Objectives: To test whether neutrophil numbers are directly correlated with interleukin-1alpha (IL-1alpha) concentrations in gingival crevicular fluid (GCF) of patients with periodontitis, and to investigate the effects of smoking on these parameters.
Materials and methods: A total of 99 GCF samples from 33 patients (14 smokers) suffering from severe chronic periodontitis were collected using Durapore filter strips. Polymorphonuclear leucocyte (PMN) numbers were counted using a Coulter cell counter and IL-1alpha levels were determined by ELISA. Total GCF protein was measured by Bio-Rad assay as a surrogate measure of GCF volume.
Results: Mean IL-1alpha concentrations were significantly reduced in smokers compared with non-smokers (non-smokers: 3.29+/-2.02 pg/microg protein, smokers 1.59+/-1.13 pg/microg protein). There was no association between PMN numbers and IL-1alpha concentrations found when analysed either by site or by patient. PMN numbers were not significantly different between the two groups (non-smokers: 1.16 x 10(6)+/-1.04 x 10(6); smokers: 7.30 x 10(5)+/-8.07 x 10(5)). Smoking did not affect mean total protein concentration of samples.
Conclusions: Smoking significantly decreased IL-1alpha concentrations in GCF without affecting GCF volume sampled. The lack of association between IL-1alpha concentration and neutrophil numbers suggests that the reduced IL-1alpha concentrations seen in smokers is independent of any possible effect of smoking on neutrophil chemotaxis, and further suggests that smoking may directly inhibit IL-1alpha production.