[Diagnostic usefulness of the tuberculin reaction by PPD-B in Mycobacterium avium complex disease]

This study was carried out to clarify the diagnostic usefulness of the skin tests of purified protein derivatives from M. intracellulare (PPD-B) and M. tuberculosis (PPDs). Study subjects consisted of 41 patients with primary infection type of M. avium complex (MAC) disease, 36 patients with pulmonary tuberculosis (TB) and 29 patients with other bacterial respiratory infections including COPD (OB). The patients were sorted out to middle (50-69 y.o.) and old (70-89 y.o.) age groups of each disease. The size of skin redness elicited 48 hours after the PPD-B and PPDs intradermal injections were compared among them. The results were as follows. 1) Both PPD-B and PPDs skin reactions were larger in the middle age group than in the old one for each disease. 2) In PPDs skin tests, the reaction of TB group was the largest among the three diseases. In PPD-B skin tests, that of MAC was the largest. 3) In TB group, PPDs skin reaction was significantly larger than that of PPD-B, while in MAC and OB groups there was no significant difference between the skin reactions of PPDs and PPD-B. 4) Defining significant positive reaction to PPD-B as PPD-B skin reaction exceeding 10 mm and larger than that of PPDs skin reaction, the rate of significant positive reaction to PPD-B was significantly higher in MAC than TB in both age groups. These results showed that the simultaneous skin tests of PPD-B and PPDs were a useful aid in the diagnosis of MAC infection disease when mycobacterial infection diseases were clinically suspected by bacteriological or chest radiographic examinations.