A possible predictive test for graft-versus-host disease in bone marrow graft recipients: the mixed-epidermal cell-lymphocyte reaction.

The possible ability of the mixed-epidermal-cell-lymphocyte reaction (MECLR) to detect alloreactivities in HLA-identical MLR negative siblings has been investigated before grafting in 30 donor-recipients pairs and their families. Results indicate that recipients' epidermal cells (EC) can induce proliferative responses of HLA-identical MLR-negative donors' lymphocytes in 55% of the pairs tested. Moreover, further evaluation of 21 patients shows that the positivity of the MECLR before the graft is correlated with later appearance of acute and chronic GVHD, and especially with the severity of cutaneous injury. EC have been shown to be more efficient antigen presenting cells than peripheral blood lymphocytes for in vitro primary proliferative responses, so these reactions could be directed against some minor histocompatibility antigens, thus leading to possible improvement in selecting bone marrow graft donors and to the detection of donor-recipient pairs with a high risk of GVHD.