COMPARISON BETWEEN THE IN-VITRO CYTOKINE PRODUCTION OF MONONUCLEAR-CELLS OF YOUNG ASTHMATICS WITH AND WITHOUT IMMUNOTHERAPY (IT)

Background The underlying mechanisms of immunotherapy (IT) are still u nknown but may be related to modifications of cytokine production of T lymphocytes. Objective In this study we determined the in vitro aller gen-induced production of IL-2, IL-4, IL-5, IL-12 and IFN gamma of per ipheral blood mononuclear cells (PBMC) of eight young asthmatics, aged 15 +/- 2 years, receiving IT (IT group) and of eight comparable asthm atics, aged 13 +/- 3.5 years, who never received IT (non-IT group). Me thods All patients suffered from perennial asthma and were allergic to house dust mite (HDM). They were selected if they showed a:positive s timulation index (SI) of PBMC after in vitro incubation with HDM (i.e. SI > 2). Cells were incubated with and without HDM (10 mu g/mL) durin g 24 h, 48 h and 7 days. Cytokines were determined in the supernatant at the three time points and are expressed as median values in pg/mL. Results In the IT group the secretion of IL-E was lower compared with the non-IT group after 7 days incubation of PBMC with HDM (0 vs 33.2, P = 0.008). In both groups maximal secretion of IL-2 was observed afte r 48 h. In the non-IT group a high value of IL-2 persisted after 7 day s, whereas in the IT group a significant decline of IL-2 occurred afte r 7 days. Although IL-4 secretion was low in all subjects, more patien ts of the non-IT group showed detectable IL-4 in the HDM cultures afte r 24 h and 48 h, although the difference was not statistically signifi cant (P = 0.08 and P = 0.28, respectively). Furthermore, IL-4 secretio n was lower in the HDM cultures after 24 h in the IT group (1.75 vs 4. 1, P = 0.011) and 48 h (2.2 vs 4.1, P = 0.035). IL-5 secretion was low er in the HDM cultures after 24 h (12.4 vs 47.6, P = 0.035) and 48 h ( 26.8 vs 135, P = 0.046) in the.[T group than in the non-IT group. Afte r 7 days of incubation with HDM there was no difference between the gr oups. There was no difference between both groups in secretion of IFN gamma and IL-12. Conclusions These results show a difference in vitro cytokine secretion of PBMC of asthmatics receiving IT compared with as thmatics who never received IT. PBMC of patients receiving IT secrete less IL-2 and IL-5 after in vitro incubation with HDM and show a tende ncy to secrete less IL-4. The efficacy of IT may be attributed to a mo dified cytokine secretion of PBMC.