Abstract :
Background: Traditionally, the kinetics of tuberculin testing has been studied up to 72 hours. In this study,
we have studied the Mitsuda type of late response, usually seen in patients with leprosy after three weeks
and also evaluated its significance in patients with pulmonary tuberculosis.
Materials and Methods: Thirty patients of pulmonary tuberculosis were divided into two groups based on
sputum Acid-fast bacilli (AFB) examination. Group I patients were sputum AFB positive relapse (n=13).
Group II patients were previously treated for pulmonary tuberculosis with negative sputum AFB (n=17).
The induration was measured on day 3 and day 21, after tuberculin test with Purified protein derivative
(PPD). A punch biopsy was taken from the site of induration on day 21 to study the histo-pathological
characteristics.
Results: Four patients (23.5%) of Group 2 had an induration of more than 10 mm on day 21, while none
from Group I had more than 10 mm size of induration. Granulomas, typical feature of ‘Mitsuda’ type of
late response were seen in 92% and 100% in Group I and II respectively. The incidence of a granulomatous
type of late response is 96.7% in patients with pulmonary tuberculosis.
Conclusions: The Mitsuda type of late response can be induced by the PPD, which we are using for
conventional tuberculin testing. The late response appears to offer no protection in preventing relapse in
previously treated patients for pulmonary tuberculosis.
Keyword :
Mitsuda response, Tuberculin test, Pulmonary tuberculosis, Relapse.