Filtration of buffy coat free red cell concentrates in additive solution.

Leukocyte poor RCC's (LP-RCC) are indicated in chronically transfused patients in order to prevent non-hemolytic transfusion reactions and HLA alloimmunization. In this study buffy coat free red cell concentrates (BCF-RCC) in additive solution (SAG-M) stored for four weeks were leukocyte depleted by filtration with three different filter systems (Erypur Optima (E), Sepacell R500 B (S) and, Pall RC, 50 TM (P)). The BCF-RCC's were prepared using 'bottom and top (BAT)' systems and automatic separation containing about 20% leukocytes and 5% platelets of fresh whole blood. The leukocyte concentration could be reduced to less than 5 x 10(6) per RCC with all filter systems equally: Leukocytes/RCC's: E .58 +/- .94, S .36 +/- .55, P .55 +/- .69 x 10(6). The leukocyte depletion was even in case of filtering two RCC's through one filter (double filtration) efficient enough in order to keep leukocyte contamination below the 'critical immunogenic load for leukocytes (CILL)'. But significant differences concerning the damage of red cells (free hemoglobin, LDH, HBDH) were measured which were even considerable: free hemoglobin E = 3.69 +/- 2.28, S = 1.31 +/- 1.24, P = 3.58 +/- 2.34 g/l. Double filtration was only performed with filter system S showing the best blood compatibility. But the second BCF-RCC also showed considerable hemolysis. Therefore, double filtration of RCC's only seems to be indicated under optimal conditions with blood compatible filters for selected patients. Bed side filtration cannot be recommended because of the risk of hemolysis that makes quality control necessary.(ABSTRACT TRUNCATED AT 250 WORDS)

[Filtration of buffy coat-free erythrocyte suspensions in additive solution]. / Filtration buffy-Coat-armer Erythrozytensuspensionen in additiver Lösung.

Buffy coat-free red cell concentrates in SAG-M (RCC) were produced by BAT system (leukocyte content 132 x 10(6)/RCC). They were stored for 4 weeks and filtered by Erypur Optima (E), Sepacell R 500 B (S) und PALL RC 50 TM (P). Leukocyte depletion was very effective (E: 0.56 x 10(6)/RCC; S: 0.36 x 10(6)/RCC; P: 0.55 x 10(6)/RCC) but hemolysis was remarkable (E: 301 +/- 195; S: 127 +/- 123; P: 368 +/- 256 mg/RCC). Therefore preparation of two RCC per filter was only acceptable with S. In S and P loss of red cells was tolerable (E: 90.5; S. 41.8; P: 38.2). In contrast, E should be rinsed with sodium chloride at the end of the preparation. In E and S filtration times were short without additional pressure (E: 6.6 min; S: 4.7 min; P: 20.3 min). We conclude from our results that the use of buffy coat-free red cell concentrates in additive solution considerably reduces the problems of filtration, e.g. storage interval, leukocyte reduction, hemolysis, filtration flow. Despite this, bedside filtration is not recommended because quality assurance is necessary.

Biocompatibility and safety of cytapheresis.

Cytaphereses are safe and can be used routinely like whole blood donations on the premise that standard techniques based on appropriate guidelines and regulations are performed. Before the introduction of a new cell or plasma separator, a thorough clinical investigation is always recommended in order to demonstrate biocompatibility and safety features. In this context cell loss and damage as well as activation of coagulation and complement should be tested primarily. The examination should consist of a direct comparison with an approved system. In addition, it is necessary to repeat periodically on multicenter studies adverse donor reactions such as those already described so that it is possible to recognize even rare side effects. Of special importance are long-term studies of donors undergoing frequent cytaphereses for many years in order to detect relevant immunological changes. On the other hand, harm caused by the plasticizer or cancer due to cancerogenicity of the plastics are only speculative at the moment.

Improvement of blood component quality--automatic separation of blood components in a new bag system.

We report here on a new multiple bag system with top and bottom drainage of the primary bag which allows automatic separation of blood components on a routine basis. 100 units of 450 ml fresh whole blood (CPD) were centrifuged by hard spin centrifugation and then separated into leukocyte-poor red cell concentrates in additive solution (volume 284 +/- 22 ml, Hct 63.5 +/- 3.2%, platelets 3.1 +/- 1.4 X 10(9)/unit [3.1 +/- 1.2%], leukocytes 1.9 +/- 1.2 X 10(8) [8.3 +/- 5.0%]) and plasma (FFP) with acceptably low cell contamination (volume 262 +/- 33 ml, platelets 14.6 +/- 5.6 X 10(3)/microliter, leukocytes 0.04 +/- 0.03 X 10(3)/microliter). The residual buffy coat of whole blood stored for 16-20 h at room temperature was suitable for the preparation of leukocyte-poor platelet concentrates (n = 20; platelets 0.67 +/- 0.17 X 10(11) (69.8 +/- 15.0%); leukocytes 0.1 +/- 0.1 X 10(8] which showed quite good platelet function in vitro. The removal of leukocytes and platelets caused significantly less in vitro hemolysis during storage when compared to conventionally prepared red cell concentrates with and without buffy coat. Further advantages of the reduction of the cell contamination in red cell concentrates before storage are discussed. From this it can be concluded that leukocyte-poor red cell concentrates with less than 20% residual leukocytes should become the regular red cell preparation also for surgery, especially as the recommended separation technique can easily be performed on a routine basis. Red cell concentrates still containing the whole buffy coat are no longer acceptable.