mart-1-antigen and Hepatitis-C--Chronic

Hepatic perivascular epithelioid cell tumors (PEComas) are very rare. We report a primary hepatic PEComa with a review of the literature. A 56-year-old women presented with a nodular mass detected during the management of chronic renal failure and chronic hepatitis C. Diagnostic imaging studies suggested a nodular hepatocellular carcinoma in segment 5 of the liver. The patient underwent partial hepatectomy. A brown-colored expansile mass measuring 3.2×3.0 cm was relatively demarcated from the surrounding liver parenchyma. The tumor was mainly composed of epithelioid cells that were arranged in a trabecular growth pattern. Adipose tissue and thick-walled blood vessels were minimally identified. A small amount of extramedullary hematopoiesis was observed in the sinusoidal spaces between tumor cells. Tumor cells were diffusely immunoreactive for human melanoma black 45 (HMB45) and Melan A, focally immunoreactive for smooth muscle actin, but not for hepatocyte specific antigen (HSA).

Topics: Actins; Antibodies, Viral; Female; gp100 Melanoma Antigen; Hepatitis C, Chronic; Humans; Liver Neoplasms; MART-1 Antigen; Melanoma-Specific Antigens; Microscopy, Fluorescence; Perivascular Epithelioid Cell Neoplasms; Tomography, X-Ray Computed; Ultrasonography

A major breakthrough in cellular immunology has been the development of HLA class I tetramers to analyze CD8(+) T cell responses. However, in many situations, including persistent virus infection, specific T cell responses are rarely detected using this technology. This raises the question of whether such responses are 'deleted' (or 'exhausted') or present below the conventional detection limit for class I tetramer staining. In particular, persistent hepatitis C virus (HCV) infection is characterized by very weak or apparently absent specific CD8(+) T cell responses, even though they are readily detectable in acute disease. Therefore, we assessed the use of anti-PE-labeled magnetic beads to enrich tetramer-positive HCV-specific T cells and identify previously undetectable populations. Using the enrichment technique, HCV-specific T cells could be detected in the majority of infected individuals, whereas these responses were not detected using conventional tetramer staining (8/15 vs. 1/15; p=0.01). Magnetic enrichment could reliably detect very rare HCV-specific responses at frequencies of >0.0011% of CD8(+) T cells (approximately 1/million PBMC), and phenotypic analysis of these rare populations was possible. Therefore, this direct ex vivo technique revealed the persistence of very low frequencies of virus-specific CD8(+) T cells during chronic virus infection and is readily transferable to the study of other viral, self- or tumor-specific T cells.

Topics: Antigens, Neoplasm; CD8-Positive T-Lymphocytes; Hepacivirus; Hepatitis C Antigens; Hepatitis C, Chronic; HLA-A2 Antigen; Humans; Immunomagnetic Separation; MART-1 Antigen; Neoplasm Proteins; Phycoerythrin