CD4 and chronic periodontitis: ANN models are also used to classify patients with aggressive or chronic periodontitis based on the levels of immunologic parameters (levels of immune cells such as CD4, CD8, CD3, monocytes, eosinophils, neutrophils and lymphocytes; levels of inflammatory markers such as TNF, IL‐1/2/4, INF‐γ, antibody levels against periodontal pathogens such as A. actinomycetemcomitans and P. gingivalis.