Abstract Antineutrophil cytoplasmic antibodies (ANCA)‐associated vasculitis (AAV) is an autoimmune disease characterized by B cells‐derived ANCAs, and ANCA was proved to be a key factor in its pathogenesis. Follicular regulatory T (Tfr) follicular helper (Tfh) cells were T‐cell subsets that play important roles B‐cell maturation antibody production. However, their significances microscopic poly...