[Measuring of the level of IGG antibodies against mycobacterial A60 antigen in the differential diagnosis of lung tumors].
In some cases it is difficult to define an etiology of lung tumour in the other way than thoracotomy. In these diagnostic difficulties patients with tuberculous tumour are also involved. The aim of the present study was to define if A60-ELISA test, a new valuable tool in the diagnosis of tuberculosis, might be useful in the differential diagnosing of lung tumours. The levels of IgG antibodies against A60 antigen of mycobacteria was measured with the use of the ELISA test. 228 persons were enrolled into the study: 58 healthy controls (Group I), 26 nonmalignant and nontuberculous patients (Group II), 56 patients with the diagnosis of pulmonary tuberculosis bacteriologically confirmed (Group III), 54 pulmonary tuberculosis patients culture negative (Group IV), 16 patients with lung tumour, without histologic diagnosis before thoracotomy (Group V) and 18 patients with defined diagnosis of lung cancer (Group VI). By using 200 U/ml as a cut-off point the test was positive in: 2/58 subjects from Group I, 2/26 from Group II, 44/56 from Group III, 31/54 from Group IV, 3/16 from Group V and 0/18 from Group VI. In three patients from group V having positive result of A60-ELISA test pulmonary tuberculosis was diagnosed when the thoracotomy was performed. We conclude that the new, simple, noninvasive and inexpensive A60-ELISA test migt be the useful tool in the differential diagnosing of lung tumours because of its good sensitivity and specificity in pulmonary tuberculosis. We also consider that in lung tumour patients with the positive result of this test the prophylactic antituberculosis treatment have to be ordered before planned thoracotomy.