Successful treatment of BK virus nephropathy using therapeutic drug monitoring of mycophenolic acid.
We report the successful management of BK virus nephropathy (BKVN) using therapeutic drug monitoring (TDM) of mycophenolic acid (MPA). A 40-year-old woman was admitted for a protocol biopsy 3 months following primary kidney transplantation. Histological features were distributed in mainly two sections: the corticomedullary junction and cortical area. In the former, massive interstitial mononuclear cell infiltration and mild to moderate tubulitis with nuclear inclusion bodies were found. SV40 staining was positive in the injured tubules. These findings were compatible with BKVN. In the latter, focal interstitial inflammation and severe tubulitis without cytopathic changes were identified outside of SV40-positive areas. Based on the histological findings, we diagnosed BKVN and we also suspected of the complication with acute T-cell-mediated rejection. We started steroid pulse therapy and reduced the dosage of immunosuppressive therapy under careful monitoring, using not only a trough level of tacrolimus but also a 12-h area under the curve (AUC0-12 ) of MPA. After the treatment, the patient maintained kidney function. This case report demonstrates the usefulness of MPA AUC0-12 for more accurate adjustment of immunosuppressive therapy and the difficulty of pathological differentiation of BKVN and acute cellular rejection.
Division of Kidney and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
Akimitsu
A
Kobayashi
Izumi
I
Yamamoto
Yasuyuki
Y
Nakada
Satoshi
S
Kidoguchi
Nanae
N
Matsuo
Yudo
Y
Tanno
Ichiro
I
Ohkido
Nobuo
N
Tsuboi
Hiroyasu
H
Yamamoto
Keitaro
K
Yokoyama
Takashi
T
Yokoo
D000328:Adult; D000903:Antibiotics, Antineoplastic / Q000008:administration & dosage / Q000009:adverse effects; D001739:BK Virus; D016903:Drug Monitoring / Q000379:methods*; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D016030:Kidney Transplantation / Q000009:adverse effects*; D009173:Mycophenolic Acid / Q000008:administration & dosage* / Q000009:adverse effects; D009393:Nephritis / Q000188:drug therapy / Q000276:immunology / Q000821:virology; D027601:Polyomavirus Infections / Q000188:drug therapy* / Q000276:immunology; D013256:Steroids / Q000627:therapeutic use; D014412:Tumor Virus Infections / Q000188:drug therapy* / Q000276:immunology
D000903:Antibiotics, Antineoplastic; D007166:Immunosuppressive Agents; D013256:Steroids; D009173:Mycophenolic Acid
BK virus nephropathy; MPA AUC; acute T-cell-mediated rejection