Effects of restraint stress on NALT structure and nasal IgA levels

The effects of stress on the mucosal immune responses in inflammatory disorders of the gut, as well as on salivary and intestinal IgA levels are well known. However, its effects on the structure and function of the NALT have not yet been reported, and are examined in the present study. Balb/c mice were submitted to restraint stress for 3 h per day during 4 or 8 d. The immunohistochemistry and flow cytometric analysis revealed that repeated restraint stress (4 and 8 d) decreased the percentage, compared to the control group, of CD3+ and CD4+ T cells, without affecting the percentage of CD8+ T cells or B220+ cells (B cells). The numbers of IELs (CD4+ and CD8+ T cells) were lower at 4 d of stress and higher at 8 d. IgA+ cells in NALT and nasal IgA levels showed a similar pattern, being significantly lower at 4 d of stress and significantly higher at 8 d. In summary, repeated restraint stress altered the distribution and number of lymphocytes and IgA+ cells in nasal mucosa, probably due to changes in norepinephrine and corticosterone levels.