Introduction Although most patients recover within several weeks after acute COVID‐19, some of them develop long‐lasting clinical symptoms. Renal transplant recipients have an increased mortality risk from COVID‐19. We aimed to describe complications occurring after COVID‐19 in this group of patients. Methods A prospective single‐center cohort study was conducted at University Hospital Centre Zagreb. Patients with two negative reverse transcriptase‐polymerase chain reaction (RT‐PCR) tests for SARS‐CoV‐2 after COVID‐19 were eligible for further follow‐up at our outpatient clinic. They underwent detailed clinical and laboratory assessments. The primary outcome was the development of complications after COVID‐19. Results Only 11.53% of renal transplant recipients who survived acute COVID‐19 were symptomless and free from new‐onset laboratory abnormalities during the median follow‐up of 64 days (range: 50–76 days). Three patients died from sepsis after discharge from the hospital. In 47 patients (45.2%), clinical complications were present, while 74 patients (71.2%) had one or more laboratory abnormalities. The most common clinical complications included shortness of breath (19.2%), tiredness (11.5%), peripheral neuropathy (7.7%), self‐reported cognitive impairments (5.7%), and dry cough (7.7%). Most common laboratory abnormalities included shortened activated partial thromboplastin time (50%), elevated D‐dimers (36.5%), elevated fibrinogen (30.16%), and hypogammaglobulinemia (24%). Positive RT‐PCR for cytomegalovirus (8.7%), Epstein–Barr virus (26%), or BK virus (16.3%). Multivariate analysis identified the history of diabetes mellitus and eGFR CKD‐EPI as predictors for the development of post‐COVID clinical complications. Six months after acute COVID‐19, elevated D‐dimers persisted with normalization of other laboratory parameters. Twenty‐nine patients were hospitalized, mostly with several concomitant problems. However, initially reported clinical problems gradually improved in the majority of patients. Conclusion Post‐COVID‐19 clinical and laboratory complications are frequent in the renal transplant population, in some of them associated with significant morbidity. All patients recovered from acute COVID‐19 should undergo long‐term monitoring for evaluation and treatment of complications.

Current knowledge on histopathological changes occurring after COVID‐19 in transplanted kidneys is limited. Herein, we present renal allograft pathology findings in patients recovered from COVID‐19. Six patients underwent indication biopsy, and one required allograft nephrectomy after acute COVID‐19. Demographic data, clinical characteristics, and laboratory findings were recorded. The histopathological analysis included light microscopy, immunostaining, and electron microscopy. Five patients were hospitalized for acute COVID‐19, and all were diagnosed with imaging‐confirmed pneumonia, one requiring mechanical ventilation, and two requiring dialysis. Two patients had mild form. Histopathologic examination of renal allograft specimens revealed collapsing, perihilar, tip‐lesion and secondary FSGS in one patient each. One patient had borderline acute cellular rejection, and two had chronic antibody‐mediated rejection. Histopathologic changes of glomerular tufts were accompanied by acute tubular injury in four patients. None of our patients had signs of viral inclusions in kidney cells. One patient died and one remained dialysis‐dependent after the good initial response to treatment. Patients with collapsing and perihilar FSGS had further progression of their chronic allograft nephropathy still without need for dialysis. In conclusion, diverse kidney pathology may be found in SARS‐CoV‐2–infected renal transplant patients. It seems that viral infection may affect the immune system with triggering of glomerular diseases, while the acute tubular injury is of multifactorial etiology. Direct viral effect is less likely.

Background The aim of this study is to determine the incidence, etiology, clinical characteristics, and outcomes of renal transplant recipients diagnosed and treated for central nervous system (CNS) infection at our institution. Methods We analyzed data from all renal transplant recipients between January 2007 and December 2019 that were diagnosed and treated for CNS infections at our institution. Results Of 1374 patients who received renal allografts, 13 were diagnosed with CNS infections (9 males), with a mean age of 53.5 years. Patients were diagnosed with CNS infections between 2 months and 11 years after the transplantation. Causative agents included JC virus, Streptococcus pneumoniae, Cryptococcus neoformans, Herpes zoster virus, Mycobacterium tuberculosis, Listeria monocytogenes, and West Nile virus. One patient had concomitant Nocardia and Neisseria infection. Immunosuppression was reduced in all patients. The patient with JC encephalitis and the patient with concomitant Neisseria and Nocardia meningitis died. One patient was returned to dialysis. Other patients recovered with differing levels of neurologic sequelae. Conclusion Central nervous system infections in renal transplant recipients are rare. However, they are associated with significant morbidity and mortality. A high level of awareness is needed: neurological symptoms may be nonspecific and caused by non‐infectious conditions related to the underlying disease, or side‐effects of immunosuppressive drugs.