Genetic variants associated with neutrophil function in aggressive periodontitis and healthy controls.

BACKGROUND

Genetic polymorphisms that influence neutrophil function were proposed as possible risk factors for aggressive periodontitis (AgP). The aim of this study is to test whether a clinical diagnosis and specific genetic variants are associated with neutrophil activity in subjects with AgP and healthy subjects.

METHODS

This study describes the results of neutrophil analyses performed in 40 subjects (20 subjects with AgP and 20 healthy control subjects). Neutrophils were extracted from peripheral blood and analyzed in a masked manner for phagocytosis and oxidative burst by flow cytometry in response to Escherichia coli, Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans), and Porphyromonas gingivalis. Genomic DNA was extracted and genotyped for the nicotinamide adenine dinucleotide phosphate p22 phagocytic oxidase subunit (p22(phox)) cytochrome b alpha gene (CYBA) C242T, crystallizable gamma fragment (Fcgamma)IIa H/R, and FcgammaIIIb neutrophil antigen (NA)1/NA2 polymorphisms.

RESULTS

Analyses in pairs of white subjects (n = 24) revealed that patients with AgP exhibited a higher oxidative burst in response to E. coli (P = 0.002) and P. gingivalis (P = 0.002) compared to healthy control subjects. The p22(phox) CYBA 242 T allele was associated with an oxidative burst in response to the challenge by two strains of A. actinomycetemcomitans (P = 0.018 and P = 0.046). The FcgammaIIa polymorphism was associated with the phagocytic index of E. coli (P = 0.024).

CONCLUSION

This study confirms previous reports of a higher oxidative burst associated with AgP and presented preliminary evidence that genetic factors may influence neutrophil function in patients with AgP and healthy individuals.