Analysis of Antibody Response to Sars-Cov-2 Vaccination and Natural Infection in a Tertiary Centre Cohort of Lupus Nephritis Patients

ABSTRACT

Background/Aims The immune response to SARS-CoV-2 is known to be reduced in the immunocompromised. However, extent to which immunity is affected by immunosuppression in specific disease cohorts remains poorly characterised. Furthermore, implications of the ongoing vaccination booster programme require further study. Individuals with lupus nephritis (LN) require prolonged high-dose immunosuppression in order to maintain disease control, rendering them important to study in this context. We evaluated SARS-CoV-2 nucleocapsid and spike antibody response in this cohort during the Spring/Summer 2022 booster vaccine campaign. Nucleocapsid antibody indicates previous infection whilst spike antibody indicates previous infection and/or vaccination response. Titre of spike antibody to prevent infection is not known, but presence of antibodies is likely to protect against severe disease. Methods SARS-CoV-2 spike and nucleocapsid antibody were measured in adult patients with LN attending a tertiary centre rheumatology clinic. Data was collected retrospectively on disease, immunosuppression, vaccine status and history of natural exposure. Results 35 cases of LN were investigated, of which LN III, IV and V were predominant biopsy diagnoses. Regarding immunosuppressants, the Eurolupus Cyclophosphamide protocol had been used in the majority of patients to achieve initial control, with 3/35 patients still receiving pulsed courses at data collection. 18/35 were on Mycophenolate Mofetil;a further 13/35 had previously received this. 31/35 took at least 5mg Prednisolone daily;25/35 took Hydroxychloroquine;7/35 took Azathioprine;7/35 had previously been on Methotrexate, 3/35 took Tacrolimus;1/35 took Ciclosporin. Regarding B-cell depleting monoclonal antibody therapy, 13/35 had received Rituximab and 8/35 were receiving Belimumab. Antibody levels were measured between 4 weeks and 13 months after last dose of vaccination;mean duration was 6 months. 11/35 had confirmed COVID-19 infection;a further 8/35 reported a possible history. Of the 35, 32 (91%) had mounted detectable SARS-CoV-2 spike antibody above the bottom 10% of assay detection, indicating some immunity to vaccination or natural exposure. 20 (57%) had detectable nucleocapsid antibody, suggesting natural infection with antibody response. Only 2 (6%) had not mounted any antibody response. Of note, neither were fully vaccinated one had 1 vaccination with blood test 8 months subsequent;one had 2 vaccinations with blood test 7 months subsequent. The latter was also notably on haemodialysis. All who received 3+ vaccinations had detectable spike antibody responses, as well as 75% of those who had received 2 vaccinations. Conclusion Our study is the first analysis, to our knowledge, of SARS-CoV-2 antibody response in a LN cohort. Whilst neutralising capacity and level of antibody providing protection remains under research, these findings provide at least some reassurance that individuals with LN on immunosuppression are capable of mounting an immune response against SARS-CoV-2. Further work is required to establish extent and duration of protection with serial vaccinations in this cohort.