Th9, Th22 and C-reactive Protein are Detected in Periodontitis Patients

Objectives: Periodontitis are infectious diseases caused by the anaerobic gram-negative bacteria residing in the subgingival biofilm. These bacteria can cause direct destruction of periodontal tissues; however, their pathogenicity is mainly based on the activation of the immune response, in particular activation of T helper (Th) lymphocyte-associated responses. Recently, two new phenotypes of Th lymphocytes have been described, Th9 and Th22; however, their role in the pathogenesis of periodontitis have not yet been described. Th9 and Th22 lymphocytes could be associated with a pro-inflammatory response during periodontitis and, eventually, induce the expression of acute phase inflammation factors, such as C-reactive protein (CRP) and interleukin (IL)-6. This study was aimed to analyze whether the Th9 and Th22 lymphocytes play a role in the pathogenesis of the periodontitis.
Methods: Gingival biopsies were taken from healthy subjects (n=5), gingivitis (n=3) and moderate/severe chronic periodontitis (n=5) patients. The expression levels of the cytokines IL-6, IL-9, IL-22, and CRP and the transcription factors Spi.B and AhR, master-switch genes associated with the Th9 and Th22 lymphocyte differentiation and activation, respectively, were quantified by real-time RT-PCR.
Results: Higher levels of IL-6, IL-22, CRP, and AhR mRNAs were expressed in periodontal tissues from periodontitis patients compared with either healthy or gingivitis subjects. Higher levels of IL-9 mRNAs were expressed in periodontitis patients compared with healthy subjects. The mRNA levels of IL-9 and Spi.B mRNAs were similar between periodontitis and gingivitis patients
Conclusions: CRP and IL-6 have a potential pro-inflammatory role during the pathogenesis of the periodontitis and could be associated with systemic inflammatory responses. The Th9 and Th22 lymphocytes may participate in the pathogenic events described in periodontitis; however, additional studies are necessary to determine if they induce pro-inflammatory and/or bone-resorptive activities.
Supported by grant FONDECYT 1140904.