PPIB and systemic lupus erythematosus: Among the earliest autoAbs to emerge were all of the tested SS-associated antibodies (Ro52/SS-A, Ro60/SS-A, La/SS-B, CENP-B), and a variety of lupus-associated autoantibodies targeting DNA complexes, ribonucleoproteins, and connective tissue/structural antigens, collectively including nuclear, cytoplasmic, membrane-bound, and extracellular targets.