R2. 하효정 / 윤휘중 교수님 NEJM

Introduction  Transplantation of hematopoietic cells  acute GVHD ?  The recipient and donor are HLA-DPB1–mismatched  Risk, but the mechanisms are unknown.  ‘rs ’ is associated with HLA-DPB1 expression  GVHD risk correlates with the rs allele linked to the mismatched HLA-DPB1 in the recipient ??

METHOD Study Population  We genotyped rs in 3505 persons  Clinical outcomes : 2029 recipients of transplants from unrelated donors (acute leukemia, CML, MPS / between 1988 and 2008 )  1441 (only one HLA-DPB1 mismatched)  588 (HLA-A,B,C,DRB1,DQB1,DPB1–matched unrelated donor)

METHOD Genotyping and Linkage Analysis  Phasing : The three haplotypes  cell lines by first separating chromosomes  genotyping HLA-DPB1, rs , and rs on each haplotype

RESULT Effect of rs Allele on HLA-DPB1 Expression  rs AA : rs GG = : 24.95

RESULT Clinical Outcome grade II,III, or IV acute GVHD G-linked > A-linked Risk of relapse G-linked < A-linked  similar overall mortality

RESULT Clinical Outcome  In HLA-A,B,C,DRB1,DQB1,DPB1–matched transplantation Acute GVHD  rs G(+) > rs G (HR for 146 HLA-DPB1–matched rs AG transplants vs. 420 rs AA transplants, 1.86; 95% CI, 1.21 to 2.84; P = 0.004; and hazard ratio for 22 rs GG transplants vs. 420 rs AA transplants, 1.53; 95% CI, 0.55 to 4.25; P = 0.41)  Among rs A recipients of transplants from rs A donors Acute GVHD  rs G-linked > rs Alinked (HR for grade II, III, or IV acute GVHD, 1.60; 95% CI, 1.25 to 2.06; P<0.001; and hazard ratio for grade III or IV disease, 1.66; 95% CI, 1.16 to 2.35; P = 0.005)  rs is a better predictor of the risk of GVHD than is rs

RESULT Clinical Outcome  High risk of GVHD (T-cell epitope “nonpermissive”) & Low risk (“permissive”)  Associated with rs ? rs A in both recipient and donor (the A-A group) : 90.7% the G-G group : 31% Correlation between permissiveness indicated by T-cell epitope and permissiveness indicated by rs  The risk of grade III or IV acute GVHD epitope-permissive mismatches  A-G (HR 1.50), G-A (HR 1.38), G-G(HR 1.53) > A-A group epitope-nonpermissive mismatches  A-G (HR 1.03), G-A (HR 1.72), G-G(HR 1.70) > A-A group After isolation of the T-cell epitope effect, rs contributes additional information about the risk of GVHD

RESULT Probability of Finding Donors with a Permissible HLA-DPB1 Mismatch  one or two rs G-linked HLA-DPB1 alleles rs AG (55 recipients) or rs GG (15 recipients) 1. Among 55 recipients with rs AG : 30 (55%) had acceptable donors, the other 25 (45%) had only donors with a mismatch for the recipient’s rs G-linked HLA-DPB1 2. None of the 15 recipients with rs GG had HLA-DPB1– matched donors.  Recipients with rs AA rs AA(76 recipients ) (50%) (either completely matched or matched for graft-versus-host allorecognition) (42%) (mismatched for one HLA-DPB1 allele) 3. 6 (8%) (mismathced for two HLA-DPB1 allele)

Conslusion  The risk of GVHD associated with HLA-DPB1 mismatching was influenced by the HLA-DPB1 rs expression marker.  Among recipients of HLA-DPB1–mismatched transplants from donors with the low-expression allele, recipients with the high expression allele had a high risk of GVHD