Our own immunorosette depletion technique and the two tested CD34 selection methods for stem cell transplants both resulted in a very efficient T-cell depletion with the recovery of 40-60% of the CD34 haematopoietic stem cells present in the transplant.

The influence of a 2,3-diphosphoglycerate (2,3-DPG)-induced displacement of the oxygen dissociation curve (O.D.C.) on the isolated perfused rat liver was studied at different levels of anaemic hypoxia. Rat livers were perfused either with fresh or with 2,3-DPG-depleted human erythrocytes at different haematocrit values (from 30% to 2.5%) at constant Po2 of the inflowing perfusate and at constant blood flow rate. The 2,3-DPG-induced difference in oxygen affinity of the red cells did not cause a significant difference in perfusion pressure during the perfusion experiments. Therefore, there is no evidence that 2,3-DPG did alter the vascular resistance of the liver, since blood flow rate could be adusted at equal values. The decrease in oxygen supply brought about by decrease of haematocrit caused a decrease of O2 consumption, of bile flow rate and of venous Po2 and an increase of lactate/pyruvate (L/P) ratio and of beta-hydroxybutyrate/acetoacetate (betaOH/Acac) ratio. There was no influence of a difference in 2,3-DPG content of the erythrocytes on the above-metioned parameters during severe anaemic hypoxia. At moderate anaemic hypoxia the venous Po2 was higher during perfusion with fresh erythrocytes than during perfusion with 2,3-DPG-depleted erythrocytes. Thus, although 2,3-DPG may play a compensatory role during conditions of mild anaemia, no such effects can be observed during conditions of severe hypoxia.

Intravenous administration of certain immunoglobulin preparations may cause severe adverse reactions, especially in immunodeficient patients. These reactions are generally assumed to be related to the anticomplementary activity of the preparations, caused by IgG aggregates. Because the exact mechanism of the adverse reaction is unknown, we investigated the reactions induced in anesthetized rats on rapid intravenous administration of different human immunoglobulin preparations. The most conspicuous observation was a severe, long-lasting hypotension, induced by standard immunoglobulin preparations (for intramuscular use), which appeared to be independent from the concomitant complement and neutrophil activation. The long-lasting hypotension was not related to the presence of prekallikrein activator, which induced a transient hypotensive reaction only after sensitizing the rats to bradykinin. The reactions appeared to be associated with IgG aggregates. It was found that certain aggregates induced mainly complement activation, whereas others had mainly a hypotensive effect or no effect at all. It was concluded that the rat model provides a sensitive and reproducible test system for vasoactive properties of immunoglobulin preparations for intravenous administration that cannot be predicted from in vitro measurements, such as anticomplementary activity, aggregate content or prekallikrein activator activity. It is suggested that the test may also be used for other plasma products for intravenous administration.

Our results indicate that the current cryopreservation method for PBSCTs can be improved by either lowering the DMSO concentration to 5 percent or by using the theoretically optimized freezing curve. Infusion of less DMSO and more viable cells might improve the outcome of PBSCT.