Citrate Toxicity Research Articles

Citrate Pharmacokinetics in Critically Ill Patients with Acute Kidney Injury

IntroductionRegional citrate anticoagulation (RCA) is gaining popularity in continous renal replacement therapy (CRRT) for critically ill patients. The risk of citrate toxicity is a primary concern during the prolonged process. The aim of this study was to assess the pharmacokinetics of citrate in critically ill patients with AKI, and used the kinetic parameters to predict the risk of citrate accumulation in this population group undergoing continuous veno-venous hemofiltration (CVVH) with RCA.MethodsCritically ill patients with AKI (n = 12) and healthy volunteers (n = 12) were investigated during infusing comparative dosage of citrate. Serial blood samples were taken before, during 120 min and up to 120 min after infusion. Citrate pharmacokinetics were calculated and compared between groups. Then the estimated kinetic parameters were applied to the citrate kinetic equation for validation in other ten patients’ CVVH sessions with citrate anticoagulation.ResultsTotal body clearance of citrate was similar in critically ill patients with AKI and healthy volunteers (648.04±347.00 L/min versus 686.64±353.60 L/min; P = 0.624). Basal and peak citrate concentrations were similar in both groups (p = 0.423 and 0.247, respectively). The predicted citrate curve showed excellent fit to the measurements.ConclusionsCitrate clearance is not impaired in critically ill patients with AKI in the absence of severe liver dysfunction. Citrate pharmacokinetic data can provide a basis for the clinical use of predicting the risk of citrate accumulation.Trial RegistrationClinicalTrials.gov Identifier NCT00948558

Mitochondrial DNA Instability in Cells Lacking Aconitase Correlates with Iron Citrate Toxicity

Aconitase, the second enzyme of the tricarboxylic acid cycle encoded by ACO1 in the budding yeast Saccharomyces cerevisiae, catalyzes the conversion of citrate to isocitrate. aco1Δ results in mitochondrial DNA (mtDNA) instability. It has been proposed that Aco1 binds to mtDNA and mediates its maintenance. Here we propose an alternative mechanism to account for mtDNA loss in aco1Δ mutant cells. We found that aco1Δ activated the RTG pathway, resulting in increased expression of genes encoding citrate synthase. By deleting RTG1, RTG3, or genes encoding citrate synthase, mtDNA instability was prevented in aco1Δ mutant cells. Increased activity of citrate synthase leads to iron accumulation in the mitochondria. Mutations in MRS3 and MRS4, encoding two mitochondrial iron transporters, also prevented mtDNA loss due to aco1Δ. Mitochondria are the main source of superoxide radicals, which are converted to H2O2 through two superoxide dismutases, Sod1 and Sod2. H2O2 in turn reacts with Fe2+ to generate very active hydroxyl radicals. We found that loss of Sod1, but not Sod2, prevents mtDNA loss in aco1Δ mutant cells. We propose that mtDNA loss in aco1Δ mutant cells is caused by the activation of the RTG pathway and subsequent iron citrate accumulation and toxicity.

Simplified regional citrate anticoagulation using a calcium-containing replacement solution for continuous venovenous hemofiltration

Regional citrate anticoagulation (RCA) is not widely used because it requires complex therapeutic modalities, a specialized calcium-free replacement solution, and continuous intravenous calcium infusion. We designed a simplified protocol for RCA using a commercial calcium-containing replacement solution for continuous venovenous hemofiltration (CVVH). Thirty-six patients were treated with RCA-based pre-dilution CVVH using a calcium-containing replacement solution (ionized calcium 1.50mmol/L). We pumped a 4% trisodium citrate solution into the arterial line of extracorporeal circulation at a starting rate of 200mL/h while adjusting the rate to achieve a post-filter ionized calcium level of between 0.25 and 0.5mmol/L. The initial blood flow was set at 150mL/min. The replacement solution was delivered at 35mL/kg/h. We measured the serum and effluent citrate concentration during CVVH at 0, 24, 48, and 72h. The mean hemofilter survival was 61.3±21.6h (range 14-122h). The mean 4% trisodium citrate solution pumped was 207 (190-230)mL/h, and the mean pre-filter and post-filter ionized calcium levels were 0.96-1.02 and 0.34-0.38mmol/L, respectively. Ninety-two, 63, and 48% of the hemofilters were patent at 24, 48, and 72h. The mean serum citrate concentration was not significantly different at 24, 48, and 72h. No bleeding episodes were found, and no patient showed the symptoms and signs of hypocalcemia or citrate toxicity. Our simplified RCA protocol using a calcium-containing replacement solution for CVVH is effective and safe, and obviates the need for a separate peripheral or central venous catheter for continuous intravenous calcium infusion.

Donor safety in triple plateletpheresis: results from the German and Austrian Plateletpheresis Study Group multicenter trial

The objective was to investigate potential risks for apheresis donors associated with a triple-plateletpheresis (TP) program. Eleven hemapheresis centers randomly assigned 411 repeat donors (ratio, 1:1.2) to either double plateletpheresis (DP; 185 donors) or TP (226 donors) with a platelet (PLT) target content of at least 5.0×10(11) PLTs/DP and at least 7.5×10(11) PLTs/TP. The primary endpoint was procedure-related postapheresis PLT count of at least 150×10(9) /L (probability, ≥98%). Secondary endpoints were apheresis characteristics and donor adverse reactions. In 6 of 1133 DPs (0.5%) in 4 of 185 donors (2.2%) and in 20 of 1020 TPs (2.0%) in 14 of 226 donors (6.2%), postapheresis PLT counts were below 150×10(9) /L. There were marginal but significant differences in collection efficiency (DP, 69.2±9.1%; TP, 70.9±9.0%; p≤0.0001) and collection rate (DP, 10.4×10(9) ±2.3×10(9) PLTs/min; TP, 10.8×10(9) ±2.3×10(9) PLTs/min; p≤0.005). The PLT yields were 5.9×10(11) ±0.8×10(11) PLTs for DP and 8.3×10(11) ±0.9×10(11) PLT for TP (p≤0.0001) at processing times of 59±13 minutes (DP) versus 80±16 minutes (TP; p≤0.0001). Significant PLT recruitment (1.10±0.14 vs. 1.20±0.23; p<0.0001) was seen for both DP and TP. DP and TP did not differ with regard to venous access problems (VAPs) without discontinuation (3.8% for both), but DP induced fewer VAPs with discontinuation (1.1% vs. 3.0%; p<0.01). Mild citrate toxicity (1.7% vs. 3.9%; p<0.01) and circulatory reactions (0.4% vs. 2.2%; p<0.01) were more often noticed in TP, but caused no increase in discontinuations. TP results in an increase in mild donor reactions but does not significantly impair donor safety or product quality.

Regional citrate anticoagulation in patients with liver failure - time for a rethink?

Regional citrate anticoagulation (RCA) for continuous renal replacement therapy (CRRT) has become increasingly attractive in recent years due to its favourable low bleeding risk profile. Its use in liver failure, however, has been limited due to the risk of citrate accumulation and toxicity. In the previous issue of Critical Care, Schultheiss and colleagues look at CRRT using RCA in liver failure patients. They demonstrate that citrate accumulation can be predicted using the total calcium (Catot) to ionised calcium (Caion) ratio (Catot/Caion), and determine that despite the occurrence of significant citrate accumulation, the effects of citrate accumulation are not as severe as might have been expected. This study raises interesting prospects with regard to RCA use in liver failure, and we postulate that citrate may have a role as a prognostic marker of metabolic capacity much as in the way of lactate and methacetin. However, further studies are warranted, in particular examining its application in subgroups of liver failure (chronic, acute, hyperacute and subacute), before its use becomes commonplace.

Intérêt des érythraphérèses à la phase initiale du traitement des hémochromatoses génétiques de type 1 : expérience à propos de 30 cas

Purpose of the study Weekly phlebotomy schedule is commonly recommended to achieve iron depletion in hereditary hemochromatosis (HH). However, in patients with severe iron overload, more than 2 years may be required, leading to fatigue and lack of compliance. For more than 10 years, we have used erythrocytapheresis (EA) as an alternative treatment. Patients and methods To assess the number of EA to achieve iron depletion and the duration of the iron depletion therapy as well of the tolerance, we retrospectively analysed the data of newly diagnosed hemochromatosis patients, homozygote for the C282Y mutation, followed in our department between 2001 and 2007. EA were performed using a discontinuous or a continuous flow cell separators. The protocol consisted in a bimonthly EA until normalisation of the serum ferritin, with the aim of reducing the patient's hematocrit between 32–35% at the end of each session. Then we performed monthly EA until complete desaturation, defined as serum ferritin concentration below 50 μg/L and transferrin saturation below 40%. Results Thirty patients were included (23 male, mean age 52 years, range 25–78) and 625 procedures analyzed. The mean volume of removed erythrocytes in each procedure was 416.4 mL (range 150–948), which equals to 374 mg of removed iron. Iron depletion (ferritin < 50 μg/L) was achieved after 11 months with 20 sessions (range 14–78). No serious adverse reactions or citrate toxicity were observed during and after the apheresis procedures. No specific fatigue was reported during the iron depletion therapy. Patient compliance was 100%. Clinical improvement was noted in 12 out of 18 of symptomatic patients. Conclusion We conclude that HH patients treated with bimonthly EA achieved iron depletion in less than 1 year under good condition of tolerance. These data support the use of EA in patients with a severe iron overload, since it may reduce the number of the procedures as well as the duration of the iron depletion therapy.

Regional Citrate Anticoagulation in Predilution Continuous Venovenous Hemofiltration Using Prismocitrate 10/2 Solution

Regional citrate anticoagulation (RCA) for continuous renal replacement therapy (CRRT) is associated with a longer filter life and fewer bleeding events. Complexity of the regimen is the major hurdle preventing widespread application. This study describes a simple predilution continuous venovenous hemofiltration (CVVH) protocol utilizing a commercially prepared replacement solution containing citrate (Prismocitrate 10/2). Ten patients with acute renal failure were evaluated. The Prismaflex system was used for predilution CVVH, with Prismocitrate 10/2 running at 2500 mL/h as the main predilution replacement. An 8.4% sodium bicarbonate solution was infused at 50 mL/h in the first 2 h followed by 30 mL/h; 10% calcium gluconate was given to achieve an ionized calcium (iCa) level of 1-1.2 mmol/L. The circuit was run for 72 h unless there was filter clotting, transportation was required, or the patient did not require further CRRT. Total treatment duration was 504.5 h. The post-dilution equivalent ultrafiltration rate was 32.9 mL/kg/h (interquartile range [IQR] 31.6-38.2) and the median circuit life was 50.3 h (IQR 25.5-72.0). None of the circuit was changed due to circuit clotting. The median systemic iCa was 0.98 mmol/L (IQR 0.91-1.08). The total calcium-to-iCa ratio was 2.33 (IQR 2.21-2.45). None of the patients developed hypernatremia (Na ≥ 150 mmol/L) or citrate toxicity (total Ca-to-iCa ratio > 2.5 plus increasing metabolic acidosis), and metabolic alkalosis (pH ≥ 7.5) occurred in one patient. This simple RCA CVVH protocol using commercially-prepared solution could be a feasible, relatively safe, and effective alternative to the conventional regimen for patients with a body weight up to 80 kg.

Collection of peripheral blood progenitor cells for autologous use: Performance enhancements of COBE spectra, auto-PBSC

Collection of peripheral blood stem cells (PBSC) must be performed in a safe and effective manner. Issues like automation, collection efficiency (CE), and adverse events must be considered. Auto-PBSC (COBE Spectra) is a fully automated program for PBSC collection. Changes in the protocol were made to achieve high CE, low product volume, and resulted in three groups of patients. Standard operating procedures (SOPs) were developed to reduce citrate toxicity and patients with central venous catheter. Twenty patients and 27 collections (Group 1), 88 patients and 112 collections (Group 2), and 158 patients and 194 collections (Group 3) were recorded. The protocol changes increased CE significantly from 31% (Group 1) to 57 and 59% (Group 2 and 3). Adjusting endpoint according to the preapheresis number of CD34+ cells reduced the collection time and the volume of the product significantly (median 227 min and 56 mL) without affecting CE. Mean level of ionized calcium before collection was 1.22 mmol/L, measured in 31 patients. This declined to a mean of 1.07 mmol/L after 1 h of collection and remained unchanged despite continuous calcium infusion. The number of patients with mild symptoms of citrate toxicity was reduced from 20 to 6%. A central venous catheter was used in 15%. Compared to peripheral access no differences in blood flow rate or time to perform the collection were found. Changes in the Auto-PBSC protocol resulted in an improved CE and a small product. SOPs reduced the number of patients with citrate toxicity and with central venous catheter.

Donor safety issues in high‐dose platelet collection using the latest apheresis systems

SUMMARYThe practice of high‐yield or double‐dose platelet (DDP) collection through automated apheresis is gradually increasing. Very few studies have examined donor safety issues in DDP collection. The present study highlights the process of DDP donor selection as well as the product quality and donor safety issues on 67 donors. All procedures were performed following the departmental standard operating procedure. We observed a significantly higher mean platelet yield with the Amicus separator than the Fresenius separator (5.4 × 1011vs. 5.1 × 1011, P = 0.03). The Fresenius separator processed a mean blood volume of 3974 mL and collected a mean platelet amount of 444.9 mL, and these were significantly higher when compared with Amicus (P &lt; 0.0001). Mean values of procedure‐related parameters, such as acid‐citrate‐phosphate volume, donation time, needle time, processing time and whole blood processed, and donor‐related parameters, like citrate toxicity and vasovagal reactions, were significantly higher during DDP than single‐dose platelet collection (P &lt; 0.05). We conclude that obtaining eligible donors for DDP from a shrinking donor population with low normal platelet values is a difficult task. Therefore, each transfusion service should set their own guidelines for DDP collection with the objectives of donor safety and optimal product quality.

Regional Citrate Anticoagulation for PrismaFlex Continuous Renal Replacement Therapy

Since Mehta et al. reported the first successful use of regional citrate anticoagulation (RCA) for continuous renal replacement therapy (CRRT) in 1990, RCA is increasingly used for CRRT because it provides filter patency with minimal risk of bleeding. However, RCA has been associated with significant metabolic complications including hypocalcemia, hypernatremia, metabolic alkalosis, and citrate toxicity. To describe our experience with a newly implemented RCA protocol with acid citrate dextrose formula A (ACD-A) and intravenous calcium gluconate, for use with PrismaFlex CRRT in critically ill patients with acute kidney injury. A retrospective chart review was conducted from May 1, 2006, until May 1, 2007, in a 16-bed medical-surgical university-affiliated intensive care unit. Data collected included dialysis filter life, patient and circuit metabolic parameters, and units of packed red blood cells transfused. Forty-eight patients received dialysis with citrate (n = 178 filters). Circuit clotting occurred in 24% of all filters. Mean +/- SD filter life was 38.4 +/- 25.9 hours, and filter survival at 48 hours was 38.2%. Persistent metabolic alkalosis while on CRRT was identified in 6 of 45 (13.3%) patients. Mild hypocalcemia (ionized calcium <3.6 mg/dL) occurred in 11 (23%) patients, but no patient had an ionized calcium level less than 2.8 mg/dL. Six patients, 3 with acute leukemia, required transfusion of 2 or more units of packed red blood cells in 24 hours. We found that anticoagulation of PrismaFlex CRRT with ACD-A and intravenous calcium gluconate provided reasonable filter patency, but with minor metabolic complications. Close monitoring of electrolyte and acid-base balance is required to minimize metabolic derangements.

Intraoperative dialysis during liver transplantation with citrate dialysate

Liver transplantation for acutely ill patients with fulminant liver failure carries high intraoperative and immediate postoperative risks. These are increased with the presence of concomitant acute kidney injury (AKI) and intraoperative dialysis is sometimes required to allow the transplant to proceed. The derangements in the procoagulant and anticoagulant pathways during fulminant liver failure can lead to difficulties with anticoagulation during dialysis, especially when continued in the operating room. Systemic anticoagulation is unsafe and regional citrate anticoagulation in the absence of a functional liver carries the risk of citrate toxicity. Citrate dialysate, a new dialysate with citric acid can be used for anticoagulation in patients who cannot tolerate heparin or regional citrate. We report a case of a 40-year-old female with acetaminophen-induced fulminant liver failure with associated AKI who underwent intraoperative dialytic support during liver transplantation anticoagulated with citrate dialysate during the entire procedure. The patient tolerated the procedure well without any signs of citrate toxicity and maintained adequate anticoagulation for patency of the dialysis circuit. Citrate dialysate is a safe alternative for intradialytic support of liver transplantation in fulminant liver failure.

WAA apheresis registry in the Czech Republic: Two centers experience

Introduction Hemaphereses are sophisticated procedures performed for many indications even in severely ill patients. Many authors consider quite necessary to register as many details as possible of treatments with therapeutic apheresis. WAA meets the requirement to compare data with centers not performing apheresis for the same diagnosis. In Czech Republic hemaphereses are used in a broad spectrum of indications. Since the year 2004 data on hemaphereses done in Czech Republic have been registered. In this paper we present a survey of our to date recordings. Patients and methods Data of performed therapeutic hemaphereses (plasma exchange, erythrocytapheresis, leukapheresis, thrombocytapheresis, photopheresis, immunopheresis, and rheopheresis) have been entered in WAA registry with many details. We have been evaluated 1289 procedures in 216 patients done in our two centers (center I, center II). Results Center I registered 129 procedures in 41 patients, center II 1260 procedures in 175 patients. The patients are divided according to centers specialization (center II has registered 12 long-term treated patients with LDL-apheresis; mean time of therapy 7.1 years and a median of 34 procedures/patient. Side-effects registered in center I and center II were 3.1% and 5.6% of the procedures, respectively. Most frequent side-effects were citrate toxicity, neurovegetative lability, problems with venous access and hypotension. All were easy to treat, no serious events or death occurred. Conclusions In Czech Republic hemaphereses are performed in a broad scale of indications and now it is nearly 5 years that data are registered in our two university centers. In 2004 we entered WAA registry because it meets the requirement to compare data with centers that do not perform aphereses for the same diagnosis. This comparison would certainly improve efficacy of the hemapheresis therapy even further. To enter WAA registry is easy, at no expense and without any problems.

Adverse events among 2408 unrelated donors of peripheral blood stem cells: results of a prospective trial from the National Marrow Donor Program

AbstractLimited data are available describing donor adverse events (AEs) associated with filgrastim mobilized peripheral blood stem cell (PBSC) collections in unrelated volunteers. We report results in 2408 unrelated PBSC donors prospectively evaluated by the National Marrow Donor Program (NMDP) between 1999 and 2004. Female donors had higher rates of AEs, requiring central line placement more often (17% vs 4%, P < .001), experiencing more apheresis-related AEs (20% vs 7%, P < .001), more bone pain (odds ratio [OR] = 1.49), and higher rates of grades II-IV and III-IV CALGB AEs (OR = 2.22 and 2.32). Obese donors experienced more bone pain (obese vs normal, OR = 1.73) and heavy donors had higher rates of CALGB toxicities (> 95 kg vs < 70 kg, OR = 1.49). Six percent of donors experienced grade III-IV CALGB toxicities and 0.6% experienced toxicities that were considered serious and unexpected. Complete recovery is universal, however, and no late AEs attributable to donation have been identified. In conclusion, PBSC collection in unrelated donors is generally safe, but nearly all donors will experience bone pain, 1 in 4 will have significant headache, nausea, or citrate toxicity, and a small percentage will experience serious short-term adverse events. In addition, women and larger donors are at higher risk for donation-related AEs.

Study of single donor platelet (SDP) preparation by Baxter CS 3000 plus and Haemonetics MCS plus

Background : In plateletpheresis blood is withdrawn from a donor in anticoagulant solution and separated into components. Platelets are retained and the remaining components are returned to the individual. Methods : The present study was aimed to compare the platelet yield and collection efficiency of Baxter CS 3000 plus and Haemonetics MCS plus cell separators and to study adverse donor reactions. Donors were selected as per the set criteria for single donor platelet (SDP) preparation. Donors' samples for pre donation and post donation platelet count were collected in EDTA and for product counts in the sample pouch attached with apheresis kits. The results were obtained by haematology analyzer. Platelet yield and collection efficiency were calculated. Result : Results were tabulated for both the cell separators and analyzed. Platelet yield was marginally better with Baxter CS 3000 plus but collection efficiency was better with the Haemonetics MCS plus. Residual white cells were more in single donor platelet concentrate preparation by MCS plus. Adverse donor reactions were similar with both cell separators, in form of mild citrate toxicity and mild to moderate pain at phlebotomy site. Conclusion : Findings of the present study along with other factors such as less priming time for kit, portability of cell separator, better patient comfort owing to single arm venous access and lesser cost suggest that Haemonetics MCS plus is a better choice as compared to Baxter CS 3000 plus cell separator.

Comparative study of automated plateletpheresis using five different apheresis systems in a tertiary care hospital

Different types of cell separators are available nowadays based on either continuous or intermittent flow technology to meet the growing demands for single donor apheresis platelets. This prospective study compares the five machines used in our center with regard to procedure parameters, product quality and adverse effects on the donor. A total of 477 plateletpheresis on various machines were performed on eligible donors over a period of 28 months after taking informed consent. All procedures were performed following the departmental standard operating procedure (SOP) and manufacturer’s instructions. All donor and procedure related details were obtained from the procedure register. Statistical analysis was done using the SPSS statistical package (version 12, USA). The median age, BSA and BMI of our plateletpheresis donors were calculated to be 29 years, 1.69 m 2 and 23.1 kg/m 2, respectively. Analyzing the parameters related to donor comfort such as donation time (DT), needle time (NT) and processing time (PT), the MCS machines were not “donor friendly” compared to Amicus and Fresenius. Platelet yield by Amicus was significantly higher as compared to other cell separators ( p < 0.05). Plateletpheresis associated citrate toxicity was higher with the Amicus and MCS 3p and vasovagal side-effects was observed least with the CS 3000 machine. Though, quality of apheresis product in terms of yield is comparable with all the machines, there are differences in the systems with regard to donor safety, procedure time and donor retention.

Adverse reactions in blood and apheresis donors: experience from two Italian transfusion centres.

Blood and apheresis donations are widely considered to be safe with a low incidence of adverse reactions and injuries; however, data reported in the medical literature on the prevalence of adverse events in donors and studies on the predictive risk factors for donor reactions are limited and contradictory. From January 2002 to December 2006 we recorded every adverse reaction verified during 240,596 consecutive blood and apheresis donations (183,855 homologous whole blood donations, 6,669 autologous whole blood donations, 38,647 plasmapheresis, 2,641 plateletpheresis and 8,784 multicomponent donations) at the Italian Transfusion Centres of Verona and Ragusa,. Using a special, pre-arranged form within the quality system, a total of 686 adverse reactions (related to 0.28% of all donations) were recorded. Vasovagal reactions, mostly of mild intensity, were the most commonly observed adverse reactions, with a frequency of 0.20% (487/ 240,596). The frequency of the vasovagal reactions varied according to the different types of donation, being 0.19% (346/183,855) for homologous whole blood donations, 0.24% (16/6,669) for autologous whole blood donations, 0.16% (63/38,647) for plasmapheresis, 0.68% (18/2,641) for plateletpheresis and 0.49 (43/8,784) for multicomponent donations. Citrate toxicity was reported in 0.38% (189/50,072) of apheresis donations. Severe adverse reactions were very rare, as they occurred in 0.004% of the donations (10/240,596). In conclusion, the results of our 5-year survey document that apheresis and blood donation are safe procedures for the donor with a low incidence of adverse reactions; the adverse reactions that did occur were mostly mild and resolved rapidly.

Effect of Leukapheresis on Gene Expression Profiles of Donor’s Peripheral Blood Mononuclear Cells

Leukapheresis has commonly been used to obtain the cell products intended for clinical cell therapy. Hypocalcemia related to citrate toxicity and some circulatory effects such as hypovolemia and hypotension are well-known complications of leukapheresis. In this study, we analyzed the gene expression profiles of peripheral blood mononuclear cells (PBMCs) obtained before and after leukapheresis to determine if the hemodynamic changes can affect the gene expression profiles of leukocytes. PBMCs were isolated from EDTA blood from 5 healthy donors collected before and immediately after apheresis. RNA was isolated, amplified, and analyzed using a cDNA microarray with 17,500 genes. Hierarchical clustering analysis was performed to evaluate the differences of gene expression profiling. Hierarchical clustering separated PBMCs from different donors with each other, but did not separate PBMCs collected before and after leukapheresis. Comparison of gene expression by PBMCs collected before and after leukapheresis found only 25 genes were differentially expressed (15 were up-regulated and 10 were down-regulated after leukapheresis) (F-test, P<0.005). Stress induced apoptosis-related genes, ANXA3, DEDD, and ATXN2L, and cytokine-related genes, IL13RA1 and IK, which were also related to stress, were up-regulated after leukapheresis. Genes involved in DNA and protein binding, such as CLSTN3, LRBA, SATB2, and HSPA8, were down-regulated. Leukapheresis had little effect on gene expression of PBMCs. Some genes showing differences between before and after leukapheresis were mainly involved in stress-related reactions.

Exclusive use of acid citrate dextrose for anticoagulation during extracorporeal photopheresis in patients with contraindications to heparin: An effective protocol

Extracorporeal photopheresis (ECP) routinely uses heparin for anticoagulation. For patients with contraindications to heparin, alternative anticoagulation using acid citrate dextrose (ACD-A) has been reported to be safe and effective. However, detailed ECP protocols that exclusively use ACD-A anticoagulation and minimize citrate toxicity have not yet been published. We report a protocol that completely replaces heparin with ACD-A for ECP, which was developed at the University of California, Los Angeles (UCLA), and our experience since its implementation. ECP was performed with the UVAR XTS photopheresis system using ACD-A and control of the rate of citrate infusion. Calcium gluconate solution was administered prophylactically and as needed for symptoms of citrate toxicity. The medical records of patients who underwent ECP using the ACD-A protocol between January 2003 and July 2006 were reviewed. The incidence and severity of citrate toxicity and the technical data for all procedures were analyzed. During this period, 94 ECP procedures were performed with ACD-A anticoagulation on five patients. All patients tolerated the procedures well without significant complications. Only minimal symptoms of citrate toxicity (grade 1) were observed in 24.5% of all procedures; symptoms resolved promptly following administration of additional calcium gluconate. In conclusion, an effective protocol for ECP using ACD-A anticoagulation exclusively in patients with contraindications to heparin employs continuous monitoring of flow rates and prophylactic administration of calcium gluconate to minimize citrate toxicity.

Distinct Clinical Syndromes Are Defined by ADAMTS13 Activity in Idiopathic TTP: Results of the SERF-TTP Study.

Background: The Surveillance, Epidemiology & Risk Factors for TTP (SERF-TTP) study is the largest prospective cohort of idiopathic TTP cases to date.Methods: Patients with first episode of idiopathic TTP were enrolled at 11 sites in the US. Exclusion criteria include solid organ or allogeneic stem cell transplant, anti-neoplastic therapy or malignancy. All patients underwent therapeutic plasma exchange (TPE). Remission is defined as platelet count >150,000/mm3. ADAMTS13 activity was measured by fluorescence resonance energy transfer assay (FRETS-vWF73, Peptides Int.). ADAMTS13 inhibitor was assessed by ELISA (Technozym ADAMTS13 INH ELISA, Technoclone) and functional inhibition of normal ADAMTS13 activity (modified FRETS). Differences between the groups was evaluated by Chi-square test, t-test or Fisher's exact test.Results: Complete data is available for 57 cases. 84% were female & median age was 42. ADAMTS13 was severely deficient (<10%) in 53%, moderate (10–50%) in 8%, & normal (>50%) in 39%. Adverse events were frequent & most commonly include citrate toxicity and allergic reactions. Long-term followup was available for 56 patients, and overall relapse rate was 25% with median time to relapse of 11 months. The relapse rate was 41% in patients with severe ADAMST13 deficiency & 0% in patients with normal ADAMTS13 activity (p=0.0077).Conclusions: Severe ADAMTS13 deficiency does not define all cases of idiopathic TTP, yet is associated with a unique syndrome characterized by severe thrombocytopenia, normal renal function, presence of ADAMTS13 neutralizing autoantibodies & high risk of relapse. Non-ADAMTS13 deficient idiopathic TTP has clinical features similar to thrombotic microangiopathies associated with stem cell transplant or drugs such as quinine, yet has a better than expected overall survival after TPE. There is likely an alternate disease mechanism for this cohort, possibly immunologic, which may be responsive to TPE and warrants further study.ADAMTS13 < 10% n=30ADAMTS13 > 50% n=22p-valuePresenting LabsHemoglobin (mean)8.59.20.22*Platelet count (mean x10^9/L)1957<0.0005*Serum creatinine (mean)1.333.90.0012*ADAMTS13 antibody (neutralizing & non-neutralizing) %10063.60.0004**ADAMTS13 neutralizing antibody %8335.0003#Presenting SymptomsNeurologic symptoms present4552.40.23#Diarrhea2330.40.79#Infection4043.50.79#Past Medical HistoryConnective Tissue Disease %108.50.28#Family history of TTP %04.60.11#Remission LabsHemoglobin (mean)12.28.50.16*Platelet count (mean x10^9/L))1691520.15*Serum creatinine (mean)1.023.70.0009*OutcomesTherapy-related Adverse events %71550.24#Time (days) to remission (plt > 150,000)9.79.20.89*Early remission (< 8 days) %73570.20#30 day Exacerbation rate %35280.63#30 day Survival %96.690.00.56**Long-term Relapse %4100.0077*** t-test, ** Fisher's Exact Test, # Chi-Square Test

Complications of apheresis in children

Although the frequency of complications in adults undergoing therapeutic apheresis is low, there are little data in children. A retrospective study of 186 children who had undergone a total of 1632 apheresis procedures between 1994 and 2002 was conducted. Adverse reactions were prospectively documented. The procedures were plasma exchange (67%), hematopoietic progenitor cell collection (18%), red blood cell exchange (6.9%), leukodepletion (0.7%), and plasma exchange with immunoadsorption (6.7%). Adverse reactions, most minor, were reported in 55 percent of procedures in 82 percent of patients. The most frequent complications, per procedure and per patient during an entire course of therapy, were hypotension (14 and 48.4%), hypotension requiring fluid bolus (4.8 and 26.9%), symptomatic hypocalcemia (9.7 and 28.5%), allergic reactions (4.4 and 5.9%), catheter-related thrombosis (1.7 and 12.4%), catheter-related infection (2.1 and 16.1%), and severe anemia (hemoglobin [Hb] level, <7 g/dL; 2.5 and 17.2%). There were two deaths (1% of patients). Risk factors for complications by multivariate analysis were lower body weight, lower preapheresis Hb level, apheresis in a critical care unit, and number of procedures per patient. The 55 percent incidence of complications per procedure in our pediatric cohort is much higher than the 4.3 to 28 percent incidence reported in adults. The excess of adverse reactions in children are mostly related to citrate toxicity, higher relative vascular volume shifts, and the need for vascular access. Pediatric apheresis presents unique challenges and is associated with higher complication rate compared to adults. It is recommended that this procedure be performed in specialized centers.