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Rhodococcus equi infection in AIDS patients: protective role of humoral immunity.
Mastroianni CM; Vullo V; Delia S; Dept. of Infectious and Tropical
December 30, 1994
Int Conf AIDS. 1994 Aug 7-12;10(2):136 (abstract no. PB0556). Unique

OBJECTIVE: In previous investigations, we demonstrated that clinical severity of R. equi pneumonia in AIDS patients was correlated with lower specific antibody response. The aim of this study was to further evaluate the humoral immune response to R. equi infection in AIDS patients as well as in healthy subjects. Moreover, the immunoreactivity of human intravenous immunoglobulin (IVIG) to R. equi antigens was also examined. METHODS: Specific antibody response to whole cell antigens of R. equi was analyzed by enhanced chemiluminescence immunoblotting in 22 serum samples from 5 AIDS patients with R. equi pneumonia, in 20 from AIDS patients without R. equi infection, in 30 from healthy controls and in a commercial lot of IVIG (Ig VENA, lot 192, Sclavo, Italy). RESULTS: The sera from 3 AIDS patients, who fully recovered from R. equi pneumonia, had a stronger antibody response to R. equi antigens than that found in AIDS patients without R. equi infection and healthy controls. Conversely, the sera from 2 patients with severe R. equi infection showed little or no reaction with R. equi antigens. Finally, immunoblotting experiments showed that IVIG exhibited an intense reactivity with all antigenic components of R. equi. DISCUSSION AND CONCLUSIONS: Our findings suggest that: i) R. equi antibodies naturally occur in humans; ii) humoral immunity may play an important role both in the protection against and recovery from R. equi infection in AIDS patients. Further studies are in progress to investigate the value of IVIG or other immunotherapies in AIDS patients with R. equi infection.

Acquired Immunodeficiency Syndrome/COMPLICATIONS/IMMUNOLOGY Actinomycetales Infections/COMPLICATIONS/*IMMUNOLOGY/THERAPY Antibodies, Bacterial/*BIOSYNTHESIS/BLOOD Antigens, Bacterial AIDS-Related Opportunistic Infections/COMPLICATIONS/*IMMUNOLOGY/ THERAPY Human Immunity, Natural Immunoblotting Immunoglobulins, Intravenous/PHARMACOLOGY Immunotherapy In Vitro *Rhodococcus equi/IMMUNOLOGY ABSTRACT

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