Suppressor cell function is preserved in pemphigus and pemphigoid

Abstract

Human peripheral blood lymphocytes (PBL) are activated to become suppressor T cells (S-T-C) by incubation with Concanavalin-A (Con-A). This has become the standard method for evaluation of suppressor function in patients. S-T-C function has been found to be impaired in several autoimmune diseases, including systemic lupus erythematosus (SLE). Using this assay, we have investigated suppressor-cell function in 2 autoimmune disorders, bullous pemphigoid (BP) and pemphigus vulgaris (PV), studying 6 patients from each group. Three patients with active SLE (positive controls), and 11 normal donors (negative controls) were also included. None of these patients had received systemic therapy with the exception of 2 patients with PV who were treated with gold in the past. PBL from these patients were incubated with and without 40 μg/ml Con-A for 72 hr to generate suppressor cells. Both groups of PBL were then irradiated with 1500 r cobalt. Co-cultures were set up in sex tuplicate using normal PBL as responders. Responder PBL were stimulated with 0.5, 1.0, and 2.0 μg/ml of phytohemagglutin (PHA) and 5.0, 10.0, and 20.0 μg/ml of Con-A. Cultures were pulsed on day 3 with 3H-thymidine and harvested on day 4. Data were analyzed using Student's t-test. S-T-C function was found to be significantly impaired in SLE vs normal (p = 0.0316). No statistically significant difference was seen in BP (p = 0.5883) and PV (p = 0.0921) as compared with normals. A defect in suppressor cell function may still be present in patients with PV and BP for the defect may be antigen-specific and therefore remain undetected by the Con-A suppressor assay.