Natural immunity in recurrent aphthous ulceration.

In the present study we investigated immunophenotypes of peripheral blood lymphocytes, natural killer (NK) cell activity as well as spontaneous migration, ingestion, digestion and antibody-dependent cell-mediated cytotoxicity (ADCC) as effector functions of polymorphonuclear neutrophil granulocytes (PMNs) in 51 patients with acute stage recurrent aphthous ulceration (RAU), during remission, and 47 age-matched healthy individuals. Statistically significant lower B-lymphocyte (CD19) values were found between patients with acute RAU, and those during the remission period (P<0.001), when compared with those of the controls. Total T-lymphocyte (CD3) percentages were lower in patients with RAU, and also during the remission period, when compared with the controls (P<0.001). The percentages of CD4 lymphocytes were significantly lower in patients with RAU in comparison with those of the controls (P<0.001). T-suppressor cells (CD8) were unchanged in all three groups of participants. Significantly lower spontaneous migration and ingestion values were found in patients with acute RAU, when compared with those of the controls, and during the remission period (P<0.001). Digestion values differed insignificantly between the patients with acute RAU and during the remission period. During the remission period, digestion values were significantly elevated when compared with those of the controls (P<0.05). ADCC values were lower during the remission period (P<0.001), when compared with the values during acute RAU and with those of the controls. Significantly depressed NK activity (P<0.001) was observed in patients with acute RAU, when compared with that of the controls. During the remission period, values of NK activity were also lower (P<0.001) when compared with those of the controls. These results suggest either a specific or nonspecific immunological disorder in patients with RAU.