Gene frequencies of the HPA-1 to 6 and Gov human platelet antigens in Thai blood donors.

Human platelet alloantigens (HPA) are important in neonatal alloimmune thrombocytopenia (NAIT), posttransfusion purpura (PTP), platelet transfusion refractoriness, passive alloimmune thrombocytopenia, and transplantation-associated alloimmune thrombocytopenia. Thus, HPA genotyping is essential in diagnosis and treatment. We analyzed HPA-1 to 6 and Gov alleles, using PCR with sequence specific primers (PCR-SSP) in 500 Thai blood donors who had been HLA class I antigen typed. HPA-4a was present in all samples. HPA-1b, -2b, -5b, and -6b were rare, and HPA-4b was not found. HPA-3a and -3b showed frequencies of 56.0 percent and 44.0 percent, respectively. Gova and Govb showed frequencies of 49.1 percent and 50.9 percent, respectively. The prevalence rates of HPA-1 to 6 gene frequencies (GFs) were consistent with those of other Asian populations rather than those of Caucasians. We also report on the GFs of Gova and Govb, which also are comparable to those of Asian populations. Our results could establish a useful HPA- and HLA-matched plateletpheresis donor file and provide an improvement of platelet alloantibody detection in alloimmune thrombocytopenic patients, and, therefore, a more effective platelet transfusion program.

Monitoring of T-cell subsets in patients treated with anti-CD 25 antibody.

Daclizumab and basiliximab, the antibodies to the interleukin-2 receptor (anti-IL-2R), decrease the incidence of acute rejection in renal transplantation. However, prolonged blockade of IL-2 receptor (IL-2R:CD25) may hamper apoptosis of reactive T-cell clones and thus may obstruct tolerance induction. We determined the effect of varying doses of anti-IL-2R on the number of CD3+CD25+ cells as an index of CD 25 blockade. The number of CD3+CD25+ cells was determined in four groups of induction therapies: no antibody induction; two doses of 50 or 25 mg daclizumab on day 0 and day 14; and two doses of 20 mg basiliximab at day 0 and day 4 (n=10, 24, 10, and 10, respectively). The number of CD3+CD25+ cells were monitored in whole blood before antibody infusion as well as 24 hours thereafter and weekly after transplantation. With two doses of 50 mg daclizumab, two doses of 25 mg daclizumab, and two doses of 20 mg basiliximab, the expression of CD3+CD25+ cells was completely suppressed for 12, 10, and 12 weeks posttransplantation, respectively. The reappearance of CD3+CD25+ cells above the baseline for each induction regimen was: 17 weeks for two doses of 50 mg daclizumab, 11 weeks for two doses of 25 mg daclizumab, and 13 weeks for two doses of 20 mg basiliximab. Monitoring of CD3+CD25+ cells may be utilized to tailor anti-IL-2R administration at a minimal dosage, yet retaining adequate IL-2R blockade for at least 3 months posttransplantation.

Neonatal alloimmune thrombocytopenia due to anti-Nak(a).

BACKGROUND: The accurate diagnosis of neonatal alloimmune thrombocytopenia is essential in the effective treatment of potentially serious bleeding in neonates. CASE REPORT: Reported here is a case of a full-term female baby who was delivered by vacuum extraction from a gravida 1 para 1 healthy mother. She presented with generalized petechiae and bilateral cephalhematoma, which she had had since birth. At 7 hours of life, she had an upper gastrointestinal hemorrhage and was found to have severe anemia and marked thrombo-cytopenia. Coagulation screening tests were normal. The diagnosis of neonatal alloimmune thrombocytopenia was suspected, and maternal serum was collected for further study. The baby was treated with a single dose of hydrocortisone (10 mg/kg) and IVIG (400 mg/kg) while waiting for irradiated platelets from her mother. After 30 mL of a transfusion of maternal platelets, the baby's platelet count rose dramatically, from 15,000 to 162,000 per microL, and it remained stable at that level. She was discharged on the 10th hospital day in good condition. During the follow-up period of 8 months, her growth and development were satisfactorily normal, as well as her platelet count. A high-titered platelet antibody was detected in the maternal serum by use of a solid phase platelet adherence technique. RESULTS: The specificity of the platelet antibody was identified as anti-Nak(a) by the mixed passive hemagglutination test method. CONCLUSION: These findings suggested a diagnosis of NAIT caused by anti-Nak(a).

CHOP versus CHOP plus ESHAP and high-dose therapy with autologous peripheral blood progenitor cell transplantation for high-intermediate-risk and high-risk aggressive non-Hodgkin's lymphoma.

The purpose of the study was to compare conventional cyclophosphamide/doxorubicin/vincristine/prednisolone (CHOP) chemotherapy with CHOP (3 courses) plus etoposide/methylprednisolone/high-dose cytarabine/cisplatin (ESHAP), high-dose therapy (HDT), and autologous peripheral blood progenitor cell transplantation (PBPCT) as front-line treatment for poor-prognosis aggressive non-Hodgkin's lymphoma (NHL). Between May 1, 1995, and April 30, 1998, 58 patients, aged 15-55 years, newly diagnosed with poor-prognosis aggressive NHL (category F-H by the Working Formulation) were enrolled. According to the age-adjusted international prognostic index, 65% of the patients were high-risk cases and 35% made up the high-intermediate group. After 3 courses of CHOP, 25 of 48 patients were randomized to continue with CHOP, and 23 were randomized to receive 2-4 cycles of ESHAP followed by HDT and PBPCT. There was no significant difference in the rate of complete remission between the two groups (36%, 95% confidence interval [CI]: 18%-57% in CHOP vs. 43%, 95% CI: 23%-65% in ESHAP/HDT) (P = 0.77). With a median follow-up duration of 39 months, the 4-year failure-free survival (FFS) was superior in the ESHAP/HDT group (38%, 95% CI: 18%-58% vs. 15%, 95% CI: 4%-32%) (P = 0.04). The disease-free survival was marginally different in favor of the ESHAP/HDT arm (90%, 95% CI: 47%-98% vs. 37%, 95% CI: 7%-69%) (P = 0.06). The 4-year overall survival between the two treatment arms was comparable (51%, 95% CI: 28%-70% for ESHAP/HDT vs. 30%, 95% CI: 13%-48% for CHOP) (P = 0.25). Treatment-related mortalities were not significantly different between both groups (17%, 95% CI: 5%-39% for ESHAP/HDT vs. 8%, 95% CI: 1%-26% for CHOP) (P = 0.41). However, only 61% of the patients assigned to the ESHAP/HDT arm underwent HDT and PBPCT. As compared with CHOP, the corporate regimen of CHOP/ESHAP/HDT seems to improve the FFS in patients with newly diagnosed, poor-prognosis aggressive NHL.

Comparative analysis of serological and molecular results for HLA-DR typing in 120 Thai subjects.

In this study, serological HLA-DR typing results were compared to typing results obtained with sequence-specific primers in the polymerase chain reaction (PCR-SSP). HLA-DR typing was performed on 120 random Thai individuals. Differences in HLA-DR typing results were found in 18 out of 120, which were due to cross reactive antibodies and the lack of potent antisera to define proper HLA-DR splits by serology. Furthermore, PCR-SSP is fast and easy to perform as HLA-DR typing results can be obtained within 2 hours. From the results of this study it can be concluded that PCR-SSP is a reliable and promising technique for HLA-DR typing which can replace the serological technique in routine clinical practice.

Studies of immune response to hepatitis B vaccine in Thai blood donors.

The immunogenicity of heat-inactivated plasma derived hepatitis B vaccines were studied in one hundred and eighty-two adult blood donor volunteers whose HBV markers (HBsAg, anti-HBs) were negative. They were randomized for four regimens of 3 micrograms intramuscular Hepaccine-B vaccine at the schedules of 0, 1, 2, 9 months, 0, 1, 3, 9 months, 0, 2, 6, 12 months, 0, 1, 6, 12 months and another regimen of 5 micrograms Hevac-B Pasteur vaccine at 0, 1, 2, 9 months. Blood specimens, tested for serological marker (anti-HBs), were drawn at 1, 3, 6, 9, 12 and 15 months following the initial injection. The outcome revealed that the Hepaccine-B vaccinated group in the schedules of 0, 2, 6, 12 and 0, 1, 6, 12 months yielded seroconversion rates of 48.7% and 56.8%, respectively one month after vaccination. After that, the immune response (anti-HBs titer) regularly increased every three months until it reached 100% with a geometric mean (GMT) of 135 and 130 mIU/ml respectively in the fifteenth month. Taking the Hepaccine-B and the Hevac-B Pasteur with the same schedule (0, 1, 2, 9 months) into consideration, we found that the former yielded the higher seroconversion rate, one month after the initial injection, which increased to the highest rate of 95.8% in the ninth month. After that it was steady until the fifteenth month with higher GMT (584 mIU/ml) than that of Hevac-B Pasteur (323 mIU/ml). The seroconversion rate of Hevac-B Pasteur in the first month was lower than that of Hepaccine-B but it yielded the highest rate of 100% in the sixth month. After that, it gradually decreased and again increased to 100% in the fifteenth month.