The results showed that the expression of IL-21 in Tfh cells was significantly higher in patients with RA than in HCs, but was not correlated with the DAS28-CRP, indicating the augmented capacity of circulating Tfh cells to secrete IL-21 in patients with RA and increased potency to promote B cell proliferation, differentiation, and antibody production. The gene discussed is CRP; the disease is rheumatoid arthritis.