No abstract

GB virus C or hepatitis G virus (GBV-C/HGV), a novel Flavivirus, is detected in 1.5% of US blood donors. The prevalence is higher in multiply transfused patients and in persons with liver disease. Because of the increased incidence of hepatitis in Asia, sera from healthy Vietnamese were tested for the presence of GBV-C/HGV RNA by the reverse transcription polymerase chain reaction. Viral RNA was detected in 5.7% of those tested; 6 of 81 volunteer blood donors had positive samples as did 5 of 97 army recruits and 2 of 50 postpartum women. When the 188-bp product from 6 subjects was sequenced, there was 75%-85% homology at the nucleotide level compared with published sequences, indicating a high degree of genotypic variation, even within a putatively well-conserved region of the viral genome. Viremia with this non-cell-associated novel virus appears to be common among normal persons in Vietnam.

Little is known about the influence of environmental and ethnic factors on the epidemiology of immune thrombocytopenic purpura (ITP). Therefore we compared the initial presentation and condition after 6 mo in 90 Vietnamese and 89 German and Swiss children with newly diagnosed ITP. Data from the two cohorts were collected within the same time period. No differences in age and sex were observed between the Asian and European cohorts, but significant differences between initial platelet count, the occurrence of dry versus wet bleeding symptoms, and infection preceding the onset of ITP were found. Children who had chronic ITP also differed with respect to platelet count and postinfectious state, but not initial bleeding type. In addition, chronic ITP occurred more often than expected with a male to female ratio of 1.2 in Vietnam and 2 in Germany and Switzerland. The data support the potential influence of environmental or ethnic factors on the different aspects of ITP, and point to the need for further epidemiologic investigations.

In Vietnam, the carrier rate for ␤-thalassemia varies from 1.5% to 25% depending on the ethnic groups of the population. The molecular basis of ␤-thalassemia in South Vietnam was studied in 50 unrelated ␤-thalassemia patients. Of these, 31 had ␤-thalassemia/Hb E, 18 were homozygous for ␤-thalassemia, and 1 carried the ␤-thalassemia trait. The majority of the patients were Kinh, four were Chinese, and two were Kinh-Chinese. All had severe anemia and received blood transfusions regularly, every 1-3 months. Hepatosplenomegaly was found in all patients, and splenectomy had been done in six patients. Normal ␣-globin genotype (␣␣/␣␣) was found in all subjects. Reverse dot-blot hybridization using oligonucleotide probes specific for Southeast Asian mutations can detect ␤-thalassemia in 60 chromosomes in addition to 31 chromosomes with ␤ E mutation.

In Vietnam, the first three cases of Allo-BMT were successfully performed in 1995 at the Blood Transfusion and Hematology Hospital (BT-H) of Ho Chi Minh City. Donors were HLA fully matched siblings (HLA-A, HLA-B and HLA-DRB1). The patients were a 26-year-old man with CML in chronic phase (CP), a 12-year-old woman with b-thalassemia/Hb E and a 9-year-old girl with b-thalassemia/Hb E. All patients were engrafted with the median time to recover ANC40.5 Â 10 9 /l, and platelet count 420 Â 10 9 /l was 16 and 38 days. At 12 years after transplantation, all three patients are alive and well. Today, Vietnam has five SCT centers; in the north, there are three centers: 108 Military Hospital, Pediatric Institute and Blood transfusion and Hematology Institute; in the middle of Vietnam is Hue Hospital and in the south, the BT-H Hospital of Ho Chi Minh City. Until now, 65 patients have had SCT in Vietnam; among them, 52 patients had SCT at the BT-H Hospital, Ho Chi Minh City. Because of no connection of data between different SCT centers, we present here only the results performed at the BT-H Hospital, Ho Chi Minh City. With Allo-SCT we performed 19 cases with 3 procedures: BMT (4 cases), PBSC (6 cases) and cord blood transplantation (9 cases); patients were diagnosed with AML (n ¼ 7), ALL (n ¼ 1), CML (n ¼ 5) and b-thalassemia (n ¼ 6). Following transplantation, 7 patients (36.84%) relapsed, 12 (63.16%) remained alive and overall survival times: 6.81 ± 1.35 years, disease-free survival times: 6.69 ± 1.4 years (range 0.5-12 years). With Auto-SCT: since November 1996, we have performed 33 cases of autologous PBSC transplantation consisting of without cryopreservation (24 cases) and with cryopreservation (9 cases); patients were diagnosed with AML in CR1 (n ¼ 21), ALL in CR1 (n ¼ 6), CML in CP (n ¼ 5) and non-Hodgkin's lymphoma in CR1 (n ¼ 1). The median age of the patients was 35 years (range 18-46). The median time to recover ANC 40.5 Â 10 9 /l and platelet count 420 Â 10 9 /l was 14 days (range 9-25 days) and 35 days (range 9-120 days). Following transplantation, 18 patients (54.50%) relapsed, 15 (45.45%) remained alive and overall survival times: 5.74 ± 0.82 years and disease-free survival times: 5.48 ± 0.92 years. There was no statistically significant difference of overall survival and disease-free survival between Allo-SCT and Auto-SCT procedures (P40.05). These preliminary data suggest that HSCTs have been used as one of the standard treatments for hematological diseases and malignancies in Vietnam and that cord blood is an alternative source of hematopoietic stem cells for allogeneic transplantation in children.