Immunological findings in blood and bronchoalveolar lavage fluid in chronic bronchitis patients with recurrent infectious exacerbations

Abstract

Tobacco smoking induces profound immunological and inflammatory changes, both in the airways and systemically. Smoking impairs host defences and increases susceptibility to infection [1,2].The literature on the effects of smoking on the immune system is extensive and has been reviewed by several authors [2][3][4]. Evidence of a considerable influence on both humoral and cell-mediated immunity has been presented. Decreased serum immunoglobulin (Ig) levels, mainly IgG, have been reported in smokers [5,6]. Data concerning immediate skin reactivity to common allergens [7,8] as well as specific antibody responses to inhaled antigens [9] and vaccinations [10], indicate depressed immune responses in smokers. There are several reports of decreased activity of natural killer (NK-) cells, both from peripheral blood [11,12] and the lung [13]. Results from functional studies of circulating T-lymphocytes are conflicting, with reports of increased [14], unchanged [15] and decreased [16,17] responses to mitogenic stimulation in vitro. Alterations in immunoregulatory T-lymphocyte subsets with a decreased fraction of helper/inducer and an increased fraction of cytotoxic/suppressor cells have been reported, both locally in the lung [18], and in the peripheral circulation [19,20].Bronchial infections are common in smokers [2], but why only some smokers develop problems with repeated bronchial infections is largely unknown. Hypothetically, smokers prone to bronchial infections might differ immunologically from smokers without this disposition. To our knowledge, there are no studies addressing this issue in which smoking habits of study and control groups have been taken fully into account.Since the disposition for bronchial infections in smokers seems to be related to the presence of chronic bronchitis (CB) [21], a state of chronic mucus hypersecretion [22], and appear in the form of recurrent infectious exacerbations, patients with CB prone to infectious exacerbations were chosen for the study group. We decided to analyse most of the immunological parameters known or thought A significantly (p<0.05) lower level of IgG 3 was found in the CB group, and a significantly (p<0.01) higher proliferative response of PBMCs was found in the CB group after stimulation with diphtheria toxoid. Detectable levels of interleukin (IL)-6, tumour necrosis factor-α (TNF-α) and interferon-γ, but not of IL-2, IL-4 or transforming growth factor-β2, were found in supernatants from cultured cells in both study groups. Stimulated TNF-α production was significantly (p<0.05) higher in the CB group. NK-cell activity did not differ significantly between the study groups. There were no major differences between the groups in lymphocyte subpopulations in blood or BAL.In conclusion, no major alterations in the analysed indices of cell-mediated and humoral immunity were found in patients with chronic bronchitis prone to recurrent infectious exacerbations when compared with asymptomatic smoking controls. Eur Respir J 1998; 11: 46-54.

IgG subclasses in smokers with chronic bronchitis and recurrent exacerbations

“…In previous studies of smokers with CB we have found significantly lower levels of IgG1 and IgG2 than in healthy never smokers 8. However, when asymptomatic smokers and smokers with CB and recurrent exacerbations were compared in a later study, the only difference between the groups was a slightly lower level of IgG3 in the patient group 9. No other studies addressing this issue with a relevant control group have been undertaken.…”

“…In most of these studies smoking habits were either not considered16 or the composition of the study and control groups made an analysis of changes not related to smoking and sex difficult 817 We previously analysed IgG subclass concentrations in smokers with and without CB and found a possible connection between low levels of IgG3 and recurrent exacerbations 9. This was not confirmed in the present larger study where no significant differences of possible clinical relevance between asymptomatic smokers and smokers with CB and recurrent exacerbations were found.…”

Increased levels of interleukin-16 in the airways of tobacco smokers: relationship with peripheral blood T lymphocytes

“…There were 34 tobacco smokers, all of whom had been smokers for more than 10 years, consuming at least 10 cigarettes per day. We recently presented characteristics other than IL-16 for the group of tobacco smokers 24. Among the tobacco smokers, 18 subjects were clinically asymptomatic smokers who did not have chronic bronchitis and 16 were smokers with symptoms of chronic bronchitis as defined by the American Thoracic Society 25.…”

The tuberculin skin test in relation to immunologicalin vitroreactions in BCG-vaccinated healthcare workers

“…The assay was performed simultaneously for the subjects in each matched pair, using a modification of a previously published technique [22]. For stimulation with mycobacterial antigens, 1610 6 cells were added to the microtitre plates.…”

“…IFN-c concentration was measured in supernatants from cells stimulated with the previously mentioned mycobacterial antigens and Con A, as well as in supernatants from unstimulated cells, using a sandwich enzyme-linked immunosorbent assay (ELISA) technique as described by QUARFORDT et al [22]. The maximum values given were w10,000 units?mL -1 .…”