Pathogen inactivation/reduction of platelet concentrates: turning theory into practice.

Background Pathogen reduction technology (PRT) has been proven to reduce the residual risk of transmission of infectious agents. Reduction of various contaminating bacteriae, viruses and parasites by few to several log steps and efficiency to prevent GVHD has been shown. Aim To evaluate and compare advantages and disadvantages of PRT available for practical application in platelets. Materials and Methods PRT for the treatment of platelets is currently offered by two formats: Amotosalen (INTERCEPT, Cerus, Concord, CA, USA) and vitamin B2 (Mirasol, Caridian, Denver, USA). Results from different studies and our own experiences with the two techniques are compared and discussed. Results and Discussion For both technologies, different groups of investigators have shown acceptable in-vitro results with respect to functional and storage data for platelets stored for up to 5 days after production and before transfusion. Initial clinical studies showed no inferiority of the treated platelets in comparison to untreated controls in thrombocytopenic patients. However for both techniques a tendency towards lower CCI has been reported, which may be more pronounced in the platelets treated with the Intercept process. For introduction of PRT many countries require not only CE mark but licensing with the respective authorities since treatment for pathogen reduction is regarded as creating a 'new' blood product. With respect to a platelet loss during pathogen reduction it seems recommendable to increase the lower limit of platelet content of the product to 2.5 × 1011. Particularly for the Intercept system, where a considerable amount of platelets is lost in the purification of the product from Amotosalen, a change in the production process to increase the platelet yield may be necessary. Data from our group show a tendency for improved functional and storage parameters for platelets treated with the Mirasol process. Compared to conventional manufacturing of platelets by apheresis or pooling of buffy coats, pathogen reduction requires additional labour, space, and quality control. Shelf life of platelets is limited in most countries because of the risk of bacterial contamination (in Germany presently to 4 days). A prolongation to 5 or more days after pathogen reduction seems feasible but remains a topic for future studies. Conclusion Results of in vitro and clinical studies of pathogen reduced platelets are promising. Larger clinical trials will help to determine whether PRT proves to be beneficial (reduction of transmission of infections, less alloimmunisation) and overall cost effective (bearing in mind that additional costs may be compensated for by omission of gamma irradiation and potential longer shelf life).

Functional characteristics of apheresis-derived platelets treated with ultraviolet light combined with either amotosalen-HCl (S-59) or riboflavin (vitamin B2) for pathogen-reduction.

BACKGROUND: To examine if different pathogen-reduction technologies (PRTs) induce different degrees of platelet (PLT) storage lesion. DESIGN: Twenty-seven split triple-dose apheresis PLTs were PRT treated using ultraviolet light with either riboflavin (M) or psoralen (I) or remained untreated (C). Samples taken on days (d) 0 to 8 were analysed for PLT count, blood gas (pH, pO(2) and pCO(2)), metabolism (lactate, glucose, ATP content), in vitro function [swirling, hypotonic shock response (HSR) and aggregation], activation (p-selectin expression) and cellular integrity (JC-1 signal, annexin A5 release). RESULTS: Platelet counts of all study groups remained unchanged during storage indicating that PRT treatment did not induce relevant cell lysis. Although M units demonstrated the highest values for HSR until d5, PRT treatment lowered all parameters examined with significant differences to untreated controls by d7 of storage. During final storage, M was significantly superior over I for HSR, aggregation with TRAP-6 as agonist (collagen was similar), annexin A5 release and JC-1 signal. Regarding blood gas and metabolic analysis, the most evident effect of PRT was an elevated glycolytic flux combined with higher acidity due to increased lactate accumulation. Most likely due to impaired O(2) consumption, pH and ATP decreased more rapidly in I relative to C and M. CONCLUSION: Pathogen reduction technology-treated PLTs remained comparable to untreated units throughout 7 days of storage. Mitochondria-based oxidative respiration appeared up-regulated after the riboflavin-based PRT. Compared to the psoralen-based PRT, this resulted in significantly better ATP maintenance and in vitro function during the last storage period (d7, d8).

Effect of blood donation on well-being of blood donors.

The demand for blood products steadily increases. Concurrently, blood donor recruitment becomes more and more difficult. This study aimed to investigate effects of blood donation on blood donors, which could be helpful for blood donor recruitment and retention. In addition to cortisol measurements in saliva, three questionnaires quantifying mood (good/bad), vigilance (awake/tired), agitation (calm/nervous), actual strain and asking for donation-related effects perceived were distributed to 110 whole blood donors (DON). Results obtained were compared with 109 control subjects (CON) lacking the blood donation experience. Overall, 216 subjects completed the questionnaires. Sixty-eight percent of DON reported at least one effect perceived with blood donation. Exclusively, positive, negative or mixed effects were described by 26.5%, 23.5% and 17.6%, respectively. Among positive effects (i.e. physical/psychological well-being, feeling satisfied, happy, proud), no significant differences were observed between males and females (P = 0.07), whereas mixed or negative effects (i.e. vertigo, dizziness, tiredness, pain) were significantly (P = 0.03; P = 0.049) more associated with females. DON showed higher levels of well-being than CON as indicated by better mood (P = 0.004), higher vigilance (P = 0.015) and relaxation (P = 0.003). The latter even increased after donation with maximum values after 15 and 30 min. Despite significantly higher initial strain scores (P = 0.008), first-time donors maintained a better mood (P = 0.025) than repeat donors. DON showed a statistically better psychological well-being than CON, although the donation experience was perceived as stressful, especially for first-time donors. The results may facilitate donor recruitment and retention as blood donation may become less frightening and perhaps even attractive.

Antiplatelet therapy preceding coronary artery surgery: implications for bleeding, transfusion requirements and outcome.

BACKGROUND AND OBJECTIVE: Bleeding after cardiac surgery correlates with morbidity and mortality. The aim of this study was to determine the influence of antiplatelet therapy on bleeding and transfusion rates in coronary artery bypass grafting. METHODS: Forty patients receiving aspirin and/or clopidogrel/ticlopidine within 7 days prior to surgery were retrospectively compared to 40 control patients lacking antiplatelet therapy for at least 8 preoperative days. Blood loss was assessed as chest-tube drainage during the first 12 h after surgery. Units transfused were recorded intraoperatively and during stay in the intensive care unit. RESULTS: Both groups were comparable for pre- and intraoperative data. Irrespective of single or combined antiplatelet therapy, treated patients demonstrated lower fractions of the creatine-kinase isoenzyme MB (5.8 +/- 3.1 vs. 8.2 +/- 4.1%; P = 0.004) and infarction rates (0 vs. 3; P = 0.240) than control patients, but had significantly more haemorrhages (940 +/- 861 mL vs. 412 +/- 590 mL; P = 0.002) and transfusion requirements (red cells: 4.5 +/- 4.9 vs. 1.5 +/- 2.3, plasma: 4.9 +/- 6.4 vs. 1.3 +/- 2.5, platelets: 1.5 +/- 1.3 vs. 0.1 +/- 0.2; all P < or = 0.001). The differences to control patients were more pronounced for only short antiplatelet therapy free intervals or ongoing antiplatelet therapy (P < or = 2 days < or = 0.019). For antiplatelet therapy free intervals longer than 2 days, bleeding and transfusion rates (except for platelets) were nonsignificantly higher as compared to control patients (P > or = 0.058). CONCLUSIONS: To overcome increased blood loss and transfusion rates, antiplatelet therapy should be discontinued for at least 2 days before elective coronary surgery. Whether patients at high risk for myocardial infarction might benefit from ongoing antiplatelet therapy remains to be investigated.

Evaluation of concurrent collection of in-line filtered platelets and packed red blood cells by multicomponent apheresis with three last-generation apparatuses.

BACKGROUND AND OBJECTIVES: Multicomponent apheresis enables the collection and procession of different blood products in a single donation. Different apparatuses vary in terms of principle and efficiency. Knowledge of them is essential to analyse cost effectiveness. MATERIALS AND METHODS: A total of 30 donors, well matched for baseline parameters, were randomly assigned to the concurrent collection of red blood cells (RBCs) and platelets (PLTs) with the Baxter Amicus (AM), the Haemonetics MCS plus (MCS+), and the Gambro Trima Accel (TA). The procedures were prospectively evaluated, focusing on yield, time, efficiency, citrate donor load and in vitro quality. RESULTS: PLT yield (x 10(11)/unit; mean +/- standard deviation) was 3.09 +/- 0.34 (AM), 2.53 +/- 0.35 (MCS+), 2.51 +/- 0.32 (TA). Absolute RBC mass (ml/unit; mean +/- standard deviation) was 177.4 +/- 2.7 (AM), 161.5 +/- 0.7 (MCS+), and 163.7 +/- 5.4 (TA). The programmed RBC collection target of 160-180 ml was reached by all instruments, whereas the programmed PLT yield of 3.0 x 10(11) was met satisfactorily by AM only. All units contained < 1 x 10(6) WBCs. In vitro RBC quality was equivalent among the systems. No significant differences were noted with collection efficiency, processed whole blood or citrate donor load. Owing to high collection and draw rates, the TA was the fastest of all the systems. The MCS+ had the longest donation/needle time and the highest PLT activation, but compensated with significantly lower draw and citrate infusion rates. The overall processing time was longest with the AM, as a result of manual procedures from donor disconnection to the final products. CONCLUSIONS: Multicomponent apheresis was performed safely and efficiently with all three instruments. There was no 'magic apparatus' as each system combined advantages and pitfalls for the diverse parameters evaluated.

Leucodepletion leads to component-like storage stability of whole blood--suggesting its homologous use?

BACKGROUND AND OBJECTIVES: Leucodepleted whole blood (LWB) is already widely used for autologous donations and could also be appropriate for certain instances of allogeneic transfusion provided that storage quality can be preserved at component-like levels. MATERIALS AND METHODS: Sixteen units of whole blood (WB), donated by healthy volunteers into CPDA-1 according to German guidelines, were leucofiltered prestorage and stored for up to 49 days. Unfiltered WB in CPDA-1 (UFWB, n=16) and filtered red blood cells in SAGM (RCC, n=14) served as controls. Several haematological, biochemical and coagulatory quality parameters were determined at designated time-points during storage. RESULTS: Apart from significant differences (P<0.05) in haematocrit (56.2+/-3.6 vs. 37.9+/-3.9%), and in the plasma concentrations of free haemoglobin (93.1+/-37.8 vs. 57.8+/-24.3 g/dl), K+ (38.9+/-5.3 vs. 31.5+/-4.3 mm) and ATP (2.7+/-0.2 vs. 1.6+/-0.4 micromol/g haemoglobin), with higher levels detected in RCC, no remarkable differences (P>0.05) were observed regarding haemolysis (0.23+/-0.07% vs. 0.31+/-0.13) and pH value (6.63+/-0.03 vs. 6.62+/-0.02) between RCC and LWB at the end of storage. Lack of leucodepletion manifested in significantly (P<0.05) higher rates of haemolysis (0.44+/-0.21%), free haemoglobin (89.6+/-43.5 g/dl) and lower pH values (6.56+/-0.04). During 42 days of LWB storage, sufficient amounts (% of the initial mean value) were observed with stable (factor XI, 97.5+/-15.0) and labile (factor V, 92.9+/-18.0; factor VIII, 69.2+/-17.1) clotting factors and inhibitors (antithrombin III 88.9+/-9.5), without any signs of activated coagulation. CONCLUSIONS: Our data indicate that the quality of LWB is comparable to that of components during 42 days of storage. Thus, LWB could be an interesting option for using to facilitate and economize the blood supply, especially for surgical or trauma patients.

[Heparin induced thrombocytopenia. A frequently unrecognised complication after major orthopedic surgery]. / Die heparininduzierte Thrombozytopenie. Eine oft verkannte Komplikation nach grösseren orthopädischen Eingriffen.

The application of unfractioned (UFH) and low molecular weight heparins (LMH) has reduced the incidence of thromboembolic events. However, the frequency of heparin-induced thrombocytopenia (HIT II) in orthopedic patients, particularly susceptible for both thromboembolic complications and HIT II with potentially life threatening complications, is about 0.5% for LMW and 3% UFH. Induced by an immune response, the excessive activation of platelets and endothelial cells causes massive thrombin generation and, as a result, thrombotic vessel occlusion. The rates of mortality and amputation in HIT II are estimated to be 30% and 20%, respectively. The clinical course is highly dependent on early therapeutic intervention, consisting of compatible and adequately dosed anticoagulation drugs. Vitamin K antagonists as well as platelet substitution may lead to disastrous sequelae. We summarize the current state of the pathophysiology, diagnosis and therapy of HIT II and illustrate therapeutic mistakes in a case report.

Evaluation of processing characteristics of photochemically treated pooled platelets: target requirements for the INTERCEPT Blood System comply with routine use after process optimization.

To ensure good performance of pathogen inactivation with the INTERCEPT blood system, specific target requirements must be met for platelet dose, volume, plasma content and residual red blood cells (RBCs) prior to photochemical treatment (PCT). A two-arm in vitro study was conducted to compare quality parameters of pooled platelet concentrates (PCs), either treated (test units) or nontreated (control units). PCs meeting European requirements were evaluated with reference to their compliance with INTERCEPT guard bands. Of 50 PCs (25 tests and 25 controls) meeting European quality requirements, 24% (three test and three controls units) did not reach INTERCEPT requirements, particularly in terms of sufficient volumes and RBC contamination. The buffy-coat optimization procedure assessed prior to this study ensured plasma contents well within target limits of 30 to 45%. Due to PCT-related in-process loss of 11% in volume (34.38 +/- 3.94) and in platelet dose (0.41 +/- 0.14), the mean platelet dose was significantly (P < 0.001) lower in test units: 3.1 +/- 0.3 versus 3.6 +/- 0.4 x 10(11). After treatment, six of the overall 25 test units (25%) would not have met the European guideline for platelet dose (3.0 x 10(11)). Before implementation of techniques for pathogen reduction, each centre should optimize processing steps during a validation procedure to ensure PC complying with INTERCEPT targets before and European targets after treatment. Besides buffy-coat optimization for sufficient plasma reduction, centrifugation profiles need to be optimized as well to prevent PC with low volumes and, in particular, with higher than acceptable RBC contamination.