[Measurement of alloreactive anti-recipient helper T-cell precursors after allogenic bone marrow transplantation].

Acute graft-versus-host disease (GvHD) is a severe complication after allogenous bone marrow transplantation (BMT). The compatibility of major histocompatibility complex antigens (MHC) is the strongest stimulus for GvHD, which also occurs in patients with a genetically MHC-identical sibling donor. In such cases it would be helpful to recognize anti-recipient (interleukin-2-producing) T-lymphocyte precursors to detect a minor histocompatibility antigen (mH), which escapes from typing methods. To quantitate the alloreactive immune response initiating acute GvHD, we established the helper T-lymphocyte precursor test (HTL-p) as described by Theobald et al. in 'GvHD direction', using a limiting dilution assay. Serial dilutions of the donor peripheral blood mononuclear cells (PBMCs) were cultured for 14 days with constant numbers of stimulator PBMCs from the recipient, followed by an unspecific restimulation step with phytohemagglutinin (PHA) or specific restimulation with EBV-transformed blast cells from the recipient. The Il-2 production of specific T cells was assessed by addition of CTLL-16 cells, whose proliferation was measured by an ELISA. We suppose that the HTL-p test is a good tool for measuring the number of anti-recipient T-lymphocyte precursors as a predictive value for the intensity of GvHD.