AMERICAN COCKROACH CR-PI ALLERGEN INDUCES LYMPHOCYTE-PROLIFERATION AND CYTOKINE PRODUCTION IN ATOPIC PATIENTS

Background Previous studies have shown cockroach-induced antigen-speci fic IgE-mediated asthma. In cockroach-infested areas, more then 50% of asthmatic subjects may have positive skin reactions to this allergen. Partial purified Cr-PI allergen from American cockroaches contains al lergens with molecular weights of 72 and 78 kDa; however, little is kn own about its effect on the lymphocyte proliferation and cytokine prod uction. Objective IgE synthesis is known to be regulated by interleuki n-4 (IL-4) and interferon gamma (IFN gamma). Therefore, we studied Cr- PI allergen-induced cytokine production in atopic patients and healthy normal controls to understand each factors' role in the disease. Meth ods Peripheral blood mononuclear cells (PBMC) from cockroach skin-sens itive patients and controls were stimulated with mitogen and Cr-PI for proliferative response and cytokine production. Cr-PI antigen-specifi c T-cell cultures of atopic patients and healthy normal controls were used to test Cr-PI-induced proliferation and cytokine mRNA expression. Results PMBC of atopic subjects showed a significantly (P < 0.01) hig her stimulation index for Cr-PI induced proliferation (SI = 11.8 +/- 3 .7) when compared with that of non-atopic subjects (SI = 4.1 +/- 0.8) and cord bloods (SI = 2.1 +/- 0.4). Cr-PI-induced IL-4 was observed on ly in the PBMC of atopic patients, whereas Cr-PI-induced IFN gamma was detected in both atopic patients and normal controls. Likewise, Cr-PI -induced IL-4 mRNA expression in T-cell cultures was detected in all a topics but only one of nine controls. Conclusion IL-4 mRNA expression and IL-4 production in PBMC and T-cell cultures of atopic patients sho wed good correlation with clinical symptoms, skin-reactivity, specific IgE and proliferative response to Cr-PI. These results suggests that cockroach allergen may be a hidden cause of asthma and other atopic di seases.