Biol Blood Marrow Transplant. 2018 Nov 6. pii: S1083-8791(18)30692-X. doi: 10.1016/j.bbmt.2018.10.021. [Epub ahead of print]

The role of regulatory T cells in non-inherited maternal antigen-related tolerance in cord blood: an in vitro study.

Kwok J¹, Chu P², Ong C³, Ka-Wai Law H⁴, Ip P⁵, Godfrey CC⁵, Lu I⁶.

Abstract

Cord blood (CB) is an alternative stem cell source for allogeneic haematopoietic stem cell transplantation (HSCT). The unique advantages with CB as a stem cell source lies in a degree of permissibility for human leukocyte antigen (HLA) mismatch, rapid availability, and relatively risk-free cell collection. Since HLA is highly polymorphic and population specific, optimal HLA matched unrelated donors or cord blood units (CBUs) may not be available. In view of the chance that matched CBUs which include non-inherited maternal antigens (NIMA) might contain acceptable HLA mismatches, we attempted to determine the degree of allo-reactivity of CB mononuclear cells (MNC) upon stimulation by the maternal, paternal and unrelated stimulator cells. Suppression of T-cell proliferation, cytotoxicity and cytokine profile indicating suppressed Th1 and elevated IL-10 and TGF-β1 responses were observed in the mixed lymphocyte reaction (MLR) in response to NIMA. The increase in IL10 and TGF-β1 production may be due to the Th2 response and/or regulatory T (Treg) cells. The reduction of IL-10 and TGF-β1 production after CD25 depletion could have been due to removal of Treg cells from the CB cells. Thus Treg cells appear to play an important role in the CB MNC response to NIMA and this could be due to induction of IL10 and TGF-β1. We hope that our work can provide some evidence of the beneficial effect of NIMA.