Thymopoietin pentapeptide (TP-5) improves clinical parameters and lymphocyte subpopulations in atopic dermatitis.

In a double-blind prospective study, eighteen patients with atopic dermatitis (AD) were treated with thrice-weekly injections of 50 mg thymopoietin pentapeptide (TP-5) or placebo for 6 weeks. Clinical parameters, lymphocyte subsets defined by monoclonal antibodies, and serum IgE were modified. Younger patients (age less than 34) responded to TP-5 with much greater improvement in severity scores than TP-5-treated patients of age greater than 34 or than placebo-treated patients of either age group (p less than 0.05). Both absolute lymphocytes and OKT8+ cytotoxic/suppressor cells were significantly increased (p less than 0.05) in the TP-5 group, whereas they were not significantly increased in the placebo group (p greater than 0.05). Conversely, Ia+ cells were significantly increased in the placebo group (p less than 0.05), but remained the same in the TP-5 group (p greater than 0.05). Serum IgE levels were not significantly altered in either group. Thus, TP-5 had a beneficial clinical effect in AD, especially in younger patients, and increased the reduced OKT8+ cytotoxic/suppressor T cells and prevented an increase of Ia+ cells during pollen season.