B cell hyperactivity in patients with pSS is revealed by a number of biological signs, such as increased levels of serum free light chains and the presence of anti-Sjögren-syndrome-related antigen A (SSA; also known as Ro) antibodies, anti-Sjögren-syndrome- related antigen B (SSB; also known as La) antibodies, and rheumatoid factor (RF). This evidence concerns the gene SSB and peeling skin syndrome.