Immunological and Microbiological Findings in Psoriatic Arthritis, Psoriasis, and Periodontitis Individuals

ABSTRACT Objectives Emerging evidence suggests a link between psoriasis (PSO), psoriatic arthritis (PSA), and periodontitis (PE), similar to other systemic conditions. This study aimed to evaluate the levels of Porphyromonas gingivalis , Treponema denticola , Tannerella forsythia , Prevotella intermedia , and Aggregatibacter actinomycetemcomitans (qPCR), as well as salivary biomarkers RANKL, OPG, Survivin, and IL‐17 (ELISA) in individuals with PSO and PSA, compared to non‐psoriatic controls with and without PE. Subjects and Methods From a case–control study ( n = 655), 192 non‐smokers and non‐diabetics were randomly selected and divided into six gender‐matched groups ( n = 32 each): control, PSO, and PSA, with and without PE. Results Higher counts of P. gingivalis , T. forsythia , and T. denticola were found in individuals with PE, particularly in PSA + PE and PSO + PE groups, along with significant intergroup differences in IL‐17 and survivin, with higher levels in PSA than PSO and controls. In PSA + PE individuals, OPG, IL‐17, and survivin were significantly increased. Positive correlations were observed between RANKL, IL‐17, survivin, and clinical periodontal parameters, with negative correlations for OPG ( p < 0.001). Conclusions Psoriatic individuals with PE show higher levels of classical red‐complex periodontopathogens and heightened inflammatory biomarker levels, especially in PSA. These findings highlight the need for integrated care between dermatologists and periodontists.