Dinitrochlorbenzene (DNCB) treatment of viral warts. A 5-year follow-up study

A series of 43 patients with therapy-resistant viral warts of long-duration were treated with dinitrochlorbenzene (DNCB). Of the 37 patients, who completed the treatment, 19 were cured, including five of seven patients with hyperkeratotic tumor-like warts. The majority of the patients showed a depressed cell-mediated immune response. 25 patients were reexamined 5 years later and 8 additional patients answered on inquiry. Six (18%) of these patients had warts. Eight of the 21 primarily tuberculin-negative patients had developed immunity to tuberculin, and none of them had warts. Five of the 6 patients with warts were still tuberculin-negative. The reaction to DNCB had reverted to negative in 17 (68%) out of 25 tested patients and in the majority of the remaining cases a weak reaction only was seen. The study does not tell if the cure is a consequence of the DNCB treatment or a function of time. However, it shows that cure is associated with normalization of the cell-mediated immune response. The DNCB hypersensitivity seemed to disappear with time and late complications were not documented.