Survival and recovery of apheresis platelets stored in a polyolefin container with high oxygen permeability.

BACKGROUND AND OBJECTIVES: Oxygen permeability is important in platelet storage media. We compared a new polyolefin container with enhanced oxygen permeability (PO-80; Kawasumi, Tokyo, Japan) to a widely used alternative (PL2410; Baxter Healthcare, Deerfield, IL, USA). MATERIALS AND METHODS: In vitro characteristics of paired platelet concentrates (PCs; mean 4.2 x 10(11)/250 ml plasma/bag) stored in PO-80 or PL2410 were assessed through 9 days of storage. In vivo recovery and survival of 7-day-old autologous PCs were assessed according to the Murphy method. RESULTS: Laboratory assessment of platelet quality favoured PO-80 during 9 days of storage with statistically significant differences in glucose consumption (2.75 vs. 4.93 mmol/10(12)/24 h in the interval 120-168 h), lactate generation (4.37 vs. 8.11 mmol/10(12)/24 h in the interval 120-168 h), pressure of oxygen (pO(2)) (59.3 vs. 38.1 mmHg at day 1), and HCO(3)(-) (14.7 vs. 13.4 mmol/l at day 1). Statistically significant differences were not seen in aggregation, hypotonic shock response or pH. In vivo assessment of autologous platelets stored 7 days in the PO-80 container revealed that recovery was 82.1% and survival was 81.0% of fresh control. Seven-day stored PCs in PO-80 were shown in vivo to be non-inferior to fresh platelets, with upper confidence limits (UCL(95)) in recovery and survival of stored PCs below the maximum acceptable difference (MAD); 15.3% UCL(95) < 20.4% MAD and 2.1 days UCL(95) < 2.1 days MAD. CONCLUSIONS: The in vitro characteristics of PCs stored in a highly oxygen-permeable container were stable at least 7 days. The in vivo study supports the suitability of PO-80 for 7-day platelet storage.

Platelet storage solution affects on the accuracy of laboratory tests for platelet function: a multi-laboratory study.

BACKGROUND AND OBJECTIVES: Extent of shape change (ESC) and hypotonic shock response (HSR) have been widely used to characterize the in vitro function of platelets and have been shown to correlate with in vivo viability. These assays have been routinely performed using platelet-poor plasma (PPP) as the test sample diluent. Because of the increasing popularity of storing platelets in synthetic media, it is important to understand the effects of using these synthetic media as test diluents for ESC and HSR measurements. The objective of this study was to determine the effect of using platelet storage solutions vs. plasma for the in vitro testing of ESC and HSR. MATERIALS AND METHODS: Six laboratories participated in this study. Platelets were prepared by apheresis, the platelet-rich plasma (PRP) method, or derived from buffy-coats. Each platelet preparation was divided, half being stored in plasma and the other half in storage solution. ESC and HSR testing were performed in duplicate on days 1 and 5, using each of three diluents: autologous plasma; fresh-frozen plasma; or storage solution. RESULTS: For both ESC and HSR, dilutions made in each of the three diluents yielded significantly different results. Dilutions made in storage solutions were more than 30% lower for ESC and HSR than those made in autologous plasma (P < 0.0001). Dilutions made in thawed fresh-frozen plasma were more than 16% lower for ESC and HSR than those made in liquid autologous plasma (P < 0.0005). CONCLUSIONS: ESC and HSR test results are significantly affected by the test diluent. Platelets should be diluted in plasma (preferably autologous) for the in vitro testing of ESC and HSR, regardless of the media in which they are stored.

Transfusion to blood group A and O patients of group B RBCs that have been enzymatically converted to group O.

BACKGROUND: The transfusion of ABO-incompatible RBCs is the leading cause of fatal transfusion reactions. Group O RBCs, lacking terminal immunodominant A and B sugars to which humans are immunized, are safe for transfusion to persons of any ABO blood group. With the use of a recombinant alpha-galactosidase to remove terminal galactose from group B RBCs, the safety and efficacy of enzyme-converted group-B-to-group-O (ECO) RBC components were studied in transfusion-dependent patients. STUDY DESIGN AND METHODS: Twenty-four patients (blood groups A and O) were randomly assigned to receive transfusion(s) of either ECO or control group O RBCs. If a second transfusion was given, the other blood component was administered. RESULTS: Twenty-one patients were given ECO RBCs; 18 also underwent control transfusions. One patient received only a small aliquot for RBC survival studies, instead of a full-unit transfusion, because his serum was incompatible with ECO RBCs. No adverse events occurred. Both ECO and control transfusions resulted in appropriate Hb increments and comparable (51)Cr-labeled RBC survival studies. One patient developed a transient, weak-positive DAT, without hemolysis. Two weeks after transfusion, 5 of 19 evaluable ECO RBC recipients had increases in anti-B titers. CONCLUSION: ECO RBCs were comparable to group O cells for safety and efficacy in this study. The clinical significance of the increase in anti-B and of occasional serologic incompatibilities with ECO RBCs is unclear. If strategies can be developed to remove A epitopes, enzymatic conversion could be used to create a universal (group O) donor blood supply.

Removal of methylene blue from plasma via an adsorbent filter.

OBJECTIVE: To evaluate adsorbent filtration of methylene blue (MB) and leukocytes from plasma. METHODS: Plasma (750 ml) from apheresis of 10 normal subjects was split into three aliquots: control (A), filtration (B) and MB addition (to 1 microM), phototreatment and filtration (C). Biochemical and coagulation tests were performed: units A and B were reinfused. RESULTS: Filtration reduced MB to undetectable (< 0.05 microM) levels and leukocytes by 3 log10. Biochemical analytes were unchanged. The partial thromboplastin time was prolonged with MB addition (11 +/- 13%) or filtration (26 +/- 12%, p < 0.05), but the effects were not additive. Autologous transfusion was well tolerated. CONCLUSION: Adsorbent filtration can reduce residual MB to undetectable levels and yields a component suitable for transfusion.

Evaluation of a new prestorage leukoreduction filter for red blood cell units.

BACKGROUND AND OBJECTIVES: Prestorage leukoreduction offers a variety of potential benefits and is becoming more commonly practiced. The LeukoNet prestorage leukoreduction filtration system is intended for leukoreduction of red blood cells and uses a vent to allow automatic drainage of red cells from the filter. MATERIALS AND METHODS: We studied the functional characteristics and the in-vivo and in-vitro properties of leukoreduced AS-1 Red Blood Cells prepared with this new system. Units of AS-1 Red Blood Cells were filtered at 4 degrees C through the LeukoNet filter 24-48 h after collection and stored under usual conditions for 42 days. Residual leukocytes were enumerated using a Nageotte chamber or with a polymerase chain reaction (PCR) technique. In the clinical trial (phase one), 21 donors had units stored with and without leukoreduction for 42 days; biochemical assays were done before and after storage, and 51Cr/99mTc red cell recovery studies at the end of the storage period. RESULTS: Leukocyte content after filtration was 3.2 +/- 2.6 x 10(4)/unit (n = 21), and all units had < 1 x 10(5) leukocytes (median: 3.8 x 10(4)). In-vivo paired studies showed no difference in 24-hour recovery (control: 82.1 +/- 5.8%; test: 82.9 +/- 6.0%). Hemolysis was halved with leuko-reduction (0.59 +/- 0.30 vs. 0.29 +/- 0.11%; p < 0.05), and glucose consumption was reduced by 5% compared to control units (p = < 0.05). Other biochemical parameters showed no differences. In the practical trial (phase two), filtration time was 41 +/- 23 min. With a residual leukocyte content of 6.6 +/- 4.9 x 10(4)/unit and 14 +/- 3% red cell loss (n = 84). Six additional units underwent leukocyte enumeration by PCR and had 2.6 +/- 1.1 x 10(4) residual leukocytes. CONCLUSIONS: Under the conditions studied, the LeukoNet leukoreduction filtration system produces about 4-5 log10 leukocyte content reduction.

Sterility of plastic tubing welds in components stored at room temperature.

BACKGROUND: The ability of a sterile connecting device to maintain sterility when being used to weld tubing of a blood component to be stored at room temperature, such as a platelet unit, has not been adequately documented, nor has it been determined when the tubing to be welded is filled with liquid. STUDY DESIGN AND METHODS: The sterility of sterile connecting device welds of polyvinylchloride tubing were challenged after intentional contamination of the exterior of the tubing with both gram-positive and gram-negative organisms (4 x 10(4) to 3 x 10(6) colony-forming units/mL). Welding (n = 244) was performed with the contaminated area either being wet or having been allowed to dry. At the time of the welding, the tubing segments were either empty or filled with liquid (either aliquots of white cell-reduced apheresis platelets or bacteriologic growth medium). After the welding, the liquid was passed across the weld and held in the attached transfer pack for 5 to 7 days at room temperature. RESULTS: Two welds were found to be incomplete and leaky, and both of the units involved had positive cultures. One transfer pack had inadvertently been contaminated at the time of its initial, postweld culture by a bacterium other than the one used in the experiment. Aside from these three nonevaluable units, all of the welds were sterile when cultured after the packs were held for 5 to 7 days. CONCLUSION: This study documents the ability of the sterile connecting device to maintain a closed system in the welding of blood component units to be maintained at room temperature. All welds should be closely inspected at the time of completion to detect leaks that may lead to contamination.