IGE SYNTHESIS SUPPRESSOR FACTOR - MODIFICATIONS IN THE COURSE OF LONG-TERM IMMUNOTHERAPY

Many authors have described an increase in total serum IgE values duri ng the first few months of immunotherapy (IT), followed by a subsequen t decrease. In previous studies in patients undergoing medium-term IT, we detected an IgE synthesis suppressor factor (SF), which was modifi ed during the course of IT. In this study, we investigated the influen ce of long-term IT on the production of SF and the lymphocyte response to its stimulus. Mixed bidirectional cultures of lymphocytes isolated from healthy individuals (n=62) and allergic patients (n=98) were car ried out after different periods of IT. The resulting supernatants wer e subjected to affinity chromatography, from which two fractions were obtained. the first one, likely to contain SF, was added to lymphocyte cultures from 13 allergic patients undergoing no IT (LyG1) and 6 alle rgic patients with > 3 years of IT (LyG5), in order to assess its inhi bitory effect on IgE synthesis. We found that patients undergoing IT f or > 3 years presented a significant increase in SF production and an important lymphocyte response to exogenous SF from most of the groups studied, but little response to their own SF. These results could be a scribed to an alteration in the quantity and/or structure of the lymph ocyte receptors likely to be sensitive to these factors induced by IT.