Immunohistochemical detection of hepatitis C virus (genotype 4) in B-cell NHL in an Egyptian population: correlation with serum HCV-RNA

Abstract

Background and aim: Retrospective evaluation of hepatitis C virus (HCV) prevalence in lymphoma tissues has important applications in clarifying the contribution of viral factors to the pathogenesis. Trials for detection of HCV at the cellular level in lymphoma tissues are, so far, minimal with unsatisfactory results. We aimed to study the detection and localization of HCV in the tissues of B-cell non-Hodgkin lymphoma (NHL) patients.

Design: We performed immunohistochemistry to detect the HCV nonstructural 3 protein in paraffin-embedded tissue specimens of B-cell NHL patients, in 39 serum HCV-RNA positive samples and 35 serum HCV-RNA negative samples as controls. The serum analysis was carried out for HCV antibodies using enzyme-linked immunoassay and for HCV-RNA using reverse transcription-polymerase chain reaction. Reverse transcription-polymerase chain reaction was used to detect the HCV-RNA in tissues in immunohistochemically positive cases. We correlated the results with the clinicopathologic characteristics of the patients.

Results: A diffuse cytoplasmic immunohistochemical staining for HCV in the lymphoid cells was detected in 8 of 39 serum positive cases (20.5%), all of which were genotype 4, which is the most prevalent HCV genotype in Egypt. Only 2 out of 35 serum negative control samples showed positive staining and in 1 of them HCV-RNA was detected in tissue. No significant correlation was detected between HCV positive cases and the clinicopathologic features of the patients.

Conclusions: Immunohistochemical detection of HCV proteins in lymphoma tissues supports a potential role of viral replication in lymphomagenesis. The low number of cases showing expression of viral proteins may represent a low viral load in lymphoid tissue and/or restriction of HCV protein expression to certain subtypes of B-cell NHL. Immunohistochemistry can be used as a complementary tool for specific HCV detection in the paraffin-embedded material of lymphoma tissues not suitable for RNA analysis.

FIGURE 1

Two cases of B-cell non-Hodgkin lymphoma showing immunohistochemical staining for hepatitis C virus nonstructural 3 protein. Avidin-biotin peroxidase complex method. A, Strong cytoplasmic staining in the lymphoid cells. Original magnification 400 ×. B, Diffuse cytoplasmic staining in the lymphoid cells. Original magnification 400 ×.

FIGURE 2

Agarose gel electrophoresis of hepatitis C virus reverse transcription-polymerase chain reaction products from formalin-fixed paraffin-embedded tissue of a seronegative non-Hodgkin lymphoma with positive (PC) and negative (NC) controls.