Focus on the importance of soluble HLA-G as a marker for embryo selection in ART

8 10 2013

To the Editor:

We have read with interest the paper by Kotze et al. (1), reporting the retrospective analysis of 2,040 patients for the expression of soluble HLA-G (sHLA-G) by day-2 embryos after intracytoplasmic injection. The data represent further confirmation of the role of sHLA-G molecule quantification in embryo culture supernatants as a marker for embryo selection (2). In pregnancy several tolerance mechanisms have been demonstrated to counteract the maternal immune response. Among these, the expression of HLA-G by invasive cytotrophoblasts has been shown to play a fundamental role in creating a tolerogenic condition at the feto-maternal interface (2).

By now, more than 15,000 embryo culture supernatants have been evaluated for sHLA-G expression, with a positive correlation with embryo implantation rate and pregnancy outcome. However, further research is needed in HLA-G investigation in assisted reproductive technology (ART). Three aspects should be taken into consideration: 1) recognition of a common sHLA-G detection protocol; 2) necessity to identify a standardized range for positivity, as reported by Kotze et al. (1); 3) comprehension of the factors involved in the differential expression of sHLA-G between equal stage embryos originating from the same woman (3). Read the rest of this entry »


Vitrification Carriers and European Regulation

6 03 2012

To the Editor:

We read with interest the recent article by Valbuena et al. (1) comparing the efficiency of Cryotip vs. Cryotop for blastomere vitrification. The authors concluded that it is preferable to preserve individual human blastomeres using Cryotip, which is a closed system. Furthermore, they suggest that this has the advantage of complying with European Union directives.

We would like to point out that European Union directives on tissue manipulation (European Union Tissues and Cells Directive EUTCD: 2004/23/EC, 2006/17/EC and 2006/86/EC) have been issued by the European Parliament in order to increase the safety and quality of tissues – including reproductive cells – processed for human re-implantation through the control of equipment, devices and environment. These regulations require specific procedures in embryo/oocyte/ovarian tissue cryopreservation in order to minimize the risk of any hypothetical contamination of human cells due to direct contact with accidentally contaminated liquid nitrogen (LN2). Read the rest of this entry »