AIMS: To examine the expression of the Bcl-2 family of proteins (Bcl-2, Bcl-x, Bcl-xL and Bax) in classical Hodgkin's lymphoma (cHL) and to correlate the expression of these proteins with proliferation, apoptosis and the presence of Epstein-Barr virus (EBV).
METHODS AND RESULTS: Expression of the Bcl-2 family of proteins was detected by immunohistochemistry, proliferation was determined by Ki67 labelling and apoptosis by TUNEL in-situ hybridization. EBV was detected by Epstein-Barr virus early RNA (EBER) in-situ hybridization. Expression of Bcl-2, Bcl-x, Bcl-xL and Bax was detected in the Hodgkin/Reed-Sternberg (H/RS) cells in 43.7% (27/62), 87.5% (56/64), 67.2% (41/61) and 74.6% (47/63) of the cHL cases, respectively. EBER was detected in 53% (35/66) of the cases, whereas Ki67 was observed in 86.7% (52/60) of the cases. Apoptotic H/RS cells were observed infrequently, and only 43.2% (11/26) of the cases showed an apoptotic index of > or = 10% in the H/RS cells. A statistically significant inverse relationship was observed between the expression of Bcl-2 and the presence of EBV (P = 0.003). Bcl-xL showed an inverse correlation with apoptosis in the H/RS cells (P = 0.004).
CONCLUSIONS: The higher Bcl-xL expression (67.2%) compared with Bcl-2 expression (43.5%) observed in cHL as well as the statistically significant inverse relationship between Bcl-xL and apoptosis suggests that Bcl-xL plays an important role in the survival of H/RS cells. Expression of Bax may be neutralized by other anti-apoptotic members of the family such as Bcl-2 and/or Bcl-xL.
The pattern of childhood non-Hodgkin's lymphoma (NHL) usually differs in adults. The most common subtypes are lymphoblastic, Burkitt's and anaplastic large cell lymphoma. Recent data indicate that a higher risk of developing lymphoma is associated in children of certain ethnic origins. The difference is probably related to the underlying etiological factors of these diseases, and Epstein-Barr virus (EBV) is a strong candidate. The present study aims to determine the disease pattern of childhood lymphomas in the University Hospital Kuala Lumpur, for a direct comparison to the reported data of adults from the same medical center. A total of 69 and 34 childhood NHL and Hodgkin's lymphomas, respectively, were retrieved. The most common subtypes were lymphoblastic (23 cases), Burkitt's (25 cases) and anaplastic large cell lymphomas (9 cases). Epstein-Barr virus association was more prevalent in B-cell (23%) than T-cell (12%) lymphomas. The most common EBV-associated tumor was Burkitt's lymphoma, and there was an increased risk of EBV association for Burkitt's lymphoma in Chinese patients. In conclusion, the pattern of childhood lymphoma in Malaysia is relatively similar to children elsewhere in the world. The EBV association of B- and T-NHL differs between children and adults from the same medical center because of differences in the subtype composition in these two age groups.
Banna virus (BAV, genus Seadornavirus, family Reoviridae) is an arbovirus suspected to be responsible for encephalitis in humans. Two genotypes of this virus are distinguishable: A (Chinese isolate, BAV-Ch) and B (Indonesian isolate, BAV-In6969) which exhibit only 41% amino-acid identity in the sequence of their VP9. The VP7 to VP12 of BAV-Ch and VP9 of BAV-In6969 were expressed in bacteria using pGEX-4T-2 vector. VP9 was chosen to establish an ELISA for BAV, based mainly on two observations: (i). VP9 is a major protein in virus-infected cells and is a capsid protein (ii). among all the proteins expressed, VP9 was obtained in high amount and showed the highest immuno-reactivity to anti-BAV ascitic fluid. The VP9s ELISA was evaluated in three populations: French blood donors and two populations (blood donors and patients with a neurological syndrome) from Malaysia, representing the region where the virus was isolated in the past. The specificity of this ELISA was >98%. In mice injected with live BAV, the assay detected IgG-antibody to BAV infection 21 days post-injection, which was confirmed by Western blot using BAV-infected cells. The VP9 ELISA permits to determine the sero-status of a population without special safety precautions and without any requirements to propagate the BAV. This test should be a useful tool for epidemiological survey of BAV.