## 3 Results
### Levels of IL-23/IL-17A Axis and Receptors in the Gingival Tissue  
In this study, we found an increase in IL-23 in the gingival tissue of patients with periodontitis compared with HS (Figure 2a). On the other hand, IL-23R levels in the gingival tissue were found to be higher in healthy subjects compared with patients with periodontitis (Figure 2b).  
Figure 1: IL-23, IL-17A, sIL-23R, and sIL-17 RA levels in plasma. plasma levels of IL-23 (**a**), sIL-23R (**b**), IL-17A (**c**), and sIL-17 RA (**d**) from healthy subjects (HS) and periodontitis patients (P) were detected by ELISA and are expressed as pg/mL. The results are shown as median and interquartile ranges. * A \(p\)-value \(\leq\) 0.05 was considered significant.  
Figure 2: Levels of IL-23, IL-17A, IL-23R, and IL-17 RA in gingival tissue. gingival tissue levels of IL-23 (**a**), IL-23R (**b**), IL-17A (**c**), and IL-17 RA (**d**) from healthy subjects (HS) and periodontitis patients (P) which were detected by ELISA and are expressed as pg for each mg of gingival tissue. The results are shown as median and interquartile ranges. * A \(p\)-value \(\leq\) 0.05 was considered significant.  
Regarding IL-17A in gingival tissue, it was found to be elevated in patients with periodontitis compared with HS (Figure 2c). Similarly, IL-17 RA in gingival tissue was found elevated in periodontitis patients compared with HS (Figure 2d).  
Correlation between IL-23, IL-17A, IL-23R, and IL-17 RA with Clinical Parameters in Plasma and Gingiyal Tissue  
A Spearman correlation test was implemented in IL-23, IL-17A, IL-23R, and IL-17 RA levels between plasma and gingival tissue and the clinical parameters. Only a positive correlation was observed in plasma molecules: IL-17 RA vs. IL-23R r = 0.381 \(p\) = 0.003. Regarding the clinical characteristics, two positive correlations were found between IL-17 RA vs. RBL % r = 0.575 \(p\) = 0.010 and PS vs. CAL r = 0.855 \(p\) = 0.000.  
Regarding the gingival tissue, several positive correlations were observed: IL-17A-GT vs. IL-23-GT r = 0.592 \(p\) = 0.000; IL-23-GT vs. IL-17 RA-GT r = 0.683 \(p\) = 0.000; IL-17A-GT vs. IL-17 RA-GT r = 0.448 \(p\) = 0.013. As well as negative correlation: IL-23-GT vs. IL-23R-GT r = \(-\)0.329 \(p\) = 0.033. In the same way, correlations were found with the specific clinical parameters of the gingival tissue obtaining areas: IL-23R-GT vs. PS-GT r = \(-\)0.514 \(p\) = 0.000; IL-23R-GT vs. CAL-GT r = \(-\)0.508 \(p\) = 0.000; IL-17A-GT vs. PS-GT r = 0.462 \(p\) = 0.030; IL-17A-GT vs. CAL-GT r = 0.469 \(p\) = 0.037; IL-17 RA-GT vs. CAL-GT r = 0.371 \(p\) = 0.024, and PS-GT vs. CAL-GT r = 0.877 \(p\) = 0.000.  
Finally, we made a correlation of the IL-23/IL-17 axes molecules between plasma and GT as well as with the clinical characteristics obtained. We found both positive and negative correlations: IL-17A vs. IL-17A-GT r = \(-\)0.592 \(p\) = 0.001; IL-23R-GT vs. PS r vs. = \(-\)0.477 \(p\) = 0.000; IL-23R-GT vs. CAL r = \(-\)0.480 \(p\) = 0.001; IL-17 RA-GT vs. CAL r = 0.320 \(p\) = 0.047; PS vs. PS-GT r = 0.895 \(p\) = 0.000; PS CAL-GT r = 0.808 \(p\) = 0.000; CAL vs. PS-GT r = 0.821 \(p\) = 0.000; CAL vs. CAL-TG r = 0.944 \(p\) = 0.000; BoP % vs. PS-GT r = 0.501 \(p\) = 0.004, and BoP % vs. BoP %-GT r = 0.891 \(p\) = 0.000 (Figure 3).  
Figure 3: Correlation between the IL-23/IL-17A axis molecules and IL-23R IL-17 RA receptors with clinical parameters in plasma and gingival tissue were analyzed using the Spearman correlation test. PD: probing depth, CAL: clinical attachment loss, BoP%: bleeding on probing percentage, RBL%: percentage of radiographic bone loss in plasma and (GT): gingival tissue values. * \(p\)\(\leq\) 0.05, **\(p\)\(\leq\) 0.01.