Variation and significance of secretory immunoglobulin A, interleukin 6 and dendritic cells in oral cancer

The present study aimed to determine changes in the concentration of secretory immunoglobulin A (SIgA) and interleukin 6 (IL-6) in the saliva of patients with oral cancer, to evaluate the abnormal expression of cluster of differentiation (CD) 1a, CD83, CD80 and CD86 on dendritic cells (DCs) of oral cancer tissues and to discuss the interaction between SIgA, IL-6 and DCs in oral cancer. A total of 40 patients between 27 and 70 years of age, median age 52 years, with primary oral cancer were enrolled in the present study, and a group of 20 healthy male and female volunteers was used as the control group. The concentration of SIgA and IL-6 in the saliva of the preoperative patients was determined by ELISA. The expression levels of CD1a, CD83, CD80 and CD86 were detected by immunohistochemistry and flow cytometry, which was performed on histopathological sections from paraffin-embedded tumor and corresponding adjacent control tissues. The specimens were assessed using the semi-quantitative immunoreactive score (IRS). The concentration of SIgA in the saliva from patients with oral cancer decreased, whereas the IL-6 level significantly increased compared with the control subjects (P<0.05). In addition, the decrease of SIgA level and increase of IL-6 level exhibited a negative correlation (r=−0.543, P<0.05). According to the IRS score, the expression levels of CD1a, CD83, CD80 and CD86 in the cancer tissue were lower than the expression levels of the control group (P<0.05). Furthermore, the expression of CD80 and CD86 exhibited no correlation with histological grade or pathological type (P>0.05), but exhibited a negative correlation with clinical stage and lymph node metastasis (P<0.05). The concentration of SIgA and IL-6 in saliva may be used as an auxiliary diagnostic indicator for oral cancer. The detection of CD80 and CD86 expressed on DCs in oral cancer tissue may be useful for the diagnosis and evaluation of the prognosis of tumors. The present study hypothesized that the use of SIgA vaccines or IL-6 inhibitors may be useful for reversing the immune deficiency associated with DCs in oral cancer.