Optimized processing for pathogen inactivation of double-dose buffy-coat platelet concentrates: maintained in vitro quality over 7-day storage.

BACKGROUND AND OBJECTIVE: Efficient pathogen inactivation (PI) offers the possibility of increasing the number of buffy coats per pool without the concurrent increased risk of pathogen transmission. Here, we describe the findings of in vitro analyses of platelets from pools of eight buffy coats treated with amotosalen and UVA light (INTERCEPT Blood System for Platelets) using INTERCEPT disposable processing sets with plastic materials sourced from alternate suppliers and split afterwards to obtain two therapeutic transfusion doses. METHODS: Double-dose platelet concentrates were prepared from pools of eight buffy coats in additive solution (SSP+) using either previous 6-lead or new 8-lead pooling sets and PI processing sets in previous or alternate supplier sourced plastics (AS). Platelets were treated with the INTERCEPT Blood System then stored for up to 7 days and tested for in vitro quality. RESULTS: All tested units (n = 30) were in conformity with European guidelines. Using AS sets more effectively maintained glucose reserves (P < 0·01), reduced lactate production (P < 0·01), reduced CD62P expression (P < 0·01) and downregulated levels of surface CD42b (P < 0·01) overtime. AS set maintained JC-positive cells (NS) between day 2 and day 7 and sustained platelet integrin activation (PAC-1) between day 2 and day 7 (NS). Overall sCD40L and PGDF accumulated in an equivalent way (P < 0·01) within series. SUMMARY/CONCLUSIONS: In summary, our data demonstrate that PI treatment using AS sets, in combination with the new pooling set for double-dose platelet preparation, maintained the platelet in vitro quality over 7 days of storage.

Pathogen inactivation of double-dose buffy-coat platelet concentrates photochemically treated with amotosalen and UVA light: preservation of in vitro function.

BACKGROUND: The INTERCEPT Blood System for Platelets (PLT) utilizes amotosalen (S-59) in combination with ultraviolet A (UVA) light to inactivate viruses, bacteria, protozoa and leucocytes that may contaminate PLT concentrates. However, limited data are available on the quality of INTERCEPT-treated double-dose (DD) buffy-coat (BC) PLT units allowing a single treatment procedure to produce two pathogen-inactivated PLT units for transfusion. STUDY DESIGN AND METHODS: The objective of this study was to evaluate potential in vitro effects of the INTERCEPT treatment on pools of 7 BCs as compared to untreated units. Functional, phenotypic and mitochondrial properties of DD BC PLTs during storage over 7 days were studied. RESULTS: For some parameters measured, small yet significant differences were observed including PLT count (P < 0·05), pH, pCO2 and glucose concentration. Throughout storage, no significant differences were observed in ATP levels, ESC, HSR reactivity and CD62P expression. Similarly, no differences were observed in the expression of PAC-1, CD42b and PECAM-1 at any time-points. The mitochondrial membrane potential (MMP) determined by JC-1-labelling was well maintained until day 7 in all treated and untreated units (>90%). The release of sCD40L increased over time (P < 0·01) in all units but without any significant differences between treated and untreated PLTs. CONCLUSION: Our data demonstrate that photochemical pathogen inactivation of DD-BC PLT concentrates with the INTERCEPT Blood System had no influence on the PLT in vitro quality over the 7 day of storage. However, whether in vivo efficacy of INTERCEPT-treated PLTs is affected may require clinical evaluation.

A randomized study of buffy coat platelets in platelet additive solution stored 1-5 versus 6-7 days prior to prophylactic transfusion of allogeneic haematopoietic progenitor cell transplant recipients.

BACKGROUND AND OBJECTIVE: Storage of platelets > 5 days provides improved availability, logistical management and decreased outdating. Promising results on in vitro parameters and on in vivo post-transfusion recovery and survival of autologous platelets in healthy volunteers have earlier been shown. To provide additional verification, randomized patient transfusion studies are needed. MATERIALS AND METHODS: Sixty allogeneic haematopoietic progenitor cell transplant recipients were randomized to receive buffy-coat (BC) platelets stored in platelet additive solution (PAS) for 1-5 days the first time a prophylactic transfusion was needed after transplantation, followed the second time by platelets stored for 6-7 days or vice versa. The corrected count increment (CCI) for 1 and 24 h were calculated. RESULTS: CCI 1 h and CCI 24 h were higher for platelets stored 1-5 days as compared to 6-7 days, 10.4 +/- 5.1 vs. 7.4 +/- 3.8 (P < 0.001) and 5.4 +/- 4.1 vs. 2.6 +/- 2.6 (P < 0.001), respectively. Time to next platelet transfusion was significantly longer after a transfusion of platelets stored for 1-5 days as compared to platelets stored for 6-7 days: 2.2 +/- 1.1 vs. 1.6 +/- 0.8 days, respectively (P < 0.005). No differences in bleeding events and no transfusion reaction were recorded. CONCLUSION: The advantage of an extension of platelet storage time beyond day 5 should be balanced against the increased need for platelet transfusions that may occur and the conceivable risk of transfusion failure.

In vitro and in vivo effects of potassium and magnesium on storage up to 7 days of apheresis platelet concentrates in platelet additive solution.

BACKGROUND AND OBJECTIVE: Prolonged storage of platelets up to 7 days provides improved availability, logistical management and decreased wastage. Beside methods of bacterial detection, addition of magnesium and potassium to the platelet storage solution (SSP+) may further improve the quality of platelets with extended storage. MATERIALS AND METHODS: Apheresis platelets from 10 donors were divided and stored in two different platelet additive solutions (PAS) (Intersol and SSP+) for a paired comparison. A variety of in vitro platelet function and metabolic assays were performed both on day 1 and after 7 days of storage. For in vivo study, platelets were labelled with either (111)Indium or (51)Chromium after 7 days of storage and were injected into the corresponding donor. Serial blood samples were drawn for recovery and survival measurements. RESULTS: In vitro parameters for SSP+ showed significantly reduced glycolysis (lower glucose consumption and decreased production of lactate), a higher hypotonic shock response (HSR) and the extent of shape change reactivity and a lower degree of platelet activation by means of RANTES (regulated on activation, normal, T cell-expressed, and secreted), CD62p and CD63 expression. Platelet recovery on day 7 was higher for Intersol as compared to SSP+, 65 +/- 11 vs. 53 +/- 13% (P = 0.023), and survival showed no difference 4.2 +/- 1.9 vs. 3.6 +/- 1.4 days. CONCLUSION: In vitro characteristics of platelets stored in PAS with addition of potassium and magnesium indicated higher quality, but this could not be verified by the in vivo parameters by means of recovery and survival.

Characteristics of the m2000 automated sample preparation and multiplex real-time PCR system for detection of Chlamydia trachomatis and Neisseria gonorrhoeae.

We evaluated a new real-time PCR-based prototype assay for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae developed by Abbott Molecular Inc. This assay is designed to be performed on an Abbott m2000 real-time instrument system, which consists of an m2000sp instrument for sample preparation and an m2000rt instrument for real-time PCR amplification and detection. The limit of detection of this prototype assay was determined to be 20 copies of target DNA for both C. trachomatis and N. gonorrhoeae, using serially diluted linearized plasmids. No cross-reactivity could be detected when 55 nongonococcal Neisseria isolates and 3 non-C. trachomatis Chlamydia isolates were tested at 1 million genome equivalents per reaction. Concordance with the Roche Amplicor, BDProbeTec ET, and Gen-Probe APTIMA Combo 2 tests was assessed using unlinked/deidentified surplus clinical specimens previously analyzed with these tests. For C. trachomatis, concordance for positive results ranged from 93.7% to 100%, while concordance for negative results ranged from 98.2% to 100%. For N. gonorrhoeae, concordance for positive and negative results ranged from 91.4% to 100% and 99.3% to 100%, respectively. A workflow analysis of the prototype assay was conducted to obtain information on throughput under laboratory conditions. At 48 samples/run, the time to first result for both C. trachomatis and N. gonorrhoeae was 4.5 h. A total of 135 patient specimens could be analyzed in 8.9 h, with 75 min of hands-on time. This study demonstrated the technical and clinical feasibility of the new Abbott real-time PCR C. trachomatis/N. gonorrhoeae assay.

K, Fy(a), and Jk(a) phenotyping of donor RBCs on microplates.

BACKGROUND: In many cases, the search for compatible blood for patients with clinically significant RBC alloantibodies is difficult and time-consuming. To date, it has been considered necessary only to phenotype the blood donors for ABO group and D. There has been long experience with automated routine analysis (ABO, C, c, D, E, and e typing and RBC antibody screening), using robotic dispensers and computerized interpretation of microplate results. The purpose of this study was to explore the possibilities of also phenotyping for K, Fy(a), and Jk(a), as antibodies directed against these antigens (together with Rh antigens) are the most common clinically significant alloantibodies in the Swedish population. STUDY DESIGN AND METHODS: One thousand thirty-one EDTA samples from blood donors were phenotyped for K, Fy(a), and Jk(a) by use of an IAT with PEG on microplates. The findings were compared to those using conventional IAT in tube's and the microcolumn gel test (DiaMed-ID, DiaMed). RESULTS: All typing results with the microplate method were correct. All reactions for K and Fy(a) typing could be interpreted by the computer. The results for Jk(a) were indeterminate in 1.4 percent (14/1031) of the samples. CONCLUSION: The PEG-IAT microplate method gave reliable results that were suitable for routine phenotyping, thus making available a stock of phenotyped blood at reasonable cost, ready for delivery when required.