Aplastic anaemia complicating infectious mononucleosis

Viruses and the blood

Haematological syndromes attributed to viruses demonstrate geographical variations in incidence and great dependence on host factors. Severe haematological disease is the exception rather than the rule in dengue virus infection, and probably depends at least in part on the host immune response to the virus. The increased incidence of hepatitis-associated aplasia in east Asia may reflect distribution of an infectious agent, an environmental toxin, or genetic predisposition, but probably represents some combination of these factors. Agents with apparently universal distribution, such as parvovirus B19 and Epstein-Barr virus, are associated with bone marrow failure only in a very narrow range of hosts. These examples teach us that viral causes cannot automatically be excluded from the differential diagnosis of syndromes whose occurrence is rare or apparently sporadic. Further investigation of these syndromes should include more detailed characterization of host factors, particularly immunological characteristics, and possible infectious and toxic cofactors which are associated with morbidity.

Successful outcome of severe aplastic anemia following Epstein-Barr virus infection

Severe aplastic anemia has been reported in children following Epstein-Barr virus (EBV) infection. The pathophysiology of disease is not known, but an immunologic mechanism is suspected because of the rapid response to steroids. A patient with severe aplastic anemia following EBV infection experienced bone marrow recovery after treatment with high-dose prednisone. After reviewing the literature it is concluded that steroid therapy is indicated in this select group of patients.

Fatal aplastic anaemia complicating infectious mononucleosis

A 7-year-old boy developed fatal aplastic anaemia, 2 weeks after the first signs of infectious mononucleosis. Although some drugs were administered, infection with the Epstein-Barr virus, leading to infectious mononucleosis, is assumed to be the cause of this aplastic anaemia. Some mechanisms possibly leading to the aplasia are discussed.

Variable phenotypic expression of an X-linked recessive lymphoproliferative syndrome

Investigation of a family with cancer in boys revealed that at least 20 males had the X-linked recessive lymphoproliferative syndrome. A variety of phenotypes occurred: aproliferative phenotypes consisted of aplastic anemia, agranulocytosis or acquired hypogammaglobulinemia; and proliferative phenotypes of B cells included disorders associated with the Epstein-Barr virus, American Burkitt's lymphoma, immunoblastic sarcoma of B cells, fatal infectious mononucleosis or plasmacytoma. The lymphoproliferative disorders observed in males could have resulted from an immunodeficiency to Epstein-Barr virus. The variable phenotypic expression could have resulted from individual differences in the viral dose, duration of exposure and age at which the boys were exposed to the virus. Aproliferative phenotypes such as acquired hypogammaglobulinemia could have ensued from excessive suppressor-cell activity on B cells, whereas proliferative phenotypes such as Burkitt's lymphoma or fatal infectious mononucleosis could have resulted from infection by Epstein-Barr virus and failure to stop proliferation of B cells.