Overlapping cases with psoriasis and Sjögren syndrome: a study of lymphocyte response to staphylococcal enterotoxin B

Sjgren syndrome (SjS) is an auto-immune disease and immunological mechanisms have recently been suggested in the pathogenesis of psoriasis; however, co-existence of these diseases is relatively rare. To determine whether or not there exist the nature of common underlying abnormalities, five patients with psoriasis and SjS were studied. Two patients had psoriasis vulgaris (PV), two had psoriasis arthropathica (PA), and the other had generalized pustular psoriasis (GPP). Lymphocyte response against staphylococcal enterotoxin B was examined by 3H-thymidine incorporation. In one patient with GPP, T-cell receptor (TCR) V beta repertoire of infiltrating T-cells into the lesional skin was examined by reverse transcriptase-polymerase chain reaction (RT-PCR). Stimulation index (S.I.) level of patients with psoriasis and SjS did not show any significant increases compared with patients with psoriasis or SjS alone; however, one patient with PV and SjS, who showed several serological immune imbalances, demonstrated a significant increase of S.I. level. Analysis of TCR V beta repertoire of the lesion of GPP showed strong expression of V beta 14 and 16 with mild expression of V 13-2 and 19, which may suggest that TCR V beta repertoire became oligoclonal in case of complication of these two disorders. In conclusion, our data did not suggest any common immunological responses to staphylococcal enterotoxin in induction of both psoriasis and SjS.