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Relationship between IL 2 synthesis and the proliferative response to PHA in different primary immunodeficiencies

Abstract:

In PBM obtained from 24 immunodeficient patients (two severe combined immunodeficiencies, three cases of Wiskott-Aldrich syndrome, two immunodeficiencies with hyper IgM, three cases of X-linked agammaglobulinemia, and 14 common variable immunodeficiencies) and from 19 age-matched controls, we have studied 1) the proliferative response to optimal and suboptimal doses of PHA after 'in vitro' supplementation of the cultures with mitogen-free supernatants containing Il 2 (IL 2 Sup), and 2) the production of IL 2 in response to an optimal dose of PHA. Addition of IL 2 Sup to cultures of normal PBM stimulated with 1% or 0.05% PHA did not cause significant augmentation of proliferative response, and only at a very low PHA dose (0.02%) did the addition of IL 2 Sup induce an increment of the DNA synthesis. On the other hand, addition of IL 2 Sup to lymphocytes from immunodeficient patients stimulated with the suboptimal dose of PHA (0.05%) caused an enhancement of the DNA synthesis, which in most cases never reached the levels observed in normal individuals, and was more manifest in those patients who showed a PHA response below the normal level. The production of IL 2 was significantly lower (p < 0.01) in the immunodeficient patients with a reduced proliferative response to PHA, and was in the normal range (p < 0.03) in immunodeficient patients with a normal or borderline PHA response. When all the data from controls and patients were pooled for regression analysis, a significant correlation was found between DNA synthesis and IL 2 production (r = +0.64, p < 0.01), between the DNA synthesis and its enhancement after IL 2 Sup addition (r = -0.48, p < 0.01), and between IL 2 production and the enhancement of DNA synthesis after IL 2 Sup addition (r = -0.48, p < 0.01). The main conclusion is that the hyporesponse to PHA, in our group of immunodeficient patients, is associated with, but not exclusively due to, a defect in the production of IL 2.