Correlation between magnitude of MLC and kidney graft survival in intrafamilial transplantation

The role of HLA-A and-B and HLA-D compatibility was analyzed in 63 recipients of intrafamilial kidney grafts. At 1 year post-transplantation the survival of grafts from HLA-A and-B compatible donors was 89% and that of grafts from HLA-A and/or-B incompatible donors 77%. Recipents with a Relative Response (RR) in MLC of less than 20% towards their donors, indicating HLA-D compatibility, had a 4-year graft survival of 100%. After 1 year the graft survival of this group was statistically different (p less 0-01) from the 63% graft survival of recipients with an RR greater than 60%. An RR greater than 60% indicates HLA-D incompatibility between recipient and donor. For patients with RR less than 60% the 2-year graft survival was 46%. This was lower than that of patients with RR less than 20% (P less than 0.001) and that of patients with an RR of 20--60% (P less than 0.01). The recipients with an RR of 20--60%, indicating slight HLA-D incompatibility with their donors, had a 2-year graft survival of 88%. We concluded that graft survival was correlated to the magnitude of MLC response between recipients and donors in such a way that a high MLC response indicating HLA-D incompatibility was associated with a high frequency of graft rejection while a low MLC response was associated with graft survival. HLA-D compatibility correlated with an excellent outcome in five cases in spite of HLA-A and-B incompatibility.