Blood Transfusion Supplement 1 (off subscription) (January)
The plasma levels of soluble HLA-G molecules correlate directly with CD34+ cell concentration and HLA-G 14bp insertion/insertion polymorphism in cord blood donors
Authors:  Cristina Capittini, Paola Bergamaschi, Sara Sachetto, Mariarosa Truglio, Monica Viola, Andrea Marchesi, Valeria Genovese, Bina Romano, Marco Guarene, Rossella Poma, Miryam Martinetti, Carmine Tinelli, Laura Salvaneschi
Pages:  361-366
To cite this article:  Blood Transfus 2014; 12 Suppl 1: s361-6
Doi:  10.2450/2012.0144-12
Published online:  23/01/2013

Background. Cord blood provides haematopoietic stem cells for allogeneic transplantation and, thanks to the naivety of its immune system, has several advantages over other sources of stem cells. In the transplantation setting, the presence of immunosuppressive human leucocyte antigen (HLA)-G molecules has been advocated to prevent both rejection and Graft-versus-Host disease. HLA-G is physiologically expressed throughout pregnancy and is contained in cord blood at birth. Moreover, it has recently been reported that not only cord blood mesenchymal cells, but also CD34+ cell progenies produce soluble HLA-G (sHLA-G). We tried to identify the largest producer of sHLA-G among 85 healthy cord blood donors at Pavia Cord Blood Bank, correlating the sHLA-G concentration with the HLA-G 14bp insertion/deletion (INS/DEL) genotype and CD34+ cell concentration.
Materials and methods. Wemeasured sHLA-G levels in 36 cord blood plasma stored at −20 °C for 2 months and 49 cord blood plasma stored at −196 °C for 4-6 years, by enzyme-linked immunosorbent assay. All cord blood donors were genotyped for the HLA-G 14bp INS/DEL polymorphism by polymerase chain reaction. For each cord blood unit, we measured the cell concentration by flow cytometry.
Results. We did not finddifferences insHLA-G levels between cord blood plasma aliquots stored for 4-6 years at −196 °C and cord blood plasma aliquots stored for 2 months at −20 °C. We observed a higher sHLA-G concentration in cord blood plasma donors who carried the HLA-G 14bp INS/INS genotype and had higher CD34+ cell concentrations (P =0.006).
Discussion. This is the first report showing that the best cord blood stem cell donor is also the best sHLA-G producer, particularly if genetically characterized by the HLA-G 14bp INS/INS genotype. If the therapeutic role of sHLA-G molecules were to be finally established in the transplantation setting, our data suggest that cord blood plasma donors can provide a safe source of allogeneic sHLA-G immunosuppressive molecules ready for transfusion.
Keywords: cord blood plasma, soluble HLA-G, liquid nitrogen cryostorage, HLA-G 14bp polymorphism, CD34+ cells.
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