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

To characterize the antibody response to COVID-19 mRNA vaccination in patients with Systemic Lupus Erythematosus (SLE) and identify predictors of poor response.

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.

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.

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.