Sequential analysis of HLA-C-specific killer cell inhibitory receptor (CD158b) expressing peripheral blood mononuclear cells during chronic graft-versus-host disease

We have sequentially investigated the expression of natural killer cell inhibitory receptors (KIRs) for HLA-C (CD158b) on peripheral blood mononuclear cells (PBMC) in three patients with extensive chronic graft-versus-host disease (cGVHD) after allogeneic bone marrow transplantation (alloBMT), Clinical symptoms of cGVHD were not cured and worsened in the first patient whose CD158b-positive cells increased to 18.5% during cGVHD and decreased to 9.4% at 8 months after transplantation. On the other hand, cGVHD was cured and did not relapse in the second patient whose CD158b-positive cells increased up to 45.9% during cGVHD and sustained 19.4% at 8 months after transplantation. In contrast, CD158b-positive cells were less than 10% during the course of cGVHD in the third patient, and her cGVHD did not respond to treatment. Therefore, it appears that chronic allostimulation augments the expansion of CD158b-positive cells and these expanded CD158b-positive cells may have some role in the control of alloresponse in some patients.