Risk of COVID-19 in young kidney transplant recipients. Results from a single-center observational study.

Abstract

To the editor: Coronavirus Disease 2019 (COVID-19) represents a global public health emergency, recently taken on pandemic proportions, with over 2.7 million confirmed cases worldwide.1 Children/young adults seem to have a less severe clinical manifestation of COVID-19,2 but data on disease susceptibility in pediatric transplant recipients on chronic immunosuppressive therapy are limited.3, 4 This poses major uncertainties regarding pediatric transplant activity and management of anti-rejection therapy. We have prospectively followed up a cohort of 160 kidney transplant recipients, 64 children (≤18 years), and 96 young adults (19-30 years), with currently stable graft function, who underwent a transplant in our center between January 2010 and March 2020 (nine between January and March 2020). All patients have been living in Italy, in areas where prevalence of SARS-CoV-2 ranges between 2 and 10 per 1000 people (Figure S1). According to the Italian guidelines for COVID-19 monitoring, asymptomatic patients receiving chronic immunosuppressive treatment underwent SARS-CoV-2 nasopharyngeal swab test only after direct contact with a positive cohabitant. From February 24 to April 12, 2020, patients have been interviewed weekly for 7 consecutive weeks to evaluate their health status and the health status of cohabitants (Details of the 12-points structured questionnaire are provided in the Appendix S1). At the time of the interview, triple immunosuppressive therapy with steroids, calcineurin inhibitors, and mycophenolate mofetil was the most frequent anti-rejection strategy (Table 1); forty-eight (30%) patients were in treatment with renin angiotensin-aldosterone inhibitors. Patients had median creatinine serum levels of 0.9 mg/dL and low proteinuria (Table 1). None of the 160 patients reported clinical symptoms for COVID-19, including cough, fever (>37°C), sore throat, fatigue, ageusia, or gastrointestinal disorders. Among them, we detected two subjects whose cohabitants were tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by nasopharyngeal swab test (Table 1). Due to the risk related to the immunosuppressive treatment, they were tested for SARS-CoV-2 and both of them resulted negative at two successive tests. Anti-SARS-CoV-2 antibodies negative as well. Immunosuppressive therapy was not modified during the 48 hour-wait period for the test result and it was maintained after then. None of the two subjects reported any symptoms neither during nor at the end of the incubation period of 21 days. The two patients were subsequently tested for anti-SARS-CoV-2 antibodies and resulted negative. As limitations, we report that in accordance with the Italian guidelines, no routine testing for SARS-CoV-2 was performed in the present cohort. This report of a single-center cohort suggests that chronic immunosuppression might not be associated with an increase of the risk of COIVD-19 in young kidney transplant recipients. Our data support the recommendations by the Italian Center of Transplantation,5 suggesting that transplant activity should be maintained also in areas with high incidence of SARS-CoV-2 infection. Based on these data, we recommend not to alter the immunosuppressive therapy in young transplant recipients with no symptoms, even if exposed to close contacts with individuals with COVID-19. In case of positivity to SARS-CoV-2, a tapering of usual transplant immunosuppression is to consider, but further clinical studies are still needed to define best management strategy. The authors of this manuscript have no conflicts of interest to disclose as described by Clinical Transplantation. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.