Randomized placebo-controlled study of oral calcium carbonate administration in plateletpheresis: I. Associations with donor symptoms

BACKGROUND: The effect of oral calcium (Ca) supplements in preventing citrate-induced symptoms during plateletpheresis was evaluated in a randomized, blinded, placebo-controlled trial. STUDY DESIGN AND METHODS: Twenty-three donors (12 men, 11 women) underwent four plateletpheresis procedures each, ingesting either 1 or 2 g of oral Ca carbonate or an equivalent placebo 30 minutes before donation. Ten of these subjects subsequently ingested 4 g of open-label Ca before a fifth procedure. All procedures were conducted at the same citrate infusion rate (1.5 mg/kg/min) for 90 minutes. RESULTS: Ingestion of 2 g of oral Ca resulted in a significant reduction in the severity of paresthesias and a significant, though modest, increase in serum ionized calcium (iCa), but no significant improvement in total symptom scores, compared to placebo. Minimal effects were seen with the 1-g dose. The two factors most highly correlated with development of severe symptoms were decreased levels of iCa and ionized magnesium (iMg) at 30 minutes into apheresis. Lower preapheresis serum albumin, creatinine, vitamin D, iMg, and total Mg concentrations were also significantly associated with symptoms. Women experienced more frequent and severe symptoms than men, however, gender was not associated with symptoms after adjustment for lower serum albumin, creatinine, and Mg levels. Ingestion of 4 g of Ca offered no improvement in symptoms or iCa levels compared with the 2-g dose. CONCLUSION: Prophylactic oral Ca was associated with modest improvements in citrate-induced symptoms and laboratory parameters. Baseline albumin and Mg levels were strongly predictive of the development of symptoms. In donors with a prior history of uncomfortable citrate-related effects, a 2-g oral Ca dose before apheresis is recommended.     

Donor exposure to the plasticizer di(2-ethylhexyl)phthalate during plateletpheresis

BACKGROUND: Di(2-ethylhexyl)phthalate (DEHP) is a plasticizer that is contained in most PVC devices, including apheresis disposables. Because DEHP can be extracted from apheresis disposables as the blood passes through the apheresis device, DEHP exposure was determined in healthy donors undergoing plateletpheresis performed with commercially available apheresis systems. STUDY DESIGN AND METHODS: The study population consisted of 36 healthy PLT donors undergoing plateletpheresis with either continuous or discontinuous apheresis devices. Serum concentrations of DEHP were determined from peripheral blood obtained before and after plateletpheresis, with gas chromatography-mass spectroscopy. RESULTS: Plateletpheresis performed with standard collection disposables resulted in a median increase of 232 percent of serum DEHP compared to levels before apheresis, corresponding to a total amount of DEHP exposed during a single apheresis of a median of 6.46 (range, 1.8-20.3) microg per kg of body weight. Endogenous levels of triglycerides showed a positive correlation with the amount of DEHP released. Increase in serum DEHP was short-term as serum DEHP rapidly returned to levels obtained before apheresis within 3 hours after completion of the apheresis course. Donor exposure to DEHP led to no variation in liver cell function within 48 hours after plateletpheresis. CONCLUSION: Commercial plateletpheresis disposables release considerable amounts of DEHP during the apheresis procedure, but the total dose of DEHP retained by the donor is within the normal range of DEHP exposure of the general population.     

Calcium and magnesium levels during automated plateletpheresis in normal donors

It is well known that citrate induces ionized hypocalcaemia by the chelating effect during plateletpheresis. However, the kinetics of serum magnesium (Mg) ions has not been well documented. We, therefore, evaluated biochemical changes in healthy donors during plateletpheresis procedure. Ten healthy donors underwent plateletpheresis on continuous cell separator (CS3000, Baxter, Round Lake, IL, USA) and 10 on intermittent flow cell separator (MCS 3p, Hemonetics, Braintree, MA, USA). Serum levels of total and ionized calcium (tCa and iCa, respectively) and Mg (tMg and iMg, respectively) were measured before, during and after the procedures. Although, the fall in tCa (from 2.62 +/- 0.12 to 2.36 +/- 0.12 mmol L(-1)) and tMg (from 0.89 +/- 0.01 to 0.79 +/- 0.01 mmol L(-1)) was modest and not significant; drop in iCa (from 1.33 +/- 0.1 to 0.84 +/- 0.1 mmol L(-1)) and iMg (from 0.53 +/- 0.01 to 0.35 +/- 0.1 mmol L(-1)) was statistically significant (P < 0.001). There were no significant differences observed between the CS3000 and MCS 3p cell separators regarding the fall in Ca and Mg. None of the donors experienced any adverse reactions during the procedures. In the study, an acute ionized hypocalcaemia and hypomagnesaemia have been observed after the plateletpheresis; therefore, measurement of both the ions may be monitored. However, there is no justification for prophylactic supplementation of either of these elements.     

Hypocalcemic symptoms during plateletpheresis using the COBE Spectra: A comparison of oral combination of 600mg calcium+300mg magnesium+100IU vitamin D3 vs. a 1000mg calcium in symptomatic donors.

BACKGROUND: The aim of this study was to find an effective treatment for hypocalcemic symptoms during plateletpheresis and to evaluate if a combination of calcium, magnesium and vitamin D3 is more effective in comparison to routine calcium supplementation. MATERIAL AND METHODS: A study group consisting of 10 donors, having a history of previous hypocalcemic symptoms during plateletpheresis, donated platelets twice in a one-month period. During the first donation combination tablets (600mg Ca+300mg Mg+100IU vitamin D3) were used to treat hypocalcemic symptoms while routine treatment calcium carbonate tablets (1000mg Ca) were used during the second donation. If symptoms persisted after 10min the same dose was repeated. A control group, with no supplementation, consisting of five donors, with no history of hypocalcemic symptoms, were included. Donor subjective symptoms were graded and recorded on four occasions: at the start of plateletpheresis, when symptoms appeared, 10min after the first tablet and at the end of donation. Samples for analysis of ionized calcium (iCa), magnesium and potassium were also taken at the same occasions. RESULTS: All donors from the study group experienced minor or medium hypocalcemic symptoms and needed a second dose of supplementation. Calcium carbonate tablets completely relieved the hypocalcemic symptoms in six donors, it had no effect on three donors and one donor experienced aggravated symptoms. The combination tablets completely relieved the symptoms in three donors, one donor experienced a partial relief and six donors had no relief of symptoms. There were no significant differences in iCa, potassium and magnesium levels were noted in the study group irrespective of which tablets were used for treatment of hypocalcemic symptoms. After plateletpheresis the median iCa levels declined by 30% and potassium levels declined by 3-11% in all donors while the magnesium levels were not significantly affected. There was no correlation between the presence of symptoms and the changed levels of iCa or magnesium. CONCLUSION: Addition of magnesium and vitamin D3 to calcium seems to have no beneficial effect in the treatment of hypocalcemic symptoms in plateletpheresis donors.     

Serial monitoring of ionised calcium levels in plateletpheresis donors: A study from tertiary care oncology centre in India

BackgroundPlateletpheresis is a safe procedure, and the most common reaction is hypocalcemia which is transient and self-limiting, but it can have an impact on donor experience and donor return rate.AimTo serially monitor the ionized calcium levels of the plateletpheresis donors and to correlate with symptoms of hypocalcemia if any.MethodsIt was a prospective observational study in 126 healthy voluntary donors eligible for plateletpheresis as per the Departmental SOP and after taking written informed consent. Procedures were conducted on continuous flow centrifugation (CFC) and intermittent flow centrifugation (IFC) cell separators. Donor blood samples were collected in pre-heparinized syringes at different intervals to measure ionized calcium levels (iCa++) by venous blood gas analysis (Cobas 221).ResultsThere was a continuous and gradual decrease in iCa++ from start to 30–45 minutes during the procedure; while the levels showed a gradual increase at end of the procedure and reached near the baseline values after 15?30 min of completion of the procedure. The change in iCa++ was statistically significant at 30 min and 45 min (p < 0.05), which was correlated with symptoms of hypocalcemia observed in 32.5 % (41/126) of the donors. Females experienced more symptoms of hypocalcemia as compared to males (p < 0.01). Donors who underwent plateletpheresis on the IFC machine experienced more symptoms of hypocalcemia as compared to the CFC machine (p < 0.05).ConclusionFor donors with persistent symptoms of hypocalcemia which are unrelieved by procedural modifications (reducing blood return rate, citrate infusion rate, etc.) measurement of iCa++ and administration of oral calcium tablets may be considered.     

Clinical and clinicopathologic effects of plateletpheresis on healthy donor dogs

BACKGROUND: The safety and feasibility of plateletpheresis using a commercially available apheresis system (COBE Spectra, Gambro BCT) were evaluated in donor dogs, with characterization of its clinical and clinicopathologic effects. STUDY DESIGN AND METHODS: Fourteen adult dogs (18‐27.7 kg) underwent a plateletpheresis procedure. Complete blood counts were obtained at baseline, 2 hours after apheresis, and daily for 1 week. Blood was collected every 15 minutes for acid‐base and electrolyte analysis and measurement of serum citrate concentration. Dogs were monitored by continuous electrocardiogram and indirect blood pressure measurement. All dogs received prophylactic calcium (Ca) supplementation (10% Ca gluconate infusion at 15 mL/hr [139.5 mg Ca ion/hr]; the rate was increased based on serial measurement of ionized Ca [iCa] concentration). RESULTS: A high‐quality platelet concentrate (PC) was collected, with a mean total yield of 3.3 × 10¹¹ platelets (PLTs). The mean donor PLT count decreased from 356 × 10⁹ to 159 × 10⁹ per L after apheresis. The procedure was generally well tolerated, with no evidence of hypotension. Serum citrate concentration progressively increased, causing the ionized magnesium concentration to decrease by 45 percent and iCa to decrease to less than 1 mmol per L (mean baseline, 1.2 mmol/L) in 10 dogs, despite receiving 0.9 mg of Ca ion per mL acid‐citrate‐dextrose formula A. Lip licking was noted in 3 dogs, and generalized tremors and ventricular ectopy were noted in 1 dog. CONCLUSION: Canine plateletpheresis using the COBE Spectra is a feasible option for production of a PC. Hypocalcemia, however, is a potential serious adverse effect of plateletpheresis in dogs. Ca supplementation is recommended to limit clinical signs of hypocalcemia during the procedure.     

碳酸钙口服片和碳酸钙咀嚼片对多次机采血小板男性献血者血清Ca2+和甲状旁腺激素水平的影响

目的 探讨碳酸钙口服片和咀嚼片对多次机采血小板男性献血者血清Ca2+和甲状旁腺激素(PTH)水平的影响.方法 采用简单随机抽样方法,选择2016年6月15日至7月15日,于深圳市血液中心捐献血小板的76例多次机采血小板男性献血者为研究对象.采用简单随机分组方法,将其分为3组:碳酸钙口服片组(n=27,机采前20 min口服碳酸钙D3片1片),碳酸钙咀嚼片组(n=25,机采前20 min口服碳酸钙D3咀嚼片1片)非未补钙组(n=24,机采前未服用任何补钙制剂).采用MCS+型血细胞分离机采集3组献血者血小板.并且分别于血小板机采前(机采前20 min),机采开始时,机采过程中(机采开始后约30 min),机采结束时,留取献血者静脉血5 mL.分别采用邻甲酚酞络合酮比色法和化学发光法,检测3组献血者的血清Ca2+和PTH水平.于血小板机采结束后,向碳酸钙口服片组和碳酸钙咀嚼片组献血者发放调查问卷,调查其对所服用碳酸钙制剂的满意度.采用统计学方法,比较3组献血者在血小板机采不同时间点的血清Ca2+和PTH水平,以及碳酸钙口服片组和碳酸钙咀嚼片组献血者对碳酸钙制剂的满意率.3组献血者一般资料比较,差异均无统计学意义(P＞0.05).结果 ①血小板机采前、机采开始时,3组献血者的血清Ca2+水平分别比较,差异均无统计学意义(P＞0.05).机采过程中,碳酸钙口服片组、碳酸钙咀嚼片组及未补钙组献血者的血清Ca2+水平分别为(2.26±0.06)mmol/L、(2.28±0.04) mmol/L和(2.24±0.06)mmol/L,3组比较,差异有统计学意义(F=3.47,P=0.04);碳酸钙口服片组与碳酸钙咀嚼片组,碳酸钙口服片组与未补钙组分别比较,差异均无统计学意义(P=0.08、0.36);碳酸钙咀嚼片组与未补钙组比较,差异有统计学意义(P=0.01).机采完成时,3组献血者的血清Ca2+水平分别为(2.25±0.06) mmol/L、(2.26±0.04) mmol/L和(2.17±0.05)mmol/L,3组比较,差异有统计学意义(F=21.29,P＜0.01);其中,碳酸钙口服片组和碳酸钙咀嚼片组比较,差异无统计学意义(P=0.56);但是均高于未补钙组,并且差异均有统计学意义(P＜0.01).②血小板机采前、机采开始时,3组献血者的血清PTH水平分别比较,差异均无统计学意义(P＞0.05).机采过程中,碳酸钙口服片组、碳酸钙咀嚼片组及未补钙组献血者的血清PTH水平分别为(110±21)pg/L、(102±26) pg/L和(161±40) pg/L;碳酸钙口服片组与碳酸钙咀嚼片组比较,差异无统计学意义(P=0.32);但是均低于未补钙组,并且差异均有统计学意义(P＜0.01).机采完成时,3组献血者血清PTH水平分别为(95±23)pg/L、(91±25)pg/L和(147±38)pg/L;碳酸钙口服片组与碳酸钙咀嚼片组比较,差异无统计学意义(P=0.09);但是均低于未补钙组,并且差异均有统计学意义(P＜0.01).③本研究共计发放调查问卷52份,均填写完整并收回.碳酸钙咀嚼片组献血者对碳酸钙制剂的满意率为92.0％(23/25),高于碳酸钙口服片组的59.3％(16/27),二者比较,差异有统计学意义(x2 =7.42,P＜0.01).结论 血小板机采前20 min口服碳酸钙咀嚼片,可使多次机采血小板男性献血者于机采过程中及机采结束后血清Ca2+和PTH水平保持稳定.碳酸钙咀嚼片口感良好,服用方便,可用于机采血小板献血者献血前使用.     

The effect of continuous-flow automated plateletpheresis on fibrinolytic activity of donor plasma

Blood circulating in extracorporeal circuit of the apheresis sets has a contact with an artificial surface. The data on the influence of plateletpheresis on fibrinolytic activity are very limited and difficult to interpret. The aim of our study was to estimate the effect of plateletpheresis on the activation of fibrinolysis. Plateletpheresis was performed in 17 healthy blood donors using continuous-flow cell separator COM.TEC (Fresenius, Bad Homburg, Germany). Before and after plateletpheresis, blood samples were taken and markers of fibrinolysis (PAP, t-PA, PAI-1) as well as factor XII activity have been measured. We observed statistically significant decrease in t-PA and factor XII activities after plateletpheresis. There were no significant changes in concentrations of t-PA, PAI-1 and PAP as well as PAI-1 activity after plateletpheresis. Plateletpheresis performed by COM.TEC cell separator has very little, if any, effect on the activation of fibrinolysis. The mechanism of the inhibition of t-PA activity needs further investigations.     

Safety issues of plateletpheresis: comparison of the effects of two cell separators on the activation of coagulation, fibrinolysis, and neutrophils and on the formation of neutrophil-platelet aggregates

BACKGROUND: Although many donors undergo repeated plateletpheresis, data on the consequences of plateletpheresis for the donor's health remain scarce. Thus, the effect of plateletpheresis on the activation of coagulation, fibrinolysis, and neutrophils was investigated. STUDY DESIGN AND METHODS: Part 1: Sixteen healthy men were randomly assigned to undergo plateletpheresis on a cell separator (AMICUS, Fenwal Baxter; or MCS 3p, Haemonetics). The effects of plateletpheresis on plasma levels of prothrombin fragment (F(1+2)), D-dimer, plasmin-plasmin inhibitor (PPI) complexes, and plasminogen activator inhibitor (PAI-1); on the activation of neutrophils (% L-selectin+); and on the frequency of platelet-neutrophil aggregates (% CD41+ neutrophils) were compared. Part 2: Ten healthy men received infusions of ACD-A and placebo without apheresis in a randomized, double-blind crossover study to control for the pharmacologic effects of citrate. RESULTS: Part 1: No change in F(1+2) occurred (p>0.05), which indicated that plateletpheresis did not enhance coagulation. Levels of D-dimer, PPI, and PAI-1 decreased over time on the AMICUS (p<0.001). Plateletpheresis did not activate neutrophils (p>0.05), but it decreased the percentage of CD41+ neutrophils (p<0.003). An approximately 80-percent drop in mononuclear cells was observed in the extracorporeal circulation of the AMICUS (p<0.001 vs. baseline and p = 0.005 vs. MCS 3p), and circulating lymphocyte and monocyte counts decreased concomitantly. Part 2: Infusion of ACD-A slightly decreased D-dimer levels (p<0.05), and both infusions decreased the circulating lymphocyte counts. CONCLUSION: Plateletpheresis can be regarded as safe with respect to the activation of coagulation or neutrophils. The consequences for the donor's health of the decrease in D-dimer, PPI, and PAI-1 may deserve further investigation.     

不同缓冲剂碳酸盐透析液对维持性血液透析患者血压及血钙的影响

目的 比较枸橼酸碳酸氢盐透析液和醋酸碳酸氢盐透析液对维持性血液透析患者血压及血钙的影响,为临床选用最佳透析液提供理论依据.方法 16例透析患者进行自身前后对照研究,前3周使用枸橼酸透析液,透析液钙浓度依次是1.75mmol/L （DCa1.75）、1.5mmol/L （DCa1.5）和1.25mmol/L（DCa1.25）.后3周使用醋酸透析液,依次是DCa1.75、DCa1.5、DCa1.25.比较使用不同透析液透析前后患者血清总钙（tCa）、离子钙（iCa）及平均动脉压（MAP）的变化.结果 ①DCa1.75时,2种透析液均使患者透析后tCa、iCa升高,对透析后MAP无影响.②DCa1.5时,醋酸透析液使透析后tCa、iCa升高,枸橼酸透析液对透析后tCa、iCa无影响,二者对透析后MAP无影响.③DCa1.25时,枸橼酸透析液使透析后tCa、iCa降低,MAP由（97±16） mmHg降至（86±21）mmHg （P＜0.05）.使用醋酸透析液患者透析后tCa降低,而iCa、MAP无变化.结论 DCa1.5的枸橼酸透析液对透析患者血清tCa、iCa水平及MAP影响最小.     

Platelet activation during plasma-reduced multicomponent PLT collection: a comparison between COBE Trima and Spectra LRS turbo cell separators

BACKGROUND: The wide diffusion of multicomponent collection in donor apheresis has led to the yielding of different components, such as plasma-reduced platelet-pheresis at high PLT concentration. We investigated whether this collection modality could induce more PLT activation compared to standard plateletpheresis. STUDY DESIGN AND METHODS: Forty-one plateletpheresis collections (20 Trima and 21 Spectra LRS Turbo v.7.0, COBE) were evaluated. Donor, procedure, and product data were recorded. ADP, collagen, and U46619 (a thromboxane-A2 analog)-induced PLT aggregation was investigated in basal (donor) and final (plateletpheresis unit) samples. The expression of PLT activation marker P-selectin (CD62P) was studied using flow cytometry in basal and final samples. In all cases, P-selectin was investigated in final samples after stimulation with ADP to assess for a possible further release of the antigen. Four additional plateletpheresis procedures were performed in donors from Group A, using the traditional, nonplasma-reduced program. RESULTS: Plateletpheresis obtained by means of the Trima device showed a lower response to in-vitro induced PLT aggregation and a higher percentage of P-selectin-expressing PLT when compared to products obtained using the Spectra device. Moreover, P-selectin release after ADP stimulation was reduced in plateletpheresis units obtained using the Trima device. These differences disappeared when a nonplasma-reduced collection program was used. In-vivo evaluation did not detect any difference between plateletpheresis obtained by means of the two cell separators. CONCLUSIONS: Plateletpheresis units obtained by means of multicomponent collection show a higher degree of PLT activation compared to traditional plateletpheresis procedures when high-concentration plasma-reduced products are collected. Randomized clinical studies are needed to assess the real impact of these findings in terms of in-vivo efficacy of plasma-reduced plateletpheresis units.     

Effectiveness of supplemental oral calcium drink in preventing citrate-related adverse effects in peripheral blood progenitor cell collection

Peripheral blood progenitor cells (PBPCs) are a predominant graft source in allogeneic hematopoietic cell transplantation. Citrate-induced hypocalcemia remains the most frequent side effect of PBPC apheresis. Although the method for preventing severe adverse events is established, more efficient prophylaxis is required so that volunteer donors can donate PBPCs without pain and anxiety. We studied 80 healthy donors who underwent PBPC harvest between February 2014 and June 2020. Of these, 23 donors who underwent apheresis between February 2014 and December 2015 received only the standard prophylaxis of intravenous calcium gluconate. Oral calcium drinks were provided to 57 donors who underwent apheresis from January 2016 to June 2020 to supplement intravenous calcium gluconate prophylaxis. The ionized calcium (ICa) levels at multiple time intervals and the hypocalcemic symptoms were evaluated. Oral supplementation with a calcium drink maintained significantly higher ICa levels. Analysis using the inverse probability weighted regression adjustment method suggested that calcium drinks reduced the frequency of citrate-related reactions by 39.2 %. Administering a prophylactic oral calcium drink before apheresis with intravenous administration of calcium gluconate is promising to further reduce citrate-induced hypocalcemia in volunteer donors.     

Switching iron‐deficient whole blood donors to plateletpheresis

BACKGROUND: Iron deficiency is a frequent side effect of whole blood (WB) donation. In contrast, less red blood cell loss and therefore less iron loss results from plateletpheresis. STUDY DESIGN AND METHODS: WB donors presenting a decrease in either hemoglobin (Hb) or ferritin levels were offered to switch to plateletpheresis with or without iron supplementation. We analyzed the effect of this intervention on deferral rates for an insufficient Hb level in 168 donors. Further, we assessed how this intervention affected Hb and ferritin levels, anemia occurrence, and platelet (PLT) concentrate yields in the donors who presented at least four successive times for thrombapheresis. RESULTS: Switching WB donors to repetitive plateletpheresis procedures resulted in an increase of median Hb (+12 g/L, p < 0.001) and ferritin (+15.5 ng/mL, p = 0.002) values. Anemia and deferral rates were reduced by 23% (p = 0.004) and 13% (p < 0.001). Between high‐ and low‐frequency apheresis donors, no significant differences in Hb and ferritin levels were found. Similarly, discrepancies in Hb and ferritin values between donors that adopted iron supplementation and those who did not were insignificant. The median PLT concentrate yield was 5.43 × 10¹¹ PLTs. CONCLUSION: Switching iron‐deficient WB donors to plateletpheresis was an effective intervention that permitted us to correct low Hb and ferritin levels while retaining donors in our pool.     

Effects of nitric oxide on platelet activation during plateletpheresis and in vivo tracking of biotinylated platelets in humans

BACKGROUND: The use of platelet transfusions has risen considerably over the last few years, which leads to the collection and transfusion of a greater number of donor plateletpheresis units. Plateletpheresis activates platelets in platelet concentrates, which determines the degree of the storage lesion subsequently observed. STUDY DESIGN AND METHODS: As nitric oxide (NO) is a potent inhibitor of platelet aggregation and activation, a placebo-controlled crossover trial was performed in healthy young male volunteers to determine whether the NO-donating compound, sodium nitroprusside (SNP), decreases platelet activation during apheresis and whether activated (p-selectin+) platelets circulate in vivo after transfusion. The study also investigated whether nonradioactive biotin labeling of apheresis platelets is feasible for the study of platelet recovery after transfusion in humans. RESULTS: Platelet activation increased after plateletpheresis in the platelet components, but SNP did not inhibit platelet activation during apheresis, as measured by the percentage of p-selectin expression and the secretion of soluble p-selectin and RANTES. Only a minor increase in p-selectin+ platelets was seen in peripheral blood at 60 minutes after transfusion of the platelets, a rise that was considerably less than that calculated in p-selectin+ platelets if they all were recovered as activated platelets after transfusion. Biotin-labeled platelets averaged 1.5 percent at 10 minutes after transfusion and increased slowly to 2.6 and 3.4 percent after 60 minutes and 24 hours, respectively (p<0.05). CONCLUSION: SNP does not decrease platelet activation during apheresis and subsequent storage, and only a minor proportion of activated (p-selectin+) platelets circulate after transfusion in men. Moreover, biotin labeling of PCs can safely be used in humans for the study of platelet recovery after transfusion, and measuring recovery at 1 hour may lead to an underestimation of the true recovery when activated platelets are transfused.     

Flow cytometric analysis of platelet membrane antigens during and after continuous-flow plateletpheresis

BACKGROUND: The influence, extent, and duration of changes in platelet antigen expression caused by blood-biomaterial interaction in plateletpheresis were assessed. STUDY DESIGN AND METHODS: Twenty-two apheresis donors were studied by using two automated continuous-flow apheresis devices. Blood samples were taken before, during, and for 4 days after extracorporeal circulation. The platelet surface expression of glycoproteins CD41a, CD42b, CD62p, and CD63 was analyzed by flow cytometry. RESULTS: Over the course of plateletpheresis, there was a significant increase in mean channel fluorescence intensity (MCFI) of CD62p, from 25.1 +/− 7.9 (mean +/− SD) to 50.4 +/− 28.9, and of CD63, from 22.3 +/− 6.5 to 33.3 +/− 13.2. There was a significant decrease in CD41a expression as measured by the MCFI, from 1129.8 +/− 125.0 to 1066.6 +/− 102.2, and in CD42b MCFI, from 329.6 +/− 49.4 to 321.4 +/− 52.0. The two apheresis devices showed different platelet activation kinetics, but the overall MCFI of CD62p and CD63 did not significantly diverge after 60 minutes of apheresis. CD62p and CD63 expression as measured by the MCFI returned to preapheresis levels during the follow- up period in 25 and 25 of 44 procedures, respectively, within 24 hours; in 10 and 13 of 44 procedures after 48 hours; in 7 and 3 of 44 procedures after 72 hours; and in 2 and 3 of 44 procedures on Day 5. CONCLUSION: The varying kinetics of expression, as measured by the MCFI, of platelet antigens CD62p, CD63, CD41a, and CD42b during extracorporeal circulation may be useful for biocompatibility testing. Activated platelets continue to circulate in donors for several days after cytapheresis, which suggests that a sufficient interval between apheresis procedures is necessary to avoid the collection of activated platelets.     

Change of coagulation parameters after double plateletpheresis.

In the previous studies, some authors reported that automated apheresis leads to a hypercoagulable state. We tried to find out changes in coagulation parameters after double plateletpheresis in this study. Forty-five donors were recruited to the study, and coagulation parameters were assessed before and after double plateletpheresis. After double plateletpheresis, fibrinogen, factor V, factor VIII and factor IX were decreased compared with the values before apheresis. Although serum levels of this coagulation parameters are decreasing, they are still in the normal limits. Therefore, we suggest that double plateletpheresis is a safe procedure for healthy volunteers taking into account these coagulation parameters.     

Strategies to recruit plateletpheresis donors from a registry of HLA- typed, unrelated, bone marrow donors

Rising demand for single-donor platelet components–from random donors, to maintain platelet inventories, or from HLA-compatible donors, to support alloimmune platelet-refractory patients–necessitated increasing the size of a community plateletpheresis donor registry. This study compares two strategies for recruiting whole-blood donors into a plateletpheresis program. The whole-blood donors who were asked to participate in this study had recently joined an unrelated bone marrow donor registry and had been HLA-typed as part of that process. An in-person recruitment strategy, which was time-intensive for the apheresis donor coordinator, served as the standard. A by-mail strategy involved the mailing of recruitment materials to marrow-donor registry participants. Marrow-donor registry participants were approached about apheresis participation after they had indicated an interest in the plateletpheresis program by returning a tear-off section of an informational brochure that was sent to them along with their marrow- donor registry materials. A total of 852 marrow-donor registry participants were randomly assigned to one of two recruitment strategies, and the recruitment rates were the same (46%) for both methods. In addition, levels of apheresis participation and attrition rates of donors recruited by either strategy were comparable. Thus, the simple strategy of mailing information about a plateletpheresis program is a very cost-effective method of recruiting donors.     

单采血小板前后献血者血清甲状旁腺素及电解质的变化

目的观察单采血小板前后献血者血清甲状旁腺素及电解质浓度的变化。方法选择单采血小板献血者45名,分为补钙组(n=11)和未补钙组(n=34),分别检测血小板采集前后血清甲状旁腺素(PTH)和钙、磷、钾、钠、镁离子浓度;献全血组(n=24)。结果单采后补钙组PTH浓度有统计学意义(t=2.472,P<0.05),未补钙组单采后磷浓度升高(t=3.191,P<0.05);单采血小板献血者采前血清磷、钙、钠的浓度低于对照组(t值分别为2.477,2.349和2.064,P<0.05),但仍在正常范围内。结论单采血小板会引起献血者血钙浓度短暂降低,但机体可自身迅速调节,不必常规补钙;单采血小板献血者采集前血清磷、钙、钠的浓度低于全血献血者。     

Increase in endogenous thrombopoietin in healthy donors after automated plateletpheresis

BACKGROUND: Thrombopoietin (TPO) is a key cytokine involved in the regulation of megakaryocytopoiesis and platelet production. The aim of the present study was to test whether platelet donation is associated with changes in the serum TPO levels in healthy donors undergoing plateletpheresis. STUDY DESIGN AND METHODS: The study group consisted of 23 healthy donors undergoing single-donor plateletpheresis for the first time. Serum TPO levels and platelet counts were determined before platelet collection, at the end of apheresis, and for 4 days thereafter. Serum TPO levels were determined by a TPO-specific enzyme- linked immunosorbent assay. RESULTS: In relationship to platelet donation, serum TPO levels showed a temporary increase from baseline levels of 69.2 +/? 7.1 pg per mL to 117 +/? 6.8 pg per mL 2 days after plateletpheresis (p < 0.05). Further evaluation revealed a decline in serum TPO levels as platelet counts increased. Female donors showed a delayed normalization of circulating platelet numbers and serum TPO levels as compared to male donors. There was no significant correlation between serum TPO levels and the absolute platelet number during normalization of the donors' platelet counts after plateletpheresis. CONCLUSION: Single-donor plateletpheresis results in a temporary increase in serum TPO levels in healthy platelet donors, which may be part of a compensatory response-boosting megakaryocytopoiesis after platelet collection.     

Current topics on centrifugal plasmapheresis technologies.

In the field of plasmapheresis centrifugal technology has recently focused on the collection of peripheral blood stem cells (PBSCs) for both autologous and allogeneic transplantation in patients with malignancies or hematological diseases and on donor plasmapheresis. PBSC transplantation is rapidly replacing bone marrow transplantation in such patients. Various kinds of apheresis equipment were applied and described for PBSC collection. Comparison among machines is described. Allogeneic PBSCs were collected from healthy normal donors. Specific attention to the dose and administration duration of granulocyte colony-stimulating factor and a careful apheresis procedure should be made for donor safety. In platelet transfusion practice, a platelet concentrate product derived plateletpheresis from a single donor is preferable to minimize and to prevent adverse transfusion reactions. The status of platelet collection and its efficacy by various kinds of plateletpheresis equipment are discussed. The Amicus and CCS might be preferable plateletpheresis machines because of their collection efficiencies and wider indication for donors. With the limited number of donors, it is essential that plateletpheresis should be more effectively performed and managed by each regional blood center. The status of plasma and red cell collection by apheresis technologies is described also briefly.