Therefore, the present study aimed to re-evaluate the occurrence and clinical relevance of IgE autoantibodies against the most relevant antigens in patients with SLE, SS, and MCTD, namely towards SSA/Ro52, SSA/Ro60, SSB/La, U1-C RNP, RNP 68, RNP A, RNP B and dsDNA. This evidence concerns the gene TRIM21 and mixed connective tissue disease.