Imbalance of Th17, Treg, and helper innate lymphoid cell in the peripheral blood of patients with rheumatoid arthritis

INTRODUCTION: Rheumatoid arthritis (RA) is a chronic inflammatory disease involving a variety of immune cells, including adaptive T and B cells and innate lymphoid cells (ILCs). Understanding the pathogenic role of these immune cells in RA provides new insights into the intervention and treatment of RA. METHODS: A total of 86 patients with RA (RA group) and 50 healthy controls (HC) were included in the study. The immune cells of CD4(+), CD19(+) B, NK, Th17, Treg, ILCs, and their subsets (i.e., ILC1s, ILC2s, and ILC3s) were characterized in peripheral blood mononuclear cells by flow cytometry. Cytokines (i.e., IFN-γ, IL-4, IL-10, IL-17A, IL-22, and IL-33) in sera were detected using ELISA. The above immune cells and cytokines were analyzed in patients with different disease activity status and positive ( +) or negative ( −) rheumatoid factor (RF)/anti-citrullinated protein antibodies (ACPA). RESULTS: Patients with RA had higher percentages of CD4(+) T, CD19(+) B, Th17, ILC2s, and ILC3s and lower percentages of Treg and ILC1s than HC. Patients with RA had elevated levels of IFN-γ, IL-4, IL-17A, and IL-22 and decreased level of IL-10. Compared with HC, patients with high disease activity had higher percentages of Th17, ILC2s, and ILC3s; lower percentages of ILC1s; and lower level of IL-10. The percentage of Treg cells in remission, low, moderate, and high disease activities decreased, whereas the level of IL-17A increased compared with HC. Furthermore, RF(+) or ACPA(+) patients exhibited elevated percentages of CD19(+) B, ILC2s, and ILC3s and had decreased percentage of ILC1s and Treg cells than HC. The percentage of Th17 cells increased in RF(−)/ACPA(−) and RF(+)/ACPA(+) patients. However, the above immune cells between RF or ACPA positive and negative patients were not significantly different. CONCLUSION: Th17, Treg, and ILC subset dysregulations are present in patients with RA but may not be associated with conventionally defined seropositive RF and ACPA. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10067-022-06315-8.