CXCL13 and inclusion body myositis: In IBM compared to non-myopathic controls, there was significant overexpression of BAFF (mean 0.028 ± 0.037, P=0.0004), APRIL (mean 0.0021 ± 0.0019, P=0.001), CXCL-12 (mean 0.039 ± 0.06, P=0.003), and CXCL-13 (mean 0.00046 ± 0.00024, P=0.04) (Figure 1).