[Determination of antibodies against A-60 antigen for diagnosis of M. tuberculosis infection. A useful tool for rationalization of chemoprophylaxis in HIV patients].

OBJECTIVE

To identify M. tuberculosis infection in HIV patients by use of PPD and an ELISA test detecting the presence of antibodies against antigen A-60 of M. bovis.

METHODS

116 incoming HIV patients were classified according to the CDC. The status of M. tuberculosis infection was probed with PPD (RT-23) and the state of anergy was estimated by a Multitest CM1 (Multitext). The presence of circulating antibodies of the IgG class against antigen A-60 was analysed by an ELISA. The clinical course of the patients was followed for 24 month.

RESULTS

A positive serology (A-60) was found in 52.58% of the patients, coinciding with 70.45% of the positive PPD (p < 0.003). This statical observation was found when we studied all of the individuals, and those with more than 500 CD4 lymphocytes. The Multitext was positive in 11.11% of the patients with PPD (-), all of them without antibodies against A-60. However, 42.2% of the patients who were PPD and Multitext (-), had circulating antibodies against A-60. The following up of the patients during 24 months allowed the detection of 7 news cases of pulmonary tuberculosis, 4 of them had a positive A-60 serology, and 4 were anergy.

CONCLUSIONS

HIV patients with M. tuberculosis infection have circulating antibodies against A-60 antigen of M. bovis with independence of their immunity status. In anergic patients the presence of this antibodies can be an useful tool for rationalizing the prophylaxis against M. tuberculosis. A seropositivity (A-60) indicates as well as does PPD a previous contact with M. tuberculosis.