARE EXEMPLARS OF
NATURAL SELECTION AND BALANCED
POLYMORPHISM.
HETEROZYGOUS -- ARE ASYMPTOMATIC
AND PROTECTED FROM THE SEVERE
FORMS OF MALARIA.
THIS COMPENSATES FOR THE LOSS OF
THE SEVERITY -- THE IMPROVED
FITNESS OF HETEROZYGOUS ALLOWS
THE FREQUENCY OF THESE DISORDERS
TO INCREASE.
THIS MALARIA HYPOTHESIS WAS
FIRST PROPOSED BY JBS HALDANE IN
1949 FOR THALASSEMIA AND ALISON
IN 1954 FOR SICKLE CELL DISEASE.
BOTH NOTED A STRIKING OVERLAP IN
THE GEOGRAPHIC DISTRIBUTION OF
MALARIA AND THESE DISORDERS.
SOME IN VITRO STUDIES HAVE
PROVIDED SUPPORT FOR THE
PROTECTIVE ROLE OF HEMOGLOBIN S
AGAINST THE MALARIAL PARASITE
BUT IT WAS FRED PIEL IN OXFORD
WHO FORMALLY INVESTIGATED AND
PROVIDED THE GEOGRAPHICAL
EVIDENCE IN SUPPORT OF THE
MALARIAL HYPOTHESIS.
HE SHOWED THAT GLOBALLY, THE
HEMOGLOBIN S FREQUENCY INCREASES
FROM EPIDEMIC TO HYPOENDEMIC AND
THEN FROM MESOENDEMIC TO
HYPERENDEMIC AND THEN TO
HOLOENDEMIC.
AND THE EVIDENCE WAS ACTUALLY
DERIVED FROM MICRO MAPPING OF
THE HEMOGLOBIN S ALLELE IN
RELATION TO THE HISTORICAL
DISTRIBUTION OF P FALCIPARUM.
SURVIVAL ADVANTAGE OF THE AS OR
THE CARRIERS IN THE MALARIA
ENDEMIC REGIONS HAVE DRIVEN THIS
GENE FREQUENCY UP TO 30% IN
HISTORICALLY ENDEMIC REGIONS.
SO CURRENTLY IT IS ESTIMATED
THERE ARE ABOUT 5.5 MILLION
BIRTHS OF AS ANNUALLY, AND
300 MILLION PEOPLE ARE AFFECTED,
WHICH IS ABOUT 5% OF THE WORLD
POPULATION.
AND HOW DID SICKLE ALLELE ARRIVE
TO THE U.S. WAS PROBABLY
IMPORTANT.
FROM AFRICA WITH THE FIRST
MIGRATION BETWEEN 16TH AND THE
19TH CENTURY AND CURRENT
ESTIMATE IS THAT THERE ARE ABOUT
3 MILLION PEOPLE WHO ARE
CARRIERS FOR SICKLE CELL, THE
MAJORITY OF WHICH ARE BLACK
AMERICANS, WHERE THE FREQUENCY
IS ABOUT 7 TO 9%.
SO WHAT IS SICKLE CELL?
THE SICKLE HEMOGLOBIN OR
HEMOGLOBIN S IS AN ABNORMAL
STRUCTURE VARIANT, A RESULT
OF -- SUBSTITUTION IN THE --
CHAIN OF HEMOGLOBIN TETRAMER AND
CAUSE FOR SUBSTITUTION.
CARRIERS OF THE SICKLE ALLELE
ARE CLINICALLY ASYMPTOMATIC, BUT
HOME SI ZYGOTES SUFFER FROM SICE
CELL DISEASE, CHRONIC ANEMIA AND
ACUTE EVENTS MOST OF WHICH ARE
ACUTE SEVERE PAIN, SO SEVERE
IT'S OFTEN REFERRED TO AS A
CRISIS.
AND WITHOUT TREATMENT, THE VAST
MAJORITY OF HEMOGLOBIN SERS DAIS
WE SEE IN SUB-SAHARAN AFRICA.
AND HOW DOES THE SICKLE CELL
TRAIT IMPACT PHYSIOLOGICAL
FUNCTION?
THERE ARE NUMEROUS STUDIES AND
IT'S DIFFICULT FOR ME TO DO
JUSTICE TO ALL OF THESE
PUBLICATIONS, BUT THIS IS THE
GIST OF WHAT WE HAVE GLEANED
FROM THE PUBLISHED PAPERS IN A
REVIEW THAT I AUTHORED WITH A
CLINICAL FELLOW.
SO IMPORTANT TO BARE IN MIND
THAT SICKLE CELL TRAIT IS A
BENIGN CARRIER STATE BUT
NONETHELESS, IT'S IMPORTANT TO
KNOW IF ONE IS A CARRIER FOR
GENETIC COUNSELING PURPOSES AND
ALSO EVALUATION OF RARE
SICKLE-TYPE SYMPTOMS.
LIFE EXPECTANCY IS NOT REDUCED
WIBUT THOUGHT TO BE ASSOCIATED
WITH HIGHER RISK FOR CERTAIN
RENAL COMPLICATIONS LIKE
HEMATURIA, CHRONIC KIDNEY
DISEASE, RENAL MEDULLARY
CARCINOMA, AND A RARE AND
AGGRESSIVE RENAL TUMOR ALMOST
EXCLUSIVELY DESCRIBED IN YOUNG
ADULTS WITH SICKLE CELL TRAIT.
THERE'S ALSO SOME ASSOCIATION
WITH END STAGE KIDNEY DISEASE
BUT EVIDENCE IS LOW.
AND PLEASE NOTE SOMETHING I'LL
COME BACK LATER, THE
COINHERITANCE OF ALPHA
THALASSEMIA IS AN ATTENUATING
FACTOR FOR CHRONIC KIDNEY
DISEASE.
EVIDENCE FOR VENOUS THROMBOTIC
EVENTS IS PARTICULARLY STRONG
FOR PULMONARY EMBOLISM BUT NOT
SO MUCH FOR DEEP VENOUS
THROMBOSIS, AND THE RISK FOR
THESE VTEs MAY BE MORE
PRONOUNCED IN SOME SETTINGS,
LIKE PREGNANCY AND POSTPARTUM.
AND HERE IS ANOTHER SYNDROME
WHICH IS A PRESENTATION IN
ITSELF REFERRED TO AS ECAST,
EXERCISE COLLAPSE ASSOCIATED
WITH SICKLE CELL TRAIT, SUDDEN
DEATH DURING STRENUOUS PHYSICAL
ACTIVITY IN AS.
IT'S UNCLEAR WHETHER THERE IS A
RELATIONSHIP OR WHETHER THERE
ARE ALSO COINHERITED GENETIC
FACTORS, BUT DEHYDRATION IS A
BIG, BIG FACTOR.
AND RARELY YOU CAN SEE SICKLE
CELL DISEASE -- OR THEY MAY HAVE
THIS DOMINANT BETA S ALLELES
LIKE HEMOGLOBIN JAMAICA PLAIN.
THIS IS A GRAPHIC SUMMARY OF THE
STRENGTH OF ASSOCIATION OF THE
VENOUS SICKLE CELL TRAIT.
SO THE STRONG EVIDENCE FOR CKD,
PROTEINURIA, VTEs, IN
PARTICULAR, PULMONARY EMBOLISM,
HYPOSTHENURIA, AND RENAL
MEDULLARY CARCINOMA.
NOW ON TO ALPHA THALASSEMIA.
SO THE EVIDENCE THAT ALPHA
THALASSEMIA IS HIGHLY PROTECTIVE
AGAINST MALARIA WAS PROVIDED BY
JONATHAN FLINT, WHO COMPARED
FREQUENCIES OF ALPHA THALASSEMIA
IN THOSE EXPOSED TO THE
DIFFERENT -- OF MALARIA AND ALSO
THOSE IN NEW GUINEA LIVING AT
DIFFERENT ALTITUDES.
THIS IS PROBABLY THE MOST RECENT
REPRESENTATION OF THE GLOBAL
PRESENCE OF ALPHA THALASSEMIA.
AND FIRST I WANT YOU TO SEE THAT
THERE ARE MANY MORE DIFFERENT
FLAVORS OF ALPHA THALASSEMIA
COMPARED TO ONE SINGLE MUTATION
FOR HEMOGLOBIN S.
AND MOST OF THE ALPHA
THALASSEMIA, HOWEVER, IS CAUSED
BY A SINGLE DELETION, AND SINGLE
ALPHA DELETIONS ARE MOST COMMON.
AND NOTE HERE THAT THE ONES
PRESENT IN AFRICA IS A SINGLE
ALPHA GENE DELETION.
AND AGAIN, IT'S MOST LIKELY THAT
THE ALPHA THALASSEMIA WAS
IMPORTED INTO THE U.S. WITH THE
FIRST MIGRATION FROM AFRICA
BETWEEN 14TH AND 19TH CENTURY.
BUT FOR US IN THE U.S., THE
SINGLE ALPHA GENE DELETION
PREDOMINATES AS FOUND IN
AFRICANS.
SO THE QUESTION IS, DO THE
DIFFERENT ALPHAS MATTER?
-- WHICH IS HIGHLY DEPENDENT ON
THE AMOUNT OF ALPHA GLOBIN CHAIN
BUT IT'S ENCODED BY FOUR ALPHA
GLOBIN GENES.
TWO ON EACH CHROMOSOME.
SO A NORMAL PERSON SHOULD HAVE
FOUR ALPHA GENE COPIES.
DELETION OF A SINGLE COPY
PRODUCES A PHENOTYPE THAT CANNOT
BE DISTINGUISHED FROM NORMAL.
LOSS OF TWO ALPHA GLOBIN GENES
CAN BE FROM THE SAME CHROMOSOME
OR ACROSS OPPOSITE CHROMOSOMES,
AND THESE ARE ASSOCIATED WITH
THE SAME PHENOTYPE OF -- ANEMIA.
BECAUSE THE ALPHA THAL VARIANT
IN AFRICANS AND BLACK AMERICANS
IS A SINGLE ALPHA GENE DELETION,
THE MOST SEVERE PHENOTYPE THAT
ONE CAN GET IS ACTUALLY LOSS OF
TWO ALPHA GLOBIN GENES, AND THIS
IS -- ALSO LOSS OF FOUR CAUSES
HEMOGLOBIN BART'S HYDROPS
SYNDROME WHICH IS NOT COMPATIBLE
WITH LIFE.
THIS IS HOW YOU DESCRIBE IN
AFRICAN AMERICANS OR BLACK
AMERICANS FOR THE OBVIOUS
REASONS THAT TWO ALPHA GENE
DELETION IS NOT COMMON OR HIGHLY
FOUND.
-- MINIMAL CLINICAL IMPACT ON
ITS OWN OR SO IT WAS THOUGHT,
UNTIL THE APPEARANCE OF THIS
NATURE ARTICLE IN 2012.
SHOWING THAT ALPHA GLOBIN GENE
IS EXPRESSING ALPHA THALASSEMIA
CELLS AND REGULATES NITRIC OXIDE
SIGNALING WHICH MEANS THAT THE
NUMBER OF ALPHA GLOBIN GENES
COULD HAVE A ROLE IN REGULATING
VASCULAR TONE.
THIS PAPER SPARKED UP A COUPLE
OF STUDIES.
WITH A QUESTION AS TO WHETHER
THE FUNCTIONAL LOSS OF ALPHA
GLOBIN INFLUENCED THE RISK OF
HYPERTENSION.
THE FIRST STUDY WAS CARRIED OUT
ON KENYAN ADOLESCENTS LIVING IN
THE FREE PART OF NYROBI,
AMBULATORY BLOOD PRESSURE WAS
MEASURED 24 HOURS USING A
VALIDATED DEVICE THAT ALSO
MEASURES -- WAVE VELOCITY.
ALPHA GLOBIN GENOTYPE -- THE
STUDY CONCLUDED THAT ALPHA
THALASSEMIA GENOTYPE DOES NOT
AFFECT BLOOD PRESSURE OR
ARTERIAL STIFFNESS IN KENYAN
ADOLESCENTS LIVING WITHIN
NON-MALARIA ENDEMIC ENVIRONMENT.
A MORE RECENT STUDY THAT IS MORE
RELEVANT TO THE U.S. POPULATION
CAME FROM HANS ECKERMAN AND HIS
GROUP AT NIH.
HANS AND HIS GROUP LEVERAGED
RESOURCES OF THE REGRDS STUDY
COHORT WHICH WAS DESIGNED TO
ADDRESS THE REASONS FOR RACIAL
DISPARITIES IN -- DECLINE IN
BLACK AND WHITE AMERICANS AGE 45
YEARS AND ABOVE.
SO MORE THAN 30,000 COMMUNITY
DWELLING SUBJECTS WERE
RECRUITED, ENROLLED WITHIN 2003
AND 2007, AND OF THESE, 41% WERE
BLACK AMERICANS.
ALPHA GLOBIN GENOTYPING WAS
DETERMINED BY DIGITAL PCR,
AND -- EXCLUSION CRITERIA 9,680
FOWRP SAMPLES COULD BE ANALYZED
FOR PREVALENT HYPERTENSION.
BLOOD PRESSURE STATUS WAS
DETERMINED USING A COMBINATION
OF APPROACHES INCLUDING
MEASUREMENT BY TRAINED PERSONNEL
IN HOME VISITS.
THE STUDY CONCLUDED THAT ALPHA
GLOBIN GENE COPY NUMBER WAS NOT
ASSOCIATED WITH RESISTANT,
PREVALENT OR INCIDENT
HYPERTENSION IN THE ADULT BLACK
AMERICANS.
THE NEXT QUESTION WAS, THIS DOES
ALPHA GLOBIN GENE COPY NUMBER
INFLUENCE RISK OF KIDNEYS
DISEASE?
TWO GENETIC VARIANTS THAT
CONTRIBUTE TO THIS RISK INCLUDE
SICKLE CELL TRAIT AND PROTEIN LN
IN BLACKS BUT THEY'RE ONLY
PARTLY EXPLAINED SOME DISPARITY.
SO HANS AND HIS GROUP THEN ASKED
IF COINHERITANCE OF ALPHA THAL
PREVALENT IN BLACK AMERICANS
COULD CONTRIBUTE TO THIS
DISPARITY.
THE STUDY AGAIN LEVERAGED
RESOURCES OF THE REGARDS COHORT.
INFORMATION ON VARIOUS VARIABLES
INCLUDING PHYSICIAN DIAGNOSED
CO-MORBID CONDITIONS ARE
COLLECTED, BLOOD AND URINE
SAMPLES AND VARIOUS VARIABLES
SUCH AS HIGH WAVE BLOOD PRESSURE
WERE COLLECTED BY TRAINED
PERSONNEL DURING HOME VISITS,
AND THE STUDY WAS ALSO --
ANALYSIS WAS ADJUSTED FOR
COVARIATES INCLUDING
HYPERTENSION, DIABETES,
HEMOGLOBIN S, PRESENCE OF THIS
APOL1 HIGH RISK GENOTYPE AND
OTHERS.
WHAT THEY SHOWED WAS THAT HAVING
ALPHA THALASSEMIA ACTUALLY
PROTECTS AGAINST CHRONIC KIDNEY
DISEASE, AND THAT EACH
ADDITIONAL COPY OF ALPHA GLOBIN
GENE INCREASED CKD PREVALENCE BY
14%, AND END STAGE KIDNEY
DISEASE PREVALENCE BY 32%.
SO DOES FUNCTIONAL LOSS OF ALPHA
GLOBIN GENE INFLUENCE RISK OF
HYPERTENSION?
NO.
DOES ALPHA GLOBIN GENE COPY
NUMBER INFLUENCE RISK OF KIDNEY
DISEASE?
YES.
INCREASING ALPHA GLOBIN GENE
COPY NUMBER WAS ASSOCIATED WITH
A GREATER PREVALENCE OF CKD AND
INCIDENCE OF END STAGE KIDNEY
DISEASE.
SO IN THE PREVIOUS SLIDE, I
MENTIONED THAT SICKLE CELL
DISEASE COULD INFLUENCE --
FACTOR FOR KIDNEY DISEASE.
THIS SLIDE REMINDS US OF THE
EPIDEMIOLOGY OF THE HEMOGLOBIN
DISORDERS THAT OVERLAP WITH
MALARIA.
THERE'IT IS NOT UNCOMMON FOR SOY
WHO HAS SICKLE CELL TRAIT OR
SICKLE CELL DISEASE TO HAVE
COINHERITED ALPHA THALASSEMIA.
AND THIS IS A VERY IMPORTANT
POINT WHEN ANALYZING THE EFFECTS
OF SICKLE CELL TRAIT OR SICKLE
CELL DISEASE, BECAUSE THE
PATHOLOGY OF THESE DISORDERS IS
HIGHLY DEPENDENT ON THE -- S
CONCENTRATION AND THIS IN TURN
IS AFFECTED BY THE NUMBER OF
COPIES OF ALPHA GLOBIN GENES.
WHY?
BECAUSE ALPHA GLOBIN GENES ARE
POSITIVELY CHARGED.
THEY FORM DIMERS THROUGH THE --
CHAINS THAT ARE NEGATIVELY
CHARGED, AND BECAUSE BETA S
CHAIN IS LESS NEGATIVELY CHARGED
THAN BETA A OF HEMOGLOBIN A,
ALPHA CHAIN WILL ALWAYS COMBINE
MORE READILY WITH BETA A.
SO YOU SEE HERE IN AS, THERE
WILL ALWAYS BE MORE HEMOGLOBIN A
AND THEN THE A DEFICIT IN ALPHA
THALASSEMIA WILL LEAD TO FALL IN
HEMOGLOBIN S, SHOWN VERY NICELY
HERE -- WHO CORRELATED THE MEAN
HEMOGLOBIN S FRACTION WITH THE
NUMBER OF ALPHA -- GENE COPIES
AND MORE -- THEY ARE THE HIGHEST
HEMOGLOBIN S FRACTION.
AND THIS CONCEPT WAS REALLY VERY
NICELY SUMMARIZED IN THE
BEAUTIFUL STUDY MORE THAN 30
YEARS AGO INVOLVING -- IN NIDDK.
INDIVIDUALS' ABILITY TO
CONCENTRATE URINE, THIS IS DUE
TO THE MOL MERRIZATION OF
HEMOGLOBIN S IN THE HIGHLY
CONDUCIVE ENVIRONMENT OF THE
RENAL MEDULLA.
BUT THIS IMPACT ABILITY IS
HIGHLY VARIABLE.
AND THEY ASKED THEN SINCE ALPHA
THAL INFLUENCES THE
CONCENTRATION OF HEMOGLOBIN S,
COULD THIS BE ONE OF THE
REASONS.
AND ALPHA.
THAL IS DETERMINED
BY -- STATE OF THE ART
TECHNOLOGY THEN.
THEY SHOWED THAT ALPHA THAL
REDUCED -- PERCENTAGE AS SHOWN
EARLIER AND THAT THIS MAXIMAL
URINE CONCENTRATING ABILITY
ACTUALLY CORRELATED INVERSELY
WITH A NUMBER OF HEMOGLOBIN
ALPHA GENE COPY NUMBERS, AND
THIS CONCENTRATING ABILITY
ACTUALLY DECREASES THROUGH
INCREASING HEMOGLOBIN S.
SO GIVEN ITS PREVALENCE AND ITS
MODIFYING EFFECTS ON SO MANY
TRAITS, IT IS IMPORTANT TO
ACCOUNT FOR ANY CONFOUNDING
EFFECTS OF ALPHA THALASSEMIA TO
RULE OUT --.
MANY GROUPS HAVE ATTEMPTED TO
DERIVE ALPHA THAL GINO TYPES.
THIS PAPER HERE IS A TYPICAL
EXAMPLE WHERE THEY CONCLUDE THAT
IN FACT THE CAUSE OF THE COMPLEX
HAPLOTYPE STRUCTURE ACROSS THE
HEMOGLOBIN A GENE REGION BECOMES
VERY CHALLENGING AND PREDICTION
WAS NOT ACCURATE ENOUGH.
SO SAM AND NCI FELT THEY WERE
NOT CONFIDENT ENOUGH TO PREDICT
ALPHA THAL FROM THE GENOME SCAN
DATASET AND APPROACHED US TO
HELP WITH THE ALPHA GENOTYPING
AND IN EXCHANGE FOR THE SICKLE
CELL BRANCH PERFORMING ALPHA
GENOTYPING, NCI WILL GENOME SCAN
SAMPLES FROM ANOTHER STUDY.
AND OUR FIRST TASK WAS TO
OPTIMIZE OUR DIGITAL DOPPLER PCR
ASSAY.
THEN ABLE RELIABLE RESULTS USING
A MINIMAL AMOUNT OF DNA, AND
SECONDLY TO -- AND THIS WAS
METICULOUSLY CARRIED OUT BY OUR
GROUP.
HE TESTED DIFFERENT
CONCENTRATIONS OF DNA AND THEN
COMPARED THE WET DNA WITH DNA
AIR DRIED, AND AS YOU CAN SEE,
BELOW 6.5 -- RESULTS ARE
QUESTIONABLE SO WE OPTED FOR
20-NANOGRAMS DNA DRIED DOWN.
SAM AND HIS GROUP THEN -- PLATES
AND THIS WAS ACTUALLY TASKED
TO -- STUDENTS, FRANCINE BAKER
FROM THE NCI AND TEMI, A STUDENT
IN OUR GROUP.
THEY COLLECTED 5,000 SAMPLES.
HERE YOU CAN SEE THE FREQUENCY
OF ALPHA THALASSEMIA IN THE
EMBLEM COHORT, VERSUS THE U.S.
POPULATION, AND WHAT I'D LIKE TO
POINT OUT IS THAT THE FREQUENCY
OF ALPHA THALASSEMIA IN AFRICAN
COHORT IS HIGHER THAN THAT IN
THE SICKLE CELL DISEASE COHORT
AS WELL AS THE REGARDS STUDY,
AND THIS IS MOST LIKELY DUE TO
RACIAL -- MIXTURE.
WHICH IS CLEARLY SHOWN HERE WHEN
WE LOOK AT AS INDIVIDUALS, NO,
WE LOOK AT ANOTHER COHORT OF --
ANOTHER COHORT IN OUR PROTOCOL
WHERE YOU COMPARED THE ALPHA
GLOBIN -- ALPHA THALASSEMIA
FREQUENCIES, AND HERE YOU CAN
SEE THERE IS AN INCREASED
FREQUENCY IN ALPHA THAT WILL THH
EACH COPY O OF -- S.
SO IT'S KUNDE INVESTIGATED A
SIMILAR -- WHOLE GENE SEQUENCE
DATA ON THE REFERENCE DATASET --
WE WERE QUITE EXCITED WHEN WE
SAW THIS ALPHA THALASSEMIA BUT
IN FACT IT DOES NOT SEEM SO
SIMPLE.
THE NON-DELETIONAL AND THE RARE
4.2 DELETIONS -- SO WE REACHED
OUT TO NHGRI AND NANCY HANSEN
CAME UP WITH THE ANSWER
GENERATING AN ALGORITHM USING AI
AND MACHINE LEARNING FROM A
WHOLE GENOME SEQUENCE DATASET
DATA.
AND SHE COMPARED HER MACHINE
LEARNING METHOD TO OUR WET BENCH
DDPCR.
THE CONCORDANCE RATE WAS LIKE
92%, AND WE ARE CURRENTLY
REPEATING THE WET BENCH ASSAYS
FOR THE SAMPLES THAT DO NOT
AGREE, WHICH IS IN RED, TO
VALIDATE THE ACCURACY.
WHAT IS IMPORTANT USING THIS
MACHINE LEARNING APPROACH IS
THAT IT COULD PICK UP
4.2 DELETION AND THE
NON-DELETION ALPHA THAL
VARIANTS, ALTHOUGH THESE ARE
VERY UNCOMMON IN PEOPLE OF
AFRICAN DESCENT.
SO WITH THAT I'D LIKE TO HAND
OVER TO SAM, BUT BEFORE THAT, I
WOULD LIKE TO THANK THE PEOPLE
WHO HELPED IN THIS PRESENTATION
HERE.
MY APPLAUSE GOES TO THE TWO
STUDENTS, FRANCINE AND TEMI.
ALSO TO XUNDE, WHO WAS A DIRECT
MENTOR FOR TEMI, AND NANCY, WHO
HELPED WITH THE ANALYSIS.
SO OVER TO YOU, SAM.
>>THANK YOU VERY MUCH,
DR. THEIN, FOR INTRODUCING OUR
RESEARCH.
AND THANKS TO THE GRAND ROUNDS
STAFF FOR INVITING US TO PRESENT
AND ORGANIZING THIS GRAND ROUND.
MY TALK WILL FOCUS ON BURKITT
LYMPHOMA AS A PHENOTYPE OF
MALARIA, AND SICKLE CELL TRAIT,
AS WELL AS ALPHA THAL GINO TYP
TYPES.
WE'LL BE SHARING THE EMBLEM
STUDY, MALAWI CHILDHOOD
INFECTIONS AND CANCER STUDY
WHICH I'LL REFER TO AS MALAWI.
THE TWO QUESTIONS WE'LL BE
ADDRESSING, DOES MALARIA CAUSE
BURKITT LYMPHOMA AND DO THE
SICKLE CELL TRAIT AND ALPHA
THALASSEMIA ALEGA ALLELES PROTET
AGAINST BURKITT LYMPHOMA, AND
THEN CONCLUSIONS OF OUR DATA.
PUBLICATION OF THIS REPORT BY
DENNIS BURKITT.
CHILDREN WITH MALIGNANT SARCOMAS
IN AFRICA.
THERE WERE TWO KEY INTERESTING
FEATURES ABOUT THESE CASES.
THE FIRST ONE WAS THE AGE
DISTRIBUTION MOST CASES OCCURRED
BETWEEN 2 AND 7 YEARS.
WE SUGGESTED THAT THE MALIGNANCY
WAS SUBACUTE IN THE CHILDREN.
THE SECOND UNIQUE FEATURE WAS
THE GEOGRAPHIC DISTRIBUTION
INITIALLY NOTED IN UGANDA BUT
ALSO ELSEWHERE IN AFRICA.
THIS MAP SHOWS THE GEOGRAPHIC
DISTRIBUTION OF CASES IN AFRICA.
MOST WERE CONCENTRATED IN THE
EQUATORIAL REGIONS, MOSTLY
AROUND THE GREAT LAKES, LIKE
LAKE VICTORIA IN KENYA, TANZANIA
AND UGANDA.
AND LAKE MALAWI IN MALAWI.
THERE WERE CASES CLUSTERED ALONG
THE COASTAL REGIONS AS WELL.
MOSTLY ALONG THE GREAT RIVERS.
THESE KEY TEE FEATURES SUGGESTED
THIS CONDITION WAS MOSTLY
PEDIATRIC, IT WAS ENDEMIC IN
AFRICAN REGIONS WHERE MOSQUITOES
WERE COMMON AND IT COULD BE
CAUSED BY A PATHOGEN -- BY
HOSPITALS.
THOSE INFERENCES ATTRACTED
INTEREST WORLDWIDE, AND LED TO
THE DISCOVERY OF EPSTEIN-BARR
VIRUS AS A FIRST HUMAN VIRUS
LINK TO THE HUMAN CANCER.
THERE WAS OTHER RESEARCH ABOUT
THIS DISEASE INCLUDING WHETHER
IT COULD BE CURED BY
CHEMOTHERAPY.
TODAY WE KNOW BURKITT LYMPHOMA
OCCURS GLOBALLY.
IN THIS SLIDE I'M SUMMARIZING
DATA FROM 64 COUNTRIES FROM THE
INCIDENCE IN -- REPORT PRODUCED
BY THE WORLD HEALTH
ORGANIZATION.
THE MAP SHOWS THAT THE
DISTRIBUTION OF BURKITT LYMPHOMA
RANGES FROM LESS THAN 1 TO
2 CASES PER MILLION, MOSTLY IN
ASIA.
COUNTRIES LIKE INDIA, CHINA,
JAPAN AND SOUTH KOREA, RATES ARE
INTERMEDIATE BETWEEN 2 AND
4 CASES PER MILLION PEOPLE IN
EUROPE, NORTH AMERICA AND LATIN
AMERICA.
AND COUNTRIES IN AFRICA HAVE
HIGHER RATES RUNNING FROM 4 TO
OVER 10 CASES PER MILLION.
DISTRIBUTION IN AFRICA REALLY
MIRRORS WHAT DENNIS BURKITT
REPORTED FIVE DECADES AGO.
ON THE RIGHT, I'M SHOWING A BAR
GRAPH WHICH SHOWS THE INCIDENCE
BY SEX, AND YOU CAN SEE ALMOST
IN ALL COUNTRIES WHERE BURKITT
LYMPHOMA HAS BEEN STUDIED, CASES
OCCUR MORE IN MALES THAN
FEMALES.
WE DON'T KNOW WHY THAT IS THE
CASE.
BUT IT DOES SUGGEST THAT IN
ADDITION TO MALARIA AND
EPSTEIN-BARR VIRUS, THERE ARE
OTHER RISK FACTORS YET TO BE
DISCOVERED.
THE TWO STUDIES THAT I SUES HAVE
CLOSE TO FI 5,500 PARTICIPANTS
ENROLLED INCLUDING CLOSE TO 200
BURKITT LYMPHOMA CASES.
CLOSE TO 5,000 PARTICIPANTS OF
WHOM 800 ARE CASES.
THE MAJORITY OF THE DATA COME
FROM THE EMBLEM STUDY, WHICH --
WITH CLOSE TO 5,000 SUBJECTS AND
ABOUT 900 BURKITT LYMPHOMA
CASES.
THE EMBLEM STUDY IS IN THE AREAS
SHOWN ON THAT MAP.
IT'S POPULATION-BASED.
CASES COME FROM THE DEFINED
GEOGRAPHIC AREAS AND THE
CONTROLS WHERE -- FROM 300
RANDOM VILLAGES.
WE HAVE QUESTIONNAIRE, LAB
RESULTS AND VILLAGE-LEVEL DATA,
AS WELL AS BIOSPECIMENS FOR
STUDIES.
600 SUBJECTS IN THE MALAWI
STUDY, CASES WERE ENROLLED AT A
TERTIARY LEVEL HOSPITAL, TH WE
CHARACTERIZE THEM AS CASES AND
OTHERS I USED AS CONTROLS.
WHOLE BLOOD SPECIMENS FOR OUR
GENETIC STUDIES.
IN ADDRESSING THE QUESTION DOES
MALARIA INCREASE BURKITT
LYMPHOMA RISK, I'LL FOLLOW THREE
STRATEGIES.
THE FIRST ONE IS TO USE PUBLIC
HEALTH METRICS AS INDICATORS OF
MALARIA BURDEN AND SEEK
ASSOCIATION WITH VARIOUS
INDICATORS.
THE SECOND ONE IS TO CORRELATE
MALARIA BURDEN WITH BURKITT
LYMPHOMA RISK WITHIN DEFINED
GEOGRAPHIC AREAS OF EMBLEM.
AND THE THIRD ONE, THIS IS WHERE
MY COLLABORATION WITH DR. SWEE
LAY -- ASKS THE QUESTION WHETHER
IT DOES PROTECT AGAINST BURKITT
LYMPHOMA AS WELL.
SO IN THIS SLIDE I'M SHOWING YOU
MY FIRST RESULTS USING THE FIRST
STRATEGY.
WHERE WE ASKED INDIVIDUALS ABOUT
VARIOUS HEALTH METRICS THAT
INDICATE FROM THE GOVERNMENT
PERSPECTIVE THAT WE LIVE IN AN
AREA WHERE MALARIA BURDEN IS
HIGH.
I SHOW IN THE FIRST PART OF THAT
TABLE, BURKITT LYMPHOMA CASES
WERE MORE LIKELY TO REPORT THAN
CONTROLS BEING IN AN AREA WHERE
THE GOVERNMENT HAD DISTRIBUTED
MOSQUITO BED NETS WHERE THEY HAD
THEM BUT DID NOT USE THEM, OR WE
WHERE THEY HAD THEM AND USED
THEM, OR WHERE THEY LIVED IN
HOUSES THAT HAD BEEN SPRAYED BY
THE GOVERNMENT WITH RESIDUAL
SPRAYING OR THEY USED REGULAR
INSECTICIDE SPRAYS RANGING FROM
3 TO 9.
WE ALSO ASKED WHETHER THE
CHILDREN HAD HAD A HISTORY OF
MALARIA 12 MONTHS BEFORE
ENROLLMENT IN THE EMBLEM STUDY.
AND THE INTEREST HERE WAS 12
MONTHS BEFORE ENROLLMENT BECAUSE
WE WERE AWARE THAT BURKITT
LYMPHOMA IS A SUBACUTE
CONDITION, NOT AN ACUTE
COMPLICATION OF MALARIA SO WE'RE
LOOKING FOR -- HISTORY OF
MALARIA EXPOSURE.
MORE LIKELY TO REPORT INPATIENT
MALARIA TREATMENT AS WELL AS
OUTPATIENT MALARIA TREATMENT.
THESE RESULTS INDICATE A VERY
STRONG ASSOCIATION BETWEEN
EXPOSURE TO HELY MALARIA AND
BURKITT LYMPHOMA RISK.
IT DOESN'T GIVE US A QUALITATIVE
VALUE OF HOW MUCH MALARIA IS
NEEDED TO INCREASE BURKITT
LYMPHOMA RISK.
TO TRY AND GET AT THAT QUESTION,
WE USED OUR GEOGRAPHIC DATA FROM
EMBLEM FIRST TO ESTIMATE BURKITT
LYMPHOMA INCIDENCE IN 49
DISTRICTS WHERE WE HAD COMPLETE
LOCATION DATA FOR THE CASES AS
WELL AS POPULATION BASED DATA.
ON THE LEFT, I SHOW THE MAP OF
THE STUDY AREA WITH THE BURKITT
LYMPHOMA INCIDENCE DATA SHADED
THERE AS COLORS.
THE INCIDENCE RANKED FROM ZERO
TO 60, WITH MORE INTENSE COLORS
INDICATING HIGHER INCIDENCE.
AND THEN FOR THE SAME REGIONS,
WE WERE ABLE TO CALCULATE THE
NUMBER OF INFECTIONS, OF MALARIA
INFECTIONS A CHILD HAD BY YEAR.
TO DO THAT, WE USED DATA FROM
THE MALARIA ATLAS PROJECT.
THE MALARIA ATLAS PROJECT
COMPILES MALARIA INFECTION DATA
GLOBALLY AT A VERY HIGH
RESOLUTION OF -- OF AREA.
SO WE WERE ABLE TO EXTRACT DATA
FOR THE 49 DISTRICTS AND USED
MATHEMATICAL FORMULAE TO CONVERT
IT INTO THE NUMBER OF INFECTIONS
BY CHILD BY YEAR.
ON THE RIGHT, I SHOW THE DATA
FOR MALARIA BURDEN.
WHAT WE FOUND WAS WITHIN THE
STUDY AREA, CHILDREN WERE
GETTING BETWEEN 100 AND 400
INFECTIONS BY CHILD BY YEAR.
THAT'S AN ENORMOUS NUMBER, IF
YOU USE COVID AS AN EXAMPLE, IF
SOMEBODY HAD 20 INFECTIONS OF
COVID THAT WOULD BE ENORMOUS,
BUT THIS IS 100 TO 400
INFECTIONS BY CHILD BY YEAR.
WHAT WAS INTERESTING IS WE
CORRELATED THE MALARIA BURDEN TO
BURKITT LYMPHOMA INCIDENCE, WE
FOUND A STRONG CORRELATION,
CLOSE TO .6, THAT IS
STATISTICALLY SIGNIFICANT.
THESE ARE THE CLEAREST DATA
INDICATING THAT AS THE NUMBER OF
MALARIA INFECTIONS INCREASE IN A
POPULATION, SO DOES THE BURKITT
LYMPHOMA RISK IN THAT POPULA
POPULATION.
THE WEAKNESSES HERE ARE WE STILL
DON'T KNOW WHAT THE -- RISK FOR
BURKITT LYMPHOMA IS SO WE WANTED
TO ALSO GET TO THAT.
IN THIS SLIDE, I'M SHOWING YOU
RESULTS WHERE WE ATTEMPTED TO
ESTIMATE THE INFECTION RISK FOR
BURKITT LYMPHOMA IN OUR
POPULATION.
AND WHAT WE DID, WE ESTIMATED
THE NUMBER OF INFECTIONS A CHILD
IN A GIVEN LOCATION OR A GIVEN
EDGE WOULD HAVE HAD AT A GIVEN
TIME.
AND THEN COMPARED WHAT CHILDREN
WHO DID NOT HAVE GIVEN EDGE FROM
THE SAME LOCATION WOULD HAVE
HAD.
AND WHAT THE RESULTS IN THE LEFT
GRAPH SHOW, BEGINNING WITH THE X
AXIS, I'M SHOWING YOU
ACCUMULATED NUMBER OF
INFORECASTS WE CALCULATED AND ON
THE Y AXIS I'M SHOWING THE
BURKITT LYMPHOMA INCIDENCE
RATIO.
WHEN YOU COMPARE THE CHILDREN
THAT HAD 50 INFECTIONS, EACH
ADDITIONAL 100 INFECTIONS AFFECT
9% INCREASE IN BURKITT LYMPHOMA
WHICH WAS STATISTICALLY
SIGNIFICANT.
THIS IS THE FIRST PART INFECTION
ESTIMATE THAT IS AVAILABLE.
WE WERE INTERESTED IN FINDING
OUT IF THE INTENSITY OF
INFECTION, IF THE NUMBER OF
INFECTIONS A CHILD SABAWI
IBRAHIM AL-HHAS, HAS --ON THEIR.
ON THE RIGHT IS THE THREE
INFECTION LEVELS.
ONE INFECTION A YEAR, 10
INFECTIONS PER YEAR AND 20
INFECTIONS PER YEAR.
THE Y AXIS SHOWS THE INCIDENCE
RATIO AS BEFORE, BUT THIS TIME
THE X AXIS IS SHOWING THE RISK
BY AGE.
AND WHAT YOU CAN SEE VERY
CLEARLY AS THE NUMBER OF
INFECTIONS A CHILD IS EXPOSED TO
IN THAT AREA INCREASES, SO DOES
THE -- RISK INCREASE, WITH THE
RISK BEING HIGHEST IN --
COMPARED TO THOSE EXPRESSING ONE
INFECTION PER YEAR.
WE WERE THEN ABLE TO ASK ANOTHER
QUESTION, WHETHER THERE WERE
DECREASING TRENDS IN MALARIA
INFECTION RATES WITHIN OUR STUDY
POPULATION -- AND WE WERE ABLE
TO SHOW THAT BETWEEN 2000 AND
2015, WHERE WE ANALYZE DATA, P
FALCIPARUM INTUCKS RATES FELL BL
BY 50%.
WHAT WAS INTERESTING IN THE SAME
PERIOD WHEN WE ENROLLED CASES,
BURKITT LYMPHOMA RISK FELL BY
10%, SHOWING FOR THE FIRST TIME
DECLINING RATES OF P
FALCIPARUM -- THESE RESULTS
INDICATE A -- CORRELATION
BETWEEN MALARIA AND BURKITT
LYMPHOMA.
THE LIMITATIONS OF THE DATA ARE
THAT WE REALLY DON'T KNOW
WHETHER IT IS THE BURKITT
LYMPHOMA CASES WHO ARE
EXPERIENCING THE HEAVY MALARIA
BURDEN BECAUSE WE CONDUCTED
THESE -- PRESENT BEFORE MALARIA
AND IF SOMEBODY HAS THAT MARKER
THEY'VE HAD LESS MALARIA THAN
ONE WHO DOESN'T HAVE THE MARKER.
AND THAT'S WHEN WE TURNED TO THE
SICKLE CELL TRAIT AND ASKED THE
QUESTION, IS THE CORRELATION
BETWEEN CARRYING THE SICKLE CELL
TRAIT AND BURKITT LYMPHOMA?
TO BE HONEST, WE'RE NOT THE
FIRST TO THINK ABOUT THIS IDEA,
WHEN WE LOOKED IN THE
LITERATURE, WE FOUND THERE ARE
FIVE STUDIES THAT HAVE LOOKED AT
THIS IDEA IN THE PAST.
BEGINNING WITH THE FIRST ONE IN
1966, IN A STUDY CONNECTED IN
NIGERIA, WHERE THEY FOUND THAT
CHILDREN WITH SICKLE CELL TRAIT
WERE SIGNIFICANTLY LESS LIKELY
TO HAVE BURKITT LYMPHOMA.
THAT WAS A STATISTICALLY
SIGNIFICANT RESULT.
HOWEVER, FOUR OTHER STUDIES THAT
WERE CONDUCTED AFTERWARDS HAD
MIXED RESULTS WITH SOME FINDING
DECREASED RISK THAT WAS NOT
STATISTICALLY SIGNIFICANT AND
ONE STUDY FOUND FINDING AN
INCREASED RISK THAT WAS NOT
STATISTICALLY SIGNIFICANT.
SO WE KNEW THE QUESTION WAS
STILL VERY MUCH OPEN AND
DESERVED A CAREFUL LOOK TO SEE
WHAT THE ACTUAL RELATIONSHIP
WAS.
SO THEN WE HAVE USED OUR EMBLEM
MALAWI STUDIES, ESPECIALLY THE
GENOMES AND SUBSET, WHERE WE
HAVE CLOSE TO FIVE THOWL -- DATA
TO ASK THE QUESTION, THE
MODIFICATION WE DID IN OUR STUDY
WAS -- WE DECIDED TO LOOK AT ALL
LOCI THAT HAVE BEEN PUBLISHED IN
THE LITERATURE AS HAVING AN
EFFECT ON MALARIA INCLUDING THE
SICKLE CELL.
AND WHILE WE'RE DOING THIS, WE
WANT TO ALSO INCLUDE THE ALPHA
THALASSEMIA GENOTYPES, AND THAT
IS WHEN WE DISCOVERED THAT WE
COULDN'T PREDICT WHAT THOSE
GENOTYPES BE USING OUR GENOME
SCAN DATA AND WE MOVED TO
COLLABORATION WITH DR. THEIN SO
SHE COULD HELP US TO GENOTYPE
OUR SUBJECTS.
SO I'D LIKE TO COMMENT ABOUT THE
UNIQUE STRENGTHS OF OUR STUDY TO
USE GENETIC MARKERS TO ADDRESS
THIS QUESTION.
THE FIRST GENETIC STRENGTH IS
THAT WE ALREADY KNOW THE MALARIA
BURDEN IN AFRICAN NATION FOR
EXAMPLE, EVERY CHILD LIVING IN
THIS AREA WILL EXPERIENCE
BETWEEN 100 AND 400 INFECTIONS
BY YEAR.
SO THAT'S AN ENORMOUS BURDEN OF
MALARIA THAT WE HAVE TO DEAL
WITH, AND THOSE WHO HAVE
GENOTYPES THAT PROTECT THEM
WOULD HAVE AN ADVANTAGE.
THE SECOND APPROACH THAT WE USED
TO VERIFY THAT ASSUMPTION WAS
SAMPLING 100 OF OUR SUBJECTS.
50 CASES AND 50 HEALTHY
CHILDREN, RANDOMLY SELECTED FROM
THE ENTIRE STUDY.
AND WE MEASURED -- 1,000 PEOP
PEOPLE -- PROTEINS BECAUSE THE
NEW RESPONSE -- HAD DIFFERENT
PATHOGENS.
AND IN THIS SLIDE I'M SHOWING
TWO HEAT MAPS.
I'LL JUST EXPLAIN EXACTLY HOW
THEY'RE ARRAYED.
THE COLUMNS ARE INDIVIDUAL
SUBJECTS, THEIR -- 1,000
PROTEINS.
I HAVE SORTED THE PROTEINS
ACCORDING TO THE STAGE OF
MALARIA WHERE THOSE PROTEINS ARE
EXPRESSED.
SO FOR EXAMPLE, THE LITTLE GREEN
BARS ON THE SIDE INDICATES
PROTEINS EXPRESSED IN THE --
STAGE.
THE YELLOW BARS INDICATE THOSE
IN THE -- STAGE, THE BLUE ONES,
THE -- STAGE AND THE -- AND THEN
WITHIN EACH HEAT MAP OF CERTAIN
INDIVIDUALS BUT COUNTRY, SO WE
HAVE UGANDA, TANZANIA AND KENYA
AND WITHIN EACH COUNTRY I'VE
SORTED INDIVIDUALS BY AGE SO THE
YOUNGEST ARE ON THE RIGHT AND
THE OLDEST ARE ON THE LEFT.
WHAT YOU CAN SEE IS IF YOU STAND
BACK AND LOOK AT THESE HEAT
MAPS, SO THE HEAT MAP ON THE
LEFT IS FOR HEALTHY CHILDREN AND
THE ONE ON THE RIGHT IS FOR
CASE, YOU CAN SEE VERY CLEARLY
YOU CANNOT DISTINGUISH THE CASES
OR THE CONTROLS OR EVEN THE
COUNTRIES.
SO THAT WAS ANOTHER REASSURANCE
THAT OUR POPULATION IS HEAVILY
EXPOSED TO MALARIA AND
APPROPRIATE FOR THIS APPROACH.
ANOTHER STRENGTH IS HAVING
GENOME SCAN DATA BECAUSE WE
BECAME AWARE THAT BECAUSE WE
WERE USING GENETIC MARKERS,
THERE WAS POSSIBILITY OF
CONFOUNDING BY ANCESTRY IN THE
DIFFERENT POPULATION FOR AFRICAN
COUNTRIES BUT OUR COLLEAGUES AT
NHGRI -- AND CONTROL FOR -- IN
OUR ANALYSES.
AND THEN WE THOUGHT THAT COULD
BE GENETIC RELATIONSHIPS BUT WE
WEREN'T SURE, BUT AGAIN GENOME
SCAN DATA WERE ABLE TO --
QUANTITATIVELY AND WE IDENTIFY
THAT WE HAD GENETICALLY RELATED
INDIVIDUALS IN OUR UGANDAN SET
OF SAMPLES, SLIGHTLY FEWER IN
KENYA AND TANZANIA AND THIS
ALLOWED US ALSO TO INCORPORATE
JE NE AT THIS TIME RELATED LESS
IN THE MODELS.
SO THIS SLIDE SUMMARIZES THE
BASE MODEL THAT WE HAVE USED TO
DRAW GENETIC ANALYSIS.
WE CONTROL FOR AGE, SEX,
COUNTRY-SPECIFIC PCs, COUNTRY,
AND GENETIC RELATEDNESS.
SO THIS IS THE RESULT THAT WE
IDENTIFIED IN THE LITERATURE.
THE FIRST ON THE RIGHT -- FOR
THE EFFECT OF EACH LOCUS FROM
INFECTION.
IN THE FIRST PLOT ON THE LEFT
SHOWS THE EVENT OF EACH LOCUS IN
BURKITT LYMPHOMA.
WHEN WE CORRELATED THESE EFFECTS
WE FOUND THEY WERE SIGNIFICANTLY
CORRELATED WITH -- .4.
WHAT THAT MEANS IS IF THE EFFECT
OF THE LOCUS IS TO DECREASE --
INFECTION, THAT LOCUS WILL ALSO
TEND TO HAVE A -- EFFECT TO --
THE RISK FOR BURKITT LYMPHOMA.
HOWEVER, WHAT WAS EVEN MORE
INTERESTING, WE HAD TWO LOCI
THAT STATISTICALLY PROTECTED
AGAINST BURKITT LYMPHOMA RISK.
ONE LOCUS WAS IN THE -- REGION
AND THE OTHER WAS -- THE SICKLE
CELL ALLELE.
SO THIS SLIDE SUMMARIZES THE --
EFFECTS.
SO THE TWO LOCI DECREASE THE
RISK BETWEEN -- TO 40%.
WE LOOKED AT THE EFFECTS BY
COUNTRY AND WE FOUND THAT THOSE
VARIATION, SO BEGINNING WITH THE
FIRST PLOT ON THE LEFT, THAT'S
FOR THE SICKLE CELL ALLELE.
WE FOUND THAT EFFECTS WERE
SIGNIFICANT IN UGANDA AND MALAWI
BUT NOT SIGNIFICANT IN TANZANIA.
SO THE VARIATION OF EFFECT BY
COUNTRY MADE US REMEMBER WHAT
DR. SWEE LAY HAS PRESENTED WITH
THE EPISTATIC EFFECTS THAT WE'RE
SEEING BUT NOT CONTROLLING FOR
BETWEEN ALPHA THALASSEMIA AND
SICKLE CELL ALLELE SO WE LOOKED
FOR ALPHA THALASSEMIA AND
THEN -- BY SICKLE CELL STATUS.
SO IN THIS SLIDE I'M SHOWING THE
RESULTS THAT WERE GENERATED BY
DR. THEIN, FRANCINE BAKER AND
TEMI AND WE WANTED TO SEE IF --
BETWEEN THE NUMBER OF ALPHA
GLOBIN GENES WITH BURKITT
LYMPHOMA RISK.
COMPARED TO INDIVIDUALS WITH
FOUR COPIES, THOSE WITH FIVE
COPIES HAD AN ELEVATED RISK --
1.86, WHEREAS WHEN WE LOOK AT
THOSE WITH TWO COPIES, THEY HAD
A DECREASED -- RATIO ALTHOUGH
THAT WAS NOT STATISTICALLY
SIGNIFICANT.
WITH RESPECT TO WHERE THOSE --
EFFECTS BY SICKLE CELL STATUS,
WE DID A STRATIFIED ANALYSIS.
AND THESE RESULTS SUMMARIZE THE
ASSOCIATIONS STRATIFIED BY THE
SICKLE CELL STATUS.
SO THE FIRST PART OF THE TABLE
SHOWS THE RESULTS FOR ALPHA THAL
IN INDIVIDUALS WHO DO NOT HAVE
THE SICKLE CELL ALLELE.
AND THOSE INDIVIDUALS WITH FIVE
COPIES HAD AN INCREASED RISK
WITH A -- OF 1.9 WHICH IS --
WITH WHAT WE OBSERVED BEFORE
WHEREAS THOSE WHO HAD TWO COPIES
HAD A RISK OF .78 WHICH IS ALSO
STRONGER THAN WHAT WE OBSERVED
BEFORE.
NOW WHEN WE LOOK AT THE
STRUCTURE -- THE SICKLE CELL
ALLELE, WE SAW THE EFFECTS
TENDED TO BE ATTENUATED, SO
THOSE WITH FIVE COPIES HAD AN
INCREASED RISK BUT NOW THE -- IS
1.3, AS OPPOSED TO 1.9.
AND THOSE WHO HAD TWO COPIES,
THEY HAD A DECREASED RISK --
.83.
SO THESE RESULTS DID NOT
INDICATE STATISTICAL
INTERACTION, BUT WE ACTUALLY
WERE CONSISTENT WITH THE -- THAT
DR. SWEE LAY HAD TOLD US ABOUT.
SO I WILL NOW MAKE A FEW
CONCLUDING REMARKS.
FIRST QUESTION WAS, DOES THE
SICKLE CELL ALLELE PROTECT
AGAINST BURKITT LYMPHOMA?
WE SHOWED THAT TO BE THE CASE.
IN
AFRICA, AND WE THINK THAT'S
BECAUSE THE SICKLE CELL ALLELE
DECREASES MALARIA BURDEN -- AND
INFLAMMATION AND THROUGH THAT,
IT DECREASES BURKITT LYMPHOMA
RISK.
WITH RESPECT TO ALPHA
THALASSEMIA, OUR DATA SUGGESTS
THAT THE COPY NUMBERS OF THE
ALPHA GLOBIN GENES ASSOCIATED
WITH BURKITT LYMPHOMA RISK.
WE THINK THAT THE COPY NUMBERS
MIGHT INFLUENCE BURKITT LYMPHOMA
RISK BY MODULATING MALARIA
BURDEN.
AND WE ALSO SHOWED THAT THE COPY
NUMBERS OF THE ALPHA GLOBIN
GENE, THE EFFECT ON BURKITT
LYMPHOMA VARY BY COINHERITANCE
OF THE SICKLE CELL ALLELE BUT
FEPHENOTYPIC INTERRUPTIONS ARE
WEAK.
THE RESULTS ARE PRESENTS THE
STRONGEST SUPPORT FOR MALARIA
BASED ON LARGE SAMPLE SIZE,
MULTICENTER DESIGN AND
MULTIVARIATE ADJUSTMENT BUT WE
ALSO NOTED WEAKNESSES IN TERMS
OF SUBGROUP RESULTS -- IN TERMS
OF THE MECHANISMS THAT
GENERATING THOSE EFFECTS.
WE ALSO BECAME AWARE THAT THERE
ARE COFACTORS THAT HE WITH NEVER
THOUGHT ABOUT.
IN PARTICULAR, THERE IS THIS P
FALCIPARUM SICKLE CELL ALLELE
THAT WAS RECENTLY DESCRIBED.
SO IN THIS PAPER, BAND, ET AL.
AT OXFORD REPORTED THAT MALARIA
PROTECTION DUE TO SICKLE CELL
HEMOGLOBIN DEPENDS ON THE
PARASITE GENOTYPE.
SO THERE ARE SOME PARASITES THAT
HAVE ALLELES THAT SUCCESSFU
SUCCESSFULLY -- AND IF THOSE ARE
PREVALENT IN AN AREA, THEY WILL
REDUCE THE EFFECT ON THE SICKLE
CELL AND BURKITT LYMPHOMA.
SO IN THIS SLIDE, I WOULD JUST
LIKE TO ACKNOWLEDGE MANY
COLLABORATORS WHO HAVE
CONTRIBUTED TO THE DATA THAT I
HAVE SHOWED YOU IN UGANDA,
TANZANIA, MALAWI, INCLUDING THE
U.K., NIH, NH TB. RI, NHLBI.
THANK YOU.
>>THANK YOU BOTH.
>>I'LL STOP SHARING NOW?
>>YES, YOU CAN.
TWO PEOPLE ACTUALLY ASKED THIS
QUESTION.
PEOPLE WERE QUITE INTERESTED IN
EP TEEN BAR VIRUS AND THAT WAS
MENTIONED IN THE TALK.
AND ALSO I WONDERED IF THERE WAS
SOME WAY TO DISCUSS THE ROLE OF
EPSTEIN-BARR VIRUS?
>>SO WE HAVEN'T INCORPORATED
EPSTEIN-BARR VIRUS INTO THIS
ANALYSIS YET.
WE PLAN TO DO THAT.
WE'VE MEASURED EP SE EPSTEIN-BAR
VIRUS -- AND WE WILL INCORPORATE
THOSE RESULTS IN OUR ANALYSIS
AND PROVIDE AN UPDATE.
WE THINK IT'S AN IMPORTANT
COFACTOR THAT WE HAVEN'T YET
CONSIDERED IN OUR ANALYSIS.
>>GREAT.
CAN YOU ALSO ADDRESS THE ISSUE
OF POTENTIAL IMPACT IF THERE IS
A SUCCESSFUL VACCINE FOR
MALARIA?
>>SO OUR DATA INDICATE CLEARLY
THAT IF MALARIA BURDEN IS GOING
DOWN, THE BURKITT LYMPHOMA RISK
SEEMS TO BE ALSO SUPPRESSED.
AND, THEREFORE, TO THE EXTENT OF
THAT SUCCESSFUL INTERVENTIONS
AGAINST MALARIA INCLUDING -- I
THINK THEY WOULD REDUCE THE RISK
FOR BURKITT LYMPHOMA.
WHAT THE DATA SHOW CLEARLY IS
THAT YOU HAVE TO BE FOCUSING ON
THE POPULATIONS THAT -- HIGH
MALARIA BUT IS MORE THAN 20
INFECTIONS PER YEAR TO
SIGNIFICANTLY HAVE AN IMPACT ON
BURKITT LYMPHOMA RISK.
>>ANOTHER QUESTION IS, WHAT IS
THE ROLE OF MOSQUITOES AS THE
COMMON TRANSMITTER OF BOTH,
AGAIN, EBV AND MALARIA?
I THINK YOU MENTIONED, YOU KNOW,
HIGH MOSQUITO BURDEN REGIONS,
CORRECT?
>>YEAH, SO THE MOSQUITO
CONNECTION WAS LIKE -- IT'S THE
ONE THAT LED TO THE DISCOVERY OF
EPSTEIN-BARR VIRUS, BUT WE THEN
DISCOVERED THAT EPSTEIN-BARR
VIRUS IS NOT TRANSMITTED BY
MOSQUITOES, IT IS TRANSMITTED BY
CONTACT WITH SALIVA THAT IS --
PERSON TO PERSON.
HOWEVER, WE NOW KNOW FROM THE
MALARIA LITERATURE THAT
DIFFERENT MOSQUITOES HAVE
DIFFERENT EFFICIENCIES IN
TRANSMITTING MALARIA PARASITES,
AS WELL AS BITING -- SOME BITE
INSIDE THE HOUSE, SOME BITE
OUTSIDE THE HOUSE, SOME BITE
ANIMALS, SO THERE IS AN INTEREST
IN HOW DIFFERENT MOSQUITOES
MODIFY THE PHENOTYPES THAT WE'RE
LOOKING AT.
WE'VE NOT COLLABORATED WITH AN
ENTOMOLOGIST BUT THAT'S
SOMETHING WE'RE REALLY, REALLY
INTERESTED IN.
>>OKAY MAYBE A QUESTION FOR DR.
CAN YOU ADDRESS THE RELATIVE
CLINICAL IMPACT OF ALPHA
THALASSEMIA VERSUS SICKLE CELL,
AND WHETHER OR NOT THE
COMBINATION OF THE TWO ARE
IMPORTANT TO NOTE IN TERMS OF
CLINICAL PRESENTATIONS?
>>THE FIRST MODIFYING EFFECTS
ON THE SICKLE CELL DISEASE
ITSELF, AND -- IS BASED ON THE
FACT THAT ALPHA THALASSEMIA
INCREASES THE HEMOGLOBIN S
CONCENTRATION, SO THE
MODIFICATION EFFECTS ARE
SLIGHTLY DIFFERENT.
SOME ARE FAVORABLE AND SOME, YOU
KNOW, THEY CAUSE MORE SYMPTOMS
ASSOCIATED WITH MICROVASCULAR
OCCLUSION.
THIS IS IN SICKLE CELL DISEASE.
SO IN TRAIT, AS SHOWN EARLIER,
WHEN YOU HAVE ALPHA THALASSEMIA,
IT ACTUALLY REDUCES THE AMOUNT
OF HEMOGLOBIN S CONCENTRATION.
THIS TURNS OUT TO BE ACTUALLY
QUITE FAVORABLE, WHERE IT
IMPACTS THE SICKLE CELL TRAIT,
AS WE'VE SHOWN IMPAIRMENT IN
CONCENTRATING URINE IS LESS WHEN
YOU HAVE ALPHA THALASSEMIA.
AND THEN -- SO THAT'S THE MOST
OBVIOUS THING.
ALSO IMPACT THE RISK OF CHRONIC
KIDNEY DISEASE, IT LESSENS THE
RISK.
>>OKAY.
SO ONE LAST QUESTION, DR. ECKER
MADR. ECKERMAN ASKED SAM WHETHER
OR NOT THE ASSOCIATIONS WITH THE
ABOL GROUP DATA WERE THE
OPPOSITE DIRECTION FOR BURKITT'S
AND MALARIA.
HOW WOULD YOU INTERPRET THIS
RESULT?
>>SO IT IS UNCLEAR, BUT THE
EFFECTS OF ONE AN ARE NOT ALWAYS
EQUAL OR EXACTLY THE SAME
DIRECTION.
AND IT'S BECAUSE THE LOCI WERE
SELECTED FOR SEVERE MALARIA
WHEREAS WE WERE STUDYING THEM
FOR CHRONIC MALARIA.
SO WE'RE NOT SURE ABOUT THE
DIFFERENCES THERE BUT THERE
MIGHT BE SOME DIFFERENCES.
>>THANK YOU VERY MUCH, BOTH OF
YOU, FOR A WONDERFUL TALK.
AND WITH THAT, OUR SESSION IS
CONCLUDED.
>>THANK YOU.