Pediatric primary pulmonary tuberculosis.

We read the article by Merino et al in a recent issue of CHEST (May 2001)1 with interest, as childhood tuberculosis is one of the major problems in our country, and we have had quite good experience in our center.2 We believe that there are some points in the article that need to be clarified. In the article, the tuberculin skin test result was considered positive if the palpable induration was 5 mm with an intradermal injection of two tuberculin units of purified protein derivative RT 23 (equivalent to five tuberculin units of purified protein derivative test). The American Thoracic Society has recently published guidelines for determining a positive tuberculin skin test reaction, and stated that an induration 5 mm should be considered as positive only in HIV-positive patients, recent contacts of tuberculosis cases, those with fibrotic changes on chest radiograph consistent with old tuberculosis, and patients with organ transplants and other immunosuppressed patients.3 In the article by Merino et al,1 it is not mentioned whether the patients have such risks, and it is not clear why they preferred to choose a cutoff value of 5 mm. Besides, the status of bacille Calmette-Guérin vaccination of patients is not mentioned; if they are vaccinated, it should have been kept in mind that the mean reaction size among persons who have received bacille Calmette-Guérin vaccination is often 10 mm. In addition, how did the authors differentiate the patients with cavities in their lungs as a radiologic finding who have “progressive primary tuberculosis” from patients who have “reactivation tuberculosis”?