Erythrocytapheresis versus phlebotomy in the maintenance treatment of HFE hemochromatosis patients: results from a randomized crossover trial.

BACKGROUND: Phlebotomy is standard maintenance treatment of patients with hereditary hemochromatosis (HH). Erythrocytapheresis, which selectively removes red blood cells, provides a new, potentially more effective treatment option. Our aim was to evaluate the effectiveness of erythrocytapheresis over phlebotomy for maintenance therapy in patients with HH. STUDY DESIGN AND METHODS: We conducted a two-treatment-arms, randomized, crossover clinical trial, involving 46 patients, treated for 1 year with either erythrocytapheresis or phlebotomy to keep the ferritin level at not more than 50 µg/L. After 1 year, patients were switched to the other treatment modality. Primary endpoint was the number of treatment procedures per treatment year. Secondary endpoints were intertreatment intervals, several aspects of health-related quality of life, costs, and patient discomfort as well as preference for one of both treatments. RESULTS: The mean number of required treatment procedures per treatment year was significantly higher using phlebotomy versus erythrocytapheresis (3.3 vs. 1.9; mean difference, 1.4; 95% confidence interval, 1.1-1.7). The median intertreatment time was 2.3 times longer for erythrocytapheresis. There was no significant difference in overall health assessed by SF-36 and EQ-5D, respectively, between both treatments arms. The number of self-reported swollen joints was significantly higher during phlebotomy treatment. The mean treatment costs of one treatment year were 235€ for phlebotomy versus 511€ for erythrocytapheresis. Eighty percent of patients preferred erythrocytapheresis as treatment method. CONCLUSION: Erythrocytapheresis significantly reduced the number of treatment procedures per treatment year, although the mean treatment costs per year are higher in our health care system. It is the preferred treatment for the majority of patients.

Flow cytometric measurement of CD62P (P-selectin) expression on platelets: a multicenter optimization and standardization effort.

BACKGROUND: One of the variables to determine the quality of platelets (PLTs) in vitro is measurement of CD62P expression. Different protocols are in use, however, making comparison of results virtually impossible. It was our aim to develop a uniform CD62P protocol that would yield comparable results in various laboratories. STUDY DESIGN AND METHODS: The effects of fixation, source and dilution of CD62P antibody, source of immunoglobulin G (IgG) isotypic antibody, and analysis of results were investigated. Once the optimal variables were defined, comparative studies were performed at five participating centers. In the final comparative study, eight split PLT concentrates were shipped to the centers, where samples were stained and fixed according to the uniform protocol. Analyses were performed using commercially available flow cytometers (BD Biosciences and Beckman Coulter). RESULTS: Uniformity between centers could be achieved by using a single clone for CD62P and IgG monoclonal antibody. A protocol was selected using fixation with 0.5 percent methanol-free formaldehyde. To increase conformity between flow cytometers, in the analysis of electronic data the thresholds of the isotypic control were set at 0.5 percent for the BD Biosciences and 2 percent for the Beckman Coulter flow cytometers. In the final comparative study, the 95 percent confidence intervals (CIs) for CD62P ranged between 8 and 21 percent in fresh and 20 to 40 percent in 8-day-old PLT concentrates. CONCLUSION: A uniform CD62P staining protocol and subsequent analysis can be used at multiple centers using different flow cytometers, yielding comparable results with acceptable 95 percent CIs.

Platelet function in whole-blood donors is impaired: the effects of painkillers.

BACKGROUND: Aspirin (ASA) or non-aspirin-like nonsteroidal anti-inflammatory drugs (NSAIDs) influence platelet (PLT) function by inhibiting cyclooxygenase enzymes. In this study, the aim was to address the use of ASA or NSAIDs before donation and the effect on PLT function. STUDY DESIGN AND METHODS: Donors were asked questions about recent use of ASA or NSAIDs. Furthermore, PLT function was evaluated by measurement of the closure time (CT) in a PLT function analyzer (PFA-100, Dade Behring) and by aggregometry (response to ADP or arachidonic acid [AA]). RESULTS: Of 100 questioned donors, 22 percent had used ASA (n = 4), NSAIDs (n = 6), or paracetamol (n = 12) before donation. Upon assessment of the PLT function in the PFA-100, 27 donors showed values of greater than 180 seconds, indicative of impaired PLT function. Of these, only 7 had used pain killers before donation. Furthermore, 15 of 22 users had normal CTs. Aggregation after stimulation with AA was absent in 33 PLT-rich samples. Again only 8 had reported use of ASA (3), NSAIDs (1), or paracetamol (4). Of the 22 users, 14 had normal AA aggregation responses. All donor samples showed ADP-induced aggregation, indicating PLT integrity. There was no difference between the group of donors who reported the intake of ASA or NSAIDs and the group of donors who did not with respect to the tested PLT function assays. CONCLUSION: It is concluded that there is a considerable group of donors that use PLT-influencing medication before donation. A relation between the reported use and impaired PLT function in blood donors could not be established, however. Impaired PLT function as tested may have other causes than intake of ASA or NSAIDs.

Platelet ADP response deteriorates in synthetic storage media.

BACKGROUND: During storage under blood bank conditions, platelets (PLTs) are known to secrete ADP. PLT stimulation by ADP results in refractoriness to restimulation, making this response one of the most unstable PLT reactions. The goal of this study was to evaluate the ADP-induced responses of PLTs stored in full plasma or in plasma and additive solution (AS). STUDY DESIGN AND METHODS: Surface expression of P-selectin, ADP-induced aggregation, and reconstituted whole-blood thrombus formation were determined on collagen surfaces in a perfusion model with PLTs that were stored for 4 days either in plasma or in the presence of plasma with PAS-II or Composol. RESULTS: After 4 days of storage in PAS-II but not in Composol, the percentage of PLTs that had secreted granule contents (P-selectin) was increased, when compared to PLTs stored in full plasma. Maximal aggregation in response to ADP was reduced for PLTs stored in PAS-II or Composol. Resuspension of these PLTs in plasma at 37 degrees C for 1 hour caused partial recovery of the aggregation response. Addition of apyrase to PLTs in AS preserved the responsiveness toward ADP. Titration experiments indicated that this response gradually decreased with decreasing plasma concentration. The functional significance of these findings was demonstrated by perfusion experiments. Thrombus formation on collagen was significantly higher for PLTs stored in full plasma than for PLTs stored in PAS-II or Composol. CONCLUSIONS: Storage of PLTs in the presence of AS under blood bank conditions induces deterioration of the PLT responsiveness to ADP compared to PLT concentrates in 100 percent plasma. Higher plasma-to-AS ratios result in better preserved responses.