Reduction of immunoglobulin G secretion in vitro following long term lymphoblastoid interferon (Wellferon) treatment in multiple sclerosis patients.

Pokeweed-mitogen-induced IgG secretion, Con A suppression and T cell surface markers were measured in 30 chronic progressive multiple sclerosis (MS) patients and 21 healthy controls. Mean IgG secretion was higher in the MS patients than in the controls (2392 +/- 270 vs 1499 +/- 243); Con A suppression was lower (4 +/- 5% vs 24 +/- 4%) and the CD4/CD8 ratio was higher (4.1 +/- 0.4 vs 2.9 +/- 0.4). The above assays were used in vitro to monitor the effects of Wellferon (lymphoblastoid interferon) injections on this group of MS patients. Before treatment the INF-group (n = 14) did not differ from the PLA-group (n = 16). After 1 week of daily injections the level of IgG secreted was dramatically reduced in the INF group (629 +/- 96 ng/ml) compared to the PLA-group (1756 +/- 319 ng/ml). There was no change in either Con A suppression or T cell surface markers. IgG secretion remained lower in the INF-group for the 6 month treatment period. Following cessation of the injections and a 6 month washout period, IgG secretion in the INF-group rose and was equivalent to that observed in the PLA-group. A series of lymphocyte subset mixing experiments implicates the B lymphocyte subset as being directly affected by interferon injections in vitro.