In order to identify the possible factors influencing salivary SIgA and lysozyme, we performed a covariance analysis based on age, gender, active periodontal disease, volume of unstimulated saliva, neutropenia, corticoid therapy, regular chemotherapy, use of drugs with epithelial cells toxicity, antibacterial drug use, antifungal drug use, invasive treatment, and drug mouthwash in this study (Table 5). This evidence concerns the gene LYZ and periodontal disorder.