TRIM21 and Sjogren syndrome: Recently, Arentz et al. published that uniquely mutated V regions peptides could be used as a proxy for the detection of anti-Ro52 autoantibodies in sera from primary Sjögren’s syndrome patients by mass spectrometry.[28] Why these and other studies were able to identify similar or identical sequences could be explained by repertoire bias and the convergent evolution of antibodies during somatic mutation and selection.[19], [20] This selection favors specific alleles and sequences of antibodies with the optimal affinity towards the specific antigens during immune response [18], [29], [30].