Effects of tobacco smoking on salivary immunoglobulin levels in immunodeficiency

Salivary immunoglobulins and albumin were analysed in smoking and non-smoking immunocompetent and immunodeficient individuals. Stimulated and unstimulated saliva were compared as between individuals with selective immunoglobulin A deficiency (IgAd), common variable immunodeficiency (CVI) and immunocompetent individuals. Immunocompetent smokers showed increased levels of sIgA in unstimulated saliva, when compared with non-smoking immunocompetent individuals. In stimulated saliva, the immunocompetent smokers showed decreased levels of IgG and IgM. IgAd smokers showed decreased levels of albumin in unstimulated saliva, when compared with non-smoking IgAd individuals. The non-smoking individuals with IgAd showed increased levels of IgM in both unstimulated and stimulated saliva, when compared with immunocompetent smokers. The non-smoking CVI individuals showed decreased levels of IgG, IgA and IgM in unstimulated and stimulated saliva, as expected, when compared with the same group of immunocompetent individuals. The decreased levels of albumin in unstimulated saliva in IgAd smokers and comparable to that of the IgG non-smoking IgAd individuals support the observation of locally produced immunoglobulins that protect the oral mucosa. Instead of sIgA, non-smoking immunodeficient individuals with IgAd compensate with increased IgM levels in stimulated saliva. The increased levels of sIgA in unstimulated saliva in immunocompetent smokers may be a reflection of the protection of the oral mucosa.