Thrombotic microangiopathy (TMA) is a serious complication of
renal transplantation. It is a morphological expression of various etiological factors. In a renal allograft, TMA can occur de novo or be a recurrent disease. The aim of this study was to analyze the etiological factors and observe the changing trends of TMA with respect to emerging new etiological factors. We evaluated 131 graft biopsies over a period of 2½ years (2010-2012). All the renal biopsies were
formalin fixed,
paraffin embedded. Twenty serial sections were studied. Stains routinely used were
Hematoxylin and
Eosin,
Periodic Acid Schiff, Massons Trichrome and
Silver Methenamine stains. C4d by immunohistochemical method was done on all graft biopsies. Incidence of TMA in our series was 9.1%. Out of the 12 cases, five were associated with
calcineurin inhibitor toxicity, three were diagnosed as acute antibody-mediated rejection, and two were recurrent haemolytic uremic syndrome. One patient developed haemolytic uremic syndrome on treatment with
sirolimus and one patient was cytomegalovirus positive on treatment with
ganciclovir, developed haemolytic uremic syndrome during treatment course. This study describes a spectrum of etiological factors for thrombotic mciroangiopathy ranging from common cause like
calcineurin inhibitor toxicity to rare cause like
ganciclovir induced TMA.