Class I major histocompatibility complex enhancement by recombinant leukocyte interferon in the peripheral blood mononuclear cells and plasma of melanoma patients.

In vivo administration of escalation doses of recombinant alpha-interferon (IFN-alpha) during a phase I trial in malignant melanoma patients caused dose-dependent increases in the mRNA accumulation, synthesis, steady state cellular content, and plasma membrane expression of class I major histocompatibility complex molecules in peripheral blood mononuclear cells. In addition, circulating levels of class I molecules were also enhanced. These findings show that (a) antigenic enhancement by biomodifiers may occur in vivo, in humans and (b) the mechanism of class I major histocompatibility complex enhancement by IFN-alpha is similar in vitro and in vivo. Furthermore, because peripheral blood mononuclear cells of different melanoma patients display different susceptibility to IFN-alpha, the entity of their antigenic modulation may represent a useful parameter to evaluate the efficacy of different therapeutic regimens and/or assess the individual susceptibility to the molecular changes induced by IFN-alpha.