OBJECTIVES:
* To determine how a variety of immune-modulating therapies (i.e., interferon alfa \[IFN-α\] in patients with untreated acute or chronic hepatitis C, anti-tumor necrosis factor in patients with active inflammatory bowel disease (i.e., Crohn disease), and anticytotoxic T-lymphocyte antigen immunoglobulin in patients with metastatic melanoma) affect the tissue expression of indoleamine 2, 3 dioxygenase (IDO), a major immune-regulatory mechanism.
* To determine whether administration of pegylated INF-α in patients with untreated acute and chronic hepatitis C causes systemic changes in the IDO pathway, as indicated by lowered serum tryptophan (TRP) and elevated serum kynurenine (KYN).
* To determine whether administration of ticilimumab (i.e., anti-CTLA4 human monoclonal antibody CP-675,206) in patients with metastatic melanoma inhibits activation of the IDO pathway as indicated by normal serum TRP and normal serum KYN.
* To determine whether administration of infliximab in patients with Crohn disease inhibits activation of the IDO pathway, as indicated by normal serum TRP and normal serum KYN.
OUTLINE: Serum samples are collected from patients with hepatitis C and metastatic melanoma at baseline and at 3 to 4 weeks after treatment is initiated. Previously collected samples from patients with Crohn disease are also assessed at these time points. Samples are analyzed for tryptophan and kynurenine levels via high-performance liquid chromatography.
PROJECTED ACCRUAL: A total of 15 patients with untreated acute or chronic Hepatitis C, 15 patients with metastatic melanoma, and 20 patients with Crohn disease will be accrued for this study.
