ENTPD1 and periodontitis: In terms of Absolute Count, having chronic periodontitis led to a decrease in CD39 + activated CD4 regulatory T cell Absolute Count (Beta = -0.12 [-0.10, -0.13], P = 0.03) and CD39 + secreting CD4 regulatory T cell Absolute Count (Beta = -0.13 [-0.12, -0.14], P = 0.02).