De novo recipient-specific Glutathione S-transferase T1 antibody development after HLA-identical hematopoietic cell transplantation.

Donor-specific antibodies against Glutathione S-transferase T1 (GSTT1) have been associated with de novo immune hepatitis after liver transplantation. These antibodies have also been found very early in allo-HCT associated with acute hepatic GvHD but in all the cases the donor cells had experienced previous priming through pregnancies. It remained to be explored whether or not primary recognition of the antigen occurs after HCT and what could be the consequences in the long term outcome. We genotyped a cohort of 68 HCT patients and found 11 with the GSTT1 null donor/positive recipient mismatch. After testing 114 serum samples, we found a unique case of a 33-year-old patient transplanted from his HLA-identical sibling donor in which IgG GSTT1 antibodies were detected for the first time on day +178. After stimulation of peripheral blood mononuclear cells with GSTT1 peptides we could demonstrate that this patient also had GSTT1-specific T lymphocytes that became activated upon exposure to the GSTT1 antigen. In this report, we describe the first case in which simultaneous T and B cell response against GSTT1 is developed in HCT although the clinical consequences in GvHD are still unclear.