The Epstein-Barr virus (EBV) has been shown to be associated with posttransplant lymphoma, Hodgkin's disease, and T-cell lymphoma, in addition to African Burkitt's lymphoma. In a retrospective study of 56 consecutive cases of T-cell lymphoma, EBV DNA was found by Southern blot and in situ DNA hybridization in 10 (20%) of 50 peripheral T-cell lymphomas, but in none of six cases of T-lymphoblastic lymphoma. Peripheral T-cell lymphomas containing EBV DNA could be subclassified into three categories according to histology and immunophenotypic studies: (1) T-cell lymphoma of the helper phenotype, five cases. Two cases had histologic features resembling angioimmunoblastic lymphadenopathy (AILD). (2) T-cell lymphoma of the cytotoxic/suppressor phenotype, four cases. AILD-like features could also be recognized in two cases. Reed-Sternberg-like giant cells were identified in three cases designated Hodgkin-like T-cell lymphoma. (3) Angiocentric T-cell lymphoma or lymphomatoid granulomatosis in one case, initially affecting the skin and nose; no T-cell subset could be defined. Six of the eight EBV DNA-positive patients tested for serum EBV antibodies had elevated titers of IgG antiviral capsid antigen (greater than 640) and/or early antigen (greater than 10). From combined studies of Southern blot hybridization by using EBV termini fragment probe and in situ DNA hybridization, the EBV genomes appeared to be clonotypically proliferated in the neoplastic T cells. The patients in all three groups usually had prolonged fever preceding the diagnosis, hepatosplenomegaly, an aggressive clinical course, and poor response to chemotherapy; nine died with a median survival of only 8 months. We propose that these EBV-associated aggressive T-cell lymphomas, like human T-cell leukemia/lymphoma virus-positive T-cell lymphoma, have characteristic clinicopathologic features and should be treated as a separate disease entity.

A 16-year-old male Russian blue cat was presented with acute onset of paraparesis of the forelimbs that progressed to tetraparesis. Neurological examination revealed non-ambulatory tetraparesis with decreased postural reactions in all four limbs. Magnetic resonance imaging revealed multifocal nerve root swelling on the right at C6/C7 and C7/T1, while ultrasonography demonstrated swelling of the right brachial plexus. To understand the cause of the nerve swelling, the right musculocutaneous nerve arising from the brachial plexus and the pectoralis muscle were biopsied. Histologically, there was evidence of neurolymphomatosis (neurotropic lymphoma) with Wallerian degeneration and denervation atrophy of myofibres. The neoplastic lymphoid cells expressed CD79a, CD20 and CD56. Based on these findings, a diagnosis of B-cell neurolymphomatosis was made. Expression of CD56, synonymous with neural cell adhesion molecule, is rare in B-cell lymphomas and has not been reported in feline B-cell lymphomas or feline neurolymphomatosis. CD56 expression was suspected to have played an important role in neurotropism of the neoplastic cells in this case.

The prevalence of cytomegalovirus (CMV) antibody was studied in 966 children in 1984 and 927 children in 1989. The overall prevalence rate of CMV antibody was 59% for children in 1984 and 46% for children in 1989 (P less than 0.05). In both study years, the prevalence rate of CMV antibody was about 70% in infants under 6 months of age, declined to a trough between the ages of 6 and 12 months, and then increased to 40-50% between 1 and 4 years of age. The rate of CMV antibody for children above 4 years in 1984 increased steadily with age and reached 82% by 12 years. In contrast, the prevalence rate in 1989 remained at the level of 40-50% from age 4 to 10 years. It was followed by a sharp increase after 10 years of age and reached 84% at 12 years old. The seropositive rate in each of the 5-, 6-, 8-, 9-, and 10-year-old groups was higher in 1984 than that in 1989. These observations indicated that the prevalence rate of CMV antibody is decreasing in children. This change may be related to various socioeconomic factors, especially the less crowded family conditions in recent years.