Helen L. Grierson

Epstein-Barr virus and human diseases: recent advances in diagnosis.

Since the discovery of Epstein-Barr virus (EBV) from a cultured Burkitts lymphoma cell line in 1964, the virus has been associated with Burkitts lymphoma, nasopharyngeal carcinoma, and infectious mononucleosis. During the recent decade, EBV has been etiologically implicated in a broad spectrum of human diseases. The precise role of this virus in these diseases is not well understood, but clearly, defective immunosurveillance against the virus may permit an uncontrolled proliferation of EBV-infected cells. As a result, a growing number of cases of EBV-associated B-cell proliferative diseases or lymphoma have been noted in patients with primary and acquired immunodeficiencies. These lymphoproliferative diseases and others, such as chronic mononucleosis syndrome, are leading to new areas of investigation which are providing information regarding the pathogenetic mechanisms of EBV-induced diseases. The early accurate diagnosis of EBV infection can be achieved by performing EBV-specific serology, detecting for EBV-determined nuclear antigen in tissues, establishing spontaneous lymphoid cell lines, and using molecular hybridization techniques for demonstrating the presence of viral genome in affected lesions. Images

Epstein-Barr virus infections in males with the X-linked lymphoproliferative syndrome.

A registry of persons with the X-linked lymphoproliferative syndrome, which is characterized by marked susceptibility to diseases induced by the Epstein-Barr virus, has enrolled 161 patients within 44 kindreds. Fifty-seven percent of the males died of infectious mononucleosis, 29% developed acquired hypogammaglobulinemia, and 24% had malignant lymphoma. The mortality rate was 80%; 70% died by 10 years of age and 100% by 40 years. Thirty-two boys survive, most with malignant lymphoma, acquired hypogammaglobulinemia, or both. We hypothesized that the defective lymphoproliferative control locus on the X chromosome results in unregulated cytotoxic lymphocytic responses to the Epstein-Barr virus; hence, severe hepatitis and virus-associated hemophagocytic syndrome occur with the infectious mononucleosis phenotype. T-cell suppression of immunoglobulin secretion by B cells is responsible for acquired hypogammaglobulinemia. A sustained polyclonal B-cell proliferation probably converts to a monoclonal B-cell malignancy as a result of molecular alterations.

Virus-associated histiocytic proliferations in children: frequent association with Epstein-Barr virus and congenital or acquired immunodeficiencies

Nineteen children who presented with fever, hepato-splenomegaly, bone marrow and/or hepatic failure, and biopsy evidence of histiocytic proliferations were evaluated for lymphocyte dysfunction and evidence of prior viral infection. Seventeen of the children had erythrophagocytosis consistent with the previously described virus-associated hemophagocytosis syndrome (VAHS) or Familial erythrophagocytic lymphohistiocytosis (FEL). The other two had benign histiocytic proliferations in the central nervous system (CNS) with liver and bone marrow dysfunction. There were two sibling pairs and six patients with known disorders of immune deficiency. The remaining nine cases appeared to be sporadic and idiopathic. Epstein-Barr Virus (EBV) was identified in patients by serologic or DNA hybridization studies (15), EBV and cyatomegalovirus (CMV) (1), adenovirus plus EBV and CMV (1), or adenovirus and EBV (1). Herpes zoster was associated with reactivation of symptoms in one patient. Immunologic impairment was evidenced by lymphopenia in 10 of 19 patients. More extensive evaluations could be done at diagnosis on only some of the children because the histiocytic proliferative syndrome was not recognized or because there were insufficient numbers of lymphocytes in samples obtained. For those who could be evaluated, the following immune deficiencies were found: decreased lymphocyte proliferation to mitogens (4 of 9), absent or markedly decreased natural killer function (5 of 5), and decreased cytotoxic lymphocyte reactivity to allogenic EBV-infected target cells (3 of 3). A new finding reported here is a higher than expected prevalence of HLA types A30, B8, and A1/B8 among the patients tested.

Linkage analysis of seven kindreds with the X-linked lymphoproliferative syndrome (XLP) confirms that the XLP locus is near DXS42 and DXS37

SummaryAnalysis of seven kindreds indicates that the XLP locus exhibits 1% recombination with DXS42 (lod = 17.5) and no recombination with DXS37 (lod = 13.3).

Methods of detection of new families with X-linked lymphoproliferative disease☆

During the past decade, 240 males with X-linked lymphoproliferative disease (XLP) within 59 unrelated kindreds have been identified worldwide. One half of the patients have developed fatal infections mononucleosis, about one third have acquired hypogammaglobulinemia, and another one fourth have developed malignant lymphoma. Less commonly occurring phenotypes include hyperimmunoglobulinemia M, bone marrow hypoplasia, and necrotizing lymphoid vasculitis. The fatal infectious mononucleosis phenotype occurs at about 2.5 years of age, and median survival is only 33 days following onset of illness. The acquired hypogammaglobulinemia and malignant lymphoma phenotypes are associated with longer survivals, but to date no patient has been documented as living into the fifth decade of life. We summarized recent research findings and technological advances that permit accurate diagnosis of carrier females and detection of males with the XLP gene before Epstein-Barr virus infection.

Immunovirological studies of fatal infectious mononucleosis in a patient with X-linked lymphoproliferative syndrome treated with intravenous immunoglobulin and interferon-α

We have studied a 19-year-old male with X-linked lymphoproliferative syndrome (XLP) and infectious mononucleosis (IM) who was treated with high-dose immunoglobulin (500 mg/kg/day) and recombinant interferon (IFN)-alpha (2 x 10(6) IU/m2/day). Fulminant hepatitis was delayed; however, virus-associated hemophagocytic syndrome, cholestatic jaundice, and renal failure occurred terminally. Initially, nonspecific natural killer (NK) cell activity against K562 cells was normal but it gradually decreased. Although reactive T cells were markedly increased in his blood during the acute phase, spontaneous EBV-positive cell lines were easily established. Additionally, his mononuclear cells produced IFN-gamma but not IFN-alpha prior to treatment. Based on results of in vitro studies, we conclude that both IFN-alpha and IFN-gamma production are likely necessary for inhibiting EBV immortalization in vitro. Both IFN-alpha and -gamma were produced in cultures of B95-8 EBV-infected mononuclear cells from EBV-seropositive healthy individuals. These results suggest that defective EBV-specific cytotoxic T cell activity accompanied with defective or discordant IFN-alpha and -gamma production permitted the development of fatal IM in this patient. Combined treatment with immunoglobulin and IFN-alpha appeared to be partially effective during the early stage of this disease.

Partial Xq25 deletion in a family with the X-linked lymphoproliferative disease (XLP)

X-linked lymphoproliferative disease (XLP) results in exquisite vulnerability to EBV infection: fatal infectious mononucleosis (IM), acquired hypogammaglobulinemia and/or malignant lymphoma occur invariably following infection with the virus. We have identified the XLP locus using the DXS42 DNA probe having restriction length polymorphisms (RFLP). We report an interstitial deletion involving a portion of the Xq25 region in the X chromosome of an affected male, one sister, and their mother. Concordance has been established between the presence of a deletion and RFLP linkage analysis with the DXS42 probe in the kindred. This finding will contribute substantially to the mapping, cloning, and sequencing of the gene responsible for XLP.

Interferon-gamma in a family with X-linked lymphoproliferative syndrome with acute Epstein-Barr virus infection

A 20-month-old male with fulminant infectious mononucleosis and the X-linked lymphoproliferative syndrome (XLP) was studied. Epstein-Barr virus (EBV)-determined nuclear antigen (EBNA) and EBV DNA were detected in various tissues. Despite a combined treatment with acyclovir, immunoglobulin, and methylprednisolone, the patient deteriorated rapidly. Following treatment with recombinant interferon-gamma (IFN-γ), defervescence occurred and circulating EBNA-positive cells markedly decreased. IFN-γ prior to treatment ranged from 10.8 to 24.5 U/ml in the patients serum and increased linearly post exogenous IFN-γ treatment. His natural killer (NK)-cell activity remained in the normal range throughout his illness but autologous EBV-infected cells were not killedin vitro by his peripheral blood lymphocytes (PBL). These results suggest that patients with the fatal infectious mononucleosis phenotype of XLP may produce endogenous IFN-γ. Defective cytotoxic T cells against EBV-infected cells seem to be responsible for the fulminant infectious mononucleosis in this patient.

Sinus histiocytosis with massive lymphadenopathy: a spectrum of disease associated with immune dysfunction.

A detailed immunologic study of three cases of sinus histiocytosis with massive lymphadenopathy (SHML) was performed to better characterize this rare disorder. One patient had prominent cervical lymphadenopathy that regressed spontaneously, whereas the other two patients had persistent cervical lymphadenopathy and recurrent infections. The first patient was otherwise healthy and had normal immunologic studies. One of the latter patients had a relative increase in blood B cells, a decreased level of serum immunoglobulin A (IgA), decreased blood lymphocyte mitogenic responses to multiple mitogens (37-42% of controls), and cutaneous anergy. The other patient with persistent disease also had a relative increase in blood B cells, polyclonal hypergammaglobulinemia, and circulating immune complexes, as well as decreased blood T cells and markedly decreased blood lymphocyte responses to mitogens (12-37% of controls). Immunohistochemical stains of the lymph nodes of the three patients revealed a characteristic phenotype for the sinus histiocytes: S-100 protein, 3/3; CD14 (Leu M3) 3/3; CD11c (Leu M5), 1/1; CD71 (OKT9), 3/3; CD4 (Leu 3a), 2/3; CD1a (OKT6), 1/3; alpha-1-antitrypsin, 3/3; alpha-1-antichymotrypsin, 3/3; CD35 (C3b), 1/1; CD11b (Mo1), 0/3; CD15 (Leu M1), 0/3; HLA-DR, 0/3; and lysozyme, 0/3. This phenotype suggests that the cells of SHML have features of both the Langerhans/interdigitating cell and mononuclear phagocyte lineages. Emperipolesis by the histiocytes of B cells, T cells, and natural killer cells was demonstrated by a double-staining technique. Our findings indicate that patients with SHML may have a variably expressed immunodeficiency that predisposes them to recurrent infections.

Detection of X-linked lymphoproliferative disease using molecular and immunovirologic markers

PURPOSE, PATIENTS, AND METHODS Detection of males affected with the X-linked lymphoproliferative disease (XLP) was sought using immunovirologic and molecular genetic linkage techniques. The study population consisted of 20 males in six families with XLP. RESULTS Concordance for detection of affected males was 100% when linkage analysis using DXS42 and DXS37 DNA probes and antibody responses to challenge with bacteriophage phi X174 were both determined. Most affected males showing IgG subclass immune deficiency could not produce antibodies to Epstein-Barr virus nuclear antigen and had deficient responses to challenge with bacteriophage phi X174. CONCLUSION Use of only one of the techniques described can fail to lead to the diagnosis of XLP, because problems can prevail with each individual determination.