The predominant cellular population from the connective and epithelial tissues of gingiva is represented by polymorphonuclear cells (PMN). In the periodontal disease, this type of cells present in the crevicular fluid are functionally different from those of peripheral blood, having a reduced capacity of phagocytosis, a decreased activity of diacylglycerol kinases and an almost inexistent response to LXA4. A s a m arker of PMN presence in t he crevicular fluid, there are high levels of β-glucuronidases and alkaline phosphatases. In general, there is a reduction of CD4+ lymphocytes and an increase of CD8+ lymphocytes during periodontal disorders. Several studies have shown that there are more abundant Th2 cells than Th1 cells in different alterations of the periodontal tissues, the expression profile of cytokines in the gingival tissues with periodontal disease being type Tc2-like. There are hypothesis according to which, in the periodontal disease, the macrophages can have a deficiency of STAT6 with subsequent generation of excessive nitric oxide and a higher ability to induce CD4+ T cells.