Genetic Polymorphism of IL-1A, IL-1B and TNFA Predicting the Presence of Periodontopathogenic Bacteria

Background/Objectives: Periodontitis is a chronic inflammatory disease characterized by complex interactions between periodontal pathogens and the host immune response. Pro-inflammatory cytokines, particularly interleukins, may influence bacterial colonization and disease expression, but their association with specific periodontal pathogens remains unclear. This study investigated the associations between single-nucleotide polymorphisms in IL-1A, IL-1B, and TNFA and the presence of key periodontopathogenic bacteria in patients from Croatia. Methods: A cross-sectional study included 63 participants. Genotypes were determined, and subgingival plaque samples were analyzed for Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, and Treponema denticola using real-time PCR. Multivariable logistic regression models assessed associations between cytokine gene polymorphisms and periodontopathogenic bacteria presence, adjusting for age, gender, smoking status, and the presence of systemic diseases. Results: Among participants (median age 57.0 years, IQR 43.5–67.0; 58.7% female), P. intermedia (87.3%), T. forsythia (85.7%), and T. denticola (69.8%) were the most prevalent pathogens. The IL-1A CC genotype significantly increased the odds of P. gingivalis (OR = 5.54; p = 0.009) and T. denticola (OR = 3.77; p = 0.041) presence. The IL-1B CC genotype was independently associated with T. forsythia (OR = 8.48; p = 0.026). No significant associations were observed for TNFA polymorphism. Model performance ranged from moderate to good (AUC up to 0.89). Conclusions: Genetic variants in IL-1A and IL-1B may influence periodontal bacterial colonization, while demographic and lifestyle factors showed limited impact. Further studies in larger cohorts are warranted.