Tartrate‐Resistant Acid Phosphatase Deficiency in the Predisposition to Systemic Lupus Erythematosus

Our findings indicate that TRAP and OPN colocalize and that OPN is a substrate for TRAP in human immune cells. TRAP deficiency in PDCs leads to increased IFNα production, providing at least a partial explanation for how ACP5 mutations cause lupus in the context of spondyloenchondrodysplasia. Detection of ACP5 missense variants in a lupus cohort suggests that impaired TRAP functioning may increase susceptibility to sporadic lupus.