Lymphocyte subpopulations and reactivity to mitogens in patients with scleroderma.

T lymphocyte subpopulations were studied in 40 patients with scleroderma (PSS), 26 of whom were studied simultaneously for lymphoproliferative responses to phytohaemagglutinin (PHA), concanavalin A (Con A) and pokeweed mitogen (PWM). PSS patients exhibited a reduction relative to 42 age- and sex-matched controls in the absolute number and percentage of early E rosettes, late E rosettes and E rosettes formed with aminoethylisothiouronium bromide (AET) treated sheep red blood cells. There was no difference between patients and controls in the proportions of B lymphocytes. PSS patients exhibited normal lymphocyte transformation responses to PHA and ConA and an augmented response to PWM. The mitogen responses did not correlate with the absolute number or percentage of lymphocytes or T and B lymphocyte subpopulations. No correlation was observed between any immunological variable studied and the extent of skin or organ involvement, disease duration or therapy.