CXCR5 and Salla disease: In SD patients, the proportion of TFH (CXCR5 + PD‐1+ CD4+ T cells (p = .0001), CXCR5+CD4+PD‐1‐ T cells (p = .03), and PD‐1+CD4 T cells (p = .009) was higher than in the MD group.