Search

Worldwide, platelet transfusions have increased substantially, especially in hematological patients. The prophylactic and therapeutic indications for platelet substitution as well as the choice of platelet preparation are discussed for patients with acute leukemia or aplastic anemia who need the highest platelet support. Here we present our current strategy, i.e., prophylactic transfusions with random platelets in acute leukemia and therapeutic transfusions with filtered random platelets in aplastic anemia patients only.

In patients with acute leukemia, chemotherapy leads to subsequent aplasia-associated thrombocytopenia requiring the substitution of platelets to avoid and treat bleeding complications. A multitude of tests to assess the quality of platelet concentrates is available to date. In this study, we investigated the quality of platelet concentrates prepared by two different methods, preparation from platelet-rich plasma versus preparation from buffy coat, and stored under varying conditions, namely horizontal versus vertical rotation, by measuring the binding rate of corresponding antibodies to platelet membrane glycoproteins GPIb, GPIIb-IIIa, GPIa-IIa and GPIV using flow cytometry. Expression of platelet surface antigens was well maintained during platelet preparation and storage for 7 days. Preparation and storage modalities showed no significant effect on the expression of membrane glycoproteins. These results indicate that platelet function as represented by antibody binding is well maintained during platelet preparation and storage leading to sufficient hemostasis following transfusion.

In the past 10 years 201 HLA-identical bone marrow transplantations (BMT) were performed with major ABO incompatibility in 41 (20%) and minor ABO incompatibility in 35 (18%) patients. ABO compatibility between donor and recipient showed no influence on granulocyte and platelet recovery after BMT. Erythrocyte reconstitution was significantly (p0.01) delayed for about 1 week in major ABO-incompatible BMT. In addition, a pure red cell aplasia lasting for 2-5 months occurred in 6 out of 21 blood group 0 patients who received transplants of group A. The rate of graft rejection, incidence of graft-versus-host disease as well as the leukemic relapse rate were similar in ABO-compatible and ABO-incompatible BMT. The probability of a 10-year survival after BMT is independent of ABO compatibility between donor and recipient.

Autologous platelets of 5 alloimmunized patients with acute leukemia in remission were cryopreserved with 5% dimethylsulfoxide in liquid nitrogen and retransfused in the following therapy-induced thrombocytopenic phase. The mean platelet recovery after freezing, thawing and washing was 85 +/- 6%. The mean corrected 1-hour increment in platelet counts was 11 (4-27) x 10(9)/l, i.e. 61% in comparison with fresh platelet transfusions in other patients. In vivo function of frozen platelets was documented by improvement of the posttransfusion bleeding time. Cryopreserved autologous platelets function hemostatically and can be used even for completely refractory patients and thus permit curative antileukemic therapy.

Plateletpheresis with the cell separator COBE Spectra and Fenwal CS 3000 was compared in 100 identical donors. The Spectra was significantly superior with regard to collection efficiency (53% vs. 42%, p less than .001) and leukocyte contamination of the platelet products (.1 x 10(8) vs. 1.4 x 10(8), p less than .001). Additionally, it offers a selectable volume of the concentrate and a better control of the ACD infusion. The Spectra standard procedure needs more ACD, resulting in more citrate dependent donor reactions (5% vs. 1%). In conclusion, the Spectra system shows a more efficient and pure platelet separation compared with the CS 3000.

Forty-nine allogeneic and 14 autologous bone marrow grafts were processed with the Haemonetics V50 cell separator (Haemonetics Corp., Braintree, USA) for in vitro treatment with antibodies and cryopreservation respectively. The concentration of hemopoietic progenitor cells was performed without any sedimentation or density gradient agents. The recovery is given in percent (mean +/- sd) of the original marrow values: mononuclear cells (MNC) 74 +/- 10%, polymorphonuclear cells (PMC) 48 +/- 17%, red blood cells (RBC) 12 +/- 5%, granulocyte/monocyte progenitors (CFU-GM) 83 +/- 36%, and erythroid progenitors (BFU-E) 78 +/- 38%. The recovery of nucleated cells (NC) was 90 +/- 13% and the viability 82 +/- 11% after cryopreservation. The technique described provides a simple, rapid and efficient preparation of large bone marrow volumes for in vitro treatment and AB0-incompatible transplantation.