An Evaluation of HLA-matched Platelet Transfusion Effect in Patients with Platelet Refractoriness / 대한진단검사의학회지

BACKGROUND: Patients with platelet refractoriness as a result of human leukocyte antigen (HLA) alloimmunization can be effectively managed by transfusion of HLA-matched platelets. In this study, we have retrospectively evaluated the effect of HLA-matched platelet transfusion using a hospital based donor pool of 450 HLA typed donors. METHODS: For 17 patients showing platelet refractoriness to random donor platelets [1 hr corrected count increment (CCI) or =7, 500/microliter/m2) was obtained. HLA crossmatch (NIH method) negative patients showed a significantly higher platelet increment compared with crossmatch positive patients (23, 877 vs 10, 823; P=0.000). Although better transfusion effect was obtained in higher grade HLA match of A-B2U by selection of HLA compatible donors according to patients' HLA antibody specificities, an effective platelet increment was obtained in lower grade matches as well. Platelets transfused 24 hours (20, 325 vs 11, 417; P=0.029). CONCLUSIONS: Although many low grade matched donors were selected due to a relatively small size of HLA typed donor pool, effective platelet increments were obtained by selecting platelet donors on the basis of HLA antibody specificity.

Experience of HLA Antibody Testing in the International Serum Exchange Program / 대한진단검사의학회지

BACKGROUND: When organ transplantation or HLA-matched platelet transfusion is considered, accu-rate identification of HLA antibody specificity in the recipient's serum is very important. In this study, we report our experience in an international quality control program. METHODS: For external quality control in a HLA antibody test, the International Serum Exchange Program distributes serum samples, generally showing polyspecific reactivity for cross-reactive epitope groups (CREGs), to participating laboratories: 4 samples per survey, 10 surveys per year. Participating in the program from May 1998 to August 2000 (24 surveys), we performed HLA antibody identification of 96 serum samples by the AHG-CDC (anti-human globulin-complement dependent cytotoxicity) method using frozen lymphocyte trays (36 lymphocyte panels). We compared the results of our laboratory with those of the total participants (all methods combined, 72 to 92 laboratories per survey) using the analyzed survey results distributed by the program organizer. RESULTS: We analyzed the survey results for the antibodies to relatively common HLA antigens in Koreans (antigen frequency >1%). For the HLA antibodies detected in >or=20% of participants, our detection rate was higher by 10-15% than that of all laboratories (HLA-A, 76% vs 65%; HLA-B, 73% vs 57%). And for the HLA antibodies detected in >or=50% of the participants, our detection rate was as high as 88% for HLA-A and 87% for HLA-B. Our detection rate for a few antibody specificities was lower than that of all laboratories, namely HLA-A1, A3, B35, and B55. Among these, A1, A3, and B55 were of lower incidence antigens in Koreans (antigen frequency 3-4%), indicating that the low detection rate was due to a limitation in the composition of lymphocyte panels. CONCLUSIONS: In general, our detection rate of HLA antibodies was superior to the average detection rate of the total participant laboratories. We would be able to improve the low detection rate for a few antibody specificities to lower incidence antigens by refining the composition of lymphocyte panels.

Polymorphisms in the TNF-alpha Gene and Extended HLA and TNF-alpha Haplotypes in Koreans

BACKGROUND: Tumor necrosis factor-alpha (TNF-alpha) is known to play an important role in various conditions such as inflammation, autoimmunity, apoptosis, insulin resistance and sleep induction. Five single nucleotide polymorphisms (SNPs) have been known to affect the transcriptional activities of TNF-alpha: 1,-031T/C, -863C/A, -857C/T, -308G/A and -238G/A. METHODS: We have investigated 5 SNPs of the promoter region of TNF-alpha gene, the distribution of 5-locus TNF-alpha haplotypes, and their haplotypic associations with previously typed HLA-A, -B and -DRB1 loci in 107 healthy unrelated Koreans. TNF-alpha SNPs were typed using PCR-single-strand conformation polymorphism (SSCP) and PCR-restriction fragment length polymorphism (RFLP) methods. RESULTS: The allele frequencies of -1,031C, -863A, -857T, -308A, and -238A, which are known as the high-producer-type, were 19.3%, 15.9%, 14.0%, 5.9%, and 2.9%, respectively. The frequency of -308A allele, known to be associated with autoimmune diseases, was 5.9% in Koreans which was lower than Caucasians (14-17%) and somewhat higher than Japanese (1.7%). Five most common TNF-alpha haplotypes (-1,031/ -863/ -857/ -308/ -238) comprised over 95% of total haplotypes: TCCGG (58.4%), CACGG (14.8%), TCTGG (13.7%), TCCAG (5.3%), and CCCGA (3.1%). Strong positive associations (P3%) comprised around 16% of total haplotypes: A33-B58- TCCAG-DRB1*1302, A24-B52-TCCGG-DRB1*1502, A33-B44-TCCGG-DRB1*1302, A24- B7-TCCGG-DRB1*0101, and A11-B62-TCCGG-DRB1*0406. The distribution of extended HLA and TNF-alpha haplotypes showed that most of HLA haplotypes were almost exclusively associated with particular TNF-alpha haplotypes. CONCLUSION: The results obtained in this study would be useful as basic data for anthropologic studies and disease association studies in Koreans.