IMMUNOLOGICAL FINDINGS IN BLOOD AND BRONCHOALVEOLAR LAVAGE FLUID IN CHRONIC-BRONCHITIS PATIENTS WITH RECURRENT INFECTIOUS EXACERBATIONS

Bronchial infections are common in smokers and seem to be related to t he presence of chronic bronchitis (CB), Why only same smokers develop repeated branchial infections is not known. The aim of this study was to screen for immunological changes associated with disease in patient s with CB and recurrent infectious exacerbations compared to asymptoma tic smokers. Sixteen smokers with stable CB and recurrent infectious e xacerbations, and 18 asymptomatic smokers, all without any immunomodul ating treatment, underwent bronchoscopy and bronchoalveolar lavage (BA L), Smoking history and current smoking status were comparable, Serum levels of immunoglobulin (Ig)A, IgM, IgG and IgG subclasses were measu red, Blood and BAL lymphocyte phenotypes and proliferative responses o f peripheral blood mononuclear cells (PBMCs) to various stimulators we re analysed, Unstimulated and tetanus toxoid-stimulated production of cytokines in PBMC cultures was measured. Natural killer (NK-) cell act ivity was analysed, A significantly (p<0.05) lower level of IgG(3) was found in the CB group, and a significantly (p<0.01) higher proliferat ive response of PBMCs was found in the CB group after stimulation with diphtheria toxoid, Detectable levels of interleukin (IL)-6, tumour ne crosis factor-alpha (TNF-alpha) and interferon-gamma, but not of IL-2, IL-4 or transforming growth factor-beta(2), were found in supernatant s from cultured cells in both study groups, Stimulated TNF-alpha produ ction was significantly (p<0.05) higher in the CB group, NK-cell activ ity did not differ significantly between the study groups, There were no major differences between the groups in lymphocyte subpopulations i n blood or BAL, In conclusion, no major alterations in the analysed in dices of cell-mediated and humoral immunity were found in patients wit h chronic bronchitis prone to recurrent infectious exacerbations when compared with asymptomatic smoking controls.