Determination of human neutrophil antigen-1, -3, -4 and -5 allele frequencies in English Caucasoid blood donors using a multiplex fluorescent DNA-based assay

BACKGROUND AND OBJECTIVES

A number of DNA-based methods to genotype the alleles coding for HNA have been described, but all require the separate amplification and analysis of each allele. The aim was to develop a DNA-based method for simultaneous detection of HNA-1, HNA-3, HNA-4 and HNA-5 alleles.

MATERIALS AND METHODS

An allele-specific primer extension method was used in combination with magnetic beads from Luminex technology. PCR-sequence-specific primers (SSP) was used to resolve the presence of the HNA-1b allele in samples assigned by the Luminex bead assay as HNA-1a/-1b/-1c or HNA-1b/-1c. HNA allele frequencies were determined in a panel of 140 randomly selected English Caucasoid blood donors.

RESULTS

HNA allelic types were compared with historical results, and 100% concordance was found. Only eight of the 97 samples used in the validation required additional testing by PCR-SSP. Allele frequencies were determined in the blood donor population as follows: 0·318 for HNA-1a, 0·668 for HNA-1b, 0·014 for HNA-1c, 0·768 for HNA-3a, 0·232 for HNA-3b, 0·882 for HNA-4a, 0·118 for HNA-4b, 0·736 for HNA-5a and 0·264 for HNA-5b.

CONCLUSION

A multiplex Luminex bead assay for the simultaneous detection of HNA-1, HNA-3, HNA-4 and HNA-5 alleles is described that enables rapid typing of donors to support HNA alloimmunized patients who require HNA-compatible blood products.

Simultaneous detection of HFE C282Y, H63D and S65C mutations associated with type 1 haemochromatosis using a multiplex luminex bead assay

Type 1 hereditary haemochromatosis (HH) is a common genetic disorder in Caucasoids resulting from mutations in the HFE gene. Routine diagnostic testing for type 1 HH involves genotyping for two of these described HFE mutations, C282Y and H63D. In some cases typing of a third mutation, S65C is also performed. Several techniques have been reported for HFE genotyping and these include polymerase chain reaction (PCR)-sequence-specific primers (SSP), PCR-restriction fragment length polymorphism (RFLP), PCR-sequence-specific oligonucleotide probe (SSOP), real-time PCR followed by melting curve analysis and TaqMan assay. The aim of this study was to develop an alternative method to both conventional PCR and real-time PCR/TaqMan assay to detect all three HFE mutations in a single assay using Luminex technology. DNA controls of known genotypes (n = 109) were used to evaluate this approach. These controls were selected to represent the three possible genotypes (wild type, mutant, heterozygous) for each mutation. Subsequently, blind DNA samples (n = 100) were used to validate this method. This new assay was then compared with current techniques (in-house PCR-SSP and TaqMan assay). Comparison of genotypes obtained with the Luminex method with those previously reported by both in-house PCR-SSP and TaqMan assay showed 100% concordance for both DNA controls and blind DNA samples and no discrepancies were observed. Allelic frequency for C282Y, H63D and S65C mutations were 22%, 16% and 2%, respectively. We report here a high-throughput, accurate and robust multiplex luminex bead assay for routine clinical testing of C282Y, H63D and S65C mutations in the HFE gene.

Identification of two novel single nucleotide polymorphisms in the promoter of the human interleukin-18 receptor alpha

Single-strand conformational polymorphism (SSCP) was used to identify single nucleotide polymorphisms (SNPs) in the promoter region of the human interleukin-18 receptor alpha (IL-18Ralpha). Two SNPs were identified at positions -69 and -638 relative to the transcriptional start site. Two-way comparison of the two SNPs revealed strong linkage disequilibrium (chi2 = 63.45, P < 0.001). Three haplotypes were identified, namely C-69C-638, T-69C-638 and C-69T-638, with frequencies of 0.26, 0.39 and 0.35, respectively.