Analysis of short tandem repeats for the evaluation of hematopoietic chimerism following allogeneic bone marrow transplantation

84

Abstracts

6.2 #83

ANALYSIS OF SHORT TANDEM REPEATS FOR THE EVALUATION OF HEMATOPOIEflC CHIMERISM FOLLOWING ALLOGENEIC BONE MARROW TRANSPLANTATION. D SENITZER, L GAlDULlS, AND B SCHAUB, DEPARTMENT OF HEMATOLOGy/BoNE MARROW TRANSPLANTATION, CITY OF HOPE, DUARTE, CA. HEMATOPOIETIC CHIMERISM (HC) FOLLOWING ALLOGENEIC BONE MARROW TRANSPLANTATION (BMTJ HAS BEEN ASSOCIATED WITH EARLY ENGRAFTMENT, GRAFT REJECTION, DISEASE RELAPSE, AS WELL AS CLINICAL REMISSION AND THE PRESENCE OF INCOMPLETE ENGRAFTMENT (MIXED HCJ. WE HAVE DEVELOPED A STRATEGY FOR UTILIZING A SENSITIVE METHOD FOR THE DETECTION OF HC POST-BMT, THAT CAN BE APPLIED TO LARGE NUMBERS OF PATIENTS. SHORT TANDEM REPEATS (STR) ARE REPETITIVE POLYMORPHIC SEQUENCES OF 3 TO 7 BASE PAIRS OF NON-CODING DNA. WE SELECTED A GROUP OF 9

SETS OF

srR

PRIMERS, AND DESIGNED A STRATEGY TO

DETERMINE WHICH COMBINATION WOULD BE THE MOST INFCRMATIVE, AND YET REMAIN COST EFFECTIVE. THE SET INCLUDED CSF I PO, F I 3AO I,

THO

I, TPOX, F 13B,

FESFPS, HPRTB, LPL, AND VWA (vWFJ; ALL SPECIFIC PRIMERS ARE COMMERCIALLY AVAILABLE. ANALYSIS OF

16 ALLOGENEIC BMT RECIPIENTS WITH THEIR

DONORS

RESULTED IN THE FOLLOWING CONCLUSIONS: POLYMORPHISMS ARE DETECTABLE IN MORE THAN HALF THE BMTs BY EVERY STR;

FES, vWA AND HPRTB HAVE THE

HIGHEST RATES OF DETECTABLE DIFFERENCES (MOST INFORMATIVE); IN NO CASE WAS THE

srR

ANALYSIS UNABLE TO DETECT DIFFERENCES BETWEEN DONOR AND RECIPIENT

(EXCEPT IN THE CASE OF AN IDENTICAL TWINJ. IN THE I 6

CASES STUDIED THERE WAS

NO CORRELATION IN THE PATTERNS OF POLYMORPH ISMS OF THE STRs WITH THE INCIDENCE OF AGVHD OR RATE OF RELAPSE. HOWEVER, THE ANALYSIS OF STR CAN BE COST EFFECTIVE IN THE DETECTION OF HC FOLLOWING ALLOGENEIC BMT.

6.2 #84

IMPROVED IDENTIFICATION OF BOTH HLA-C GENE ALLELES BY PCR-SSP. B

SCHAUB

AND

D

SENITZER,

DEPARTMENT

OF

HEMATOLOGy/BoNE

MARROW

TRANSPLANTATION, CITY OF HOPE, DUARTE, CA. RECENT REPORTS SUGGEST THAT MISMATCHING FOR THE HLA-C LOCUS IS A RISK FACTOR IN UNRELATED BONE MARROW TRANSPLANTATION (BMTJ. THE OF ACUTE

GRAFT VS.

HOST DISEASE AND

INCIDENCE

RISK OF GRAFT FAILURE ARE

BOTH

INCREASED BY DONOR/RECIPIENT DISPARITY AT HLA-C. MICROLYMPHOCYTOTOXICITY IS THE STANDARD

METHOD FOR

IDENTIFICATION

OF

HLA-C ALLELES,

BUT IT IS

REPORTEDLY ABLE TO DETECT ONLY ONE ALLELE IN A SIGNIFICANT PROPORTION OF PATIENTS AND

POTENTIAL DONORS (200/0

SEROLOGIC TYPING FOR THE

IN CAUCASIANS;

500/0 IN ..JAPANESE).

HLA-C LOCUS ANTIGENS IS NO L.ONGER ABL.E TO PROVIDE

DEGREE OF ACCURACY REQUIRED FOR UNRELATED BMT.

COMPARED METHODS (PCR-SSP WITH SEROL.OGY)

WE THEREFORE,

FOR EFFICACY IN THE ROUTINE

IDENTIFICATION OF BOTH HLA-C GENE PRODUCTS. USING PCR-SSP WE EMPL.OYED A SET OF PRIMERS DESIGNED TO DETECT HLA-C ANALYSIS OF

1-8,

12-15, CL I

0

AND CL I

ov.

PATIENTS AND THEIR ALL.OGENEIC DONORS (1'1= 29) BY THE SEROL.OGIC

METHOD, IDENTIFIED ONE HLA-C ALLEL.E IN

20/29 (69%) CASES, AND TWO ALL.EL.ES

IN 9/29 (3 I %J. PCR-SSP ANALYSIS OF THE SAME CASES RESUL.TED IN ASSIGNMENT OF TWO ALL.EL.ES IN 25 CASES (86%), AND ONL.Y ONE ALL.EL.E IN 4 A

CASES (I 4%J.

SEPARATE ANLAYSIS OF UNRELATED BONE MARROW CASES (1'1=22) WAS ALSO

PERFORMED BY BOTH METHODS. SEROL.OGY IDENTIFIED TWO ALL.EL.ES IN 9

(4 1%)

(59%) CASES. MOL.ECULAR ANALYSIS ALL.OWED FOR THE ASSIGNMENT OF TWO AL.LELES IN 18 (82 0/0) CASES, AND ONE ALLEL.E ON 4

CASES, AND ONE ALLEL.E IN 13

( I 8 0/0) CASES. THE INCREASE IN IDENTIFICATION OF BOTH HLA-C L.OCUS ALL.EL.ES WAS 72% FOR THE RELATED AND 64% FOR THE UNRELATED CASES. IN CONCLUSION, THE INCREASED RATE OF IDENTIFICATION OF BOTH HLA-C LOCUS ALLELES BY PCR-SSP METHODOLOGY .JUSTIFIES ITS USE IN TYPING FOR BMT.