Tetragametic chimerism detected in a healthy woman with mixed-field agglutination reactions in ABO blood grouping.

BACKGROUND: The case of a healthy woman with serologic blood group AB and her biologic father showing blood group O was investigated. Further analysis, including blood, buccal swabs, and nail clippings, revealed a tetragametic chimerism. STUDY DESIGN AND METHODS: Blood grouping was performed with standard gel centrifugation test cards, ABO genotyping by sequence-specific primers (SSPs) and sequence-based typing, and HLA Class I and II typing by standard NIH cytotoxicity testing and SSP. Additionally, short-tandem-repeat (STR) and variable-number tandem-repeat (VNTR) typing was performed on blood, nail clippings, and buccal swab samples. The karyotype was analyzed by G-banded chromosomes. RESULTS: The proposita's RBCs were typed AB with a mixed-field agglutination whereas in molecular typing A, B, and O alleles were found. One paternal and two maternal haplotypes were determined by use of HLA typing. Interestingly, both paternal alleles were detected in 4 of 23 tested STR and VNTR loci only, with whole blood, nail clippings, and buccal swabs. The karyotype was identified as 46XX. The family members including the proposita's healthy twin children displayed no abnormal findings in tests performed. CONCLUSION: By investigation of DNA polymorphisms, it was possible to determine a rare case of tetragametic chimerism being the result of double parental contribution of nuclei.

Transcript level of erythroid differentiation-related factor, a candidate surrogate marker for transmissible spongiform encephalopathy diseases in blood, shows a broad range of variation in healthy individuals.

BACKGROUND: In 2001, it was demonstrated that the expression of the erythroid differentiation-related factor (EDRF) is reduced in lymphatic tissues of rodents and cattle as well as in whole blood of sheep that suffer from transmissible spongiform encephalopathy. STUDY DESIGN AND METHODS: To determine whether the normal range of EDRF expression varies in healthy individuals, mRNA levels were measured in whole blood samples from 106 healthy blood donors by quantitative real-time RT-PCR. Furthermore, the correlations of transcript levels with individual physical characteristics were analyzed. In addition, EDRF expression was examined in total RNA samples from a lymph node and the intestine. RESULTS: The data show that EDRF mRNA levels in healthy persons vary within a total range of 2 log units as well as they display a weak correlation with body height. Furthermore, it was found that EDRF is also expressed in lymph nodes and the intestine. CONCLUSION: Owing to its broad range of variation, measuring the EDRF expression does not seem to be a good surrogate marker, unless an altered expression is distinctively different from the varying level in healthy humans.