Impaired autologous mixed-lymphocyte reaction of peripheral blood lymphocytes in adult periodontitis.

The autologous mixed-lymphocyte reactions (AMLR) of peripheral blood lymphocytes from 80 patients with adult periodontitis were examined. Some but not all patients showed clearly low AMLR responses; 31 of 80 subjects (39%) showing consistently low responses in AMLR (less than the mean--2 standard deviations of the healthy control group values) were designated low-AMLR patients, whereas the 42 patients (53%) who showed normal AMLR responses were designated normal-AMLR patients. However, there were no significant differences in the clinical parameters between these two groups of patients. The phenotypic analysis of T-cell fractions revealed a lower percentage of CD45RA-positive cells in CD4-positive cells (CD4+ CD45RA+ T cells) in the low-AMLR patients than those in normal-AMLR patients and healthy control subjects. No significant differences were demonstrated between the two groups in terms of the proportion of CD4-positive and CD8-positive cells in the T-cell fractions or in the expression of human leukocyte antigen DR of the monocytes and B cells in the non-T-cell fractions. In the low-AMLR patients, the allogeneic MLR was found to be normal, but the interleukin 2 production in the AMLR was found to be significantly depressed. The depressed AMLR responses and the lower percentage of CD4+ CD45RA+ T cells in the low-AMLR patients were found to be normalized following the periodontal therapy. These results might reflect changes in regulatory T-cell function induced by development of periodontal diseases.