Brief report: Pediatric Burkitt lymphoma with concurrent chronic Epstein-Barr virus hepatitis.

PRECIADO MV; DE MATTEO E; FREIGEIRO D,; GALOPPO MC; GRINSTEIN S

MEDICAL AND PEDIATRIC ONCOLOGY

Wiley-Liss

Año: 1999 vol. 33 p. 132 - 136

0098-1532

EBV is an ubiquitous member of the herpes virus family. It has been shown to be associated with a number of malignancies such as BL, a subset of Hodgkin disease, and lymphoproliferative disorders in immunocompromised hosts (LPDs). Expression of viral latency genes varies among distinct malignancies: latency type I in BL expresses EBNA-1, latency type II in HD and nasopharingeal carcinoma expresses EBNA-1 and LMPs and latency type III in LPDs expresses all latency antigens. It has also been demonstrated that there are two EBV subtypes, EBV-1 and EBV-2, which differ with respect to the nucleotide sequence of several EBNA genes (1). The relationship between BL and EBV has been demonstrated in many studies ranging from 100% positivity in endemic BL through 50% in sporadic BL in South America to 30% in United States (2). Manifestations of EBV-associated hepatic disorders have been described; they involve a broad spectrum of clinical and histologic features, ranging from hepatitis through lymphoproliferative processes to lymphoma (3). BL with concurrent chronic EBV hepatitis an EBV-hepatitis has not heretofore been reported so our experience with such a patient is of interest. She is a 3-year-old Peruvian girl who was admitted to our hospital with intestinal disorders. An abdominal computed tomography (CT) scan showed masses on both sides of the pelvis. Biopsies of abdominal lymph nodes and the ovary were obtained and an abdominal BL was diagnosed that involved lymph nodes and the ovary The staging was established by reviewing hepatic and bone marrow biopsies (Stage III according to Murphy classification). Histologic review of the liver biopsy disclosed chronic hepatitis with mild to moderate activity. The AST (459 IU/L) and ALT (258 IU/L) were increased. Viral infection parameters were analyzed: HBsAg, anti-hepatitis C virus (HCV) antibodies, IgM anti-hepatitis A virus (HAV) and anti-cytomegalovirus (CMV) were negative. RT-nested PCR of HCV genome was negative. IgM anti-EBV-specific viral capsid antigen (VCA) and IgG anti-VCA (1/5120) were clearly positive. Autoimmunity parameters, anti-nuclear, anti-actin (SMA) and LKM-1 antibodies, were negative. The following procedures were followed: PCR EBNA-3C strain typing: High molecular weight DNA was isolated from formalin-fixed paraffin-embedded tissue according to Wright et al (4). PCR strategy reported by Sample et al (5) was used. PCR amplified DNA was subjected to electrophoresis on a 2% agarose gel containing BrEt (6). Immunohistochemistry: Immunohistochemical staining was performed as previously described by Preciado et al (7),.using streptavidin-biotin complex with HRP to detect EBV-associated proteins: LMP-1, EBNA-2 and ZEBRA using MAbs CS1-4, PE2 and BZ-1 respectively. In situ Hybridization (ISH): Fluorescein isothiocyanate (FITC)-conjugated EBERs oligonucleotides were used as probes for the hybridization procedure on paraffin sections. EBERs ISH was performed as previously described by Preciado et al (7). Results were as follows: The liver histology showed widened portal tracts with diffuse infiltrates, predominantly lymphocytic, intermixed with few histiocytes. Erosion of the limiting plate by piecemeal necrosis involved 30% of the portal perimeters. Active and short septa; portal and periportal fibrosis and minimal bile-duct lesions were found. Lobular changes included hepatocyte swelling with occasional hepatocyte necrosis. Lymphoma infiltration was absent (Figure 1a and b). The EBV association was established by PCR and EBERs ISH together with an increased of VCA-IgG titre (1/5120) in serum. A 153 bp PCR amplification product was detected in the three biopsies (ovary, abdominal lymph node and liver) indicating the presence of EBV-1. The PCR amplification signal of the ovary sample showed more intensity than the others, which might indicate the presence of a higher number of viral copies in this tissue (Figure 2). The subcellular localization of the EBERs is a helpful indication of the specificity of the reaction. EBERs ISH disclosed a signal in the inner nuclear membrane and around the nucleolus of tumor cells of the ovarian biopsy (Figure 3), but no signal was detected in the liver biopsy. The immunohistochemical detection of LMP-1, EBNA-2 and ZEBRA on the biopsies were negative. DISCUSSION The association between EBV and Burkitt lymphoma has often been demonstrated (8). The absence of LMP-1 and EBNA-2 expression in the studied biopsies is in accordance to latency type I pattern described for BL. Nevertheless, Niedobitek et al. have recently demonstrated LMP-1 expression in a proportion of tumor cells in two BL cases (9) and Carbone et al. also reported the expression of LMP-1 in 3/10 AIDS-related and in 2/6 non AIDS-related non-endemic BL (10). Both EBER ISH and PCR are very sensitive techniques, but PCR also allows strain type characterization. EBERs ISH discloses nuclear signal in the infected tumor cells identifying those cases in which EBV is expressed in malignant cells, which is usually related to a direct role of the virus in the neoplasic process. EBERs ISH failed to detect EBV in the liver biopsy because it is a slightly less sensitive technique than PCR. The absence of serological HAV, HBV and HCV markers and HCV RNA by RT-nested PCR exclude these three viruses as etiological agents. The diagnosis was confirmed by EBV PCR of the liver biopsy. Thus, a useful and sensitive laboratory test that should be used to diagnose EBV hepatitis is PCR. A large proportion of EBV-LPDs shows hepatic histopathologic changes suggestive of EBV hepatitis together with the presence of the EBV genome, which can be the result of viral reactivation or primary exposure (11,12). Moreover, a fulminant EBV hepatitis developing in a previously non-immumosipressed adult has been recently reported (13). So the viral hepatitis described here may have arisen as a result of an EBV primary infection or reactivation favored by the BL-associated immunosupression. Furthermore, EBV has also been described as a trigger for autoimmune hepatitis in susceptible individuals since during EBV infection several autoantibodies can transiently arise, due to infection and proliferation of B-cell clones (14). The autoimmune etiology of this hepatitis has been underrated since autoimmunity parameters were negative. It is worth describing this particular child because EBV hepatitis may be an infrequent but possible complication of EBV-associated pediatric BL, since in developing countries an EBV infection in early childhood is common.