Immunologic effects of the decrease of immunosuppression after sars-cov-2 infection in kidney trasplant recipients

Abstract Background and Aims The decrease of immunosuppression (IS) in kidney transplant (KT) recipients with SARS-CoV-2 infection was proposed during the first years of the pandemic due to the lack of knowledge of the course of the infection and the absence of vaccines and specific treatment. The effects of this decrease are being assessed in a medium-long term. Method Unicentric retrospective study that included 19 patients with a kidney biopsy after a SARS-CoV-2 infection (120 days). We measured acute kidney injury (AKI) after de infection, decrease in the IS during the infection, rejection episodes and renal function evolution during 24 months after the infection. Results The studied group was constituted by 19 patients from which 57.9% (11/19) men, age 56 (51, 70), being the first KT in 78.9% (15/19) of them. The IS induction was in a 57.9% (11/19) Basilximab and in a 42.1% (8/19) thymoglobulin, and the usual IS of all of them was done with prednisone, tacrolimus and mycophenolic acid. There was a graft loss in 26.3% (5/19), being all of immunologic cause, and 10.5% (2/19) of patients died. The severity of the SARS-CoV-2 infection was different between patients (21.1% (4/11) asymptomatic, 47.1% (9/19) mild respiratory symptoms, 5.3% (1/19) severe pneumonia not requiring critical care unit and 26.3% (5/19) severe pneumonia requiring critical care unit, with a decrease in IS in a 42% (8/19) of patients (steroids in monotherapy in a 31.6% (6/19) and bitherapy with steroids and tacrolimus in a 10,5% (2/19), to achieve 5-7ng/mL blood levels). AKI was found after the first month after the infection in a 57.9% (11/19) of patients, being in a 42% (8/19) AKI KDIGO1 and in a 16% (3/19) AKI KDIGO3. Renal function kept worsening until the sixth month after the infection [CKDEPI before SARS-CoV-2 37mL/min (32, 45) vs CKDEPI 6months after 34mL/min (22, 48.3); p = 0.3]. There was an improvement in renal function in 12 months after the infection (38mL/min (25, 48)). Acute graft rejection was detected in renal biopsies after the infection in 31.6% (6/19) being cellular in 15.8% (3/19), humoral in 10.5% (2/19) and mixed in 5.3% (1/19), de novo DSA were found in 15.8% (3/19). Conclusion The decrease in IS after SARS-CoV-2 in KT recipient has an elevated immunologic price. Glomerular filtrate rate decreases after 6 months from infection with a recovery at 1 year.