This finding is similar to a recent report in which ten (77%) of 13 RT-PCR-positive patients with a variety of rheumatic diseases developed SARS-CoV-2 antibodies (nine [69%] of 13 were on immunosuppressants).32 Understanding the impact of immunomodulators on antiviral antibody responses will have important implications for determining how best to approach COVID-19 vaccination in patients with SLE, especially since patients on immunosuppressants were excluded from phase 2C3 studies of COVID-19 vaccines. Although numerous studies have evaluated humoral immunity against SARS-CoV-2, cellular responses remain equally important in combating infection. surveillance during follow-up clinical visits. Findings 329 patients with SLE were included in this analysis, 146 from your WARCOV study and 183 from your NYU Lupus Cohort, and were NVP-CGM097 tested for SARS-CoV-2 antibodies between April 29, 2020, and Feb 9, 2021. 309 (94%) were women and 91 (28%) were of Hispanic ethnicity. 51 (16%) of 329 patients experienced a positive SARS-CoV-2 IgG antibody test. Seropositive patients were more likely than seronegative patients to be Hispanic (24 [47%] of 51 67 [24%] of 278). Other demographic variables, SLE-specific factors, and immunosuppressant use were not associated with SARS-CoV-2 positivity. Of the 29 patients with NVP-CGM097 COVID-19 previously confirmed by RT-PCR, 18 (62%) were on immunosuppressants; 24 (83%) of 29 patients tested positive for SARS-CoV-2 IgG antibodies. Of 17 patients who experienced symptoms of COVID-19 but unfavorable concurrent RT-PCR screening, one (6%) developed an antibody response. Of 26 patients who experienced COVID-19-related symptoms but did not undergo RT-PCR screening, six (23%) developed an antibody response. Of 83 patients who experienced no symptoms of COVID-19 and no RT-PCR screening, four (5%) developed an antibody response. Among 36 patients who were in the beginning SARS-CoV-2 IgG positive, the majority managed reactivity serially (88% up to 10 weeks, 83% up to 20 weeks, and 80% up to 30 weeks). Seven (70%) of ten patients with confirmed COVID-19 experienced antibody positivity beyond 30 weeks from disease onset. Interpretation Most patients with SLE and confirmed COVID-19 were able to produce and maintain a serological response despite the use of a variety of immunosuppressants, providing reassurance about the efficacy and durability of humoral immunity and possible protection against re-infection with SARS-CoV-2. Funding National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, and Bloomberg Philanthropies COVID-19 Response Initiative Grant. Introduction New York City was the epicentre of the COVID-19 pandemic from March 1 to June 21, 2020, with more than 200?000 confirmed and probable cases and 17? 000 deaths reported by June 21, 2020.1 Despite these high figures, during the outbreak peak in New York City, only around 12?000 individuals were tested for active infection daily, with positivity rates as high as 41C66%; undoubtedly, large numbers of people with COVID-19 were therefore not recognized.1 Serological evaluation to detect previous infections should therefore provide better insight into the prevalence of and risk factors associated with COVID-19, and enable assessment of the competency of individuals in mounting an antiviral immune response. SARS-CoV-2 IgG antibodies are generally detected 2 weeks after contamination, with higher titres recognized in patients with severe disease.2 NVP-CGM097 ELISA-based antibody assessments have greater than 95% specificity for COVID-19, although neutralising antibodies have been undetectable in a small proportion of mild cases.3 The role of serology in determining SARS-CoV-2 prevalence is still unclear, especially among subpopulations with altered immunological responses. Research in context Evidence before this study Patients with NVP-CGM097 systemic lupus erythematosus (SLE) are at an increased risk of developing viral infections due to immunological abnormalities and immunosuppressant use, which might affect humoral immune responses. To evaluate previous research related to the risk of infections, response to vaccinations and SETD2 COVID-19 in patients with SLE and rheumatic disease, we searched PubMed for articles published from Jan 1, 1980, to March 14, 2021. Search terms included systemic lupus erythematosus, and rheumatic disease in combination with viral infections, vaccination immune NVP-CGM097 response, COVID-19, SARS-CoV-2 IgG and COVID-19 antibodies. We also reviewed the online dashboard for the New York City COVID-19 case and death numbers between March 1 and June 21, 2020. Previous descriptive studies noted frequent hospital admission in patients with SLE andRT-PCR-confirmed SARS-CoV-2 infection, with risk factors for hospital admission including non-White or Hispanic ethnicity, a higher body-mass index, and having at least one other medical comorbidity. Immunosuppressant medication use was not associated with risk of hospital admission for COVID-19. Added value of this study To the best of our knowledge, this study represents the largest cohort of patients with SLE evaluated for SARS-CoV-2 IgG antibodies. Most patients with SLE and confirmed COVID-19 were able.