The relationship of defective cell-mediated immunity to visceral disease in systemic sclerosis

Phytohaemagglutinin-induced lymphocyte transformation and circulating thymus-dependent (T) lymphocyte numbers were studied in twenty-eight patients with systemic sclerosis (SS), in fifty normal controls and eleven elderly controls. Patients with SS were found to have impaired lymphocyte transformation responses which showed a positive correlation with both the number of circulating T lymphocytes and the extent of visceral involvement by the disease. This defect of cell-mediated immunity could not be attributed to the effects of increasing age, corticosteroid treatment, iron and folate deficiency or inhibitory serum factors and may have pathogenetic implications for the disorder.