Immunopathogenic role of IgG antibody and RANTES in house dust mite-induced chronic bronchitis.

Based on immunological and clinical examinations, 21 patients were diagnosed as having house dust mite (HDM)-induced chronic bronchitis and classified into three groups according to the clinical presentation of the disease: stable bronchitis, exacerbated bronchitis and asthma on top of bronchitis. Using ELISA, the levels of serum anti-Dermatophagoides farinae and anti-D. pteronyssinus IgG antibodies and plasma RANTES (regulated upon activation, normal T-cell-expressed and secreted; a chemokine with attractive and activator role for eosinophils) were measured in correlation to serum eosinophil cationic protein (ECP, a marker of eosinophil activation and degranulation measured by chemiluminescent immunometric technique). Using immunoblotting, IgG binding components of D. farinae and D. pteronyssinus were determined providing a clue for diagnosis of HDM-induced chronic bronchitis. Significant higher levels of anti-D. farinae and anti-D. pteronyssinus IgG antibodies and RANTES were found in asthmatic group followed by exacerbated chronic bronchitis in comparison to stable bronchitis and control groups. ECP level correlated significantly with IgG and RANTES levels in exacerbated bronchitis and asthmatic groups. The results provided evidence that over expression of IgG and RANTES plays a crucial role, as mediator in immunopathogenesis of HDM-induced chronic bronchitis and as marker of the immunological changes likely responsible for progression of bronchitis to asthma in HDM-sensitive patients yet, RANTES seemed to be an early indicator. Definition of the immunopathogenic role of IgG and RANTES in HDM-induced bronchitis should enable the manipulation of the critical immune response in the hope of establishing new therapies. D. farinae and D. pteronyssinu antigenic bands at > 205 and 205 KDa, respectively, considered together showed 71.4% sensitivity in diagnosis of HDM induced chronic bronchitis and 100% specificity by immuno-blotting.