Impact of mismatching CD1a, a dimorphic antigen-presenting molecule, on graft-versus-host disease after hematopoietic stem cell transplantation
Abstract
CD1a, an antigen-presenting molecule related to major histocompatibility complex (MHC) class I, is frequently described as nonpolymorphic. In humans it is dimorphic, due to two linked amino acid substitutions in the alpha 1 domain (Ile13Thr and Trp51Cys).
The CD1a gene on chromosome I is not linked to MHC and may be mismatched between human leukocyte antigen-identical siblings. We analyzed 155 donor-recipient pairs of the Eurobank cohort, 141 matched for CD1a and 14 unmatched in the graft-versus-host disease (GVHD) direction.
The burden of GVHD was not increased by CD1a mismatching. The incidence of GVHD in matched and unmatched groups was respectively: grade I-IV: 81% and 86% (P=0.492); II-IV 61% and 57% (P=0.495); III-IV 23% and 21% (P=0.608).
Adjusting for age, sex mismatch, GVHD prophylaxis, and conditioning did not reveal any significant difference. This suggests that, unlike conventional class I molecules, CD1a does not function as a transplantation antigen and does not require matching in hematopoietic stem cell transplantation.