Oral administration of Lactobacillus plantarum strain AYA enhances IgA secretion and provides survival protection against influenza virus infection in mice.

The mucosal immune system provides the first line of defense against inhaled and ingested pathogenic microbacteria and viruses. This defense system, to a large extent, is mediated by the actions of secretory IgA. In this study, we screened 140 strains of lactic acid bacteria for induction of IgA production by murine Peyer's patch cells. We selected one strain and named it Lactobacillus plantarum AYA. We found that L. plantarum AYA-induced production of IL-6 in Peyer's patch dendritic cells, with this production promoting IgA(+) B cells to differentiate into IgA-secreting plasma cells. We also observed that oral administration of L. plantarum AYA in mice caused an increase in IgA production in the small intestine and lung. This production of IgA correlated strongly with protective ability, with the treated mice surviving longer than the control mice after lethal influenza virus infection. Our data therefore reveals a novel immunoregulatory role of the L. plantarum AYA strain which enhances mucosal IgA production and provides protection against respiratory influenza virus infection.

Symptoms of atrial fibrillation in patients with and without subsequent permanent atrial fibrillation based on a retrospective questionnaire survey.

The aim of the present study was to determine whether symptoms of atrial fibrillation (AF) differ between patients with and without subsequent permanent AF. Sixty-four patients (68 +/- 10 years old, 45 males) were recruited. AF follow-up was started at the age of 61 +/- 10 years and accomplished in a median period of 4.9 years (396 person-years). Permanent AF, defined as lasting > 180 days, developed in 17 patients (14 males) (43 per 1000 person-years). The AF follow-up period was longer in the permanent AF group than in the non-permanent AF group (median, 9.8 versus 4.2 years, P < 0.001). For baseline characteristics, hypertension was less frequent in the permanent AF group than in the nonpermanent AF group (18% versus 45%, P < 0.05). A retrospective questionnaire survey regarding initial AF symptoms was conducted. The severity of AF symptoms by a 4-grade scale was significantly milder in the permanent AF group than in the nonpermanent AF group (P < 0.05). Cox proportional hazards model analysis revealed that the severity of initial AF symptoms was related to the subsequent development of permanent AF (hazard ratio 0.46 per grade, 95% confidence interval 0.23 - 0.93, P < 0.05), but age, gender, hypertension, diabetes mellitus, organic heart disease, and left atrial dimension were not. The permanent AF-free rate was significantly lower in 33 patients with mild symptoms than in 31 patients with severe symptoms (log-rank test, P < 0.05). These results point to an inconspicuous feature in the development of permanent AF.