[Show abstract][Hide abstract]ABSTRACT: Fetal microchimerism (MCH) has been implicated in the etiology of autoimmune diseases such as autoimmune thyroiditis. The goal of the study was to reliably estimate the number of fetal engrafted cells and to further investigate factors influencing the development of MCH.
Quantitative real-time PCR amplification using Y-chromosome specific (DYS14) and autosomal (beta-globin) loci was performed on thyroid gland specimens. Furthermore, we compared the distribution of ABO and rhesus systems in mothers with and without blood MCH in relation to the blood groups of the children.
MCH was detected in eight of 21 Hashimoto patients in a frequency range of 15 to 4900 male cells per 100,000 total cells (median 97 cells), but in none of 17 healthy thyroid glands. In a third group, consisting of 18 nodular goiters, only one sample was positive (182 male cells/100,000 total cells). No woman who had not had a prior pregnancy with a male fetus showed MCH. Mothers both with and without MCH showed the same rate of mother/child incompatibilities for the ABO and rhesus systems.
The percentage of microchimeric cells varies to a great extent in Hashimoto's thyroiditis, and this phenomenon can occur in nodular goiter in rare instances, but it appears to be absent from normal thyroid glands. Nevertheless, the biological significance of MCH remains unclear. Moreover, we have concluded that the tested blood group systems (as opposed to their role in graft vs host disease after transplantations) have no effect on fetal MCH.
Full-text Article · Mar 2006 · European Journal of Endocrinology
[Show abstract][Hide abstract]ABSTRACT: Sudden and unexpected death from myocardial infarction (MI) is one of the most commonly observed findings in forensic medicine. To investigate the biochemical and genetic background of this disease we investigated the genotypes for two polymorphisms associated with hypertension: TH01, a tetrameric microsatellite in the tyrosine hydroxylase gene and the single nucleotide polymorphism C825T in the GNB3 gene in 116 sudden deaths from MI (78 males, 38 females) and in a control group of 137 deaths from natural causes other than MI (52 males, 85 females). For TH01 no correlation with the prevalence of MI was found. For C825T, results were different. While for the male individuals allelic frequencies and genotype distributions were similar in both groups, T-homozygosity was significantly more common in female fatalities from MI than in the female control group (24% versus 7%; Relative Risk 2.29). Nevertheless, neither for TH01 nor for C825T an association with heart weight was found. Thus our results demonstrate that the C825T polymorphism may play a role in the development of myocardial infarctions, at least in females. They also demonstrate that the genetic component in complex diseases like MI may depend on the gender of the patients. As the influence of this polymorphism on arterial blood pressure appears to be relatively small, and G-proteins are involved in numerous intracellular signal cascades it can be speculated that T-homozygosity at this locus might influence the incidence or mortality of cardiovascular disease via hitherto unknown mechanisms.
Article · Nov 2005 · Forensic Science International
[Show abstract][Hide abstract]ABSTRACT: Forensic Y-chromosome typing applies Y-chromosomal polymorphisms to the analysis of male/female mixed stains such as vaginal swabs in rape cases. The sensitivity of this approach exceeds that of cytological techniques combined with autosomal DNA typing. Y-chromosome typing is based on the assumption that Y-chromosomal DNA found in tissue or secretions of women must originate from a male individual, usually the perpetrator. Nevertheless, it was shown recently that fetal cells can migrate into the female body during pregnancy and can persist for decades ("persisting fetal microchimerism"). The body of a woman after a pregnancy with a male embryo can thus display a small fraction of fetal cells with Y-chromosomes. Using high sensitivity PCR protocols (reamplification with nested primers and up to 60 PCR cycles) fetal cells were previously identified in a number of maternal tissues including skin, blood, muscle and solid organs. It is, however, not clear at present, whether these cells can occur in vaginal secretions, and whether they are capable of producing false positive results in forensic Y-chromosome typing. To evaluate these questions, 66 blood samples of women with at least one son and nine vaginal swabs of women without sexual intercourse in the last 2 weeks were amplified for a stretch of the SRY gene. Eight thyroid gland tissues with already established male fetal microchimerism were used as positive control samples. Blood samples of 10 young girls without history of pregnancy were used as negative controls. Using a PCR with 10 ng of extracted DNA and 30 PCR cycles ("routine sensitivity assay") none of the samples yielded positive results. However, in a PCR with 200 ng of extracted DNA and 45 PCR cycles ("high sensibility assay"), 14% of the blood samples of mothers and 33% of the vaginal swabs amplified for SRY. Our results thus show that increasing the sensitivity of the PCR method and the amount of template DNA produce positive results while protocols used for routine Y-chromosomal typing with small amounts of DNA (approximately 10 ng of DNA) and with a limited number of PCR cycles (approximately 30) can clearly eliminate this peril.
Article · Feb 2004 · Forensic Science International
[Show abstract][Hide abstract]ABSTRACT: Fetal microchimerism, the engraftment of fetal progenitor cells into maternal tissues, has been implicated in the etiology of autoimmune diseases. We used PCR analysis to determine whether microchimerism occurred in the thyroid glands of female patients suffering from Hashimoto's disease and thus may be involved in its etiology. PCR amplification was performed from thyroid gland specimens using primers unique to a Y-chromosomal sequence (SRY gene) and primers for a sequence that is Y/X-chromosomal homologous except for a 6-bp deletion in the X-chromosomal sequence (amelogenin). Microchimerism was detected in 8 of 17 Hashimoto patients, but in only 1 of 25 controls (nodular goiters). Both groups were of similar age and had comparable numbers of pregnancies and numbers of sons. All individuals with microchimerism had given birth to at least 1 son. Our results show that microchimerism is significantly more common in Hashimoto patients than in patients suffering from nodular goiter. We therefore suggest that microchimerism might play a role in the development of Hashimoto's disease, although we cannot completely eliminate the hypothesis that microchimerism is just an "innocent bystander" in a process triggered by other mechanisms.