Effect of Bacterial Extracts on the Immunologic Profile in Chronic Relapsing Brucellosis Patients

Abstract

Brucellosis is an intracellular bacterial disease of common incidence in Greece. Existing therapy is inadequate and a considerable proportion of patients become chronically ill and are immunocompromised. Defects of the monocyte-macrophage system and T-lymphocytes have been described in chronic brucellosis and can be restored after immunopotentiation therapy. Bacterial (Klebsiella pneumoniae) extracts exert immunostimulating effects on the monocyte-macrophage system and have already been used successfully in the prevention of common infections of the respiratory track. So we decided to investigate: 1) Leukocyte Migration Index (LMI), 2) Monocyte-macrophage random and directed migration against both nonspecific leukoattractant (casein) and disease specific antigens (Brucella melitensis, Brucella abortus), 3) Monocyte-macrophage phagocytosis index, 4) Delayed-type hypersensitivity (skin tests) against seven antigens, before (TO), during (T2), and after (T3) oral administration of bacterial (Klebsiella pneumoniae) extracts at conventional doses plus antibiotics or not. Our results show that: 1) Concerning the LMI, 4 out of 19 remained anergic at time T3 of the study, 2) Random migration was not affected during treatment, 3) Directed migration increased significantly without reaching control group values, 4) Phagocytosis index increased significantly and reached normal values at T3, 5) Delayed type hypersensitivity reactions (skin tests) increased significantly at the end of the study period. Reaction against Tuberculin and Candida antigens showed the most pronounced increase in skin reactivity. In conclusion, bacterial (Klebsiella pneumoniae) extracts improve peripheral monocyte locomotion and restore phagocytosis index, thus enhancing cellular immunity parameters in immunocompromised chronic brucellosis patients.