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.

Background: The novel coronavirus disease (Covid-19) can progress with mild to moderate or self-limiting clinical findings in children. The aim of this study was to investigate the disease features of Covid-19 in Turkish children. Methods: Children diagnosed by the method of RT-PCR for Covid-19 at the Dicle University Department of Pediatric, between April and June 2020, were evaluated. Hospital records were investigated retrospectively. Results: One hundred and five patients children with the mean age of 108.64±65.61 were enrolled in this study. The most common cause of transmission in pediatric patients was contacting with a family member diagnosed with COVID-19 (n=91, 86.7%).The most common admission complaints were dry cough (n=17, 16.2%), fever (n=16, 15.2%), lassitude and fatigue (n=14, 13.3%) respectively. More than 95 % of all children with Covid-19 had asymptomatic, mild, or moderate cases. CRP was identified only independent factor associated with long duration of hospitalization. Conclusion: The results of this study show preliminary results of a study investigating the effect of Covid-19 on Turkish children. A clear understanding of the local epidemiology of corona virus infections and identification of risk factors is critical for the successful implementation of the prevention and control program.