Expression Profile of the IL‐17 Receptor Family on Peripheral B Lymphocytes in Rheumatoid Arthritis

B cells are key contributors to the immunopathogenesis of rheumatoid arthritis (RA), yet the expression profile of interleukin‐17 (IL‐17) receptors on human B cells remains incompletely defined. We analyzed the surface expression of IL‐17RA–IL‐17RE on peripheral CD19 ⁺ B cells from 42 patients with RA and 20 healthy controls (HC) using flow cytometry. Receptor‐positive cell frequency and mean fluorescence intensity (MFI) were evaluated, and disease activity was assessed using the Disease Activity Score in 28 joints based on erythrocyte sedimentation rate (DAS28‐ESR). The frequency of receptor‐positive B cells differed significantly among IL‐17 receptor (IL‐17R) family members in both RA and HC, with IL‐17RD showing the highest proportion of positive cells, followed by IL‐17RA, whereas IL‐17RC was less frequent and IL‐17RB and IL‐17RE were rarely detected. The proportion of IL‐17RA ⁺ B cells was lower in RA than in HC and remained statistically significant after correction for multiple comparisons (Holm‐adjusted p = 0.0126). A nominally lower frequency of IL‐17RC ⁺ B cells in RA did not remain significant after adjustment, while IL‐17RD frequency was comparable between groups. No between‐group differences in MFI remained significant after multiple‐comparison correction. Receptor expression was not significantly associated with DAS28‐ESR disease activity categories. These findings provide a descriptive characterization of the IL‐17R family on peripheral B cells in RA and identify a lower frequency of IL‐17RA ⁺ B cells as the most robust between‐group difference, suggesting alterations in IL‐17R dynamics that may contribute to B‐cell dysregulation and disease pathogenesis.