Based on this observation and on the previously reported correlations between serum levels of anti-Jo-1 antibodies and disease activity [18], we aimed to study associations between BAFF and anti-Jo-1 antibody levels in longitudinally collected serum samples and their relation to standardised clinical measures and laboratory markers of disease activity in patients with DM/PM, with a focus on early cases and the subgroup defined by the presence of ILD. The gene discussed is TNFSF13B; the disease is interstitial lung disease.