PPD testing as a diagnostic aid in non-tuberculous mycobacteriosis. Clinical and immunological investigations in 4 children with cervical lymphadenitis.

Four children suffering from unilateral cervical lymphadenitis with histopathological changes typical of mycobacteriosis were seen during a short time. None of the Children had been BCG vaccinated. Mycobacteria belonging to the Myobacterium aviumintracellulare complex were isolated from excised lymph nodes in two of the patients. Intracutaneous tests with PPD from M. tuberculosis were negative in all the children, whereas two children responded to each of 3 PPDs prepared from atypical mycobacteria. Two patients were unreactive in all the skin tests. Lymphocyte transformation tests in vitro with a battery of various PPDs indicated sensitization to atypical mycobacteria in two children, one of which was negative in the skin tests. All the patient had normal plasma Ig concentrations but two patients had low proportions of T lymphocytes in the peripheral blood. One of these also had reduced total numbers of T cells. Nevertheless, lymphocyte responses in vitro to phytohaemagglutinin were normal in all the children. The results show that cutaneous and in vitro tests with a battery of different PPDs have a place as diagnostic adjuncts in atypical mycobacteriosis. We suggest that immunological competence is analysed in such patients.