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. 2020 Sep 22;79(12):1588–1599. doi: 10.1136/annrheumdis-2020-217646

Figure 2.

Figure 2

Tfh-cell signature and IL-21 expression correlate with lymphocytic infiltration, ELS formation and GC B-cell genes in SS SGs. (A) Unsupervised whole-genome microarray analysis from SG RNA of NSCS (n=15) and SS (n=30), segregated for the absence (ELS-, n=15) and the presence of ELS (ELS+, n=15). (B) Supervised whole-genome microarray analysis of cohort described in (A), with the signature pathways rank-ordered for expression intensity. (C–E) GSVA for indicated signatures and (F–I) gene expression intensity comparison of Tfh-cell signature pathway genes (encoding respectively for CXCR5, ICOS, SAP and PD-1) in NSCS (n=15), ELS- (n=15) and ELS+ (n=15) SG. Linear regression model statistics. All graphs represent mean±SEM. *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001. Real-time PCR expression for IL-21 (J) and IL-21 receptor (IL21R) (K) on total RNA from SG biopsies from NSCS (n=37) and SS (n=29) patients, segregated on the basis of absence (ELS-, n=7) and presence of ELS (ELS+, n=22). Quantification of IL-21 mRNA (L–O) and IL-21R expression (P–S) in SG tissue biopsies, according to histological semi-quantitative score (0 to 3) of B (CD20), T (CD3), plasma cells (CD138) and macrophages (CD68). Statistical analysis by Kruskal-Wallis-test with Dunn’s post-test correction for multiple comparison. (T–Y) Spearman correlation analysis between IL-21 mRNA in SG and indicated lymphoid and GC B-cell genes. All graphs represent mean±SEM. *p<0.05, **p<0.01, ***p<0.001, ****p<0.0001. CXCR5, CXC-motif chemokine receptor 5; ELS, ectopic lymphoid structure; GC, germinal centres; GSVA, Gene Set Variation Analysis; ICOS, inducible T-cell co-stimulator; IL-21, interleukin-21; NSCS, non-specific chronic sialoadenitis; PD-1, programmed cell death protein 1; SAP, SLAM-associated protein; SG, Salivary gland; SS, Sjogren’s syndrome; Tfh, T-follicular-helper.