Molecular Blood Group Screening in Donors from Arabian Countries and Iran Using High-Throughput MALDI-TOF Mass Spectrometry and PCR-SSP

Background and Aims: Only little is known about blood groups other than ABO blood groups and Rhesus factors in Arabian countries and Iran. During the last years, increased migration to Central Europe has put a focus on the question how to guarantee blood supply for patients from these countries, particularly because hemoglobinopathies with the need of regular blood support are more frequent in patients from that region. Therefore, blood group allele frequencies should be determined in individuals from Arabian countries and Iran by molecular typing and compared to a German rare donor panel. Methods: 1,111 samples including 800 individuals from Syria, 147 from Iran, 123 from the Arabian Peninsula, and 41 from Northern African countries were included in a MALDI-TOF MS assay to detect polymorphisms coding for Kk, Fy(a/b), Fynull, Cw, Jk(a/b), Jo(a+/a–), Lu(a/b), Lu(8/14), Ss, Do(a/b), Co(a/b), In(a/b), Js(a/b), Kp(a/b), and variant alleles RHCE*c.697C>G and RHCE*c.733C>G. Yt(a/b), S–s–U–, Velnull, Conull, and RHCE*c.667G>T were tested by PCR-SSP. Results: Of the Arabian donors, 2% were homozygous for the FY*02.01N allele (Fynull), and 15.7% carried the heterozygous mutation. However, 0.8% of the German donors also carried 1 copy of the allele. 3.6% of all and 29.3% of Northern African donors were heterozygous for the RHCE*c.733C>G substitution, 0.4% of the Syrian probands were heterozygous for DO*01/DO*01.-05, a genotype that was lacking in German donors. Whereas the KEL*02.06 allele coding for the Js(a) phenotype was missing in Germans; 0.8% of the Syrian donors carried 1 copy of this allele. 1.8% of the Syrian but only 0.3% of the German donors were negative for YT*01. One donor from Northern Africa homo­zygously carried the GYPB*270+5g>tmutation, inducing the S–s–U+w phenotype, and in 2 German donors a GYPB*c.161G>A exchange, which induces the Mit+ phenotype, caused a GYPB*03 allele dropout in the MALDI assay. The overall failure rate of the Arabian panel was 0.4%. Conclusions: Some blood group alleles that are largely lacking in Europeans but had been described in African individuals are present in Arabian populations at a somewhat lower frequency. In single cases, it could be challenging to provide immunized Arabian patients with compatible blood.

Potential of Next-Generation Sequencing in Noninvasive Fetal Molecular Blood Group Genotyping

Hemolytic disease of the fetus and newborn and fetal and neonatal alloimmune thrombocytopenia are caused by maternal antibodies against fetal alloantigens on red blood cells or platelets that are inherited from the father. After transplacental transport to the fetal circulation, antibodies of the IgG class may cause severe fetal anemia or bleeding complications. The indication for noninvasive fetal blood group genotyping is given if a clinically relevant antibody is detected in a pregnant woman and if the father is heterozygous (or unknown) for the implicated blood group allele. This mini-review will focus on the advantages and current limitations of next-generation sequencing (NGS) for noninvasive diagnosis of fetal blood groups which is, in contrast to fetal aneuploidy screening, proposed only by some research groups. Targeted massively parallel sequencing of short DNA fragments from maternal cell-free plasma samples enables counting of fetal alleles for many single nucleotide polymorphisms in parallel. This information can be utilized for estimation of the fetal fraction of cell-free DNA (cfDNA) as well as detection of the paternal blood group allele in question. Adherence to a cut-off of ≥4% fetal fraction for reporting conclusive results is recommended to avoid false-negative results due to low fetal fraction. For screening purposes of fetal RHD in RhD-negative pregnant women, real-time PCR methods are very well established. However, for diagnostic purposes, the targeted amplicon-based NGS approach has the inherent capability to estimate the fetal fraction of cfDNA. In the future, improving the accuracy of NGS by consensus sequencing of single cfDNA molecules may enable reliable fetal blood group genotyping already in the first trimester of pregnancy.

Association of ABO Blood Group Phenotype and Allele Frequency with Chikungunya Fever

Background. The objective of this study was to investigate the association of the ABO blood group phenotype and allele frequency with CHIK fever.Methods. A rural community survey in Southern Thailand was conducted in August and September 2010. A total of 506 villagers were enrolled. Cases were defined as individuals having anti-CHIK IgG by hemagglutination ≥1 : 10.Results. There were 314 cases (62.1%) with CHIK seropositivity. Females were less likely to have positive anti-CHIK IgG with odds ratio (OR) (95% CI) of 0.63 (0.43, 0.93). All samples tested were Rh positive. Distribution of CHIK seropositivity versus seronegativity (Pvalue) in A, B, AB, and O blood groups was 80 versus 46 (0.003), 80 versus 48 (0.005), 24 versus 20 (0.55), and 130 versus 78 (<0.001), respectively. However, chi-square test between ABO and CHIK infection showed no statistical significanceP=0.76. Comparison of the ABO blood group allele frequency between CHIK seropositivity and seronegativity was not statistically significant.Conclusion. This finding demonstrated no association of the ABO blood group phenotypes and allele frequencies with CHIK infection.

Association of apoprotein A-1 genetic variants with atherosclerosis development in Saint-Petersburg

Apoprotein A-1 is a major protein in antiaterogenic high density lipoproteins and it is one of key proteins regulating reverse cholesterol transport. In this study we have investigated association of APOA1 gene polymorphism with atherosclerosis development among Saint-Petersburg population. Allelic frequencies of polimorphic variants (-75)G/A and 83C/T of APOA1 gene were determined in the group of patients with angiographically proven aterosclerosis and in control group. Allele 83T of the APOA1 gene is associated with lower risk of atherosclerosis development among Saint-Petersburg population.