Recently an interesting investigation was published in Vox Sanguinis concerning in vitro evaluation of buffy coat derived granulocytes for the therapeutic use. Normally patients, who need granulocytes, are critically ill. Facing the fact, that conventional produced granulocyte concentrates contain 30 to 50 mL hydroxyethyl starch which is actually not approved for critically ill patients, this publication offers a promising possibility to produce sufficient granulocytes without the exposure to hydroxyethyl starch for both, patients and donors.
Routinely granulocytes (GTX) for the therapeutic use are collected by apheresis technology from rh-GCSF and/or steroid pretreated volunteers. Hydroxyethyl starch (HES) as sedimentation agent is crucial for an efficient collection. Since the negative impact of HES on the outcome in critically ill and septic patients is known several, medical societies like FDA, EMA … have withdrawn their regulatory approval for HES in these medical settings.
The authors collected buffy coat derived granulocytes (BCN) (a byproduct of whole blood collection), pooled in sum ten buffy coats and created a so called “super” buffy coat of small volume and high purity (> 95% granulocytes, low red cells and low numbers of platelets). They performed a lot of viability test, function test and assessed surface markers like maturation markers (EMR3), adhesion molecules (L-selectin = CD62L), integrin C3 and Fcy receptors on these granulocytes. Additionally microbial killing was assessed. Survival test of BCN were performed with (to mimic in vivo conditions) and without rh-GCSF incubation All data were compared to conventional collected granulocytes and to granulocytes of untreated controls.
In summary, BCN were not inferior in basic functions, showed no increased activation markers due to manipulation, had a normal maturation status (which is not found in conventional GTX, probably due to mobilization induced immature release from the bone marrow) and a satisfactorily survival after GCSF incubation. Also the killing mechanism was comparable to GTX and controls and even more efficient in Candida albicans eradication comprared to GTX. GTX granulocytes are known to have a significantly reduced killing capacity for C.albicans, probably due to their immature status.
A drawback may be the rather low numbers of granulocytes in BCN, but this can easily be compensated by transfusion of two or more of these pure small volume BCN units.
A. van de Geer, R. P. Gazendam, A. T. J. Tool, J. L. van Hamme, D. de Korte, T. K. van den Berg, S. S. Zeerleder & T. W. Kuijpers
Vox Sanguinis (2017)© 2017 International Society of Blood TransfusionDOI: 10.1111/vox.12481
Summary (by Gerda Leitner)
In this paper, the group from Pamplona shows data of stem cell mobilization with filgrastim (G-CSF) in 36 healthy family donors, of which 18 underwent stem cell mobilization with Neupogen and 18 with the biosimilar Zarzio. In this retrospective observational noninterventional study, they showed that with a median follow up time of 13.5 months Zarzio appears to be safe and with a comparable safety profile as Neupogen. In terms of efficacy, no differences were observed regarding circulation CD34+ cells; however, higher numbers of CD 34+ cells were harvested in donors mobilized with Neupogen. This can however be explained in part by the change of Apheresis device (in all 18 donors mobilized with Neupogen the COBE Spectra was used, and in 15 of the Zarzio mobilized donors Spectra Optia was used as apheresis device). The processed blood volume was higher with the COBE Spectra. However, 3 out of 18 donors mobilized with Zarzio failed to mobilize the optimal cell dose.
Engraftment was comparable in the two groups.
Given retrospective design of this study, the small donor numbers and the short follow up time the results have to be interpreted with care. More long term follow up data preferably in registries (such as e.g. EBMT Donor Outcome Registry) is needed to determine the safety of donor stem cell mobilization with biosimilars
Marıa Luisa Antelo,et al. , Journal of Clinical Apheresis 31:48–52 (2016)
In this paper the authors reviewed more than 50.000 extracorporeal procedures in 7.142 patients regarding incidence and severity of apheresis related adverse events.
Adverse events were graded in mild, moderate, severe and leading to death. First of all, no death occurred, but in 168 (0.4%) procedures severe side effects (hypotension, bronchospasm, arrhythmia and asystole) led to interruption of the treatment.
The authors compared diagnoses, gender, apheresis techniques (filtration or centrifugation), replacement fluids, anticoagulation and venous access.
In general extracorporeal treatment techniques are safe and are related with a small number of overall side effects. Taken together 2907 events occurred in 50.846 procedures (5.7%), most of them were mild to moderate and occurred during the 1st procedure. The main recorded side effect was tingling given in n/10.000 procedures = 174/10.000. Access problems occurred in 130cases/10.000 procedures. A central venous catheter caused more severe events than the peripheral venous access.
The authors found a clear relationship to the technique and the replacement fluid. Filtration was associated with more side effects than centrifugation. Albumin as exchange medium was associated with more hypotension and plasma with more allergic reactions, HES caused no adverse events. The matter of anticoagulation is difficult to answer. Here it seems that the citrate containing anticoagulation medium is responsible for more moderate and heparin for more mild reactions.
Interestingly calcium prophylaxis seemed to result in an increase of adverse events and thus having a negative effect. The reason for this could not be clarified in this study because of the data entered, which do not discriminate between continuous and on demand Ca++ administration. And it might be that the patients already presenting some adverse effects were given then Ca++
A multivariance analysis revealed that patients who were older, a female, received plasma as replacement and calcium as prophylaxis were at higher risk to experience severe adverse events.
The authors suggest that a careful monitoring of vital signs and an emergency equipment near by would be necessary counteract life threating side effects, although they are really less frequent (0.4%).
The question of anticoagulation and calcium prophylaxis has to be clarified in further studies.
M. Mörtzell Henriksson, E. Newman, V. Witt, K. Derfler, G. Leitner, S. Eloo , A. Dhondt, D. Deeren, G. Rock, J. Ptak, M. Blaha, M. Lanska, Z. Gasova, R. Hrdlickova,W. Ramlow, H. Prophet, G. Liumbruno, E. Mori, A. Griskevicius, J. Audzijoniene, H. Vrielink, S. Rombout, A. Aandahl, A. Sikole, J. Tomaz, K. Lalic, S. Mazic, V. Strineholm, B. Brink, G. Berlin, J. Dykes, F. Toss, C.G. Axelsson, B. Stegmayr, T. Nilsson, R. Norda, F. Knutson, B. Ramsauer, A.Wahlström
Published recently in Transfusion and Apheresis Science http://dx.doi.org/10.1016/j.transci.2016.01.003
1473-0502/© 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).