Dinitrochlorobenzene contact sensitization in pulmonary tuberculosis.

Skin sensitization with DNCB was carried out in forty-five untreated, 106 "on treatment" and fifteen fully treated patients with pulmonary tuberculosis along with fifty-five controls. Mantoux test with PPD was also carried out simultaneously. All the normal controls could be sensitized to DNCB and the degree of sensitization was 4+ in majority of the subjects. In contrast, in untreated patients only eighteen could be sensitized to DNCB and the degree of sensitivity did not reach 4+ in any patient. Similarly, fifty-five patients could not be sensitized with DNCB in the group of 106 subjects who were still suffering from active disease and were on therapy and none gave a 4+ response. The difference in the proportion of subjects who could be sensitized to DNCB in these two patient groups was significantly less in comparison to controls. Among fifteen patients who were fully treated and did not have active disease thirteeen could be sensitized with DNCB, but the degree of response was again found to be less than the controls. All the patients as well as the controls gave a high proportion of Mantoux positivity. These findings indicate that there is a subtle degree of immunodeficiency in pulmonary tuberculosis which improves simultaneously with the clinical improvement.