Fig. 1

Varicella zoster virus (VZV)-specific and Staphylococcus aureus enterotoxin B (SEB)-reactive CD4 T cells show reduced frequencies in patients with rheumatoid arthritis (RA). Whole blood was stimulated with control antigen (Co-ag, negative control), VZV antigen (VZV-ag), and the polyclonal stimulus SEB, respectively, and reactive CD4 T cells (CD69⁺IFN-γ⁺) were analyzed using flow cytometry. a Typical dotplots of a 39-year-old patient with RA are shown. Numbers indicate the percentages of reactive CD4 T cells. b Frequencies of VZV-specific CD4 T cells corrected for the negative control (left) and of SEB-reactive CD4 T cells (right), comparing samples of healthy control subjects (HC, n = 39), patients with RA (n = 74) and seronegative spondylarthritis (SpA, n = 19). c Levels of VZV-specific antibodies (immunoglobulin G [IgG]) in HC, RA, and SpA determined by IgG enzyme-linked immunosorbent assay of plasma samples. d Stratification of VZV-specific (left panel) and SEB-reactive CD4 T-cell frequencies (right panel) of patients with RA according to disease activity (three DAS28 categories; ≤ 2.6, full remission, low disease activity, n = 11; > 2.6 to ≤ 5.1, moderate disease activity, n = 32; and > 5.1, high disease activity, n = 7). Bars indicate median values and IQRs; dotted lines depict the respective detection limits (DLs) as determined before (VZV 0.02%, SEB 0.05% [10]) or as indicated by the manufacturer (IgG). Gray symbols represent patients with known history of herpes zoster. Statistical analysis was performed using the Kruskal-Wallis test and Dunn’s posttest. Significant differences in posttest are marked by asterisks (*p < 0.05; ***p < 0.001)