Acute vascular rejection during antituberculosis therapy in a kidney transplant patient

We report a case of acute vascular rejection occurring during antituberculosis therapy in a patient who had received a kidney transplant. A 29 year‐old man was admitted for a protocol biopsy; he had a serum creatinine (S‐Cr) level of 1.5 mg/dL 1 year after primary kidney transplantation. Histological examination yielded no evidence of rejection but a routine chest CT scan revealed typical lung tuberculosis and his serum was positive for QFT. We commenced antituberculosis therapy, including rifampicin, on June 29 2012. We paid close attention to the weekly trough tacrolimus (TAC) level but the S‐Cr concentration increased to 3.7 mg/dL on October 16 2012, and he was admitted for biopsy. Histological examination revealed, first, a diffuse aggressive infiltration of tubulointerstitial inflammatory cells accompanied by severe tubulitis and mild intimal arteritis and, second, peritubular capillary infiltration by inflammatory cells (including neutrophils). Laboratory data revealed that our patient did not express donor‐specific antibody and the peritubular capillaries did not exhibit C4d immunoreactivity. Upon consideration of both histological and laboratory findings, we diagnosed acute vascular rejection of Banff 2007 class ACR IIA. We commenced 3‐day sessions of intravenous steroid pulse therapy twice weekly and adjusted the trough TAC level to 5–8 ng/mL by varying the TAC dose. We next performed an allograft biopsy and found no evidence of rejection (the S‐Cr level was 2.7 mg/dL on April 1 2013). The present case report demonstrates the difficulties associated with management of TAC‐based regimens in kidney transplant patients undergoing antituberculosis therapy. We also review the relevant literature.