Background: The interest in anti-allergy immunoregulation by lactic acid bacteria (LAB) has been growing over the last few decades. There is evidence to suggest that lysed Enterococcus faecalis FK-23 (LFK), a kind of LAB preparation, could relieve the clinical symptoms of Japanese cedar pollinosis. However, little is known about how LFK plays a role in combating allergy.
Objective: The aim of this study was to clarify whether improvement of clinical manifestations is associated with enhancement of tuberculin responses in patients with allergic rhinitis treated by LFK.
Methods: One gram of LFK per day was administered orally to fifty perennial allergic rhinitis patients in an open trial that lasted 28 days. Nasal symptoms and sign scores were rated before and after administration of LFK. Tuberculin responses and peripheral blood cells were also measured before and after LFK treatment.
Results: Purified protein derivative (PPD) skin test diameter was 2.14 +/- 2.14 mm before LFK administration versus 7.26 +/- 4.81 mm at day 31 (p < 0.01). A significant inverse correlation was recognized between PPD skin test diameters and total nasal scores in the nasal provocation test before and after treatment (r= - 0.600, p < 0.001). Peripheral blood eosinophils were 248 +/- 149 cells/ml before LFK administration and then they significantly decreased to 76 +/- 98 cells/microl (p < 0.01).
Conclusions: These finding may be interpreted as a result of improved clinical symptoms in allergic rhinitis after LFK oral treatment owing to the enhanced host's Th1-type immune responses and supression of the over-expression of Th2-dominated allergic responses.