Hepatitis C virus - associated B cell non-Hodgkin's lymphoma.

The hepatitis C virus (HCV) infected patients are prone to develop bone marrow or various tissue infiltrates with monoclonal B cells, monoclonal B lymphocytosis or different types of B cell non-Hodgkin's lymphoma (BCNHL), of which the most common are splenic marginal zone BCNHL, diffuse large BCNHL and follicular lymphoma. The association between chronic HCV infection and non Hodgkin's lymphoma has been observed especially in areas with high prevalence of this viral infection. Outside the limitations of some studies that have been conducted, there are also geographic, environmental, and genetic factors that contribute to the epidemiological differences. Various microenvironmental signals, such as cytokines, viral antigenic external stimulation of lymphocyte receptors by HCV antigens, and intercellular interactions contribute to B cell proliferation. HCV lymphotropism and chronic antigenic stimulation are involved in B-lymphocyte expansion, as mixted cryoglobulinemia or monoclonal gammopathy of undetermined significance, which can progress to BCNHL. HCV replication in B lymphocytes has oncogenic effect mediated by intracellular HCV proteins. It is also involved in an important induction of reactive oxygen species that can lead to permanent B lymphocyte damage, as DNA mutations, after binding to surface B-cell receptors. Post-transplant lymphoproliferative disorder could appear and it has a multiclonal potentiality that may develop into different types of lymphomas. The hematopoietic stem cell transplant made for lymphoma in HCV-infected patients can increase the risk of earlier progression to liver fibrosis and cirrhosis. HCV infected patients with indolent BCNHL who receive antiviral therapy can be potentially cured. Viral clearance was related to lymphoma response, fact that highlights the probable involvement of HCV in lymphomagenesis. Direct acting antiviral drugs could be a solution for the patients who did not tolerate or respond to interferon, as they seem to be safe and highly effective. The use of chemotherapy in combination with rituximab for the treatment of BCNHL in patients infected with HCV can produce liver dysfunction. The addition of immunotherapy with rituximab can increase the viral replication, and severe complications can occure especially in patients co-infected with hepatitis B virus or immune immunodeficiency virus, in those with hepatocarcinoma, cirrhosis, or liver cytolysis. But the final result of standard immunochemotherapy applied to diffuse large BCNHL patients with HCV infection is not notably worse than in those without this viral infection. The treatment of patients chronically infected with HCV and having BCNHL is complex and requires a multidisciplinary approach and the risk / benefit ratio of rituximab treatment must be evaluated especially in those with liver cytolysis.