Typing of intraglomerular mononuclear cells associated with transplant glomerular rejection

To investigate the pathogenesis of glomerular injury in renal allografts, we have analyzed intraglomerular mononuclear cells from 20 biopsies with typical features of transplant glomerular rejection (TGR) (segmental or global occlusion of capillaries by swollen cells). Ten biopsies showing cellular rejection but no glomerular pathology were selected as controls. Microwave fixation and an avidin-biotin immunoperoxidase technique were used with the following monoclonal antibodies; Leu1 and OKT3 (pan T cell), Leu 3 a + b and OKT4 (helper T cell), OKT8 (cytotoxic T cell), OKB7 (B cell), OKM1 (monocyte) and OKDR (DR positive cell). The results showed a significant increase of T cells, helper T cells, cytotoxic T cells and monocytes in the patients with TGR compared with the controls (all p less than 0.001, Mann-Whitney U test). Of the T cell subsets, cytotoxic T cells outnumbered helper T cells by a mean ratio of 3.2:1. In the interstitium, the distribution of mononuclear cells was not different between the two patient groups. In both, T cells and monocytes were predominant and few B cells were found. The percentage of cytotoxic T cells was similar to that of helper T cells. In this study, there were at least four TGR patients without cytomegalovirus (CMV) infection and the distribution of intraglomerular mononuclear cells in these patients was indistinguishable from that of other TGR patients. There was no significant association of the distribution of mononuclear cells with the severity of glomerular damage. These results suggest that T cells, predominantly of the cytotoxic subset and monocytes are involved in the mediation of TGR.(ABSTRACT TRUNCATED AT 250 WORDS)