CAPILLARY DEPOSITION OF C4D COMPLEMENT FRAGMENT AND EARLY RENAL GRAFTLOSS

Clinical outcome of kidney grafts that are affected by the complex syn drome of 'early graft dysfunction' is uncertain and rather unpredictab le. In this study, an individual prognosis for dysfunctioning allograf ts (N = 93) is attempted by the immunohistological assessment of vascu lar classical complement activation in graft biopsies. Thus, capillary deposition of complement fragment C4d was observed in the majority (N = 51) of early dysfunctioning grafts. In 43 biopsies, abundant deposi tion of fragment C4d was present in all capillaries, whereas in eight specimens a segmental distribution of capillary C4d was observed. In 4 2 grafts with early dysfunction no capillary C4d was detectable. Eight een subsequent graft losses within one year (16 early losses) were rec orded in the subgroup with C4d in all capillaries, and three early los ses in the group with segmentally distributed C4d. Only four graft los ses (3 early losses) were recorded in the C4d-negative group (P = 0.00 27; Pearson's chi square test). The resulting one-year graft survival rates (72% for the study group) differed markedly between the subgroup s. Grafts with generalized or segmental capillary deposition of C4d ha d 57% and 63% survival, respectively, contrasted by 90% survival in th e C4d-negative group. It is of note, however, that also three of the f our grafts that were finally lost within the C4d-negative group, showe d distinct capillary deposition of C4d in second biopsies. Vascular de position of complement fragment C4d therefore represents a clinically relevant factor that contributes to early graft dysfunction. Its asses sment is helpful for an individual graft prognosis.