Predictors of a weak antibody response to COVID-19 mRNA vaccine in systemic lupus erythematosus

Objectives To characterize the antibody response to COVID-19 mRNA vaccination in patients with Systemic Lupus Erythematosus (SLE) and identify predictors of poor response. Methods SLE patients who are followed at the Beth Israel Deaconess Medical Center Lupus Cohort (BID-LC) were enrolled. SARS-CoV-2 IgG Spike antibody was measured in patients who received two doses of either the BNT162b2 (Pfizer-BioNTech) or the mRNA-1273 (Moderna) COVID-19 vaccine (n = 62). We defined non-responders as patients with an IgG Spike antibody titer less than two-fold (< 2) the index value of the test and responders as patients with antibody levels greater or equal to two-fold (≥ 2). A web-based survey was used to collect information regarding immunosuppressive medication use and SLE flares after vaccination. Results In our cohort of lupus patients, 76% were vaccine responders. The use of two or more immunosuppressive drugs was associated with being a non-responder (Odds Ratio 5.26; 95% CI 1.23–22.34, p = 0.02). Both Belimumab use and higher Prednisone dose were associated with vaccine non-response ( p = 0.04 and p = 0.04 ). The non-responder group had higher mean levels of serum IL-18 than the responder group ( p = 0.04 ) as well as lower C3 levels ( p = 0.01) . Lupus flares and breakthrough infections were uncommon post-vaccination. Conclusions Immunosuppressive medications have a negative impact on vaccine humoral response in SLE individuals. We observed a trend towards vaccine no-response in BNT162b2 recipients and a relationship between IL-18 and impaired antibody response that merits further investigation.