Concanavalin A induces suppressor cell activity in both T gamma and T non-gamma cells: most of the suppressor cells do not carry HLA-DR antigens

Soluble interleukin-2 receptor levels in infants with bronchopulmonary dysplasia

Soluble interleukin-2 receptors (sIL2R) in plasma have been identified as a marker of lymphocyte activation. Lymphocyte activation as a manifestation of inflammation may be important in the pathogenesis of bronchopulmonary dysplasia (BPD). To test the hypothesis that infants with BPD have higher sIL2R levels, 12 infants with or at risk of developing BPD (GA +/- SD, 27 +/- 5 weeks; BW +/- SD 1,053 +/- 733 g) had plasma sIL2R levels determined and were compared to 20 infants being ventilated for respiratory distress syndrome (RDS) (GA +/- SD, 28 +/- 3.5 weeks; BW +/- SD, 1,133 +/- 390 g: P = NS for both GA and BW, t test). Tracheal aspirates in both groups were also analyzed for sIL2R levels. To control for the effects of postnatal age (PNA) and study weight (SW) on the sIL2R levels, another group of 16 nonventilated babies (NVB) had plasma analyzed for sIL2R (PNA +/- SD: 39 +/- 40 days NVB vs. 48 +/- 36 days BPD; P = NS); (SW +/- SD: 1391 +/- 250 g NVB vs. 1212 +/- 700 g BPD; P = NS). The following data were obtained for the plasma sIL2R levels (mean +/- SEM U/mL): RDS controls, 1,231 +/- 80; BPD infants, 1,790 +/- 120; NVB controls, 1,319 +/- 76; P = 0.0005 RDS vs. BPD and P = 0.002 BPD vs. NVB. There was no significant difference in the sIL2R levels for the infants at risk of developing BPD vs. the infants with established BPD. Also, when analyzed separately, infants at risk of BPD and the infants with established BPD had higher sIL2R levels than the RDS and NVB controls. No differences were noted in the tracheal sIL2R levels in the BPD vs. RDS groups. These data indicate that infants with BPD had significantly higher sIL2R levels in plasma than either RDS or NVB controls. Therefore, lymphocyte activation may play a role in the pathogenesis of BPD.

Suppressor and cytolytic cell function in multiple sclerosis. Effects of cyclosporine A and interleukin 2

Patients with progressive multiple sclerosis (MS) demonstrated persistent reductions in levels of concanavalin A (Con A)-induced suppressor activity and heightened levels of in vitro pokeweed mitogen (PWM)-induced IgG secretion. The reduced Con A suppressor activity could not be reversed by addition of interleukin 2 (IL-2). Cyclosporine A (CsA) treatment did not alter the defect in Con A-induced suppressor activity, but did markedly inhibit T8+ cell-mediated alloantigen directed cytolytic activity; this latter defect was reversible by in vitro addition of IL-2. CsA-treated patients did not differ from placebo-treated patients with regard to levels of PWM-induced IgG secretion or proliferative responses of their mononuclear cells to Con A. The results indicate that CsA treatment of MS patients reduces cytolytic function from baseline normal values, but does not alter aberrant suppressor cell function.