Epstein-Barr virus-induced diseases in boys with the X-linked lymphoproliferative syndrome (XLP): update on studies of the registry

Role of Epstein-Barr virus in acquired immune deficiency syndrome

We have reviewed the biologic characteristics, immune responses, and diverse array of diseases occurring from Epstein-Barr virus infections in immune deficient patients. We have summarized possible roles of the virus in the risk groups for AIDS. Data is convincing that EBV is responsible for some of the cases of lymphadenomegaly and Burkitt-like, non-Hodgkin's lymphomas in patients with pre-AIDS and AIDS. A hypothesis has been proposed wherein EBV and other stimulants of B and T cells allow productive infection by the retrovirus and spread of HTLV-III throughout the helper T cell populations.

Benign and malignant disease caused by EBV

Epstein-Barr virus (EBV) causes infectious mononucleosis as a primary disease. The virus infects more than 90% of the average population and persists lifelong in peripheral B-lymphocytes. The virus is produced in the parotid gland and spread via the oral route. Serology suggests that the Epstein-Barr virus might be involved in the causation of two neoplastic diseases of humans: African Burkitt's lymphoma and nasopharyngeal carcinoma. Whereas the development of the lymphoma has an even better linkage with chromosomal rearrangements, nasopharyngeal carcinoma shows a unique association with Epstein-Barr virus. Environmental factors, including traditional Chinese medicine, may be responsible for the enhanced risk of nasopharyngeal carcinoma in certain, predominantly Chinese, populations of southern Asia. Possible mechanisms leading to the establishment of the neoplastic manifestations will be discussed.

A serum inhibitor of neutrophil chemotaxis associated with hyperglobulinaemia E in a patient with lymphoma, and recurrent skin infection

A patient with a strong serum inhibitor of neutrophil chemotaxis, a possible chemotactic factor inactivator and hyperimmunoglobulinaemia E is described. The patient had a persistent chronic dermatitis which appeared to develop following radiation of the central nervous system for an unclassified lymphoma. Other abnormalities included a general increase of serum immunoglobulins, impaired lymphocyte response to mitogens, and a high Epstein-Barr antibody titre. This case illustrates that an increased IgE level, previously reported in association with a cellular chemotactic defect, may coexist with serum inhibitors of neutrophil chemotaxis.

The Leeuwenhoek lecture, 1983. A prototype vaccine to prevent Epstein-Barr virus-associated tumours

EB virus is a herpesvirus that infects all human communities. The infection is life-long and usually asymptomatic. Excessive reaction to primary infection leads to infectious mononucleosis while immunological failures give fatal lymphoproliferative diseases. The virus is associated with endemic Burkitt's lymphoma and undifferentiated nasopharyngeal carcinoma. In world cancer terms Burkitt's lymphoma is insignificant, but nasopharyngeal carcinoma has a high incidence in certain important populations. By analogy with herpesvirus-induced animal cancers, prevention of infection should greatly reduce subsequent development of tumours. A prototype vaccine has therefore been produced based on the virus-determined antigen (MA gp340) that elicits virus-neutralizing antibodies. A sensitive assay has permitted the elaboration of an efficient antigen preparation method and the product has been rendered highly immunogenic, as tested in mice and rabbits, by incorporation in liposomes. The only animal suitable for experimental EB virus infection is the little-known cottontop tamarin; a breeding colony has been successfully established and protection against virus challenge assessed in immunized tamarins. The overall structure of the antigen has been determined in preparation for future production by synthesis or rDNA technology.

Acquired immunodeficiency syndrome is an opportunistic infection and Kaposi's sarcoma results from secondary immune stimulation

Two hypotheses are presented to explain the recent outbreak of acquired immunodeficiency syndrome (AIDS) and Kaposi's sarcoma in certain risk groups, particularly homosexuals, and the absence of these diseases from other segments of the population. According to the first, AIDS is itself an opportunistic infection. It causes disease only in individuals who are already immunocompromised by hepatitis B, cytomegalovirus, parasites, or other immunosuppressive factors. This hypothesis predicts that evidence of previous contact with the AIDS agent would be found in healthy individuals who have had the immune capability to suppress its pathogenicity. It also suggests that individuals with evidence of immunodeficiency are at risk of this syndrome and should adopt a lifestyle favouring recovery of their immune system. According to the second hypothesis, the high incidence of Kaposi's sarcoma observed in immunocompromised AIDS patients is not due to decreased immunosurveillance but to a reactive secretion of immunomodulating factors with angiogenesis-promoting activity. They are released in an attempt to bring the immune system back into balance. These factors would enhance capillary proliferation and subsequent transformation of endothelial cells, perhaps via cytomegalovirus.

Oncological consequences of impaired immune surveillance against ubiquitous viruses

The immune system is constantly challenged by ubiquitous viruses. Multiple immune defenses have evolved to meet these challenges, and thus immunocompetent individuals successfully respond to infection without sequela. X-linked lymphoproliferative syndrome patients, renal allograft recipients, and acquired immunodeficiency syndrome patients share impaired immune surveillance as a common feature. Such individuals are variously susceptible to numerous untoward complications following infection with Epstein-Barr virus, cytomegalovirus, herpes simplex virus, human papillomavirus, and hepatitis B virus. We hypothesize that failure of the immune system to control these viruses is instrumental in the occurrence of some B-cell lymphomas. Kaposi's sarcoma, and squamous-cell and hepatocellular carcinomas. Herein we review some mechanisms responsible for the breakdown of immune surveillance and the permissive role immunodeficiency plays in viral oncogenesis.

Lymphocyte subsets in Chediak-Higashi patients

Peripheral blood lymphocyte subsets were studied in 6 Chediak-Higashi patients and 12 family members. The lymphocyte subsets were characterized by monoclonal antibody reagents and fluorescence flow-cytometry. An increase in OKT8 (suppressor/cytotoxic) and a decrease in OKT4 (helper) cell populations was observed in all patients studied. No correlation was seen between the clinical status (presence or absence of the lymphoproliferative phase) and the percentage of the lymphocyte subsets. The patient's mothers also had an increased percentage of OKT8-positive cells. The significance of these findings is discussed regarding the patients clinical course.

Comparison of ADCC and NK activities of peripheral blood mononuclear cells from patients at risk for acquired immune deficiency syndrome (AIDS)

Numerous cellular immune defects have been described in patients with acquired immune deficiency syndrome (AIDS). These include anergy, reduced numbers of helper T cells, and decreased effectiveness of natural killer (NK) cells. In this study, we have measured the lytic activity of antibody-dependent cellular cytotoxic (K) cells using a recently described 51Cr release assay in patients clinically displaying lymphadenopathy syndrome (LAD). We then compared ADCC activity with NK activity, T helper/T suppressor ratios and NK cell number in these same patients. Our results indicate that a reduction of ADCC activity can occur in patients with LAD. In our study, patients that showed reduced ADCC activity also showed reduced NK cell function. Other individuals in this study had reduced NK function while ADCC values remained within the normal range. The degree of reversal of the T helper/T suppressor cell ratio was not a useful indicator of cellular immune function as measured by these assays in that individuals with very low ratios often had normal cytotoxic cell function while some patients with ratios in the normal range had decreased cytotoxicity. The percentage of NK cells as determined by HNK-1 monoclonal antibody also did not prove useful in defining potential cytotoxic activities.

Natural history of the AIDS related complex in hemophilia--relationships to Epstein Barr virus

Several cases of hemophiliacs with AIDS have been reported. These case reports have prompted studies of asymptomatic healthy hemophiliacs. During these studies, we found four hemophiliacs who presented a distinct clinical syndrome identical to the lymphadenopathy syndrome in homosexuals which has been considered a prodrome to AIDS. Our results demonstrated that the AIDS related complex in hemophiliacs is characterized by recurrent herpes viral infections. Furthermore, the clinical and laboratory data in these patients suggest that this syndrome does not inexorably lead to AIDS, and may be a manifestation of a group of disorders in which AIDS represents one end of the spectrum.