Multi-institutional randomized control study of haemolysis in stored red cell units prepared manually or by an automated system.

BACKGROUND: The haemolysis level at the end of storage is a performance parameter for RBC preparations. In the evaluation of new devices or new processes for processing blood, it is relevant to evaluate whether the haemolysis is linked to (1) specific characteristics of the blood donor, or (2) the nature of the blood-processing methodologies. MATERIALS AND METHODS: As part of the validation of a new automated whole blood processing system compared to the current manual methods, randomized, paired crossover studies were conducted evaluating measures of blood component quality, including RBC haemolysis over 42 days of storage. RESULTS: The association between haemolysis and the individual subject was evaluated by modelling haemolysis with independent predictors of treatment (control and test processing) and leucocyte reduction as fixed factors with donor and laboratory as random effects in a mixed-effects ANOVA model. It was found that the day 42 haemolysis values were strongly dependent on the donor subject, with an intraclass correlation coefficient of 0.81. CONCLUSIONS: The data reported in this study suggest a link between the specific whole blood donor and the haemolysis levels observed in red-blood-cell units stored refrigerated for 42 days. Additional research to identify possible donor characteristics associated with haemolysis during storage is warranted.

A feasibility evaluation of an automated blood component collection system platelets and red cells.

BACKGROUND: The purpose of these studies was to evaluate the functional properties of blood components collected with an automated collection system. STUDY DESIGN AND METHODS: Single-donor platelets (n = 44) and packed red cell (RBC) units (n = 10) were collected. In vitro and in vivo assays were used to assess the function of single-donor platelet components stored for 5 days and of packed RBC units after storage for 42 days at 4 degrees C. RESULTS: Adverse events observed in the 44 study subjects were minor. The mean 24-hour recovery value for the packed RBC units stored for 42 days was 83.6 +/- 5.4 percent, with a mean percentage of hemolysis on Day 42 at 0.46 +/- 0.19 percent. The 25 patients receiving platelet components achieved a mean corrected count increment of 15.1 +/- 10.4 x 10(3). All platelet concentrates had less than 1 x 10(6) total white cells. CONCLUSION: Both in vitro and in vivo testing for the packed RBCs collected and stored for 42 days met the standards for both hemolysis and percentage of 51Cr 24-hour RBC recovery. The in vitro results and transfusion data on white cell-reduced platelet components transfused to thrombocytopenic patients were comparable to those on available platelet components.

A requirement for the CD5 antigen in T cell activation.

Treatment of adult rats with a monoclonal antibody specific for the CD5 antigen led to a dramatic reduction in the number of CD5+ cells. However, a substantial number of T cells remained as assessed by other T cell-specific antibodies. These CD5- T cells did not proliferate in response to alloantigen or mitogenic stimulation, did not generate cytotoxic T lymphocytes in vitro, and did not induce graft-vs.-host disease when injected into susceptible recipients in vivo. Re-expression of the CD5 antigen occurred when CD5- T cells were placed in an environment devoid of the anti-CD5 antibody. Re-expression of the antigen was followed by return of the T cell proliferative responses. While CD5- T cells could not proliferate in response to alloantigen they could produce interleukin 2 following a short pulse with the T cell mitogen concanavalin A. However, T cell proliferative or cytotoxic responses could not be rescued by the addition of an exogenous source of interleukin 2. We conclude that the CD5 antigen appears to be required for proliferation of resting T cells.

Clinical evaluation of a staphylococcal protein A immunoadsorption system in the treatment of myasthenia gravis patients.

BACKGROUND: The role of plasma exchange is well established in the management of myasthenia gravis, an autoimmune disorder characterized by muscle weakness and caused by circulating IgG antibodies with specificity against the acetylcholine receptor. Plasma antibody removal by conventional means, however, is nonselective and uses replacement fluids (chiefly, albumin solution) derived from human plasma. STUDY DESIGN AND METHODS: The Canadian Apheresis Group undertook a study at two Canadian apheresis centers to clinically evaluate a staphylococcal protein A immunoadsorption system (EXCORIM) in myasthenia gravis patients. RESULTS: The immunoadsorption system was safe and well tolerated. Ten of 12 patients had improvement in their neurologic status, as measured by a 20-point scoring system. The mean improvement in the weakness score was significant for the group (p = 0.0013). CONCLUSION: Patients with myasthenia gravis respond to treatment with plasma immunoadsorption. Further studies are required for a cost-benefit analysis.

Evaluation of an automated system for the collection of packed RBCs, platelets, and plasma.

BACKGROUND: This study evaluated the quality of WBC-reduced platelets, RBCs, and plasma collected on a new system (Trima, Gambro BCT) designed to automate the collection of all blood components. The study also evaluated donor safety and suitability of these components for transfusion. STUDY DESIGN AND METHODS: In Phase I, the quality of the components collected on the new system was evaluated by standard in vitro and in vivo testing methods. Results were compared to those from control components collected by currently approved standard methods. In Phase II, additional collections were performed to evaluate the acceptability of the new system and the safety of platelets collected. RESULTS: In vivo 24-hour RBC recovery was 76.8 +/- 3.1 percent for the test RBC units and 77.1 +/- 4.4 percent recovery for whole-blood (control) RBCs. The differences between test and control platelet results in the in vivo and in vitro assays were not clinically significant. Plasma clotting factors and fibrinogen levels met international standards. The system was well accepted by donors, and no major adverse donor reactions were reported for the 68 procedures performed. No problems were reported with transfusing the blood components collected. CONCLUSION: Blood components collected with the Trima are equivalent to currently available components, and they meet the applicable regulatory standards. This system provides consistent, standardized components with predictable yields. It provides the option of fully automating the collection of all blood components.