To the editor: The recent paper by Aiello et al1 describes interesting differences in AR episodes, plasma cell content, immunohistology for C4d, chronic allograft nephropathy scores, and graft survival in patients with predominantly CMV infection arising in the first year after transplantation. The authors note that episodes of viral infection preceded acute rejection in eight, were concurrent in three and arose after rejection in four patients. It would be of interest to know how the measured clinical, histologic and immunopathologic parameters, in acute rejection episodes arising after viral infection differed from those arising before and during such infections. One might expect that acute rejection arising before exposure of the immune system to viral infection may not be different from matched controls. It is also tempting to speculate that acute rejection arising after viral infection may have been precipitated by reduction of immunosuppression if indeed this occurred.