Modification of cell mediated immune-response in patients treated with a polyvalent mechanical bacterial lysate

Background: Efficacy of Polyvalent Mechanical Bacterial Lysate (PMBL) in inducing the secretion of specific IgA directed to the bacterial antigens administered has been shown. Aims and objectives: In this double blind placebo controlled study, we analyzed the immunological effect of PMBL, administered to a population of elderly Chronic Obstructive Pulmonary Disease (COPD) patients. Methods: The treatment provided 1 tablet of PMBL for the first ten days of the month, followed by a 20 day rest. The treatment was repeated for other two months and the follow up was carried out up to six months. Blood cell samples were collected at time 0 (before the beginning of the study), after three months and after six months. Results: CD4+ and activated T cells increased significantly in treated group, while Treg were significantly reduced. Transitional B cells (in particular T3) were recruited and associated to an increase of early naïve B cells; recruitment of early memory cells was associated to a reduction of "classic" memory B cells. Finally, NK cells were significantly increased in treated patients, while their subpopulations remained unmodified. Conclusion: In conclusion, PMBL administration causes in COPD patients an important recruitment of cells belonging to the innate immune system, such as NK, a significant activation of early B cell compartments and a clear reduction of regulatory T cells associated to the increase of T cell activation. All these findings confirm that, also in COPD patients, a specific (and also partially polyclonal) activation of B cells occurs, and this seems to be strictly related to the significant clinical results observed.