Subacute and chronic prurigo effectively treated with recombination interferon-gamma: implications for participation of Th2 cells in the pathogenesis of prurigo
Tokura Y, Yagi H, Hanaoka K, Ito T, Towyama K, Sachi Y, Tanaka M, Sakamoto T, Sekizuka T, Furukawa F, Takigawa M.
Subacute and chronic prurigo is notoriously resistant to usual therapies. Four of five patients with a subacute or chronic form of prurigo responded well to daily intravenous injections of recombinant interferon-gamma (rIFN-gamma) (0.25-2 x 10(6) Japan Reference Unit (JRU; 1 JRU roughly corresponds to 4 NIH units) daily, for 10-14 days). In one patient examined, the dermal portion of lesional skin before the treatment contained considerable amounts of mRNA for interleukin (IL)-4, IL-5, and IL-10, indicative of infiltration of Th2 cells. Furthermore, the administration of rIFN-gamma selectively down-regulated mRNA for Th2 cytokines, IL-4 and IL-10 in peripheral blood mononuclear cells. These findings suggest that Th2 cells play a pathogenic role in these types of prurigo and that rIFN-gamma exerts its efficacy by inhibiting Th2 cells. Our pilot study suggests that the systemic administration of rIFN-gamma is a therapeutic alternative for the treatment of recalcitrant prurigo.