Cutaneous delayed-type hypersensitivity reactions in smokers with chronic bronchitis and recurrent exacerbations: Comparison with asymptomatic smokers and never-smokers

The aim of the present study was to investigate whether smoking patients wi th chronic bronchitis (CB) and recurrent exacerbations show signs of depres sed cell-mediated immunity (CMI), as reflected in the cutaneous delayed-typ e hypersensitivity (DTH) reaction, in comparison with asymptomatic smokers and healthy never-smokers. The study was a comparative clinical study performed at a university hospit al center of respiratory medicine. Sixteen smokers with stable CB and recur rent exacerbations, five of whom had mild airflow obstruction, 18 asymptoma tic smokers and 18 healthy never-smokers, all aged between 35 and 64 years, participated. No subjects treated with corticosteroids or N-acetylcysteine were included. Cutaneous DTH-reactions to seven recall antigens were asses sed with Multitest(R), a standardized in vivo test of clinical CMI. Reactio ns were assessed 48 h after application by measurement of skin induration. A score (sum in mm of positive reactions) was created to assess overall rea ctivity. Neither the score nor the number of positive reactions differed significant ly between the three study groups. Men had a significantly higher reactivit y than women (P<0.05) irrespective of group affiliation. No influence of sm oking status on DTH reactivity could be seen. In the CB group no correlatio n was found between DTH reactivity and number of exacerbations the past 2 y ears. Patients with chronic bronchitis and recurrent exacerbations did not differ from asymptomatic smokers or healthy never-smokers with respect to c utaneous DTH reactions. Depression of CMI, as measured in this study, does not seem to be a primary factor behind recurrent exacerbations in smokers w ith CB.