[When A is not A anymore: problems and pitfalls with blood group typing]

Correct blood group typing is a prerequisite for transfusion. In most cases blood group determination is without problems; however, in individual cases various factors can complicate blood group determination and sometimes lead to confusing findings. For a better understanding the clinician should have basic knowledge of blood typing. Blood group determination usually covers the AB0 blood groups, Rhesus and Kell systems; in addition, a direct Coombs test and an antibody screening test for the detection of irregular antibodies in the recipient are performed. Confusion of patients, blood samples, results or preparations can lead to severe consequences due to incompatible transfusion and must be prevented. In this context, bedside blood type testing before transfusion is of utmost importance. Problems in laboratory analysis as well as patient-related factors, such as the existence of irregular antibodies against red blood cells can complicate the immunohematology diagnostics. Certain medications, such as daratumumab, lead to a significantly increased complexity in laboratory analyses. Massive transfusions can lead to chimerism with more than one population of circulating red blood cells. Hematopoetic stem cell transplantation can also lead to a change in blood groups as well as chimerism. In addition, there are various other rare causes that can result in difficulties in blood group determination, such as rare blood groups or rare disease-associated phenomena. In the case of problems in blood group determination, early and close cooperation with transfusion medicine is essential for the clinician.

Hepatitis C Virus Transmission through Quarantine Fresh-frozen Plasma

In 1994, quarantine fresh-frozen plasma (Q-FFP) was introduced in Germany in order to reduce the risk of HIV and HCV transmission. In 1998, an acute HCV infection of a patient was reported to us. The lookback revealed that this patient had received two Q-FFP from a donor who had seroconverted for HCV in the meantime. Recipients of further plasma donations from this donor were identified. Back-up specimens of these donations were investigated in several laboratories. A total of 25 additional HCV-PCR positive plasma units had been transfused to 12 further patients. HCV infections were diagnosed in seven of these recipients, three patients had already been deceased. One of the remaining two recipients was already HCV positive prior to transfusion, in the other patient, no HCV infection was detectable. This patient had received three units of an “early” plasma donation , which was tested negative by PCR in one laboratory, but positive in the other. The subsequent, clinically infectious donation had the same discrepant PCR results. Thus, eight cases of HCV transmission were revealed and classified as “certain” with regard to causality, also due to an identical HCV genotype, i.e. 3e. Some of these infections would have been prevented by application of a different anti-HCV assay. The assay used in the respective plasmapheresis station was in-sensitive in this individual case for more than 400 days after the first PCR positive donation. This caused the release of the above mentioned infectious units. Upon re-testing the backups, three of four other anti-HCV assays revealed a positive result already 104 days after the first PCR-positive donation. The donor had increased ALAT levels (> 23 IU/L) at nine of 28 donations, two of these were higher than 2.5 times the upper normal limit, and two were higher than 68 IU/L, which is the cut-off value for male blood donors in Germany. The results of these (look-back) studies arouse several queries, i.e. differences in the diagnostic sensitivity between current anti-HCV and PCR tests, the accuracy of risk-estimates (especially when based on hemovigilance studies for Q-FFP), the value of ALAT testing, and currently practised release algorithms for Q-FFP.

CD20-Specific Immunoligands Engaging NKG2D Enhance γδ T Cell-Mediated Lysis of Lymphoma Cells

Human γδ T cells are innate-like T cells which are able to kill a broad range of tumour cells and thus may have potential for cancer immunotherapy. The activating receptor natural killer group 2 member D (NKG2D) plays a key role in regulating immune responses driven by γδ T cells. Here, we explored whether recombinant immunoligands consisting of a CD20 single-chain fragment variable (scFv) linked to a NKG2D ligand, either MHC class I chain-related protein A (MICA) or UL16 binding protein 2 (ULBP2), could be employed to engage γδ T cells for tumour cell killing. The two immunoligands, designated MICA:7D8 and ULBP2:7D8, respectively, enhanced cytotoxicity of ex vivo-expanded γδ T cells against CD20-positive lymphoma cells. Both Vδ1 and Vδ2 γδ T cells were triggered by MICA:7D8 or ULBP2:7D8. Killing of CD20-negative tumour cells was not induced by the immunoligands, indicating their antigen specificity. MICA:7D8 and ULBP2:7D8 acted in a dose-dependent manner and induced cytotoxicity at nanomolar concentrations. Importantly, chronic lymphocytic leukaemia (CLL) cells isolated from patients were sensitized by the two immunoligands for γδ T cell cytotoxicity. In a combination approach, the immunoligands were combined with bromohydrin pyrophosphate (BrHPP), an agonist for Vδ2 γδ T cells, which further enhanced the efficacy in target cell killing. Thus, employing tumour-directed recombinant immunoligands which engage NKG2D may represent an attractive strategy to enhance antitumour cytotoxicity of γδ T cells.

Direct volumetric flow cytometric quantitation of CD34+ stem and progenitor cells

OBJECTIVES

In this study, we compared a classic single-platform (SP) method applying beads for enumeration of CD45+ or CD34+ cells with a new device allowing direct volumetric measurements of stem and progenitor cells.

BACKGROUND

Following apheresis and cyropreservation, the precise enumeration of CD34+ cells as key parameter of graft quality is mandatory for the clinical course after transplantation. Currently, flow cytometry with SP technique represents the 'gold standard' for such determinations.

METHODS/MATERIALS

Fresh samples, 14 from mobilised peripheral blood (PB), 9 from apheresis products (AP) and 13 samples from frozen-thawed (FT) haematopoietic progenitor cell grafts, were analysed for CD34+ cells, CD45+ cells, and in frozen-thawed samples for viability by a bead-based flow cytometric method and in parallel by a direct, volumetric flow cytometric method.

RESULTS

Comparison of CD34+ analyses revealed a significant correlation (P < 0·01) for each material between both techniques with r = 0·95 (PB), r = 0·933 (AP) and r = 0·929 (FT). Also, for analysis of CD45+ cells µL(-1) , the measured numbers evaluated with the different techniques did not significantly differ for all three materials analysed. In frozen-thawed samples, the analysis of viability was comparable for both techniques.

CONCLUSIONS

The results of this study demonstrate that a direct volumetric analysis of CD34+ cells µL(-1) or CD45+ cells µL(-1) is feasible. This technique represents a simple and economical approach for standardisation of progenitor and stem cell analyses.

Evidence for gene recombination in FCGR3 gene variants

BACKGROUND AND OBJECTIVES

The genes encoding the Fcgamma receptors (FcgammaR) IIIa and IIIb (FCGR3A and FCGR3B) are clustered on chromosome 1 band q23-24 and exhibit allelic polymorphism. We investigated the molecular basis of additional new FCGR3 genomic variation.

MATERIALS AND METHODS

A segment shared by FCGR3A and FCGR3B containing the polymorphic nucleotide positions 141, 147, 227, 266, and 277 in exon 3 was cloned and sequenced from genomic DNA of 30 donors and 3 bacterial artificial chromosome (BAC) clones. A mixture consisting of isolated FCGR3B*2- and FCGR3A- plasmids was cloned and sequenced as well. Additionally, nucleotide databases were screened for clones with variant FCGR3 sequences.

RESULTS

A total of 12 FCGR3 variants defined by the polymorphic positions were detected in whole blood genomic DNA from 23 of 24 FCGR3B*2 and/or FCGR3B*3 positive donors, the DNA from two of three BAC clones and in the DNA mixture of isolated FCGR3B*2- and FCGR3A- plasmids.

CONCLUSION

Nucleotide exchanges of the variants were non-random and resulted from two alternative nucleotides present in one of the polymorphic position of the basic FCGR3 forms. Polymerase chain reaction (PCR) artefacts cannot be excluded as origin of new variants, but there is strong evidence that at least two variants are the result of a somatic recombination.

Proliferation-based T-cell selection for immunotherapy and graft-versus-host-disease prophylaxis in the context of bone marrow transplantation

Graft-versus-host disease (GvHD) caused by alloreactive T cells within the graft is a major drawback of allogeneic BMT, but depletion of T cells leads to higher rates of relapse, opportunistic infections and graft failure. Therefore, selective removal of GvHD-inducing alloreactive T cells might be beneficial. We describe here the separation of alloresponsive T cells, based on carboxyfluorescein succimidyl ester labeling, in vitro allostimulation and FACS-sorting. In vivo effects of the separated cell populations were investigated in the context of allogeneic BMT in murine models: in vitro resting T cells were shown to survive in the allogeneic host and retain immunoreactivity against 'third-party' antigens. As demonstrated in two different transplantation models, elimination of proliferating cells significantly reduces GvHD but offers no advantages to using T-cell-depleted bone marrow alone concerning engraftment and tumor control. Transplanting T cells that proliferate in response to tumor antigens in vitro may narrow down the spectrum of antigens recognized by T cells and therefore reduce GvHD while maintaining graft-facilitating function and tumor control. Therefore, selecting tumor-reactive T cells on the basis of their proliferative response in vitro may be beneficial for the recipient, less time consuming than T-cell cloning and still reduce the extent of GvHD.

Successful autologous stem cell transplantation in a severely immunocompromised patient with relapsed AIDS-related B-cell lymphoma

There is now evidence that the tolerability and response to systemic chemotherapy in HIV-infected patients with AIDS-related lymphoma (ARL) is significantly improved by highly active antiretroviral therapy. Here we report an severely immunocompromised AIDS patient with recurrent ARL who was successfully treated with autologous stem cell transplantation (ASCT). We also review the current literature of ASCT in HIV-infected patients.

Myelodysplastic syndrome of donor origin subsequent to successful treatment of myeloid/NK-cell precursor leukaemia with allogeneic PBSCT: two very rare conditions in one patient

We report a 36-year-old male with myeloid/natural killer (NK)-cell precursor acute leukaemia with a complex aberrant karyotype, who was treated according to an acute-myeloid-leukaemia (AML) treatment protocol (idarubicine, cytarabine, and etoposide) followed by high-dose cytarabine consolidation and achieved complete remission. He underwent allogeneic matched unrelated donor (MUD) peripheral blood stem-cell transplantation (PBSCT) and remained in remission throughout his remaining life. Seven months posttransplantation, a myelodysplastic syndrome (MDS) with (20q-) of donor origin was diagnosed causing severe thrombocytopenia and finally leading to infection and death. This patient represents one of the few cases published achieving remission for a significant period of time after being diagnosed with myeloid/NK-cell precursor acute leukaemia, a very rare malignant disease. We conclude, despite the fatal outcome due to infection, that allogeneic PBSCT is a therapeutic option for patients with this entity. In addition, the development of a myelodysplastic syndrome of donor origin is extremely rare and only very few cases are published worldwide.

Prospective, randomized, sequential, crossover trial of large-volume vs. normal-volume leukapheresis procedures: effects on subpopulations of CD34(+) cells

Some data exist on the influence of leukapheresis volume on the number of harvested peripheral blood hematopoietic progenitor cells (HPC), but less is known about the influence on the composition of HPC. We therefore performed a prospective, randomized crossover trial to evaluate the effect of large-volume (LVL) vs. normal-volume leukapheresis (NVL) on subpopulations of CD34(+) cells in the harvest product of 15 patients with breast cancer and 8 patients with non-Hodgkin's lymphoma. Patients were randomly assigned to start either with an LVL on day 1 followed by an NVL on day 2 or vice versa. The number of HPC, the extraction efficiency defined as difference between yield in the harvest and decrease in peripheral blood, and the relative proportion as well as the absolute numbers of CD34(+) cells coexpressing CD38, CD90, HLA-DR, CD117, CD7, CD19, CD41, or CD33 were evaluated. There was no significant difference with regard to the percentages of the subsets on comparison of LVL to NVL procedures. Only the absolute median number of CD34(+)HLA-DR(-) cells was significantly (P=0.02) higher in LVL harvests compared with the corresponding NVL components, which can be explained on the basis of the higher yield and the higher extraction efficiency in LVL compared with NVL. LVL results in a higher yield of CD34(+) cells and leads to an intra-apheresis recruitment of HPC but the relative composition of the harvested CD34(+) cells is not changed significantly. In addition, the amount of early, HLA-DR(-), hematopoietic HPC seems to be increased by an LVL.

Successful transplantation and engraftment of peripheral blood stem cells after cryopreservation, positive and negative purging procedures, and a second cryopreservation cycle

Transplantation of peripheral blood stem cells (PBSC), positively and/or negatively selected immediately after harvest, has become a widely applied therapeutic option in hematological or oncological patients. The following case of peripheral blood stem cell transplantation represents the first case of successful transplantation of PBSC, cryopreserved twice and purged after cryopreservation. PBSC were harvested in a 44-year-old female patient with a low-grade non-Hodgkin's lymphoma stage IV after mobilization with chemotherapy and G-CSF. A total number of 15.2 x 10(6) CD34+ cells/kg bodyweight was harvested with a 36.9% contamination of tumor cells coexpressing CD5 and CD20. After subsequent chemotherapy cycles and cyclophosphamide mobilization, only 0.77 x 10(6) CD34+ cells/kg bodyweight, not sufficient for transplantation, were achieved after positive selection. Therefore, 10.8 x 10(6) cryopreserved CD34+ cells/kg bodyweight were thawed and a positive selection was carried out with the BAXTER Isolex 300i machine. Before additional negative selection, the 0.77 x 10(6) positively selected CD34+ cells/kg bodyweight from the second mobilization were added. A total quantity of 4.4 x 10(6) CD34+ cells/kg bodyweight with a purity of 93.1% representing a recovery of 38% was obtained. Cells were again cryopreserved, stored and retransfused after conditioning the patient with TBI and high-dose cyclophosphamide. The patient engrafted with a WBC count > 1000/microliter on day eight and a platelet count > 20,000/microliter without transfusion support on day 12 post-transplantation. This case indicates that purging procedures can successfully be carried out with cryopreserved cell material and that purified CD34+ cells can be cryopreserved a second time before transplantation, without affecting their hematopoietic capacity.

Filtration of methylene blue-photooxidized plasma: influence on coagulation and cellular contamination

BACKGROUND

Virus inactivation of plasma can be achieved by photodynamic methods in the presence of phenothiazine dyes such as methylene blue (MB). Subsequent filtration may increase the efficacy of virus inactivation and reduce adverse effects of WBC contamination and MB.

STUDY DESIGN AND METHODS

This study examined the effect of filtration with three different filters (MBF1, MBF2, and MBF3) on MB concentration, residual cells, coagulation factors, and activation measures of coagulation, fibrinolysis, and complement in MB-treated (1 microM/L) plasma units.

RESULTS

Filtration reduced the concentration of MB by > or = 89 percent. WBCs were depleted by 92 percent (MBF1) and >99.9 percent (MBF2 and MBF3). Treatment with MB significantly decreased the coagulation potency from levels in untreated plasma, as measured by thromboplastin time ratio (112 +/- 18% vs. 95 +/- 11%), activated partial thromboplastin time (40 +/- 3 sec vs. 44 +/- 3 sec), thrombin time (16.9 +/- 1.1 sec vs. 18.6 +/- 1.5 sec), factor VIII (1.09 +/- 0.21 U/mL vs. 0.85 +/- 0.13 U/mL), and vWF (0.94 +/- 0.65 U/mL vs. 0.65 +/- 0.24 U/mL). Filtration did not further decrease these values, while factor XI (0.75 +/- 0.22 U/mL vs. 0.37 +/- 0.20 U/mL) and prekallikrein values decreased in MB plasma units filtered with the MBF3. In addition, activated factor XII (0.7 +/- 0.5 microg/L vs. 4.5 +/- 1.0 microg/L) increased.

CONCLUSION

WBCs and MB can be eliminated from MB-treated plasma units by filtration. Differences in biocompatibility of the different filters, especially the influence on the contact phase of coagulation, must be taken into consideration.

A cell-kinetic model of CD34+ cell mobilization and harvest: development of a predictive algorithm for CD34+ cell yield in PBPC collections

BACKGROUND

Mobilization and homing of PBPCs are still poorly understood. Thus, a sufficient algorithm for the prediction of PBPC yield in apheresis procedures does not yet exist.

STUDY DESIGN AND METHODS

The decline of CD34+ cells in the peripheral blood during apheresis and their simultaneous increase in the collection bag were determined in a prospective study of 18 consecutive apheresis procedures. A cell-kinetic, four-compartment model describing these changes was developed. Retrospective data from 136 apheresis procedures served to further improve this model. A predictive algorithm for the yield was developed that considered the sex, weight, and height of the patient, the number of CD34+ cells in peripheral blood before apheresis, the inlet flow, and the duration of the apheresis. The accuracy of this algorithm was evaluated by comparison of the predicted and the observed yields of CD34+ cells in 105 prospective autologous and 148 retrospective allogeneic apheresis procedures.

RESULTS

The correlation between predicted and observed yields was good for the autologous and allogeneic groups with a correlation coefficient (r) of 0.8979 and 0.8311 (p<0.0001), respectively. The regression is described by the equations log (measured value [m]) = 1.0118 + 0.8595 x log (predicted value [p]) for the autologous and log (m) = 2.226 + 0.7559 x log (p) for the allogeneic group. The respective equations for the zero-point regression are log (m) = 1.014 x log (p) and log (m) = 1.026 x log (p). The probability that the measured value was 90 percent or more of the predicted value was 83.8 percent for the autologous and 90.5 percent for the allogeneic apheresis procedures.

CONCLUSION

The predictive accuracy of the algorithm and the slope of the zero-point regression curve were higher for allogeneic than autologous PBPC collections. The predictive algorithm may be a useful tool in PBPC harvest, enabling the adaptation of the size of the apheresis to the needs of each patient.

Hepatitis C virus transmission through quarantine fresh-frozen plasma

In 1994, quarantine fresh-frozen plasma (Q-FFP) was introduced in Germany in order to reduce the risk of HIV and HCV transmission. In 1998, an acute HCV infection of a patient was reported to us. The look-back revealed that this patient had received two Q-FFP from a donor who had seroconverted for HCV in the meantime. Recipients of further plasma donations from this donor were identified. Back-up specimens of these donations were investigated in several laboratories. A total of 25 additional HCV-PCR positive plasma units had been transfused to 12 further patients. HCV infections were diagnosed in seven of these recipients, three patients had already been deceased. One of the remaining two recipients was already HCV positive prior to transfusion, in the other patient, no HCV infection was detectable. This patient had received three units of an "early" plasma donation , which was tested negative by PCR in one laboratory, but positive in the other. The subsequent, clinically infectious donation had the same discrepant PCR results. Thus, eight cases of HCV transmission were revealed and classified as "certain" with regard to causality, also due to an identical HCV genotype, i.e. 3e. Some of these infections would have been prevented by application of a different anti-HCV assay. The assay used in the respective plasmapheresis station was in-sensitive in this individual case for more than 400 days after the first PCR positive donation. This caused the release of the above mentioned infectious units. Upon re-testing the backups, three of four other anti-HCV assays revealed a positive result already 104 days after the first PCR-positive donation. The donor had increased ALAT levels (> 23 IU/L) at nine of 28 donations, two of these were higher than 2.5 times the upper normal limit, and two were higher than 68 IU/L, which is the cut-off value for male blood donors in Germany. The results of these (look-back) studies arouse several queries, i.e. differences in the diagnostic sensitivity between current anti-HCV and PCR tests, the accuracy of risk-estimates (especially when based on hemovigilance studies for Q-FFP), the value of ALAT testing, and currently practised release algorithms for Q-FFP.

Quality and safety of platelet apheresis concentrates produced with a new leukocyte reduction system

OBJECTIVES

Contaminating white blood cells (WBC) in apheresis platelet concentrates (PC) can cause a variety of adverse effects after platelet transfusion. To obtain PCs with low WBC contamination, a new leukoreduction system (LRS) utilizing 'fluidized particle bed' technology has recently been introduced.

METHODS

We prospectively examined the effect of LRS apheresis on the donor, the quality of the resulting PCs (n = 120), and the platelet increment in the corresponding recipients. Conventionally prepared apheresis PCs served as control group (n = 27). Platelet glycoproteins were examined by flow cytometry.

RESULTS

In LRS apheresis, we observed no serious adverse effects on the donors, but the postdonation absolute lymphocyte counts were reduced from 1,787 +/- 505/microliter to 1,405 +/- 383/microliter (p < 0.001). Comparable results were seen in non-LRS donors. The collection efficiency of the LRS procedures was 50.0 +/- 7.6%, resulting in a yield of 4.3 +/- 1.0 x 10(11) platelets/PC. In flow cytometry, platelet glycoproteins in LRS PCs were not elevated: mean fluorescence of CD62 (6 +/- 4) or CD63 (9 +/- 3) in comparison with non-LRS PCs (mean fluorescence of CD62: 7 +/- 4, CD63: 8 +/- 3). Median leukocyte contamination of the LRS PCs was 0.41 x 10(5) (range 0.07-8.5) WBCs/unit. In 43 recipients, the 24-hour corrected count increments after transfusion of LRS PCs (12,530 +/- 8,761) were essentially the same as those of 20 recipients of non-LRS PCs (13,133 +/- 9,812; p = 0.75).

CONCLUSIONS

LRS apheresis appears to be a safe procedure, which produced effective PCs with few contaminating leukocytes. With new apheresis technology, filtration of PCs may become superfluous.

Testing of individual blood donations for HCV RNA reduces the residual risk of transfusion-transmitted HCV infection

BACKGROUND

To allow cost-effective RNA testing with NAT techniques, the national authorities of several countries have planned or already introduced tests of mixed specimens, that is, plasma pools.

STUDY DESIGN AND METHODS

High-throughput extraction, amplification, and detection of HCV RNA from individual blood donations were optimized and validated. The feasibility of the method and the frequency of anti-HCV-negative, HCV RNA-positive donations were determined in a prospective study of 27,745 allogeneic and 792 autologous individual donations.

RESULTS

The 50- and 95-percent detection limits of the method were determined at 44 IU per mL and 162 IU per mL, respectively (World Health Organization HCV reference material). When 201 HCV RNA-positive sera were taken as a reference, the sensitivity was 97.5 percent. The assay specificity was determined at 99.77 percent. During a 20-month period, two seronegative blood donors tested positive in HCV PCR. The viral load of these donations was 6 x 10(6) and 3 x 10(7) copies per mL, respectively. Thus, the yield of HCV RNA testing in this study was 7. 63 per 100,000 screened donations (95% CI, 1.25-22.07). In both PCR-positive donors, seroconversion was found in subsequent blood samples.

CONCLUSION

This study compares the feasibility of single-donation HCV RNA screening, with the detection of a relatively high percentage of window-phase donations, to data reported from groups using HCV RNA testing of plasma pools. The relative yield of NAT of individual donations versus minipools should be directly investigated in the near future.

Isolated meningeal chloroma (granulocytic sarcoma)--a case report and review of the literature

Isolated chloromas (granulocytic sarcomas) are rare tumors, most of them progressing to acute myeloblastic leukemia within months. There are still no conclusive treatment strategies for this entity; however, early antileukemic chemotherapy seems to lower the probability of developing systemic disease and prolong survival. We report on a patient with isolated meningeal chloroma, primarily misdiagnosed as a high-grade Non-Hodgkin's lymphoma. Two cycles of antileukemic induction chemotherapy were administered, followed by local irradiation and intensified consolidation therapy with autologous stem cell transplantation. After 20 months, he is still in complete remission.

A prospective, randomized, sequential crossover trial of large-volume versus normal-volume leukapheresis procedures: effects on serum electrolytes, platelet counts, and other coagulation measures

BACKGROUND

LVL procedures with the administration of heparin as an additional anticoagulant are increasingly performed because of the potentially higher yield of autologous peripheral blood HPCs. A prospective, randomized crossover trial was performed to evaluate the influence of leukapheresis volume-that is, large versus normal-on serum electrolytes, platelet count, and other coagulation measures in 25 patients with breast cancer and 14 patients with non-Hodgkin's lymphoma.

STUDY DESIGN AND METHODS

Patients were randomly assigned to start either with an LVL on Day 1 followed by a normal-volume leukapheresis (NVL) on Day 2 or vice versa. In LVL, heparin was administered in addition to ACD-A. Bleeding complications, transfusion support, whole-blood counts, and several coagulation measures as well as plasma heparin levels were evaluated.

RESULTS

Although the duration, the infused amount of ACD-A, the flow rate, the drop in platelet count, and the drop in potassium were significantly greater in LVL, and although LVL patients also received heparin, there was no significant difference in clinical tolerance or bleeding complications. After LVL, patients exhibited a significantly longer activated partial thromboplastin time (APTT), with a median of 70 seconds (range, 44-100 sec), and a median anti-factor Xa activity of 0.69 IU per mL (range, 0.10-1.29 IU/mL). The value of the APTT after LVL correlated with anti-factor Xa activity (r = 0.37, p<0.05), but not with platelet count or heparin infusion rate. Markers for coagulation activation did not increase during NVL or LVL.

CONCLUSION

LVL with heparin as an additional anticoagulant seems to be a safe procedure in patients with low preleukapheresis platelet counts. No activation of coagulation occurred after NVL or LVL procedures.

A prospective, randomized, sequential, crossover trial of large-volume versus normal-volume leukapheresis procedures: effect on progenitor cells and engraftment

BACKGROUND

The influence of leukapheresis size on the number of harvested peripheral blood progenitor cells is still unclear. A prospective randomized crossover trial was thus performed, to evaluate the effect of large-volume leukapheresis (LVL) versus normal-volume leukapheresis (NVL) on progenitor cells and engraftment in 26 patients with breast cancer and 15 patients with non-Hodgkin's lymphoma who were eligible for peripheral blood progenitor cell transplantation.

STUDY DESIGN AND METHODS

Patients were randomly assigned to undergo either LVL on Day 1 and on Day 2 or vice versa. The number of progenitor cells was evaluated in the harvest and before and after leukapheresis in the peripheral blood.

RESULTS

The number of harvested CD34+ cells (4.8 x 10(6) vs. 3.4 x 10(6)/kg body weight, p < 0.001) and colony-forming units-granulocyte-macrophage (3.1 x 10(5) vs. 2.4 x 10(5)/kg body weight, p = 0.0026) was significantly higher for LVL procedures than for NVL procedures. The median extraction efficacy, defined as the difference between the yield in the harvest and the decrease in the total number of CD34+ cells in peripheral blood during leukapheresis, was significantly (p < 0.0001) higher for LVL than for NVL (2.6 x 10(8) and 8 x 10(7), respectively). In patients with breast cancer, the median amount of CD34+ cells in the harvest and the median extraction efficacy were higher for LVL than for NVL (p < 0.0001). This was not found for patients with non-Hodgkin's lymphoma.

CONCLUSION

LVL results in a higher yield of CD34+ cells and colony-forming units-granulocyte-macrophage than NVL, but only in patients with breast cancer and with high numbers of CD34+ cells in the peripheral blood before leukapheresis.

A dispermic chimerism in a 2-year-old Caucasian boy

Detection of two different cell populations in a child is a rare event. The following case of a dispermic chimera was diagnosed before surgery due to problems in blood group determination. A 2-year-old phenotypically male child was admitted for correction of a penoscrotal hypospadia and unilateral cryptorchism. During presurgical laboratory investigation, difficulties in blood group determination occurred. Blood group typing was performed by the DiaMed-ID Micro Typing System and by FACS. Additionally, cytogenetic analysis of lymphocytes and analysis of DNA polymorphisms in different tissues were performed. Two populations of red blood cells were detected, O cells accounting for 75% and B cells for 25%. Analysis of DNA-PCR polymorphisms in lymphocytes, nails, and in cells of the oral mucous membrane demonstrated a chimerism, with two alleles inherited from the father and one from the mother. A cytogenetic analysis of cultured lymphocytes showed a mosaic 46, XY/46,XX. Surgery revealed a prostatic utricle grade III, also called pseudovagina; genitography confirmed a vagina. Bilateral gonad biopsy showed a testis on one side and an ovary on the other. This case of chimerism represents a true hermaphroditism that most probably developed by double fertilization of one or more egg nuclei by two sperms.

Early intensive and myeloablative adjuvant chemotherapy in women with high-risk breast cancer

BACKGROUND

Women with breast cancer and > 10 positive lymph nodes have an unfavorable prognosis. The optimal combination and intensity of adjuvant chemotherapy is uncertain. Between July 1994 and December 1996 we treated 19 patients with early intensive followed by high-dose chemotherapy and autologous peripheral blood stem cell transplantation.

PATIENTS AND METHODS

Patients were initially diagnosed with breast cancer and multiple positive lymph nodes. Induction chemotherapy consisted of two courses VP16, ifosphamide, cisplatin and epirubicin (VIPE) and one course of mitoxantrone, cyclophosphamide and thiotepa (MCT). Peripheral blood stem cells were mobilized after the first or second course of VIPE and retransfused two days after high dose chemotherapy.

RESULTS

Stem cells were successfully collected in all patients. Major toxicities (WHO grade III and IV) were neutropenia, thrombocytopenia, alopecia, nausea, infections and mucositis. Hematopoietic recovery occurred in all patients with a median of 10 days for leukocytes and 13 days for platelets. No patient died of therapy-induced complications. The median observation time is 24 months. Two patients have relapsed, one with locoregional disease. The projected rate of patients with disease-free survival after three years is 88%.

CONCLUSIONS

Early intensive and myeloablative chemotherapy followed by peripheral blood stem cell transplantation is a highly efficient and feasible protocol for high risk patients with breast cancer.

Comparison of CD34+ cell numbers and colony growth before and after cryopreservation of peripheral blood progenitor and stem cell harvests: influence of prior chemotherapy

BACKGROUND

Quantitative determination of hematopoietic progenitor cells is a major issue in peripheral blood progenitor and stem cell collection and transfusion, although the extent is still an object of discussion.

STUDY DESIGN AND METHODS

In 116 leukapheresis collections from 42 patients, immunophenotyping for CD34+ cells, evaluation of in vitro proliferative capacity by a colony-forming unit-granulocyte-macrophage (CFU-GM) assay, and viability assessment by trypan blue exclusion were performed before and after storage in liquid nitrogen at -196 degrees C.

RESULTS

Before storage, the median number of CD34+ cells was 1.46 x 10(6) (range, 0.01-54.05 x 10(6)) per kg of body weight (BW). There was no significant difference between precryopreservation and postcryopreservation numbers. The median number of CFU-GM was 2.25 x 10(5) (range, 0.02-157.49 x 10(5)) per kg of BW before cryopreservation and significantly (p < 0.001) lower, 0.83 x 10(5) (range, 0-220.36 x 10(5)) per kg of BW, after cryopreservation. The correlation coefficient of prestorage and poststorage values was 0.92. The median ratio of poststorage and prestorage values was 42.3 percent (0-304.8%). Male patients who underwent intense chemotherapy (> 5 cycles) showed a significantly lower ratio of postcryopreservation and precryopreservation CFU-GM values than other patients (p = 0.0047). A strong linear correlation was determined between the number of CD34+ cells per kg of BW and the number of CFU-GM per kg of BW before and after cryopreservation. A viability below 50 percent predicted a high loss of in vitro proliferative capacity, while a viability above 50 percent did not correlate with a high ratio of CFU-GM from after and before cryopreservation.

CONCLUSION

A good correlation between the variables used for characterization of peripheral blood progenitor cells--the number of CD34+ cells and the number of CFU-GM--was observed. Viability assessment by trypan blue exclusion does not seem to be a substitute for assays evaluating in vitro proliferative capacity.

Frequency and causes of refractoriness in multiply transfused patients

The use of leukocyte-depleted blood components has become the standard therapy for multiply transfused patients during the past few years, as a measure to reduce the frequency of alloimmunization and refractoriness. We assessed frequency and causes of refractoriness, defined as a repeated 24-h post-transfusion platelet count below 20,000/microliters, in 145 consecutive patients who received three or more single-donor platelet concentrates during a 1-year period. Flow-cytometric detection of anti-platelet antibodies and a glycoprotein-specific ELISA were applied for the diagnosis of alloimmunization. Forty patients (27.6%) had at least one episode of refractoriness. In 25 of these 40 patients (62.5%), nonimmune factors (fever, sepsis, coagulopathy, splenomegaly) alone were the cause. In 15 refractory patients alloantibodies were detected. In seven patients (17.5%), alloimmunization alone caused an inadequate transfusion response, while in eight refractory patients (20.0%) alloimmunization and fever or sepsis were present. HLA antibodies were detected in 17 patients (11.7%); three patients (2%) had platelet-specific antibodies in addition to HLA antibodies; in two patients panreactive platelet antibodies were detectable. All 17 patients had a history of previous transfusions or pregnancy. We did not observe primary immunization in patients transfused exclusively with filtered (leukodepleted) blood products. Our data suggest that alloimmunization in patients with a negative risk history can be prevented by the exclusive use of leukodepleted blood components.

[Quality control in producing thrombocytapheresis preparations with minimal leukocyte contamination]

Passenger white blood cells (WBC) in platelet concentrates (PC) produced by apheresis can cause a variety of adverse effects in recipients after platelet transfusion. With new technologies (LRS, leukocyte reduction system), the preparation of PC with a low WBC contamination is possible without consecutive filtration. In a prospective examination, we compared the effect of LRS apheresis on the donor, the quality of the resulting PC (n = 120), and the platelet increment in the corresponding recipients with conventionally prepared PC (n = 27). In LSR apheresis, no serious adverse effects on the donors were observed, but the post-donation absolute numbers of lymphocytes were reduced from 1,787 +/- 505/microliter to 1,402 +/- 383/microliter (p < 0.001). Comparable results were observed in non-LRS donors. The collection efficiency of the LRS procedures was 50.0 +/- 7.6%, resulting in a yield of 4.25 +/- 1.03 x 10(11) platelets/PC. Flow cytometric examination concerning the expression of platelet glycoproteins in LRS PC showed no elevation in mean fluorescence of CD 62 (6 +/- 4) or CD 63 (9 +/- 3) in comparison to non-LRS PC (mean fluorescence CD 62: 7 +/- 4, CD 63: 8 +/- 3). Median leukocyte contamination of the LRS PC was 0.41 x 10(5) (range 0.06-8.5 x 10(5)) WBC/unit. In 43 recipients, the 24-hour corrected count increments (CCI) after transfusion of LRS PC (12,530 +/- 8,761) showed no significant differences when compared with the CCI in 20 recipients of non-LRS PC (13,133 +/- 9,812, p = 0.75). LRS apheresis seems to be safe procedure, resulting in PC with low WBC contamination, which causes adequate CCI values after transfusion.

Flow cytometric detection of platelet-reactive antibodies and application in platelet crossmatching

BACKGROUND

Alloimmunization against HLA or platelet antigens can cause refractoriness to platelet transfusions in multiply transfused patients. Crossmatching of platelet concentrates is effective in overcoming this problem.

STUDY DESIGN AND METHODS

A flow cytometric assay was used for simultaneous detection of lymphocyte-reactive and platelet-reactive antibodies in a single sample using fluorescein isothiocyanate-labeled anti-IgG. This assay was compared with the monoclonal antibody-specific immobilization of platelet antigens (MAIPA) assay in selected sera containing HLA and platelet antibodies. In a further study, this assay was compared with lymphocytotoxicity test results from thrombocytopenic patients, for whom platelet concentrates were ordered. The results of both assays were then correlated with the 1-hour corrected count increment, with a corrected count increment greater then 7500 considered as an adequate transfusion response.

RESULTS

The results of the MAIPA and flow cytometric assay in detecting platelet-reactive antibodies correlated well (p<0.0001, r = 0.84). The sensitivity and specificity of the flow cytometric assay in detecting platelet-reactive antibodies were 94.7 and 96.3 percent, when the MAIPA assay was taken as a reference. In unselected sera from patients, the sensitivity and specificity of the flow cytometric assays were, respectively, 72.7 and 91.7 percent in detecting lymphocyte-reactive antibodies and 70.6 and 77.7 percent in detecting platelet-reactive antibodies, when the lymphocytotoxicity test was used as a reference. With regard to an adequate transfusion response, the sensitivities and efficiencies were 20.0 and 82.1 percent, 33.3 and 84.3 percent, and 70.0 and 88.6 percent for the lymphocytotoxicity test and the lymphocyte-reactive and platelet-reactive flow cytometric assays, respectively.

CONCLUSION

Flow cytometric crossmatching appears to be an effective method of detecting platelet-reactive antibodies that may affect the success of platelet transfusions. This procedure is well-suited for routine conditions and can be performed within 2 hours.

Reduktion des Gehaltes an Methylenblau (MB) in MB-photooxidiertem Plasma durch Filtration

<i>Hintergrund: </i>Eine Möglichkeit der Virusinaktivierung von gefrorenem Frischplasma (GFP) ist das Methylenblau(MB)-Photooxidationsverfahren. Obwohl die Toxizität von MB als gering eingestuft wird, könnte seine Reduktion im Plasma vor der Transfusion sinnvoll sein, zumindest bei bestimmten Pa-tientengruppen oder bei Massivtransfusionen. <i>Material und Methode: </i>Um zu untersuchen, ob durch den Einsatz von Leukozytenfiltern die MB-Konzentration zu senken ist, wurden von uns Plasmen mittels des MB-Photooxidationsverfahrens behandelt und anschlieβend über entsprechende Filter zell-depletiert. 5 Plasmapools aus je 5 aufgetauten GFP à 200 ml wurden hergestellt. Jeder dieser Pools (1000 ml) wurde wie folgt aufgeteilt bzw. weiterbehandelt: 200 ml wurden unbehan-delt wieder bei -40 °C eingefroren (Gruppe I), die restlichen 800 ml wurden nach Zusatz von MB (Endkonzentration: 1 µmol/l) photooxidiert. 200 ml dieses MB-Plasmas wurden un-gefiltert eingefroren (Gruppe II), 600 ml durch einen Leuko-zytendepletionsfilter für Plasma (LPS 2®, Pall Biomedizin, Dreieich, Deutschland) gefiltert und anschlieβend eingefroren (Gruppe III). Die MB-Konzentration wurde photometrisch bei 660 nm bestimmt. <i>Ergebnisse: </i>Durch die Behandlung mit MB wurde der Faktor-VIII-Gehalt der Plasmen signifikant gesenkt (17 + 9%). Bei unverändertem Faktorengehalt (V und VIII) bewirkte die Filtration neben einer Leukozytendepletion (95 ± 4%) eine MB-Reduktion der ersten 200 ml filtrierten Plasmas um ca. 75%. Bei der Filtration von mehr als 200 ml nahm die Kapazität des eingesetzten Filters kontinuierlich ab. <i>Schluβfolgerungen: </i>Im Rahmen von Transfusionen mit MB-Plasma kann die MB-Belastung des Patienten durch eine vor-herige Filtration signifikant verringert werden. Die Kapazität des Filters zur MB-Aufnahme ist dabei jedoch begrenzt.

Mobilization of CD34-positive tumour cells in a patient with testicular mixed germ cell tumour

Tumour cells from a patient with recurrent testicular germ cell cancer and bone marrow infiltration were found to express CD33 and CD34 in the absence of other haemopoiesis-associated antigens. After myelosuppression and treatment with G-CSF for stem cell mobilization, CD34-positive tumour cells were detected in the peripheral blood in addition to normal haemopoietic progenitor cells. The tumour cells were decreased in the leukapheresis product. Retrospectively, the appearance of tumour cells in the peripheral blood after stem cell mobilization was the first indication of impending relapse.

Einfluß von Gamma-Bestrahlung auf die Qualität und Lagerungsstabilität von Thrombozyten

Transfusion-associated graft-versus-host disease (TA-GvHD) is a rare, but life-threatening complication of blood transfusion. It can be prevented by irradiation of blood components. It has been shown that the stability of red cells is decreased after irradiation. We therefore wanted to determine whether irradiation induces membrane glycoprotein alteration of platelets or decreases the stability of platelet concentrates. Ten platelet concentrates were produced by standard procedures and ali-quoted; one of each pair was irradiated with 30 Gy before storage. Both aliquots were stored for 5 days, and GP lb, GMP140 (by flow cytometry) as well as LDH, pH, β-thromboglobulin, and PF4 were determined at days 1,3 and 5. During storage a loss of GP lb of about 25%, an increase of GMP 140 (50%) and LDH (30%) was observed. No difference between irradiated and nonirradiated platelet concentrates was found. Our data suggest that irradiation with 30 Gy has no significant influence on the quality of platelet concentrates.

Durchflußzytometrische Untersuchungen zur Verträglichkeit von Thrombozytentransfusionen

We developed a flow cytometric crossmatch (FC-CM) for the selection of compatible donors for thrombocytopenic patients and compared its predictive value for a successful platelet transfusion in a prospective study to LCT. In case of alloimmunization, FC-CM detects bound IgG on lymphocytes and/or platelets after incubation with patient’s serum. Based on the posttransfusion increment in 122 transfusions, the specifity was 81% for LCT and 96% for FC-CM (platelet gate). In conclusion, the FACS-CM is a rapid and useful assay for donor selection in cases of alloimmunized patients with lymphocytotoxic and/or platelet-specific antibodies.

Leukocyte Depletion of Fresh Frosen Plasma

Bisher wurde davon ausgegangen, daβ Leukozyten in gefrorenem Frischplasma (FFP) den Einfrier-/Auftauvorgang nicht überstehen. In einigen Fallen wurden jedoch Graft-versus-Host-Reaktionen im Zusammenhang mit Plasmatransfusionen beobachtet. Weiterhin finden sich nach dem Auftauen noch vitale Zellen mit zum Teil proliferativer Fähigkeit im Stammzellassay. In einer prospektiven Studie wurden 40 mittels «Top-and-Bottom»-Präparation hergestellte Frischplasmen auf ihren Leukozyten- und Thrombozytengehalt vor [Leukozyten: 4.0 × 10⁶ (1-10)/Plasma; Thrombozyten 1.6 × 10⁹ (0.1-9)/Plasma] und nach [Leukozyten: 2 ×10⁵ (0.2-24)/Plas-ma;Thrombozyten: 3 ×10⁸ (0.6-11)/Plasma] einer Gefrierphase (-40 °C für minde-stens 2 Wochen) und nach einer anschlieβenden Leukozytenfiltration untersucht. Die Thrombozyten wurden in der Neubauer-Kammer (Verdünnung 1:10) und die Leukozyten in der Nageotte-Kammer (Verdünnung 1 : 5 in Ammoniumoxalat) gezählt. Die Faktoren V und VIII wurden durch die Filtration nicht beeinfluβt. Der Gehalt an Plättchenfaktor-4 (85%) und β-Thromboglobulin (35%) wurde durch die Filtration signifikant reduziert. Auβerdem wurden zellreiche Frischplasmen (n = ll) hergestellt und ohne vorheriges Einfrieren gefiltert, um die Depletionskapazität des Filters zu verifizieren. Die Ausgangskonzentrationen an Leukozyten konnten dabei um mehr als 4 Log₁₀₎-Stufen gesenkt werden [von (6,0 ± 2,6) ×10⁸ Leukozyten/ Plasma auf (2,6 ± 0,4) × 10⁴]. Die Filtration von Plasmen bietet die Möglichkeit, Präparate mit einem geringen Restzellgehalt herzustellen; ob das Risiko von Allo-immunisierungen und die Infektiosität zu senken sind, bleibt noch zu untersuchen. Zumindest bei angeschlossenem Virusinaktivierungsverfahren kann die Senkung des Restzellgehaltes im Ausgangsmaterial eine Optimierung darstellen, da zell-ständige Viren durch diese Verfahren nicht ausreichend erfaβt werden.