Figure 2.

IRAK4 kinase activity is required for the production of autoantibodies and hypergammaglobulinemia observed in lupus-prone mice. (A) Representative microscopy images of HEp-2 staining patterns of serum autoantibodies from aged Sle1, Sle1IRAK4^KD/KD, Sle1Tg7, and Sle1Tg7IRAK4^KD/KD mice. (B,C) Analysis of (B) nuclear and (C) cytoplasmic staining patterns determined by HEp-2 staining and microscopy. (D) Cytoplasmic intensity determined by HEp-2 microscopy. Serum for HEp-2 was from 3 independent cohorts with total 10–13 mice per group. (E–H) Analyses by ELISA of IgG autoantibodies with (E) nucleosome (dsDNA/histone), (F) dsDNA, or (G) snRNP or (H) RNA specificity in Sle1, Sle1IRAK4^KD/KD, Sle1Tg7, and Sle1Tg7IRAK4^KD/KD mice (18–23 mice per group). (I) Luminex analysis of circulating antibody subclasses (IgM, IgA, IgG₁, IgG_2a/c, IgG_2b, IgG₃) across the 3 cohorts (data from 17–22 mice per group). Parametric data were assessed by 1-way ANOVA (with Bonferroni's multiple comparisons test) and non-parametric data with Kruskal-Wallis (with Dunn's multiple comparisons test) ^*P < 0.05, ^**P < 0.01, ^***P < 0.001, ^****P < 0.0001. Additional comparisons between two groups were made with a Student's t test or Mann-Whitney test for parametric and non-parametric data respectively, indicated by # (^#P < 0.05, ^##P < 0.01, ^####P < 0.0001).