Analysis of immune indices in patients with rheumatoid arthritis and variations among TCM syndromes

Objective: Inflammatory response and autoimmune abnormalities play an important role in the etiology and development of rheumatoid arthritis (RA). This study sought to explore changes in immune indices among patients with RA and healthy people, and to elucidate variations among immune indices of different traditional Chinese medicine (TCM) syndromes of RA, focusing on the differences of autoimmunity and inflammatory response indicators in RA patients with damp-heat obstruction syndrome (DHOS) and cold-heat complex syndrome (CHCS). Methods: According to the diagnostic criteria of TCM syndrome differentiation, 68 patients with RA were identified, including 19 patients with DHOS and 49 patients with CHCS; these and 20 healthy individuals were included in the study. Biomarkers related to clinical immunity and autoimmunity, including myeloid-derived suppressor cells (MDSCs) and each phenotypes, Th17 and regulatory T (Treg) cells, and inflammatory cytokines were examined in the peripheral blood of all subjects. Results: Autoimmune indicators such as MDSCs, polymorphonuclear MDSCs (PMN-MDSCs), monocytic MDSCs (MO-MDSCs), Th17 cells, and serum pro-/anti-inflammatory factors were also significantly increased in RA patients relative to healthy controls (P < 0.01), but the proportion of Treg cells was decreased (P < 0.05). The proportion of MO-MDSCs in the peripheral blood of RA patients was positively correlated with the results of ESR, CRP, and complement 3, and negatively correlated with the proportion of Treg cells (P < 0.05). Furthermore, the proportion of MDSCs and PMN-MDSCs were positively correlated with interleukin-6 content and negatively correlated with Treg cell count (P < 0.05). Separately, ESR, CRP, and MO-MDSCs findings in CHCS RA patients were lower relative to those in DHOS-RA patients (P < 0.01). Conclusion: Clinical immune and autoimmune indices of RA patients were significantly abnormal relative to those of healthy people. DHOS-RA and CHCS-RA exerted different immunological profiles. It is uncertain whether ESR, CRP and MO-MDSCs can be used as important biomarkers to distinguish DHOS-RA and CHCS-RA, and further research is needed.