Variations in serum levels of interleukin (IL)-1 beta, IL-2, IL-6, and tumor necrosis factor-alpha during specific immunotherapy

Background: Cytokine production by T helper cells is essential for the indu ction and maintenance of allergic inflammation in the bronchial mucosa. Acc ording to recent views, specific immunotherapy (SIT) favors the differentia tion of T lymphocytes into cells of the Th1 rather than those of the Th2 su bset. Objective: To determine whether or not SIT induces a decrease in the inflam matory reaction by studying eventual variations in the serum levels of IL-1 beta, IL-2, IL-6, and TNF-alpha in allergic subjects during SIT. Methods: Serum levels of IL-1 beta, IL-2, IL-6, and TNF-alpha were determin ed before and after 3, 6, and 9 months of SIT by an immunoradiometric assay (IRMA) in 11 adults with perennial allergic asthma and/or rhinitis caused by house dust mites and in 6 nonatopic healthy volunteers. Results: Median serum IL-1 beta and TNF-alpha levels of the patients were s ignificantly higher at baseline than those of the controls and decreased du ring SIT to values similar to or lower (P < .01) after 6 months of SIT for TNF-<alpha> than those of the controls. Median serum IL-2, significantly lo wer at baseline than in the controls, increased during SIT to a level simil ar to that of the controls. Although the median values of IL-1 beta and TNF -alpha in the patients tended to decrease and those of IL-2 to increase dur ing SIT, the differences were not significant; the correlation coefficients (r) of the serum levels of IL-1 beta, IL-6, and TNF-alpha versus duration of SIT were negative, while that of IL-2 was positive. Conclusions: Decreases in median serum IL-1 beta and TNF-alpha levels durin g SIT, together with the increases in serum IL-2 and IL-6, compared with th ose of the controls furnish evidence supporting a reduction in the inflamma tory response in the course of SIT.