Treatment of warts with intralesional immunotherapy: factors predicting clinical response and role of mannose-binding lectin-gene polymorphism

Background Warts are skin disease caused by human papilloma virus infection and characterized by high rate of recurrence and resistance. The use of purified protein derivatives (PPD) for treatment of warts achieved good results, however, some patients do not respond to it. Deficiency of mannose-binding lectin (MBL) may be a risk for repeated viral infection. Objective To investigate the factors that may affect and predict the clinical response of warts to the treatment with PPD. Patients and methods This study was conducted on 50 patients with warts and 50 apparently healthy-control volunteers. Blood samples from all participants were investigated for the polymorphism in MBL2-gene exon-1 codon 54 by PCR before treatment. All patients were injected intralesionally in the biggest wart every 2 weeks for five sessions. Results About 56% of the patients achieved complete response, 8% attained partial response, and 36% did not show any response. We did not detect recurrence or progression during the follow-up period. There was significantly higher clinical response in patients with less than five warts and in those with warts of less than 1-year duration. There was significantly lower clinical response in patients with warts over the dorsum of hand, while higher clinical response was observed in the warts over the sole. Although higher number (48%) of patients compared with controls showed polymorphism of MBL2 gene, it has no relation of the effect of PPD injection. Conclusion Intralesional immunotherapy with PPD is effective and safe for treatment of warts. Duration, number, and site of warts might have an impact on the clinical response to PPD immunotherapy, while MBL2-gene exon-1 codon-54 polymorphism has no effect.