[Relapse of lupus nephritis in temporal association with anti SARS-CoV-2 vaccination]

During the past two years we have witness a tremendous worldwide health crisis imposed by the coronavirus disease (COVID-19). This situation led to the urgent development and implementation of vaccines in an attempt to decrease not only the SARS-CoV-2 transmissibility but also the severe forms of COVID-19. Although these vaccines were approved based on an adequate benefit-risk ratio, at the moment of their implementation in 2021 we did not have sub-studies in special populations; patients with systemic lupus erythematosus (SLE) among them. We describe two cases of lupus nephritis flare following the immunization against SARS-CoV-2 with the first component of Sputnik V and Sinopharm. Both patients were in complete remission on maintenance therapy with mycophenolate and without glucocorticoids. The flare presented with an increased protein/creatinine ratio in urine and positive anti-DNA antibodies without other relevant accompanying findings. After treatment with prednisone (20 y 10 mg/day in case 1 and 2, respectively) and an increased dose of mycophenolate (from 1.5 g/day to 2.0 g/dayand 1.08 to 1.44 g/día of sodic mycophenolate in case 1 y 2, respectively) both patients regained renal remission. These cases are of relevance as they introduce a possible association between the different anti-SARS-CoV-2 vaccine platforms and SLE flares; at the same time to suggest the need for close control in the post vaccination period in this population of patients.