This study was set in a general, university hospital in the Canary Islands, with the objective to evaluate an
enzyme-linked
immunosorbent assay (ELISA) using A60 in the serodiagnosis of
tuberculosis.
IgG antibody to A60 was determined in 205 patients with active disease [149 culture-positive patients with
pulmonary tuberculosis (positive sputum smear 94, negative sputum smear 55) and 56 patients with
extrapulmonary tuberculosis], 20 patients with inactive disease, 22 patients with
lepromatous leprosy, and 51 controls. The mean levels of anti-A60
antibodies were significantly higher in patients with active disease as compared with controls or patients with inactive disease. Differences were also found between tuberculous patients with pulmonary and extrapulmonary disease. In patients with
pulmonary disease, significant differences were detected between smear-positive and smear-negative patients. The overall sensitivity of the test (cutoff 240 ELISA units) was 52.2%. The highest sensitivity was found among smear-positive patients with
pulmonary tuberculosis (67%) and the lowest among those with
extrapulmonary tuberculosis (32.1%). We conclude that ELISA for the measurement of
IgG antibody to Mycobacterium tuberculosis
antigen A60 could be of interest, specially in smear-negative cases and
extrapulmonary tuberculosis.