Vox Sanguinis

Abstract. The present knowledge on chemical, enzymatic, serologic and genetic aspects of ABH antigens is reviewed in an effort to produce a simple and coherent genetic model for the biosynthesis of these antigens and chemically related structures. The genetic control of type 1 (Le^a, Le^b, Le^c and Le^d), type 2 (X, Y, I, and H), type 3 and type 4 ABH and related antigens in different animal and human tissues is analyzed, taking into account the properties of the glycosyltransferases which are involved in their synthesis and considering possible competition for common acceptor and donor substrates. The phylogeny of ABH determinants shows that they appeared as tissular antigens much earlier than as red cell antigens. The ontogeny of ABH antigens suggests that they behave as differentiation antigens, and an effort is made to correlate their tissular distribution in the adult with the embryological origin of each tissue.

Anticoagulant and nutrient solutions allow red blood cells to be stored and transported, enabling modern blood banking. The development of these solutions has been slow, covering 90 years, and the reasons for past formulations are best understood in a historical context. Modern red cell storage solutions work well for blood banks, allowing 5–7‐week storage, which means more than 90% of collected units find a recipient. Improved scientific understanding of the red cell storage lesion has shown a way to make even better storage solutions, which maintain red cell metabolism and reduce membrane loss.

Background  The rationale for using topical platelet gel therapy is to provide the healing tissues with concentrated platelet‐derived factors. Several systems are available to prepare platelet‐rich plasma (PRP) and from these, the platelet gel. These systems produce two‐ to six‐fold platelet and growth factor‐enriched concentrations. The bioavailability of growth factors in tissue healing depends on the amount of growth factors stored in platelets but a portion of these is lost during platelet manipulation. Very few data have been reported on the kinetics of growth factor release from PRP‐gels. The aim of this study is to assess the growth factor recovery and its bioavailability to tissues in four different PRP and PRP‐gel preparation techniques.

Materials and methods  Three commercially available devices (Fibrinet®, RegenPRP‐Kit®, Plateltex®) and one manual procedure (home made, HM) were evaluated with reference to resulting platelet concentration, growth factor content and the kinetics of growth factor release from gel.

Results  Platelet concentration increased from 1·65‐ to 4·4‐fold in comparison with whole blood initially used. The final platelet concentration (× 10³/µl) was: Fibrinet 1358 ± 419, Regen 430 ± 109, HM 1196 ± 188, and Plateltex 1160 ± 164. A high variation (5‐ to 27‐fold) was found in growth factor concentration in relation to the method used and also a high variation in the kinetics of growth factor release from gels.

Conclusions  Similar methods for platelet gel preparation revealed different performances concerning growth factor recovery and the kinetics of its release from the gel. It is unclear whether these noticeable differences are important for clinical management.

Background  Different systems for preparation of platelet‐rich plasma are commercially available, but data for comparison of these systems have not been published so far.

Materials and Methods  We investigated the performance of Vivostat PRF Preparation Kit®, PCCS Platelet Concentrate Collection System®, Harvest® SmartPReP 2 APC 60 Process, and Fibrinet® Autologous Fibrin & Platelet System.

The preparations provided by these systems are platelet concentrates with high numbers of platelets in a small volume of plasma and PDGF‐AB is released continuously during the 5 days after preparation.

Results  Vivostat PRF Preparation Kit, PCCS Platelet Concentrate Collection System, Harvest SmartPReP 2 APC 60 Process are comparable in platelet yield and total amount of released PDGF‐AB after 120 h while with Fibrinet the lowest platelet yield and PDGF‐AB content of supernatant was achieved. The ability of growth factor release was equal in all four systems.

Conclusion  In conclusion, all four systems for preparation of platelet‐rich plasma investigated result in considerable growth factor release. In what extent the total content of PDGF‐AB as a consequence of platelet yield has an impact on wound healing has to be further investigated

Abstract. The existence of 4 alleles of phosphoglucomutase (PGM₁) In human red cell lysates has been demonstrated by isoelectric focusing confirming earlier work by Bark et al. and Kühnl et al. A survey of 101 red cell lysates and the inheritance of these alleles in 24 families are now described.

Background and Objectives Current manufacture of intravenous immunoglobulin (Gamimune®N) uses four cold‐ethanol precipitation steps and solvent–detergent treatment. Our objective was to design a new manufacturing process to maximize immunoglobulin G (IgG) purity, achieve robust viral safety, preserve all the biological activities of antibody and avoid unnecessary protein loss.

Materials and Methods The new process combines multiple functions in single steps. Caprylate is added to precipitate non‐IgG proteins and to inactivate enveloped viruses. Two successive anion‐exchange columns are used to purify IgG and remove caprylate. The new product, IGIV‐C (Gamunex™, 10%) is formulated with glycine at 100 mg/ml IgG, pH 4·25. Vials are incubated for 21 days at 23–27 °C in a final virus‐inactivation step.

Results Compared with the process for production of Gamimune®N, that for IGIV‐C requires a shorter production time, achieves more robust virus inactivation, increases IGIV yield from plasma, improves physiological IgG subclass distribution (resulting in higher levels of IgG4), and improves purity, with lower levels of IgA (40 µg/ml), IgM (< 2 µg/ml) and albumin (< 20 µg/ml). Antibody binding, opsonization and protective activities are similar.

Conclusions Compared with the current commercial process, the new IGIV‐C manufacturing process produces a more highly purified preparation that contains slightly higher levels of IgG4 and retains antibody activities required for clinical efficacy.