Fig. 1

Characteristics of pathological from anti-SRP IMNM overlap SS (a, c, e, g, i, k, m) and anti-SRP IMNM patients (b, d, f, h, j, l, n). Inflammatory cell infiltrates to the endomysium (E), necrotic(N), perimysial (PM), perivascular (PV) areas. a, b Representative images of H&E stainings revealed remarkable myofibers necrosis and regenerative in both groups. c, d, e, f Representative images of CD4 + and CD68 + of both groups. o, p The numbers of anti-SRP IMNM overlap SS patients were significantly increased in the presence of CD4 + cells in both necrotic(p = 0.023) and endomysial areas (p = 0.013), as well as in the presence of CD68 + cells (p = 0.016) infiltrated the endomysial area. g, h, s Representative images of sarcolemmal MAC deposition on both groups. Deposition was more commonly seen in anti-SRP IMNM overlap SS patients (p = 0.013). i-n Representative images of CD8 + , CD20 + cells and MHC class I upregulation. q, r, t No significant differences were found between two groups. a-b scale bar is 250um, (c-n) scale bar is 100um. Data are given as mean with SE. * P < 0.05. HPF, high-power fields