Rietveld and colleagues determined the occurrence of anti-cN-1A reactivity in patients with primary Sjörgen’s syndrome and systemic lupus erythematosus being of moderate prevalence using the Anti-cN-1A ELISA.49 However, as patients with sIBM and those with primary Sjörgen’s syndrome and systemic lupus erythematosus are straightforward to differentiate clinically and immunologically, this co-occurrence is of minor relevance for clinical practice.50,51. This evidence concerns the gene NT5C1A and systemic lupus erythematosus.