Clinical-grade generation of peptide-stimulated CMV/EBV-specific T cells from G-CSF mobilized stem cell grafts

Background

A major complication after allogeneic hematopoietic stem cell transplantation (aSCT) is the reactivation of herpesviruses such as cytomegalovirus (CMV) and Epstein–Barr virus (EBV). Both viruses cause significant mortality and compromise quality of life after aSCT. Preventive transfer of virus-specific T cells can suppress reactivation by re-establishing functional antiviral immune responses in immunocompromised hosts.

Methods

We have developed a good manufacturing practice protocol to generate CMV/EBV-peptide-stimulated T cells from leukapheresis products of G-CSF mobilized and non-mobilized donors. Our procedure selectively expands virus-specific CD8+ und CD4+ T cells over 9 days using a generic pool of 34 CMV and EBV peptides that represent well-defined dominant T-cell epitopes with various HLA restrictions. For HLA class I, this set of peptides covers at least 80% of the European population.

Results

CMV/EBV-specific T cells were successfully expanded from leukapheresis material of both G-CSF mobilized and non-mobilized donors. The protocol allows administration shortly after stem cell transplantation (d30+), storage over liquid nitrogen for iterated applications, and protection of the stem cell donor by avoiding a second leukapheresis.

Conclusion

Our protocol allows for rapid and cost-efficient production of T cells for early transfusion after aSCT as a preventive approach. It is currently evaluated in a phase I/IIa clinical trial.

Electronic supplementary material

The online version of this article (10.1186/s12967-018-1498-3) contains supplementary material, which is available to authorized users.

Identification of the novel allele, HLA-A*01:234, in the mother of a German cord blood donor

HLA-A*01:234 was identified by next-generation sequencing and confirmed by Sanger sequencing.

Abstract CT028: Adoptive transfer of CMV- and EBV- specific peptide-stimulated T cells after allogeneic stem cell transplantation: A Phase I/IIa clinical trial

Allogeneic stem cell transplantation (ASCT) to date is the only permanent curative treatment for many hematological cancers. Besides the development of Graft versus Host disease (GvHD), infections are the major adverse effect of ASCT. Specifically, reactivation of viruses is highly problematic in the aftermath of ASCT. Reactivation of human CMV and EBV negatively impacts on outcome after ASCT. 40-50% of patients reactivate CMV following ASCT, while the only CMV specific antiviral therapy available is ganciclovir, with other drugs being used off-label. For the 20-30% of patients reactivating EBV, only rituximab is available to control EBV. Rituximab leads to long term B-cell depletion requiring frequent administration of immunoglobulins. To cover this unmet medical need of CMV and EBV control after ASCT, we investigate a somatic cell therapy approach by adoptive transfer of CMV- and EBV-specific peptide-stimulated T cells. We specifically are scrutinizing the effect of application of the cells to prevent virus reactivation before its onset or preemptively at the early stages of viral infection. We set up a prospective randomized controlled phase I/IIa multi-center clinical trial to evaluate the safety and efficacy of preventive and preemptive adoptive transfer of this ATMP in patients after ASCT (EudraCT number 2012-004240-30). The design of the trial allows to applicate low numbers of activated T cells, thereby reducing the potential risks of GvHD for the recipient of adoptively transferred T cells. The multi-center trial is currently recruiting, so far, 13 patients have been randomized. ASCT patients are randomly assigned to the intervention or control group. Subjects of the control group receive standard of care. For all subjects of the intervention group, a personalized cell product (ATMP) containing a standardized number of virus specific T cells is manufactured from an aliquot of the leukapheresis product previously used for ASCT and cryopreserved until being administered. Subjects receive the cell product in intervals of at least 30 days, starting with the first adoptive transfer 30 days after ASCT at the earliest. Cells are transferred as preventive, preemptive, or also as therapeutic treatment. Subjects are monitored for occurrence of GvHD, for viral load, as well as for immune reconstitution and composition of the TCR pool, especially of virus-specific T cells.

Citation Format: Michael Aigner, Regina Gary, Andreas Moosmann, Stefanie Maas, Julian Strobl, Robert Zimmermann, Jürgen Zingsem, Anita Kremer, Andreas Mackensen, Armin Gerbitz. Adoptive transfer of CMV- and EBV- specific peptide-stimulated T cells after allogeneic stem cell transplantation: A Phase I/IIa clinical trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr CT028. doi:10.1158/1538-7445.AM2017-CT028

T-cell subsets in autologous and allogeneic peripheral blood stem cell concentrates

BACKGROUND AND OBJECTIVES

Regulatory T cells (Tregs) and other T-cell subsets are of importance in the setting of autologous and allogeneic stem cell transplantations. We conducted a study to assess the content of peripheral blood stem cell concentrates and related apheresis parameters in the autologous and allogeneic setting.

MATERIAL AND METHODS

We characterized 53 donors, patients and peripheral blood stem cell concentrates (PBSC) regarding the content of CD45(+) cells, lymphocytes, CD3(+) cells, CD3(+) CD4(+) T cells, CD3(+) CD4(+) CD25(+) T cells, CD3(+) CD4(+) CD25(+) CD127(low/negative) Tregs and CD34(+) cells and calculated cell yields, recruitment factors and collection efficiency for all cell types. We compared allogeneic data with autologous data.

RESULTS

Autologous PBSC show significantly lower concentrations of T-cell subsets compared to allogeneic PBSC (17,112/μl CD4(+), 14,858/μl CD4(+) CD25(+) and 1579/μl CD3(+) CD4(+) CD25(+) CD127(low/negative) Tregs in autologous compared to 65,539/μl CD4(+), 44,208(+) /μl CD4(+) CD25(+) and 5040/μl CD3(+) CD4(+) CD25(+) CD127(low/negative) Tregs in allogeneic PBSC, respectively), in contrast to CD34(+) concentrations (5342/μl CD34(+) in autologous compared to 2367/μl CD34(+) in allogeneic PBSC, respectively). Accordantly, all T-cell yields are lower in the autologous setting compared to allogeneic PBSC. However, recruitment factor and collection efficiency of all cell types are higher in autologous compared to allogeneic PBSC, but not all parameters differ significantly when groups are compared.

CONCLUSION

T-cell subsets and especially Tregs are a substantial part of PBSC transplantation, as considerable recruitment during apheresis occurs. In large volume apheresis, the collection efficiency of Treg is comparable to that of CD34(+) cells, while recruitment factors are even higher.

Ex vivo expansion of hematopoietic stem- and progenitor cells from cord blood in coculture with mesenchymal stroma cells from amnion, chorion, Wharton's jelly, amniotic fluid, cord blood, and bone marrow

In most cases, the amount of hematopoietic stem and progenitor cells (HSPCs) in a single cord blood (CB) unit is not sufficient for allogenic transplantation of adults. Therefore, two CB units are usually required. The ex vivo expansion of HSPCs from CB in coculture with mesenchymal stroma cells (MSCs) might be an alternative. It was investigated, whether bone marrow-derived MSCs, which have to be obtained in an invasive procedure, introduce a further donor and increases the risk of transmissible infectious diseases for the patient can be replaced by MSCs from amnion, chorion, Wharton's jelly, amniotic fluid, and CB, which can be isolated from placental tissue which is readily available when CB is sampled. In a two-step ex vivo coculture mononuclear cells from cryopreserved CB were cultured with different MSC-feederlayers in a medium supplemented with cytokines (stem cell factor, thrombopoietin [TPO], and granulocyte colony-stimulating factor). Expansion rates were analyzed as well, by long-term culture-initiating cell (LTC-IC) and colony-forming unit (CFU) assays, as by measuring CD34(+)- and CD45(+)-cells. Due to the comparably low number of 5×10(2) to 1×10(4) CD34(+)-cells per cm(2) MSC-monolayer, we observed comparably high expansion rates from 80 to 391,000 for CFU, 70 to 313,000 for CD34(+)-, and 200 to 352,000 for CD45(+)-cells. Expansion of LTC-IC was partly observed. Compared to the literature, we found a better expansion rate of CD34(+)-cells with MSCs from all different sources. This is probably due to the comparably low number of 5×10(2) to 1×10 CD34(+)-cells per cm(2) MSC-monolayer we used. Comparably, high expansion rates were observed from 80 to 391,000 for CFUs, 70 to 313,000 for CD34(+)-, and 200 to 352,000 for CD45(+)-cells. However, the expansion of CD34(+)-cells was significantly more effective with MSCs from bone marrow compared to MSCs from amnion, chorion, and Wharton's jelly. The comparison of MSCs from bone marrow with MSCs from CB and amniotic fluid showed no significant difference. We conclude that MSCs from placental tissues might be useful in the expansion of HSPCs, at least if low numbers of CD34(+)-cells per cm(2) MSC-monolayer and a high TPO concentration are implemented in the expansion culture.

Comparison of a new microscopic system for the measurement of residual leucocytes in apheresis platelets with flow cytometry and manual counting

BACKGROUND AND OBJECTIVES

Since 2001, all blood components in Germany must be leucocyte depleted. Recently, a new method for quality control of depletion was introduced. Our study aimed at the validation of the method for routine use in apheresis platelet concentrates.

MATERIALS AND METHODS

We compared the new ADAM-rWBC device with manual counting in the Nageotte chamber and flow cytometry, two standard methods, by measuring residual leucocytes in 40 units of apheresis platelet concentrates and in six geometrical dilution series.

RESULTS

Cell counts of residual leucocytes in the 40 units were below 10(6) cells per component with all methods, although mean cell counts were approximately 5 and 6 times higher in flow cytometry and ADAM-rWBC, respectively, compared to the Nageotte chamber. No unit with <10(6) leucocytes was regarded as contaminated. The dilution series showed acceptable accuracy, especially in the range around the cut-off (approximately 4·5 cells/μl in components with a volume of 220 ml) for regarding a concentrate as contaminated with leucocytes. No sample spiked with more than 4·5 cells/μl was counted as having less.

CONCLUSION

In comparison with manual counting and flow cytometry, the ADAM-rWBC device performed equally. The method is suitable for routine screening of leucocyte contamination of apheresis platelets.

The novel allele, HLA-B*08:113, identified in a German cord blood donor and his mother

The novel allele HLA-B*08:113 identified in two related individuals of Caucasian origin is described.

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

BACKGROUND

The objective was to investigate potential risks for apheresis donors associated with a triple-plateletpheresis (TP) program.

STUDY DESIGN AND METHODS

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.

RESULTS

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.

CONCLUSIONS

TP results in an increase in mild donor reactions but does not significantly impair donor safety or product quality.

Human neutrophil alloantigen genotype frequencies among blood donors with Turkish and German descent

Antibodies against the human neutrophil antigens (HNA) are able to stimulate transfusion reactions, autoimmune and neonatal neutropenia. The aim of this study was to determine the HNA allele frequencies in the largest ethnic minority group in Germany in comparison with the German population for predicting the risk of alloimmunization and associated transfusion reactions, as well as the risk of developing neonatal neutropenia for the newborn of racial mixed couples. However, there exists no data about HNA genotype distribution in Turkish population. DNA was isolated from blood samples of 119 German and 118 Turkish blood donors and typed them for HNA-1, -3, -4, and -5 by using a commercial polymerase chain reaction kit with sequence-specific primers (SSP-PCR) and compared the HNA genotype distribution of both groups. In German blood donors, the gene frequencies for HNA-1a and HNA-1b were 0.391 and 0.601, for HNA-3a and -3b, 0.744 and 0.256, for HNA-4a and -4b, 0.908 and 0.092, and for HNA-5a and -5bw, 0.731 and 0.269. In Turkish blood donors, we observed 0.420/0.564, 0.737/0.263, 0.881/0.119, and 0.754/0.246 for HNA-1a/1b, -3a/3b, -4a/4b, and -5a/5bw. No statistic significant difference between genotypes in these populations was observed. This study is the first to report HNA gene frequencies in a Turkish population. It showed that there is no difference of HNA genotype in blood donors with Turkish descent in comparison with German blood donors. The alternating transfusion of blood and blood components is no increased risk for developing alloantibodies against HNA antigens. In pregnancy of mixed couples no special screening programs for HNA are necessary.

The novel allele, HLA-B*07:68:02, identified in a German cord blood donor and her father

The novel allele HLA-B*07:68:02 identified in two related individuals of Caucasian origin is described.

Association of blood group A with early-onset ovarian hyperstimulation syndrome

PURPOSE OF THE STUDY

Ovarian hyperstimulation syndrome is a potentially life-threatening complication during controlled ovarian stimulation for fertility treatment. Since no association of this condition with ABO blood groups was known, we compared ABO antigens with severity and onset of symptoms in a case-control study.

PATIENTS AND METHODS

One hundred and twenty-one patients, mainly Caucasians, were hospitalized because of ovarian hyperstimulation syndrome after receiving in vitro fertilisation, in the period from January 2000 to February 2007. Severity of symptoms, pregnancy rate and ABO blood group were collated. The ABO blood group distribution was compared to four independent control groups.

RESULTS

Blood group A was markedly more frequent and blood group O less frequent in patients with ovarian hyperstimulation syndrome compared to the blood group distribution in all control cohorts. The odds ratio for patients undergoing controlled ovarian stimulation with blood group A versus O to develop the early-onset form of this condition was 2.171 (p-value 0.002). No association for late-onset form could be found. The overall pregnancy rate was 50.4% and three times higher in the group of late-onset ovarian hyperstimulation syndrome compared to the early-onset form. Four patients developed thromboses in the jugular or subclavian vein, none of whom had blood group O.

CONCLUSION

Blood group A may be associated with early-onset ovarian hyperstimulation syndrome in Caucasians. Depending on further studies, this possible association may be considered for an individualized hormone dosing in controlled ovarian stimulation.

Automated CD14+ monocyte collection with the autoMNC program of the COM.TEC cell separator

BACKGROUND

The standard mononuclear cell (MNC) program of the COM.TEC device (Fresenius HemoCare GmbH) showed excellent collection efficiency of CD14+ monocytes. A major disadvantage was high content of residual cells in MNC harvests, which could influence dendritic cell (DC) culture.

STUDY DESIGN AND METHODS

The autoMNC program (COM.TEC) was compared with the standard MNC program (n = 12). Additionally, two cycle volumes (300 mL vs. 450 mL, n = 19) were compared (standard MNC program). Samples were assayed for white blood cells (WBCs), red blood cells (RBCs), granulocytes (PMNs), hematocrit, and platelets (PLTs) on an automated blood cell counter (Sysmex K 4500, TAO Medical). CD14+ cells were analyzed by flow cytometry (FACSCalibur, BD).

RESULTS

The autoMNC program produced 1.33 x 10(9) +/- 0.36 x 10(9) CD14+ cells, 5.60 x 10(11) +/- 0.97 x 10(11) PLTs, and 1.43 x 10(11) +/- 0.37 x 10(11) RBCs. Compared to the standard MNC program, significantly higher PLT yields but lower RBC yields and product volume were harvested. Increasing the CV from 300 to 450 mL dropped the product volume, residual PLTs, and RBCs significantly, whereas WBC and monocyte yields did not change. The WBC predonation counts of donors correlated significantly with monocyte yields.

CONCLUSIONS

The autoMNC program reduced the buffy coat (BC) volume and RBC yields in products compared to the standard MNC program. Increasing the CV (standard MNC program) reduced residual PLTs, RBCs, and the BC volume of MNC harvests. The donor WBC predonation count was a good predictor for the monocyte yield of products.

Effect of gamma irradiation with 30 Gy on the coagulation system in leukoreduced fresh-frozen plasma

BACKGROUND

The aim of this study was to investigate the effect of gamma irradiation with 30 Gy on the coagulation system in leukoreduced fresh-frozen plasma (FFP).

STUDY DESIGN AND METHODS

In 74 FFP units that had been stored for 352 +/- 103 days below -30 degrees C, the following variables were determined in parallel in an irradiated and not irradiated half: prothrombin time (PT); activated partial thromboplastin time (APTT); thrombin time; antithrombin III; protein C; protein S; von Willebrand factor antigen; ristocetin cofactor; plasminogen-alpha(2)-antiplasmin; the coagulation factors fibrinogen, factor (F)II, FV, FVII, VIII, F IX, FX, FXI, FXII, FXIII, and activated factor XII (FXIIa); D-dimer; fibrin monomer; thrombin-antithrombin complex; prothrombin fragment 1 + 2 (F1+2); plasmin-alpha(2)-antiplasmin complexes (PAPs); and platelet factor 4. The FVII activity ratio was assayed to quantify activation of FVII.

RESULTS

Irradiation with 30 Gy resulted in a reduction of APTT (35.0 +/- 4.1 sec vs. 34.4 +/- 4.1 sec; p = 0.00000006) and PT (89.8 +/- 8.2% vs. 90.7 +/- 8.0%; p = 0.002) and a significant increase of the activities of the coagulation factors FII, FV, FVII, F IX, FX, and FXII. FVIII activity decreased from 118 +/- 31 to 116 +/- 32 percent (p = 0.02). Activation of the coagulation system was shown by an increase in the FVII activity ratio (1.19 +/- 0.29 vs. 1.31 +/- 0.34; p = 0.0000001), FXIIa (0.81 +/- 0.50 ng/mL vs. 0.90 +/- 0.51 ng/mL; p = 0.006), and F1+2 (1.19 +/- 0.20 nmol/L vs. 1.24 +/- 0.20 nmol/L; p = 0.000005) after irradiation with 30 Gy, whereas an increase of PAP (16.2 +/- 11.5 ng/mL vs. 20.2 +/- 12.0 ng/mL; p = 0.0004) demonstrated activation of the fibrinolytic system. No negative influence of irradiation with 30 Gy on inhibitors of coagulation was observed.

CONCLUSION

Gamma irradiation of leukoreduced FFPs with 30 Gy results in a significant but very weak activation of the coagulation and fibrinolytic system in FFPs.

Evaluation of a new apheresis system for the collection of leukoreduced single-donor platelets

BACKGROUND

The Fresenius COM.TEC cell separator is a new device for producing white cell concentrates (WBCs) and leukoreduced single-donor platelet concentrates (SDPs) and performing therapeutic cytapheresis and plasmapheresis that might replace the Fresenius systems AS104 and AS.TEC 204. This novel system's performance was evaluated for producing leukoreduced SDPs.

STUDY DESIGN AND METHODS

In an investigational phase, each of 200 donors underwent plateletpheresis with the AS.TEC 204 and the COM.TEC systems. The collection efficiency (CE) and WBC contamination of the different techniques were compared. After some hard- and software modifications, the system was evaluated in an additional 800 procedures in the confirmatory phase.

RESULTS

In the investigational phase, the CE of the COM.TEC device was increased significantly in comparison to the AS.TEC 204 device's CE (by 45 +/- 32% when collecting 1 unit of platelets [PLTs] and 1 unit of fresh-frozen plasma and by 43 +/- 42% when collecting only 1 unit of PLTs). Although all AS.TEC products proved to be leukoreduced, 2 percent of the COM.TEC procedures led to PLT concentrates containing more than 1 x 10(6) WBCs. In the confirmatory phase, all 1300 products from 800 COM.TEC procedures proved to be leukoreduced. Furthermore, the CE increased significantly from 53.5 +/- 4.6 percent in the investigational phase to 55.5 +/- 4.9 percent (p < 0.001) in the confirmatory phase.

CONCLUSIONS

These data suggest that the new COM.TEC system offers a significantly and importantly improved CE in plateletpheresis procedures in comparison to the AS.TEC system. In the final version, the PLT products collected with this system fulfill the most stringent criteria for leukoreduced PLTs. This aim was achieved without additional filtration steps and thus without filtration-related PLT loss.

Short-term liquid storage of CD14+ monocytes, CD11c+, and CD123+ precursor dendritic cells produced by leukocytapheresis

BACKGROUND

This prospective study compared white blood cell (WBC) storage in polyvinylchloride (PVC) bags and in polyolefin (POF) bags. After leukapheresis, CD14+ monocytes, CD11c+, and CD123+ precusor dendritic cells (DCs) were analyzed under platelet (PLT) storage conditions.

STUDY DESIGN AND METHODS

Twenty-five leukapheresis procedures were performed on blood cell separators (AS.TEC204 [PVC; Fresenius HemoCare GmbH] and the COBE Spectra [POF, Gambro BCT]). Blood cell counts, glucose, lactic acid, pO(2), pCO(2), and pH were measured in mononuclear cell (MNC) harvests on Days 0, 1, 3, and 5. WBCs were analyzed by flow cytometry.

RESULTS

The WBC yields of the AS.TEC204 harvests were 25 percent higher (13.4 x 10(9) +/- 2.7 x 10(9) WBCs) compared to the COBE Spectra (9.9 x 10(9) +/- 2.5 x 10(9) WBCs). During 5-day storage, WBC counts (PVC bags) decreased significantly (24%). Storage in POF bags showed more consistent results (WBC loss, 6%). Loss of CD14+ monocytes and CD11c+ precursor DCs did not differ significantly in leukapheresis products. CD123+ precursor DCs stored in PVC bags dropped by more than 90 percent (POF bags, 24%). Lactic acid concentrations exceeded 20 mmol per L after 24 hours in PVC bags and after 72 hours in POF bags. The mean pH value on Day 5 was 6.2 (PVC) and 6.3 (POF). On Day 1, the product glucose concentration decreased by 76 percent after storage in PVC bags and by 16 percent in POF bags.

CONCLUSIONS

Storage of MNCs within 72 hours in the original harvest container assures stable WBC content and is easy to perform. POF bags should be preferred in the case of extended WBC storage. Patient studies should clarify changes in efficiency of hematopoietic reconstitution that might occur over time during MNC storage.

Comparison of the performance of microtube column systems and solid-phase systems and the tube low-ionic-strength solution additive indirect antiglobulin test in the detection of red cell alloantibodies

To compare the performance of seven currently available test systems in the detection of erythrocyte alloantibodies (ab), we tested in parallel 446 sera samples containing red cell ab [368 sera samples with ab that are assumed to be clinically significant (cs-ab) and 78 sera samples with ab that are assumed to be of minor clinical significance (ms-ab)] using the tube spin low-ionic-strength solution (addition method) indirect antiglobulin test (tube LISS-IAT), three microtube column agglutination techniques (DiaMed-ID, Ortho BioVue and Bio-Rad Scangel), one affinity adherence test system (CLB/Mast CellBind Screen) and two solid-phase tests [Biotest Solidscreen II and Immucor Capture-R Ready-Screen (4)]. To address the specificity of the three test systems under routine conditions, results of 4566 patient samples obtained using the tube LISS-IAT, results of 5205 patient samples obtained using the Scangel and results of 3560 samples obtained using the Capture-R were evaluated. The DiaMed-ID detected 344 cs-ab and 43 ms-ab, BioVue 333 cs-ab and 48 ms-ab, Scangel 348 cs-ab and 62 ms-ab, CellBind Screen 346 cs-ab and 47 ms-ab, Solidscreen 330 cs-ab and 38 ms-ab, Capture-R 358 cs-ab and 45 ms-ab and LISS-IAT 159 cs-ab and 12 ms-ab. In routine practice, erythrocyte cs-ab could be identified in 61 (67.8%) of 90 reactive sera (specificity: 98.6%) in the tube LISS-IAT, in 169 (58.7%) of 288 (94.4%) in Bio-Rad Scangel and in 101 (51.0%) of 198 reactive sera (94.3%) in Capture-R. We conclude that the sensitivity of the microcolumn, affinity adherence and solid-phase test systems in the detection of cs-ab was similar and was markedly superior to that of the conventional tube LISS-IAT. All high-sensitive test systems produced higher rates of false positives and ms-ab compared to the tube test. An individual cost-benefit analysis, considering the recent knowledge about the clinical significance of weak-reactive cs-ab, should be performed in every institution to decide whether and if so which high-sensitive screening system should be applied.

A pilot study of continuous ambulatory monitoring of blood pressure in repeated preoperative autologous blood donation

BACKGROUND

The aim of this study was to investigate the occurrence of hypotension in the 24-hour period after preoperative autologous blood donation (PABD) in patients with and without hypertension.

STUDY DESIGN AND METHODS

In 20 patients, 24-hour ambulatory blood pressure monitoring (ABPM) was performed before PABD was started and on every donation day in two repeated phlebotomies.

RESULTS

Seven patients had no hypertension and 11 patients had hypertension. In 2 additional patients, hypertension was diagnosed during the study. Overall, the mean systolic BP (SBP) decreased from 131+/-15 mmHg before donation to 128+/-13 and 127+/-10 mmHg after Donations 1 and 2; the corresponding values for the diastolic BP (DBP) were 77+/-9, 75+/-9, and 73+/-7 mmHg, both without significant differences between the groups with and without hypertension. In single patients, substantial decreases of BP occurred, especially during the night. Two patients with and 2 without hypertension showed a nightly decrease in SBP and DBP of more than 10 percent (in 1 of these patients, more than 20%). Concerning diurnal BP variability, 1 patient with and 1 without hypertension, the latter showing a nightly decrease of SBP and DBP of more than 10 percent, also changed to the pattern of a nightly "extreme dipper" after PABD.

CONCLUSION

In 25 percent of the patients, changes of BP were observed during the 24-hour period after PABD, especially during the night, which are known to be associated with an increased risk of cerebral or myocardial ischemia. Whether those changes of BP lead to major morbidity or mortality requires further investigation.

Platelet function in variable platelet split products intended for neonatal transfusion

BACKGROUND

Only a few systematic studies have examined the effect of variable produced small platelet (PLT) aliquots on PLT function before transfusion to neonates. Although neonatal transfusion could be critical, no standardization of production or systematic quality controls have been introduced so far.

STUDY DESIGN AND METHODS

PLT split products were prepared in three different ways (30- or 60-mL bag, syringe aliquot) at different times from the parent unit (Days 1-4) and stored for 2 or 4 hours. The measures of PLT function include pH, lactate, P-selectin expression, and cytokines (beta-thromboglobulin [beta-TG], PLT-derived growth factor AB [PDGF-AB]). Additionally, syringe passage (0.5 mL/min) was assessed.

RESULTS

High product variability of PLT content was found (40% deviation of PLT content from programmed target, 13%-19% PLT loss by product distribution), which resulted in PLT concentrations of split units between 0.94 x 10(9) and 1.66 x 10(9) PLTs per mL. Different gas transfer rates (pCO2) of PLT containers caused different pH values of the product (Trima 7.47 +/- 0.09 vs. COM.TEC 7.33 +/- 0.08; p < 0.0001), but acceptable results of PLT metabolism were found in all split units (minimum pH, 7.09; maximum lactate content, 13.1 mmol/L). P-selectin expression on PLTs increased by factor of 2 in the parent units stored for 4 days (16.9 +/- 8.6% 32.2 +/- 13.4%; p = 0.02). After Day 3, beta-TG and PDGF-AB increased by twofold. PLTs stored during passage for 100 minutes in syringes dropped pO(2) by 50 percent and caused 15 percent higher lactate levels.

CONCLUSION

High variability of PLT content in split units requires at least additional PLT counts before transfusion in critical preterm or neonatal infants.

Collection of hyperconcentrated platelets with Trima Accel

BACKGROUND AND OBJECTIVES

Lowering the plasma content in single-donor platelet (PLT) concentrates well below 30% implies the need to collect platelets at very high concentrations. Trima Accel (TA) is validated for collection below 4000 x 10(3) PLTs/microl. We evaluated its performance at 5000 x 10(3) PLTs/microl.

MATERIALS AND METHODS

Twenty blood donors underwent apheresis with TA twice collecting either a hyperconcentrated or a standard single-donor platelet concentrate with a target platelet concentration of 5000 or 1200 x 10(3) PLTs/microl, respectively. We analysed the collection efficiency, the collection rate and the quality of the collected by-plasma.

RESULTS

We collected 20 hyperconcentrated and 20 standard units containing 2.56 +/- 0.5 and 3.39 +/- 0.4 x 10(11) PLTs at a concentration of 4518 +/- 978 and 1374 +/- 166 x 10(3) PLTs/microl in 45 +/- 8 and 39 +/- 6 min resulting in a collection efficiency of 47.5 +/- 10.0 and 70.7 +/- 7.9% and a collection rate of 5.9 +/- 1.4 and 8.8 +/- 1.5 x 10(9) PLTs/min, respectively (all results expressed as mean +/- standard deviation). The collected by-plasma showed a very high grade of cell purity and a satisfactory recovery of the clotting factors.

CONCLUSION

Although TA is a suitable device for PLT collection at very high concentrations, improvements are desirable to further increase the productivity above its currently validated upper collect concentration limit.

CD14+ cell collection in non-cytokine-stimulated donors with the COM.TEC cell separator

BACKGROUND

The COM.TEC cell separator (Fresenius Hemocare), equipped with the MNC program (single-stage chamber) and the PBSC-LYM program (dual-stage chamber), was evaluated for CD 14+ cell collection regarding cell yields, collection efficiencies (CEs), and the content of residual cells in harvests.

STUDY DESIGN AND METHODS

Twenty-four non-cytokine-stimulated donors underwent 5-L mononuclear cell (MNC) collections on the COM.TEC device to compare both programs. Two software versions (v02.03.05 vs. v 03.00.04) were investigated for optimization of the CD 14+ cell collection process. Blood counts of donors and products were analyzed for CD 14+ cells by flow cytometry and for platelets (PLTs), white blood cells, and red blood cells (RBCs) by a blood cell counter.

RESULTS

In 5-L collections, the MNC program resulted in high CEs (83+/- 23%) and yields (1.2 x 10(9)+/- 0.6 x 10(9) per unit) of CD 14+ cells, but the products showed high residual PLTs. The use of a dual-stage chamber in the PBSC-LYM program produced a low content of residual PLTs (0.7 x 10(11) +/- 0.3 x 10(11) per unit) and RBCs but failed to reach a target of 1 x 10(9) CD 14+ cells. Modulated light to stabilize the buffy-coat detection by the interface monitor significantly improved CD 14+ cell enrichment. By use of the PBSC-LYM program, higher centrifuge velocity (1700 rpm [382 x g] vs. 1500 rpm [297 x g]) improved significantly CD 14+ cell yields (0.7 x 10(9) vs. 0.5 x 10(9) cells).

CONCLUSION

A pure CD 14+ cell product with low numbers of residual cells was obtained by the PBSC-LYM program, which could be useful for good manufacturing practice-conformed production within closed systems. The MNC program offers the collection of high CD 14+ cell yields with excellent CEs but also high residual PLT counts.

Washing platelets with new additive solutions: aspects on the in vitro quality after 48 hours of storage

BACKGROUND

Rare clinical conditions cause the need for washed platelet (PLT) concentrates (PCs). Saline-washed PCs can only be stored shortly, however, owing to lack of substrates for PLT metabolism. New PLT additive solutions (PASs) contain such substrates and might be used alternatively. The in vitro quality of apheresis PCs washed with Composol-PS or modified PAS-III (PAS-IIIM) stored up to 48 hours after wash was compared.

STUDY DESIGN AND METHODS

Twelve blood donors underwent two apheresis procedures (A and B) collecting 6.0 x 10(11) PLTs in 500 mL of plasma with a least 2 weeks in between. The PCs collected by Apheresis A were stored for 3 days and then split in two equal units before washing with Composol-PS or PAS-IIIM. The PCs collected by Apheresis B were split after collection. One unit was released for transfusion and 1 unit was stored unwashed up to Day 6 and used as reference unit. In vitro testing was performed before and after washing as well as 24 and 48 hours after wash.

RESULTS

After 48 hours of postwash storage, the units washed with either PAS showed acceptable results for hypotonic shock response (HSR), P-selectin expression, and pH, whereas PLT aggregability was significantly impaired. Throughout the storage, unwashed units showed better in vitro quality. HSR and P-selectin expression were similar before and immediately after the washing procedure.

CONCLUSION

Based on these in vitro results, 48-hour postwash storage of washed PCs with the two PASs seems to be feasible. In vivo recovery studies, however, must confirm this finding in the future.

Hyperconcentrated platelets stored in additive solution: aspects on productivity and in vitro quality

BACKGROUND AND OBJECTIVES

New platelet (PLT) additive solutions (PASs) allow a plasma carryover of < 30% in PLT concentrates. This implicates the need to collect apheresis PLT concentrates at very high PLT concentrations: so-called dry PLTs (DPs). We used the TRIMA, with software version 4 (TRIMA V4), to collect such DPs and investigated the in vitro quality of these PLTs when stored in the new modified PAS-III (PAS-IIIM).

MATERIALS AND METHODS

TRIMA V4 was programmed to collect 6.0 x 10(11) PLTs at a concentration of 5000 x 10(3) PLTs/microl. Two DPs were pooled, split into four equal parts and diluted to obtain secondary pools (SPs) consisting of 70% PAS-III/30% plasma, 70% PAS-IIIM/30% plasma, 80% PAS-IIIM/20% plasma or 100% plasma. In vitro testing was performed on days 0, 1, 5 and 7. Collection efficiency (CE), collection rate (CR) and PLT yield were calculated for each donation.

RESULTS

Thirty-two runs with TRIMA V4 were performed, collecting 6.58 +/- 0.74 x 10(11) PLTs at a concentration of 4255 +/- 914 x 10(3)/microl in 99 +/- 19.9 min, resulting in a CE of 65.3 +/- 8.2% and a CR of 6.92 +/- 1.6 x 10(9) PLTs/min. On day 0, 34-37% of the PLTs in the units prepared for storage were already activated. PLTs stored in 70% or 80% PAS-IIIM showed superior in vitro quality compared to PLTs stored in PAS-III.

CONCLUSIONS

TRIMA V4 is a suitable device for the collection of DPs. Nevertheless, improvements are desirable to further increase the ability to concentrate PLTs at very high levels. The storage of apheresis-derived PLTs in PAS III-M is a very promising approach, even at a plasma carryover of < 30%.

Frequently used plateletpheresis techniques result in variable target yields and platelet recruitment of donors

BACKGROUND

Standard plateletpheresis techniques and effects on platelet (PLT) donors were investigated to provide an informative basis for advancement of apheresis software.

STUDY DESIGN AND METHODS

Three paired groups with 33 male and 22 female blood donors were prospectively investigated by analyzing blood counts of donors and products. Four apheresis platforms, the COBE Spectra LRS and the Trima v4 (Gambro BCT) and the AS.TEC204 and the COM.TEC (Fresenius Hemocare), were compared. Deviations of the collected from programmed PLT targets and donor PLT recruitment were calculated for single-unit PLT concentrates (SU-PCs; 3 x 10(11) PLTs) and double-unit PLT concentrates (DU-PCs; 6 x 10(11) PLTs).

RESULTS

Regarding SU-PCs, the productivity of the COM.TEC machine was superior to the AS.TEC204 machine, because of shorter processing time (54 min vs. 67 min) and higher yields (2.90 x 10(11) PLTs vs. 2.75 x 10(11) PLTs). Compared to the Spectra machine, the Trima v4 machine showed higher collection efficiencies (CEs) and shorter processing time and complied better with the programmed target (SU-PCs, 3.24 x 10(11) PLTs vs. 3.70 x 10(11) PLTs; DU-PCs, 6.87 x 10(11) PLTs vs. 7.56 x 10(11) PLTs). Harvests of the Spectra machine (DU-PCs) exceeded the target by 40 percent, which resulted in high PLT loss for donors. A longer processing time resulted in some higher CEs (SU-PCs, 53%; DU-PCs, 58%), which could contribute to this result. PLT recruitment compensated PLT loss to some extent.

CONCLUSION

The major finding was that the newer devices (COM.TEC and Trima) gave more predictable yields than the older devices (AS.TEC204 and Spectra) and resulted in lower PLT deficit. PLT software should be improved to minimize relevant variations of collected yields regarding the programmed target.

Mononuclear cell variability and recruitment in non-cytokine-stimulated donors after serial 10-liter leukapheresis procedures

BACKGROUND

We introduced monitoring of mononuclear cell (MNC) counts to obtain enhanced donor control and a stable quality of MNC products, because there are limited data available about blood donors after serial leukapheresis (LP) procedures.

STUDY DESIGN AND METHODS

In a prospective paired study, 13 male healthy blood donors underwent 10-L LP procedures performed on two apheresis devices by use of two MNC program settings (COBE Spectra, Gambro BCT, SF 250 vs. SF 500; and AS.TEC 204, Fresenius Hemocare, CP 129 vs. CP 194). Donors' pre- and postdonation MNC counts were analyzed by fluorescence-activated cell sorting.

RESULTS

After each 10-L LP procedure, a transient decline (p < 0.05) of CD14+ monocyte and platelet counts appeared in donors. Loss of donors' CD3+ T cells, CD19+ B cells, and CD16+56+ natural killer (NK) cells during MNC collection was partly compensated by cell recruitment. The MNC recruitment factor (RF) seems to be higher with high-yield MNC program settings. Negative correlations (p < 0.01) were noticed between predonation counts and RFs of CD3+ T cells and CD16+56+ NK cells. Four serial 10-L LP procedures did not result in long lasting MNC depletion for donors.

CONCLUSION

MNC recruitment seems to depend on MNC program settings and collected cell yields. Low MNC counts could result in high cell recruitment that may contribute to stable collection results to some degree. Nevertheless, there seems to be a considerable individual variation of MNC recruitment in donors that should be investigated in more detail.

The in vitro quality of washed, prestorage leucocyte-depleted red blood cell concentrates

BACKGROUND AND OBJECTIVES

No data are currently available on the quality of washed prestorage leucocyte-depleted red blood cell concentrates (RCCs).

MATERIALS AND METHODS

Five groups of RCCs stored in additive solution (SAG-M) were washed. The groups differed in the age of RCCs (2-5 days or 11-15 days), the temperature during the washing procedure and a 6-h storage period (4 degrees C or room temperature) and the washing solution (saline, SAG-M or 5% albumin). We measured ATP, 2,3-diphosphoglycerate (2,3-DPG), haemolysis, blood cell count, Na(+), K(+), pH, pO(2), pCO(2) and lactate, before and after the washing procedure and hourly during the 6-h postwash storage period.

RESULTS

The erythrocyte ATP content increased by 2-13%, relative to the baseline value, during the washing procedure. The 2,3-DPG level decreased by 15-35% in 2-6-day-old RCCs and by 30-40% in 11-15-day-old RCCs (relative to baseline values) during the washing procedure. In RCCs that were washed and stored at room temperature, and in 2-week-old RCCs, a further decrease in 2,3-DPG of up to 40%, relative to the baseline value, was observed during the 6-h postwash time-period.

CONCLUSIONS

Washing of RCCs stored in SAG-M results in a considerable, significant loss of erythrocyte 2,3-DPG, especially in older RCCs. This loss increases in during a 6-h storage period postwash, even at 4 degrees C. This loss of erythrocyte quality might well outweigh the benefits of washed SAG-M RCCs during massive transfusion in neonates.

First comparison of productivity and citrate donor load between the Trima version 4 (dual-stage filler) and the Trima Accel (single-stage filler) in the same donors

BACKGROUND AND OBJECTIVES

Aside from new software the blood cell separator TRIMA (GambroBCT) also received a newly designed separation chamber offering a novel single stage separation technology, called Trima Accel. We evaluated this new system focusing on productivity and donor comfort by comparing it to the previous version (Trima version 4) in collecting single-donor platelet concentrates (SD-PCs) and plasma.

MATERIALS AND METHODS

Each of 20 donors underwent platelet apheresis using both devices. We compared the collection efficiency (CE), the collections rate (CR), the volume of the collected plasma and the residual leukocytes. Furthermore we compared donor comfort in terms of duration of the donation, flow of citrate back to the donor and platelet and white blood cell (WBC) loss.

RESULTS

While the number of collected platelets and the platelet concentration did not differ significantly between both techniques the time of the procedure was reduced by 15.6% with Trima Accel. This results in an increase of the CR and CE of 25% and 15% respectively when using Trima Accel. Log normal probability plotting of WBC counts showed that both techniques complied with the European and the US leukoreduction guidelines. The mean flow of ACDA to the donor per minute and per litre blood volume was also reduced by 20%.

CONCLUSION

These data show that the Trima Accel represents a further improvement in apheresis platelet production with a better productivity and donor comfort, especially regarding the mean flow of ACDA to the donor.

Comparison of two mononuclear cell program settings on two apheresis devices intended to collect high yields of CD14+ and CD3+ cells

BACKGROUND

In cancer and transplantation therapy apheresis devices and software of optimum standards are required for the collection of high cell yields with high purity of the desired cell fraction.

STUDY DESIGN AND METHODS

In a paired study, 15 healthy blood donors underwent four 10-L leukapheresis procedures (197 +/- 33 min) with an inlet blood flow rate of 60 mL per minute by use of two different MNC program settings of the COBE Spectra (Gambro BCT) and the AS.TEC 204 (Fresenius Hemocare) cell separators.

RESULTS

Use of the standard MNC program of both apheresis devices resulted in significantly higher (p < 0.01) collection efficiencies of CD14+ monocytes, CD3+ cells, CD4+ cells, CD8+ T cells, CD16+ CD56+ natural killer (NK) cells, and residual PLTs (p < 0.001), owing to higher centrifuge speed. The mean MNC purity of all components was more than 90 percent. By use of standard programs of either device, significant correlations (p < 0.01) between donor monocytes and preleukapheresis NK cell counts and the corresponding component cell yields were found.

CONCLUSION

Compared to the program modifications with lower centrifuge velocities the standard MNC programs were significantly more efficient regarding CD14+, CD3+, and CD16+ CD56+ cells. Enhanced centrifuge speed and inlet blood flow rate in MNC programs resulted in higher, similar composed MNC concentrations of the products.

In vitro quality control of red blood cell concentrates outdated in clinical practice

The properties of red blood cell (RBC) concentrates stored in different additive solutions have been previously examined under laboratory conditions at the end of shelf-life. However, whether these data are representative for RBC units used in clinical practice has not been shown. Therefore, we examined 164 RBC units from six manufacturers outdated after clinical usage in a hospital-based transfusion service for cellular content, hemolysis, adenosin triphosphate, 2,3-DPG, pH, oxygen saturation and levels of beta-thromboglobulin and proinflammatory cytokines interleukin (IL) 1beta (IL-1), IL-6, IL-8 and tumor necrosis factor alpha (TNFalpha). Results were correlated with the number of interruptions of recommended storage conditions and with different manufacturers. TNFalpha and IL-8 levels in the supernatant of RBC concentrates showed a weak correlation with the number of interruptions of recommended storage conditions (TNFalpha: r = 0.25, P < 0.01; IL-8: r = 0.20, P < 0.01) for the whole series. We detected no significant correlation between hemolysis and interruptions of recommended storage conditions or any of the remaining studied parameters. However, we found significant differences between RBC concentrates supplied by different manufacturers with respect to cellular content and most of the studied parameters. RBC concentrates containing SAG-M from one single manufacturer had higher in vitro hemolysis at the end of shelf-life compared to all other manufacturers (P < 0.05). We conclude from our data that interruptions of optimal conditions for storage of red cell components during cross-match testing and transport in our setting play a minor role for in vitro properties of RBC units at the end of shelf-life. The influence of processes of production, storage and/or transport until entry of RBC units into our blood component depot seems to be much more important for final product quality at the end of shelf-life than subsequent events.

Comparison of two apheresis systems for the collection of CD14+ cells intended to be used in dendritic cell culture

BACKGROUND

Monocytes collected by leukapheresis are increasingly used for dendritic cell (DC) culture in cell factories suitable for DC vaccination in cancer.

STUDY DESIGN AND METHODS

Using modified MNC programs on two apheresis systems (Cobe Spectra and Fresenius AS.TEC204), leukapheresis components collected from 84 patients with metastatic malignant melanoma and from 31 healthy male donors were investigated. MNCs, monocytes, RBCs, and platelets (PLTs) in donors and components were analyzed by cell counters, WBC differential counts, and flow cytometry.

RESULTS

In 5-L collections, Astec showed better results regarding monocyte collection rates (11.0 vs. 7.4 x 10(6)/min, p = 0.04) and efficiencies (collection efficiency, 51.9 vs. 31.9%; p < 0.001). Both devices resulted in monocyte yields at an average of 1 x 10(9) (donors) and 2.5 x 10(9) (patients), whereas Astec components contained high residual RBCs. Compared to components with low residual PLTs, high PLT concentration resulted in higher monocyte loss (48 vs. 20%, p < 0.0001) before DC culture.

CONCLUSION

The Astec is more efficient in 5-L MNC collections compared to the Spectra. Components with high residual PLTs result in high MNC loss by purification procedures. Thus, optimizing MNC programs is essential to obtain components with high MNC yields and low residual cells as prerequisite for high DC yields.

Collection of WBC-reduced single-donor PLT concentrates with a new blood cell separator: results of a multicenter study

BACKGROUND

A new cell separator (COM.TEC, Fresenius) was recently developed aimed at efficient collection of WBC-reduced single-donor PLT concentrates (SDPs).

STUDY DESIGN AND METHODS

Five German centers collected 554 WBC-reduced SDPs with help of the COM.TEC cell separator. Two multicenter cell counting studies were performed at the beginning and at the end of the study to document uniform counting results among the participating centers.

RESULTS

A total of 441 (79.6%) PLT collections were included in the study according to the protocol. A total of 342 single-dose and 99 double-dose SDPs were collected. For single-dose SDPs, an average blood volume of 2826 +/- 409 mL was processed in a donation time of 55 +/- 11 minutes. Mean PLT yield of these products was 3.11 x 1011+/- 0.40 x 1011 and the WBC contamination was 0.11 x 106+/- 0.20 x 106. For double-dose SDPs (PLT count, 5.29 +/- 0.93 x 1011), 3943 +/- 639 mL was processed. The average difference between the target and the collected PLT concentration was -2.8 +/- 12.0 percent for single-dose SDPs and -1.8 +/- 9.5 for double-dose SDPs, respectively. The collection efficiency was 53.7 +/- 5.8 percent for single-dose SDPs and 58.2 +/- 6.2 percent for double-dose SDPs. If all results of each sample from the counting study were set to unity (to the mean over all centers), most PLT determinations were very similar to the mean, for example, near or 1 if set to unity.

CONCLUSION

The COM.TEC machine makes it possible to obtain WBC-reduced SDPs that comply with current standards.

Cord blood processing with an automated and functionally closed system

BACKGROUND

Umbilical cord blood processing with standard centrifugation techniques is performed in open systems and results in varying cell and volume recoveries.

STUDY DESIGN AND METHODS

Forty umbilical cord blood donations were randomly assigned to processing either with a microprocessor-controlled cell separator equipped with closed disposables or with a manual separation procedure in blood bags. The collection efficiency of nucleated cells, MNCs, RBCs, and CD34+ cells and the processing time were analyzed.

RESULTS

Using the cell processor, mean collection efficiencies were 78.6 +/- 24.9 percent for nucleated cells, 77.4 +/- 27.8 percent for MNCs, 55.5 +/- 14.6 percent for RBCs, and 83.6 +/- 32.5 percent for CD34+ cells, while they were 73.1 +/- 13.2 percent for nucleated cells, 78.1 +/- 14.9 percent for MNCs, 26.0 +/- 12.2 percent for RBCs, and 77.0 +/- 17.6 percent for CD34+ cells when using the standard centrifugation technique. The processing time was about 20 minutes for automated processing and 60 to 80 minutes for the standard centrifugation technique.

CONCLUSION

Using the new cell processor, the collection efficiencies for nucleated cells, MNCs, and CD34+ cells are similar to those obtained by established centrifugation techniques while the RBC reduction is less effective. The main advantages of the new systems are the closed system, the more standardized processing procedure, and a significantly shorter processing time.