Conversion to mTOR-inhibitors with calcineurin inhibitor elimination or minimization reduces urinary polyomavirus BK load in kidney transplant recipients

• Published in: Journal of the Formosan Medical Association 2016-07, Vol.115 (7), p.539-546
• Main Authors: Yen, Chieh-Li, Tian, Ya-Chung, Wu, Hsin-Hsu, Weng, Cheng-Hao, Chen, Yung-Chang, Tu, Kun-Hua, Liu, Shou-Hsuan, Lee, Cheng-Chia, Lai, Ping-Chin, Fang, Ji-Tseng, Hung, Cheng-Chieh, Yang, Chih-Wei, Li, Yi-Jung
• Format: Article
• Language: English
• Subjects: Adult; BK Virus - drug effects; Creatinine - blood; Everolimus - therapeutic use; Female; Glomerular Filtration Rate; Humans; Immunosuppressive Agents - therapeutic use; Immunotherapy; Internal Medicine; Kidney Diseases - epidemiology; Kidney Diseases - virology; Kidney Transplantation; Logistic Models; Male; mammalian target of rapamycin; Middle Aged; Polyomavirus; polyomavirus BK; Polyomavirus Infections - drug therapy; Postoperative Complications - drug therapy; Postoperative Complications - virology; Retrospective Studies; Sirolimus - therapeutic use; Taiwan; TOR Serine-Threonine Kinases - antagonists & inhibitors; Viral Load - drug effects; viruria
• ISSN: 0929-6646
• DOI: 10.1016/j.jfma.2016.01.008

Abstract Background/Purpose Polyomavirus BK (BKV) reactivation causes allograft dysfunction in some kidney transplant recipients. The use of mammalian target of rapamycin (mTOR) inhibitor-based immunotherapy is associated with a lower incidence of polyomavirus-associated nephropathy compared with other immunosuppressants. This retrospective study assessed whether conversion to mTOR inhibitor-based immunotherapy directly reduced urinary BKV load. Methods A total of 63 kidney recipients were divided into mTOR inhibitor-conversion (21 patients) and nonconversion (42 patients) groups. Urinary BKV loads were determined before and at least 6 months after the conversion. Results The results demonstrated that urinary BKV titer was significantly reduced in the conversion group (3.94 ± 0.43 copies (log)/mL to 2.49 ± 0.19 copies (log)/mL) and remained unaltered in the nonconversion group (3.19 ± 0.20 copies (log)/mL to 2.90 ± 0.20 copies (log)/mL). In addition, the percentage of patients with reduced urinary BKV load was significantly higher in the conversion group (76.2% vs. 42.9%). The estimated glomerular filtration rate after 24 months mTOR inhibitor conversion was significantly increased compared with that in the nonconversion group. Conversion to mTOR-inhibitor-based immunotherapy was the only factor associated with an increase in estimated glomerular filtration rate. Conclusion This study reveals an association of conversion to mTOR-inhibitor-based immunotherapy with the reduction of urinary BKV load.