Hyporesponsiveness of peripheral blood lymphocytes to streptococcal superantigens in patients with guttate psoriasis: evidence for systemic stimulation of T cells with superantigens released from focally infecting Streptococcus pyogenes

Throat infection with Streptococcus pyogenes is the most important trigger for acute guttate psoriasis. We examined the in vitro responses of peripher al blood mononuclear cells (PBMC) to streptococcal superantigens, SPEA and SPEC, and staphylococcal superantigens, SEE and TSST-1, in patients with gu ttate psoriasis, in patients with chronic plaque psoriasis, and in healthy subjects. PBMC from patients with guttate psoriasis responded poorly to SPE A and SPEC at concentrations of 0.1 and 1 ng/ml as compared with those from patients with plaque psoriasis, but showed high responses to SEE and TSST- 1. The hyporesponsiveness recovered after improvement of the skin eruption. There was no significant difference between guttate and chronic types of p soriasis in the percentage of circulating T-cell receptor BV2 or BV8-bearin g T cells, responsive to streptococcal superantigens, indicating that T-cel l clonal anergy was a mechanism underlying the hyporesponsiveness. Our resu lts suggest that superantigens released from focally infecting S. pyogenes induce a transient activation of relevant T cells, leading to the developme nt of skin eruption and, subsequently, temporary T-cell anergy to these tox ins.