Objective: Chronic Hepatitis C virus (HCV) infection can cause severe extrahepatic manifestations, such as mixed cryoglobulins (MC), up to the development of B cell nonHodgkin's lymphoma (B-NHL). Mechanisms transforming of HCV infection into lymphoproliferative and/or autoimmune disorders are still poorly understood. In course of HCV infection, the sustained virus-driven antigenic stimulation may probably induce a B-cell clonal expansion. Measurements of serum free light chains (FLCs) levels, considered as a direct marker of B cell activity, are analyzed with increasing interest in clinical practice, for diagnosis, monitoring and follow-up of plasma cell dyscrasia. Syndecan-1 (CD138) is a transmembrane heparan sulfate proteoglycan expressed and actively shed by most myeloma cells. Membrane CD138 represents the major receptor protein for HCV attachment to the hepatocyte surface and high levels of circulating sCD138 levels are detected in patients at early stage of B-cell chronic lymphocytic leukemia. This study is aimed to evaluate sCD138 and FLC levels as diagnostic biomarkers of HCV-related MC with B-NHL.
Patients and methods: We enrolled 35 HCV-MC-NHL patients, characterized for the specific type of cryoglobulins, and 25 healthy blood donors (HBD) as negative control. Serum sCD138 levels were determined using ELISA kits specific for human sCD138. Serum FLCs were assessed by means of the turbidimetric assay.
Results: We found that serum levels of sCD138, as well as FLCs, were significantly higher in patients than in HBD (p<0.001).
Conclusions: In agreement with the definition of HCV-driven lymphoproliferative disorders as the consequence of a multifactorial and multistep pathogenetic process, we suggest that sCD138 and FLCs could be considered putative independent markers of worsening progression of the disease.