Biopsy proven BK virus nephropathy in kidney transplant recepients: A multi-central study from Turkey (BK-TURK STUDY)
Authors: ISLAM Mahmud , Gungor Ozkan , Dheir Hamad , toz huseyin , Yildiz Abdulmecit , Sinangil Ayse , Tatar Erhan , Asci Gulay , Ulutaş Özkan , Altun Eda , Altunoren Orcun , Apaydin Suheyla , Ersoy Alparslan , Korucu Berfu , Safak Seda , Derici Ulver , Yildirim Saliha , Seyahi Nurhan , Ozcan Seyda Gul , Atilgan Kadir Gokhan , Ayli Mehmet Deniz , Cavdar Caner , Uzun Ozcan , Yilmaz Rahmi , Erdut Arda , Sevinc Mustafa , Kasapoğlu Umut , Kocyigit Ismail , Uysal Cihan , Turkmen Kultigin , Ozer Hakan , Velioglu Arzu , Ok Ebru , Kaya Bulent , yılmaz Zulfikar , Ozkan Oktay , Cebeci Egemen , Turgutalp Kenan , Gursu Meltem , Yüksel Enver , Eren Necmi , Dervisoglu Erkan , Guzel Fatma Betul , Yildiz Gursel , Bakirdogen Serkan , Inci Ayca , Sevinc Can , Turkmen Aydin 
Published: January 2023

Background: Polyomavirus BK virus infection is a significant
complication of renal transplantation and is an important cause of
allograft loss. Today, despite the innovations in the pharmaceutical
industry, a curative treatment against the BK virus has not been
developed. The management is not standardized and is generally based on
reported experience from transplantation centers. However, the
literature on the subject with large samples is limited. Therefore, we
designed a study to present our countrywide experience with BK virus
nephropathy (BKVN) in renal transplant recipients. Methods: Our
study was conducted with thirty kidney transplant centers from all
provinces of Turkey. Only cases with BKVN proven by allograft biopsy
were included in our study. Demographic characteristics and laboratory
values of the patients were obtained from the archives and electronic
databases of the centers. Results: A total of 13.857 patients
from 30 transplantation centers were screened. 207 BKVN cases proven by
allograft biopsy were identified and included in the study. The mean age
was 46.4±13.1, and 146 (70.5%) patients were male. Twenty-six patients
did not receive any induction therapy, 144 patients received anti-T
lymphocyte globulin (ATLG), and 37 patients received basiliximab after
transplantation. 23.6% of the patients had acute rejection history in
the first six months of renal transplantation. all were treated with
pulse steroids, and 46 were also treated with ATLG. The mean time to
diagnosis of BKVN was 15.8±22.2 months after transplantation. At the
time of diagnosis, the patients’ mean creatinine level was 1.8±0.7
mg/dl, and the mean estimated glomerular filtration rate was 45.8±19.6
ml/min. While BKVN was solely reported in 181 cases, there were cellular
rejection findings in 21 biopsy specimens and humoral rejection in 4
biopsy specimens. In addition of dose reduction or discontinuation of
immunosuppressive drugs, eighteen patients were treated with cidofovir,
11 patients with leflunomide, 17 patients with quinolones, 15 patients
with intravenous immunoglobulin (IVIG), five patients with
cidofovir+IVIG, and 12 patients with leflunomide+IVIG. None of the
patients who received leflunomide and leflunomide+IVIG had allograft
loss. Allograft loss was observed in 12 (15%) of 78 patients treated
with antivirals or immunomodulators. Allograft loss occurred in 32
patients (15%) during follow-up out of 207 patients with BKVN. Five
patients were retransplanted, and none developed BKVN during the
follow-up. Conclusions: BKVN is still a significant cause of
allograft loss in kidney transplantation, which has not been fully
elucidated. Leflunomide appears to be an effective treatment in these
patients.