Figure 5.

IFN-γ T cell response detected by IGRA is reduced in patients with RA compared with HCWs after the booster dose.

(a) Spike-specific IFN-γ T cell response evaluated by IGRA was detected in all HCWs (n = 38) and in the majority of patients with RA (36/52). (b) T cell response was showed also stratifying patients with RA according to drug treatment: TNF-α inhibitors (n = 7), IL-6 inhibitors with or without DMARDs/CSs (n = 13), CTLA-4-Ig with or without DMARDs/CSs (n = 12), DMARDs with or without CSs (n = 12) and JAK inhibitors with or without DMARDs/CSs (n = 8). IFN-γ levels were quantified by automatic enzyme-linked immunoassay and reported after subtracting the unstimulated control value. The cut-off was set at 16 pg/ml (dashed line). (c) Venn diagram represents the number of responders for anti-RBD IgG, neutralizing antibodies and IFN-γ T cell response. Statistical analysis was performed using Mann-Whitney U-test for pairwise comparisons (a), whereas Kruskal-Wallis test adjusted with Dunn's multiple comparisons test to compare groups (b). A P-value <0.05 was considered significant.

Abs, antibodies; CSs, corticosteroids; CTLA-4, cytotoxic T-lymphocyte antigen 4; DMARDs, disease-modifying anti-rheumatic drugs; HCWs, health care workers; IFN, interferon; IGRA, IFN-γ-release assay; Ig, immunoglobulin; IL, interleukin; JAK, Janus Kinase; RA, rheumatoid arthritis; RBD, receptor-binding domain; TNF, tumor necrosis factor.