Humoral Response to SARS-CoV-2 Vaccination in Lupus Nephritis

Background: Vaccine development has been the best control measure for the SARS-CoV-2 pandemic. However, patients with lupus nephritis (LN) have not been included in studies assessing vaccine efficacy. The objective is to analyze LN patients' ability to generate antibodies against SARS-CoV-2 after vaccination while under immunosuppressive treatment. Methods: A prospective study was conducted on patients with LN. One month after receiving the second SARS-CoV-2 vaccine, a blood sample was taken to test for the presence of antibodies using an ELISA test sensitized with the Receptor Binding Domain (RBD) fragment of the SARS-CoV-2 Spike protein. Adverse effects and changes in the SLEDAI score were documented following the vaccine administration. Results: We recruited 19 patients, with a median age of 35.5 years and 89% female. The overall seroconversion rate was 63% (p=0.11). Patients in complete remission (CR) exhibited a significantly higher antibody response. The antibody production rate was higher for Pfizer® at 83% (p=0.03) compared to Sinovac at 54% (p=0.69). Patients who initially received Cyclophosphamide treatment showed a significant reduction in antibody production after vaccination (p=0.009). Conclusion: Patients vaccinated with Pfizer or in complete remission showed higher anti-SARS-CoV-2 seroconversion rates.