ABSTRACT
Although acute humoral rejection is a major cause of renal allograft loss, the diagnosis and treatment of acute humoral rejection have been very difficult because of lack of proper diagnostic tools and effective therapeutic modalities. Recently C4d deposition in peritubular capillaries of renal allografts has been demonstrated to be a sensitive and diagnostic in-situ marker of humoral rejection that correlates strongly with the presence of circulating donor-specific antibodies. Whereas conventional immunosuppressive agents are effective for the treatment of cellular rejection, specific therapeutic strategies targeting the humoral limb of immunosuppression should be necessary for the treatment of humoral rejection. Here we report a case of acute humoral rejection diagnosed with C4d immunostaining from transplant kidney biopsy and treated successfully with combination of plasma exchange, polyclonal rabbit anti-thymocyte globulin, and rituximab.