Humoral immune response in early-onset periodontitis: influence of smoking

Sixty-five patients with generalised early-onset periodontitis (G-EOP) (age range 16-42 years, 32 smokers and 33 non-smokers) were assessed for antibody titres and avidity to a panel of five suspected periodontal pathogens (Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Prevotella intermedia, Treponema denticola and Bacteroides forsythus). Thirty-four of these patients were untreated (17 smokers and 17 non-smokers), and thirty-one were in the maintenance phase of periodontal therapy (15 smokers and 16 non-smokers). Previous studies have investigated the effect of smoking on IgG levels in periodontitis patients in the context of the more extensive periodontal destruction seen in smokers. Based on this literature our hypothesis was that smokers would have depressed serum IgG levels directed against recognised periodontal pathogens compared with non-smokers. Antibody titres were measured by ELISA deploying fixed whole cells as coating. The IgG response was detected with biotin-anti-human IgG and avidin-peroxidase; avidity was determined by elution with ammonium thiocyanate. Median titres to A. actinomycetemcomitans, P. intermedia and T. denticola were significantly lower in maintenance patient smokers (p= 0.02, 0.02 and 0.002 respectively) but not in untreated patients. Avidity to P. gingivalis was also lower in smoking maintenance patients (p = 0.003) but not in untreated patients. These findings may imply some interruption of immune maturation in smokers following periodontal treatment.