In vitro lymphocyte stimulation by wart antigen in man.

The lymphocyte transformation test was used to study cell-mediated immunity to wart antigen in patients with active wart infections, in patients with past history of warts and in control subjects. A common pattern was established with wart antigen; a control baseline, followed by a rise of 14C thymidine uptake in the 'active' group and a further elevation in the 'past history' group. Five patients with active warts were followed up and re-examined at various intervals after successful wart resolution; all except one responded to wart antigen by increased DNA synthetic activity after the wart resolution. This increased response was specific for wart antigen and could still be detected 6 months after wart resolution.