Skewing of pretransplant anti-HLA class I antibodies of immunoglobulin G isotype solely toward immunoglobulin G1 subclass is associated with poorer renal allograft survival.

Sensitized patients with lymphocytotoxic immunoglobulin (Ig)G anti-human leukocyte antigen (HLA) antibodies have an increased risk of rejection and poorer graft survival. Little is known, however, about the correlation between IgG antibody subclass and clinical outcomes. We identified 20 sensitized renal transplant recipients (panel reactive antibody >15%), all of whom had anti-HLA class I antibodies of an IgG isotype with known specificity before transplantation but who received a crossmatch negative graft. We analyzed the degree of skewing solely toward IgG1 (n=11) or to other IgG subclasses with or without IgG1 (n=9) and correlated these findings with graft survival. At last follow-up (median follow-up 28 months), 6 of 11 patients (55%) with anti-HLA antibodies skewed toward IgG1 had lost their grafts compared with 0 of 9 patients (0%) with anti-HLA antibodies not skewed toward IgG1 (P =0.01 log-rank test). Anti-HLA antibodies of an IgG1 subclass may be a novel marker predicting poor graft outcome.

Will transplantation of kidneys from donors with blood group A2 into recipients with blood group B help British Indo-Asian patients with renal failure?

Despite a high incidence of renal failure, disproportionately fewer Indo-Asians in the United Kingdom receive a renal transplant, in part because of the high prevalence of blood group B. It is now clear that it is possible to safely transplant kidneys from donors with blood group A of the subtype A2 into recipients with blood group B if the latter have low titers of anti-A antibodies. We measured the anti-A titers in 25 Indo-Asian patients on dialysis being considered for transplantation and found stably low titers in all. Titers were comparable to those found in a control white population with blood group B. In addition, in a complement-dependent cytotoxicity crossmatch against group A lymphocytes, the only positive results were obtained in those with high preexisting panel reactivity (i.e., because of the presence of preformed anti-human leukocyte antigen antibodies). We conclude that there are grounds for investigating this approach further to solve the ethnic disparity in rates of transplantation.