Human leukocyte antigen (HLA) DR4 is not associated with differences in overall survival (OS), progression free survival (PFS), or graft-vs-host-disease (GVHD) following allogeneic hematopoietic stem cell transplantation (allo HSCT) for myeloid malignancies

Abstract

6552 Background: HLA DR4 is associated with autoimmune disorders and with response to cyclosporine immunosuppression in T-cell Large Granular Lymphoproliferative Disorder (BJH 2003;123(3)). We have earlier reported association of DR 15 positivity with decreased acute GVHD (aGVHD) in patients undergoing allo HSCT for myeloid malignancies (Blood, 2005 Nov 10;Epub). Therefore we investigated the role of HLA DR4 on graft-versus-leukemia effect and GVHD in HLA-matched allo HSCT performed for myeloid malignancies. Methods: A retrospective review of 119 consecutive related and 48 consecutive unrelated allo HSCT patients (pts) treated between 1992 and 2003 at RPCI was performed to investigate the influence of HLA DR4 on OS, PFS and the incidence of grade 2–4 aGVHD and chronic GVHD (cGVHD). HLA DR B1 locus typing was determined by either molecular (n=108) or serologic (n=59) methods. The proportion of patients with one or two HLA DR4 antigens was 26% (43/167) which is similar to the range seen in general Caucasian population. Pt characteristics included: AML (n=84), CML (n=63), and MDS (n=20); median age 43 years (range 11–66); Male (n=104), Female (n=63); Caucasian (>95%); Total Body Irradiation (TBI) conditioning regimens (n=124); Busulfan (Bu)/Cyclophosphamide (Cy) (n=22), Bu/TBI (n=27), Cy/TBI (n=13), Etoposide/Cy/TBI (n=84), or other combinations (n=21). Results: There was no difference in OS and the PFS between the HLA DR4 positive vs negative groups in any disease or donor subgroups (p=0.4 and 0.6). GVHD prophylaxis was similar in the two groups but aGVHD and cGVHD incidence was not different in the two groups (p=0.8 and 0.9) Conclusions: HLA DR 4 is not associated with differences in GVHD or outcomes unlike the previous finding that HLA DR15 is associated with decreased acute GVHD in myeloid malignancies. These results suggest that there are differential effects of HLA DR antigens on the incidence of GVHD and outcomes in myeloid and lymphoid malignancies. Understanding these differences may facilitate the design of pt specific GVHD prophylaxis following allo HSCT. No significant financial relationships to disclose.