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Presents questions and answers regarding the detection of platelet-reactive antibodies inpatients who are refractory to platelet transfusions. Selection of compatible donors; Technique in the detection of human leukocyte antibodies (HLA) class I; Requirementsfor the cellpanels in the detection of HLA class I; Association between the antibodies and the refractoriness.

Provides the nomenclature for factors of the human leukocyte antigen (HLA) system. Naming of additional genes within the HLA region; Naming of additional alleles; Renaming of alleles and removal of incorrect alleles; Extension of HLA allele names.

Background: The aim of this study was to demonstrate how ultrastructural morphology of platelets stored in different media correlate with the appearance of particular activation markers on their cell surface.Study Design and Methods: Concentrates of buffy coat-derived platelets were stored in plasma or a glucose-free citrate-acetate-NaCl platelet additive solution (PAS2, Baxter Healthcare Corp.). Activation markers on platelets were measured by flow cytometry and compared with changes in the platelet cell surface as demonstrated by electron microscopy. Levels of the vasoactive cytokines vascular endothelial growth factor (VEGF) and RANTES (regulated upon activation, normal T-cell expressed and secreted) were determined in the storage medium of the platelet concentrate.Results: The activation markers CD62P and CD63 and the binding of thrombospondin measured by flow cytometry were expressed to a higher extent in the PAS2 group compared with the plasma group. The difference reached significance on Day 3 (CD62P: 66.37 +/- 2.44 vs. 37.83 +/- 2.03, p < 0.001; CD63: 42.11 +/- 3.29 vs. 34.84 +/- 2.04, p < 0.05; and thrombospondin binding: 18.84 +/- 3.9 vs. 13.98 +/- 3.87, p < 0.001, respectively). The form factor that is related to changes of the platelet shape was determined by image analysis and correlated significantly with the cell surface expression of CD62P (p < 0.001) and with CD63 (p < 0.05) and with thrombospondin binding (p < 0.05). The chemokines VEGF and RANTES were measured at higher levels in the PAS2 group.Conclusions: With exception of baseline activation probably due to necessary handling procedures, platelets remain relatively unaltered and more stable in plasma in comparison to storage in PAS2. [ABSTRACT FROM AUTHOR]

Presents a nomenclature for factors of the HLA histocompatibility antigen system, released by the World Health Organization in 2000. Naming of new alleles; Serological specificities associated with alleles; Names for genes in the HLA region.

A new human leukocyte allele HLA-B*8102 has been identified in a cell provided by the UCLA International Cell Exchange scheme. The nucleotide sequences of exons 2 and 3 of the new allele are identical with HLA-B*8101. Four nucleotide differences, however, are observed in exon 1, three of them representing non-synonymous base changes. [ABSTRACT FROM AUTHOR]

The microheterogeneity of the tetranucleotide repeat locus C2_4_4 situated in the HLA class I region (6p21.3) was investigated by sequencing 50 alleles in an Austrian population sample of 240 unrelated Caucasoid individuals. Several different sequences were found in alleles of the same length. Analysis of the associations between the sequenced C2_4_4 alleles and HLA class I showed a strong linkage disequilibrium between the C2_4_4*9 sequence variants and two different HLA class I haplotypes, as well as between the most common *17 sequence and one HLA-ABC haplotype. No clear cut association could be observed in C2_4_4*16 and *18. The results of this study demonstrate that the exclusive use of microsatellite polymorphisms for the definition of HLA haplotypes is generally not possible. [ABSTRACT FROM AUTHOR]

Abstract: Two cases of allelic loss at the D19S433 locus after multiplex PCR with the AmpFlSTR Identifiler kit (Applied Biosystems) are described. In both cases the failure of PCR resulted in genetic inconsistencies due to opposite homozygosity. After singleplex PCR with published primers additional alleles were observed and Mendelian inheritance was restored. These PCR products were sequenced and in both cases the same 4bp deletion near the 3′ end of the repeat region was detected in two alleles of different length. The frequency of these null alleles (two events in 1026 allelic transfers) amounts to 0.0019 (95% confidence limits: 0.0002–0.0070). [Copyright &y& Elsevier]