An automated approach to determine antibody endpoint titers for COVID-19 by an enzyme-linked immunosorbent assay.

While a variety of therapeutic options continue to emerge for COVID-19 treatment, convalescent plasma (CP) has been used as a possible treatment option early in the pandemic. One of the most significant challenges with CP therapy, however, both when defining its efficacy and implementing its approach clinically, is accurately and efficiently characterizing an otherwise heterogenous therapeutic treatment. Given current limitations, our goal is to leverage a SARS antibody testing platform with a newly developed automated endpoint titer analysis program to rapidly define SARS-CoV-2 antibody levels in CP donors and hospitalized patients. A newly developed antibody detection platform was used to perform a serial dilution enzyme-linked immunosorbent assay (ELISA) for immunoglobulin (Ig)G, IgM, and IgA SARS-CoV-2 antibodies. Data were then analyzed using commercially available software, GraphPad Prism, or a newly developed program developed in Python called TiterScape, to analyze endpoint titers. Endpoint titer calculations and analysis times were then compared between the two analysis approaches. Serial dilution analysis of SARS-CoV-2 antibody levels revealed a high level of heterogeneity between individuals. Commercial platform analysis required significant time for manual data input and extrapolated endpoint titer values when the last serial dilution was above the endpoint cutoff, occasionally producing erroneously high results. By contrast, TiterScape processed 1008 samples for endpoint titer results in roughly 14 minutes compared with the 8 hours required for the commercial software program analysis. Equally important, results generated by TiterScape and Prism were highly similar, with differences averaging 1.26 ± 0.2 percent (mean ± SD). The pandemic has created unprecedented challenges when seeking to accurately test large numbers of individuals for SARS-CoV-2 antibody levels with a rapid turnaround time. ELISA platforms capable of serial dilution analysis coupled with a highly flexible software interface may provide a useful tool when seeking to define endpoint titers in a high-throughput manner. Immunohematology 2021;37:33-43.While a variety of therapeutic options continue to emerge for COVID-19 treatment, convalescent plasma (CP) has been used as a possible treatment option early in the pandemic. One of the most significant challenges with CP therapy, however, both when defining its efficacy and implementing its approach clinically, is accurately and efficiently characterizing an otherwise heterogenous therapeutic treatment. Given current limitations, our goal is to leverage a SARS antibody testing platform with a newly developed automated endpoint titer analysis program to rapidly define SARS-CoV-2 antibody levels in CP donors and hospitalized patients. A newly developed antibody detection platform was used to perform a serial dilution enzyme-linked immunosorbent assay (ELISA) for immunoglobulin (Ig)G, IgM, and IgA SARS-CoV-2 antibodies. Data were then analyzed using commercially available software, GraphPad Prism, or a newly developed program developed in Python called TiterScape, to analyze endpoint titers. Endpoint titer calculations and analysis times were then compared between the two analysis approaches. Serial dilution analysis of SARS-CoV-2 antibody levels revealed a high level of heterogeneity between individuals. Commercial platform analysis required significant time for manual data input and extrapolated endpoint titer values when the last serial dilution was above the endpoint cutoff, occasionally producing erroneously high results. By contrast, TiterScape processed 1008 samples for endpoint titer results in roughly 14 minutes compared with the 8 hours required for the commercial software program analysis. Equally important, results generated by TiterScape and Prism were highly similar, with differences averaging 1.26 ± 0.2 percent (mean ± SD). The pandemic has created unprecedented challenges when seeking to accurately test large numbers of individuals for SARS-CoV-2 antibody levels with a rapid turnaround time. ELISA platforms capable of serial dilution analysis coupled with a highly flexible software interface may provide a useful tool when seeking to define endpoint titers in a high-throughput manner. Immunohematology 2021;37:33­43.

Addition of rituximab to CHOP-like chemotherapy in first line treatment of primary mediastinal B-cell lymphoma.

BACKGROUND: The addition of rituximab (R) to CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone) -like therapy has improved survival in primary mediastinal B-cell lymphoma (PMBCL) patients. However, these results were obtained in young low risk patients and a reevaluation in an unselected patient cohort is warranted. METHODS: In this study, we analyzed 80 PMBCL patients treated with a CHOP-based regimen with and without rituximab. RESULTS: In the non-rituximab cohort 10-year progression free survival (PFS) was 67% and 10-year overall survival (OS) was 72% versus a PFS of 95% and a OS of 92% in the rituximab group, PFS P = 0.001, OS P = 0.023. A subgroup PFS analysis by international prognostic index (IPI) risk revealed that all risk groups benefit from addition of rituximab to induction chemotherapy. In addition, OS probability was higher in the group of non-low risk patients who were treated with rituximab compared to those patients who did not receive rituximab (P = 0.035). In multivariate analysis, only addition of rituximab to induction chemotherapy and reaching complete remission (CR) after first line therapy had a beneficial effect on both PFS and OS, whereas IPI, age, upfront high dose (HD) chemotherapy/autologous blood stem cell transplantation (ABSCT) and rituximab maintenance had no impact on survival. CONCLUSIONS: Our data demonstrate a survival benefit in unselected PMBCL patients treated with CHOP-like induction regimen and additional rituximab independently of the IPI risk score.

Performance assessment and benchmarking of autologous peripheral blood stem cell collection with two different apheresis devices.

BACKGROUND: Collection of peripheral blood stem cells (PBSCs) for autologous transplantation is a well-established process. As a new generation of leukapheresis (LP) machines has been launched, measures of benchmarking and quality control need to be defined in order to ensure consistent collection performance. OBJECTIVES: The goal of this project was to establish and evaluate a benchmarking system for autologous PBSC collection. METHODS: This retrospective study evaluated PBSC collection data of 198 patients with symptomatic multiple myeloma in first-line therapy who underwent LP in 2013 and 2014 at our institution. Half the patients in 2014 were assigned randomly to undergo LP with the new Terumo BCT Spectra Optia (Terumo BCT, Garching, Germany), while the COBE Spectra (Terumo BCT) was used in all other cases. In 2014, we implemented a previously described formula for predicting daily CD34+ cell collection. As a benchmark, we developed the performance ratio: collected/predicted CD34+ cells. RESULTS: There was no significant difference in the number of collected CD34+ cells, the collection efficiency (collected/processed CD34+ cells) and performance ratio between the two collection devices and between LP procedures in 2013 and 2014. CONCLUSIONS: We present a comprehensive benchmarking tool that is easy to implement, requires minimal expense and allows specific adjustment of LP parameters for optimisation of LP performance. With this approach, we could confirm the equal efficiency of the two compared apheresis systems.

Minimal renal toxicity after Rituximab DHAP with a modified cisplatin application scheme in patients with relapsed or refractory diffuse large B-cell lymphoma.

BACKGROUND: Rituximab (R) in combination with DHAP is a widely accepted salvage regimen for patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL). A common adverse effect of this protocol is renal toxicity which may result in treatment discontinuation. Assuming that a lower single dose of cisplatin over several days would reduce renal toxicity, our institution has chosen to administer cisplatin in a dosage of 25 mg/m(2) per day as a 3-h infusion over 4 consecutive days. METHODS: In this study, we analyzed the renal function of 122 patients with relapsed or refractory DLBCL treated with R-DHAP at our institution. Overall, 256 R-DHAP cycles were administered. 31 (25%), 61 (50%), 14 (12%) and 16 (13%) patients received one, two, three or four R-DHAP courses, respectively. RESULTS: A glomerular filtration rate (GFR) decrease was observed after each R-DHAP cycle. However, in none of the subgroups the median GFR was lower than 60 ml/min/1.73 m(2). In most patients, only renal impairment stage I and II was observed. Renal impairment stage III was seen in 10% and stage IV only in 1% of patients. CONCLUSION: We conclude that a modified R-DHAP regimen with administration of cisplatin 25 mg/m(2) over 4 consecutive cycles leads only to minimal renal toxicity.

Long-term ovarian function in women treated with CHOP or CHOP plus etoposide for aggressive lymphoma.

BACKGROUND: Chemotherapy-associated ovarian damage comprises not only infertility, but also premature menopause. The latter has been reported as a consequence of alkylating chemotherapy for breast cancer or Hodgkin's lymphoma. In this study, we assessed the long-term impact of CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone)-like regimens on ovarian function in patients with aggressive non-Hodgkin lymphoma (NHL). PATIENTS AND METHODS: Long-term survivors after CHOP or CHOP plus etoposide (CHOEP) treatment within the Mabthera International Trial or the NHL-B1 trial of the German NHL Study Group were requested to respond to a questionnaire and to consent to blood sampling for hormone assessment. RESULTS: A total of 46 of 81 contacted patients with a median age of 32.5 years at the time of enrolment into the aforementioned clinical trials responded to the questionnaire. The median follow-up after completion of treatment was 14 years. Last menstrual bleeding occurred significantly earlier in patients compared with the general population (47 versus 51 years, P < 0.0001). In comparison to the distribution of menopausal symptoms in the general population, the percentage of women with moderate or severe menopausal symptoms was increased. In 23 patients who agreed to participate in laboratory analyses, anti-Muller hormone as a marker of ovarian reserve was decreased when compared with correspondent age groups of the general population. CONCLUSION: Although most female patients regain fertility after CHOP-like chemotherapy, late ovarian impairment occurs frequently. Therefore, awareness of such delayed side-effects at the time of counselling is of importance.

The influence of rituximab, high-dose therapy followed by autologous stem cell transplantation, and age in patients with primary CNS lymphoma.

For patients with diffuse large B cell lymphoma without the involvement of the CNS, the addition of rituximab to standard chemotherapy has significantly improved survival. In this single-center, retrospective analysis, a total of 81 primary CNS lymphoma (PCNSL) patients treated in our institution between 2000 and 2011 were included. Beside first-line chemotherapy with or without rituximab, we evaluated the impact of age (≤/>60 years), autologous stem cell transplantation (ASCT +/-), and other factors upon overall survival (OS) and progression-free survival (PFS). In patients treated with rituximab (n = 27), 3-year OS was 77.8 % (95 % confidence interval (CI) 62-93 %). In contrast, in patients treated without rituximab (n = 52), 3-year OS was only 39.9 % (CI 27-53 %, Fig. 1). The difference in OS was significant in the univariate (p = 0.002) as well as in the multivariate analysis (p = 0.049, hazard ratio (HR) = 0.248). Patients ≤60 years of age (n = 28) had a 3-year OS of 78.2 % (CI 63-94 %); in patients >60 years (n = 51), 3-year OS was 38.7 % (CI 25-52 %). Patients who received high-dose therapy and ASCT had a 3-year OS of 85.2 % (CI 72-99 %), and 65.1 % were alive up to the time of analysis (range 9-131 months). Without ASCT, median OS was only 16 months (CI 11-21) and 3-year OS was 35.2 % (CI 22-48 %). Age and ASCT were significantly associated with better OS in univariate (p = 0.002 and p < 0.001) as well in multivariate analysis (p = 0.004, HR = 0.023 and p = 0.001, HR = 0.014). Rituximab treatment, ASCT, and age are independent prognostic factors for OS in the first-line treatment of PCNSL.

Autologous stem cell transplantation for elderly patients with newly diagnosed multiple myeloma in the era of novel agents.

BACKGROUND: High-dose therapy (HDT) with autologous stem cell transplantation (ASCT) is considered the standard of care for multiple myeloma (MM) patients <65 years. Safety and outcome of ASCT for patients >65 years is currently uncertain, especially since the introduction of novel agents for induction and maintenance therapy. Furthermore, there are no conclusive data available on risk assessment in elderly patients treated with HDT. PATIENTS AND METHODS: We retrospectively analyzed 202 patients ≥60 years with newly diagnosed MM who underwent ASCT at our institution. Patients were stratified by age into three groups (60-64, 65-69 and 70-75 years). For safety assessment, we compared data about hospitalization, hematopoetic reconstitution and early mortality. Remission before and after ASCT was analyzed according to age and application of novel agents. Event-free (EFS) and overall survival (OS) were analyzed to identify impact of age, remission before/after ASCT and maintenance therapy as well as ISS score and cytogenetic aberrations on outcome in elderly patients. RESULTS: The assessment of safety, remission before/after ASCT as well as EFS and OS showed no significant differences between the three groups (median EFS: 60-64 years: 27 months; 65-69 years: 23 months; 70-75 years: 23 months; median OS: not reached). Patients receiving novel agents as part of induction therapy achieved significantly higher nCR + CR rates than patients treated without novel agents. In Cox regression analysis, ISS and cytogenetics as well as remission after ASCT had the highest prognostic impact on EFS and OS. Maintenance therapy was associated with longer EFS in uni- and multivariate analyses. CONCLUSION: ASCT is feasible for selected patients >65 and >70 years without increased mortality. Age at transplantation has no prognostic significance on outcome after ASCT. Novel agents during induction therapy and maintenance therapy improves outcome of older patients eligible for ASCT. ISS and cytogenetic analysis should be carried out routinely for risk assessment.

The impact of allogeneic stem cell transplantation on the natural course of poor-risk chronic lymphocytic leukemia as defined by the EBMT consensus criteria: a retrospective donor versus no donor comparison.

BACKGROUND: In a single-center retrospective donor versus no-donor comparison, we investigated if allogeneic stem cell transplantation (alloSCT) can improve the dismal course of poor-risk chronic lymphocytic leukemia (CLL). PATIENTS AND METHODS: All patients with CLL who were referred for evaluation of alloSCT within a 7-year time frame and had a donor search indication according to the EBMT criteria or because of Richter's transformation were included. Patients for whom a matched donor could be found within 3 months (matches) were compared with patients without such a donor (controls). Primary end point was overall survival measured from the 3-month landmark after search initiation. RESULTS: Of 105 patients with donor search, 97 (matches 83; controls 14) were assessable at the 3-month landmark. Matches and controls were comparable for age, gender, time from diagnosis, number of previous regimens, and remission status. Disregarding if alloSCT was actually carried out or not, survival from the 3-month landmark was significantly better in matches versus controls [hazard ratio 0.38, 95% confidence interval (CI) 0.17-0.85; P = 0.014]. The survival benefit of matches remained significant on multivariate analysis. CONCLUSION: This study provides first comparative evidence that alloSCT may have the potential to improve the natural course of poor-risk CLL as defined by the EBMT criteria.

Familial Mediterranean fever in Germany: clinical presentation and amyloidosis risk.

OBJECTIVE: To characterize patients with familial Mediterranean fever (FMF) with and without AA amyloidosis living in Germany. METHOD: Clinical and genetic data from 64 FMF patients were analysed for amyloidosis risk factors. RESULTS: Fifty-five patients (85%) were of Turkish or Armenian origin. Thirty-one patients (48%) developed FMF symptoms before the age of 16 years. Sixteen patients (26%) became symptomatic after age 20. Symptoms reported were peritonitis (95%), fever (78%), pleuritis (59%), arthralgia (60%), arthritis (32%), erysipelas-like erythema (23%), and vasculitis (8%). FMF diagnosis was delayed for a median of 8.0 years. Genetic analysis confirmed M694V as the most prevalent Mediterranean fever (MEFV) gene mutation in 46 out of 59 patients (78%). M694V homozygosity was associated with an earlier FMF onset (median age 5.5 years, p = 0.0001) and a higher prevalence of peritonitis (p = 0.007) and pleuritis (p = 0.0007) compared to patients without an M694V mutation. AA amyloidosis was detected in 16 patients (25%) at a median age of 36.5 years and tended to be associated with a higher age at disease onset (p = 0.062) and a higher FMF activity score (p = 0.093). AA amyloidosis was significantly associated with a higher age at FMF diagnosis (p = 0.0022). CONCLUSIONS: Clinical symptoms of FMF-affected migrants living in Germany resemble those observed in their home country. In particular, patients with an onset of FMF symptoms after age 20 and a later FMF diagnosis have a high risk of AA amyloidosis. Symptomatic patients who originate from countries with a higher FMF prevalence should be screened for FMF and proteinuria.

A novel human glycoprotein ACA is an upstream regulator of human hematopoiesis.

A central issue in stem cell biology is a better understanding of the molecular mechanisms that regulate self-renewal of human hematopoietic stem cells (HSCs). Control of the specific function of HSCs like self-renewal and differentiation might be regulated by a common set of critical genes. However, the regulation among these genes is yet to be elucidated. Here, we show that activation by a novel human GPI-linked glycoprotein ACA at the surface of human peripheral blood progenitor cells induces via PI3K/Akt/mTor/PTEN upregulation of WNT, Notch1, Bmi-1 and HoxB4 genes thus, promoting self-renewal and generation of primitive HSCs. ACA-generated self-renewing cells retained their lympho-myeloid repopulating potential in NOD/SCID mouse xeno-transplantation model with long term functional capacity. We conclude that ACA is an essential regulator of the genes involved in maintaining hematopoiesis and its use in clinical praxis could overcome many of the barriers present so far in transplantation medicine.

Rituximab Chimeric Anti-CD20 Monoclonal Antibody Therapy for Relapsed Indolent Lymphoma: Half of Patients Respond to a Four-Dose Treatment Program.

PURPOSE: The CD20 antigen is expressed on more than 90% of B-cell lymphomas. It is appealing for targeted therapy, because it does not shed or modulate. A chimeric monoclonal antibody more effectively mediates host effector functions and is itself less immunogenic than are murine antibodies. PATIENTS AND METHODS: This was a multiinstitutional trial of the chimeric anti-CD20 antibody, IDEC-C2B8. Patients with relapsed low grade or follicular lymphoma received an outpatient treatment course of IDEC-C2B8 375 mg/m2 intravenously weekly for four doses. RESULTS: From 31 centers, 166 patients were entered. Of this intent-to-treat group, 48% responded. With a median follow-up duration of 11.8 months, the projected median time to progression for responders is 13.0 months. Serum antibody levels were sustained longer after the fourth infusion than after the first, and were higher in responders and in patients with lower tumor burden. The majority of adverse events occurred during the first infusion and were grade 1 or 2; fever and chills were the most common events. Only 12% of patients had grade 3 and 3% grade 4 toxicities. A human antichimeric antibody was detected in only one patient. CONCLUSION: The response rate of 48% with IDEC-C2B8 is comparable to results with single-agent cytotoxic chemotherapy. Toxicity was mild. Attention needs to be paid to the rate of antibody infusion, with titration according to toxicity. Further investigation of this agent is warranted, including its use in conjunction with standard chemotherapy.

Excellent long-term survival of 170 patients with Waldenström's macroglobulinemia treated in private oncology practices and a university hospital.

The purpose of this study was to compare treatment and outcome of patients with Waldenström's macroglobulinemia (WM) in four private oncology practices (PP) and a university hospital (UH) in southwest Germany. We retrospectively reviewed the charts of all patients with WM of the last two decades of four PP in Mannheim, Heidelberg, Karlsruhe, and Speyer and the Department of Hematology of the University of Heidelberg. One hundred seventy patients could be identified, 74 from PP, 96 from the UH. Median age was 63.3 years. Patients from PP were older (median 65.3 vs. 62.5 years, p = 0.01). Only 54 % of patients from PP have received treatment during the observation time, as compared to 78.1 % of the UH (p < 0.001). In PP, 35 % of treated patients have received rituximab, as compared to 62.6 % of the patients of the UH (p < 0.001). Sixty percent of treated patients of PP have received bendamustine, as compared to only 8 % of the patients of the UH (p < 0.001). Time to first treatment was significantly shorter in patients from the UH compared to PP (median 13.7 vs. 52.9 months, p = 0.05). A trend towards a better overall survival was observed for patients treated with a rituximab-containing first-line regimen. The International Prognostic Scoring System for WM had significant prognostic value. Median overall survival was 25.0 years and did not differ between PP and UH. Despite different treatment strategies between PP and UH today overall survival of patients with WM is excellent, and better than previously reported.

Primary mediastinal B-cell lymphoma treated with CHOP-like chemotherapy with or without rituximab: results of the Mabthera International Trial Group study.

BACKGROUND: The aim of this subgroup analysis of the Mabthera International Trial Group study was to evaluate the impact of chemotherapy and rituximab in primary mediastinal B-cell lymphoma (PMBCL) in comparison to other diffuse large B-cell lymphoma (DLBCL). METHODS: Patients were randomly assigned to six cycles of CHOP-like regimens with or without rituximab. RESULTS: Of 824 patients enrolled, 87 had PMBCL and 627 other types of DLBCL. Rituximab increased the rates of complete remission (unconfirmed) in both PMBCL (from 54% to 80%, P = 0.015) and DLBCL (from 72% to 87%, P < 0.001). In PMBCL, rituximab virtually eliminated progressive disease (PD) (2.5% versus 24%, P < 0.001), whereas without rituximab, PD was more frequent in PMBCL than in DLBCL (24% versus 10%, P = 0.010). With a median observation time of 34 months, 3-year event-free survival (EFS) was improved by rituximab for PMBCL (78% versus 52%, P = 0.012) and for DLBCL (81% versus 61%, P < 0.001). Overall survival benefit was similar for DLBCL (93% versus 85%, P < 0.001) and PMBCL (89% versus 78%, P = 0.158). CONCLUSION: In young patients with PMBCL (age-adjusted International Prognostic Index 0-1), rituximab added to six cycles of CHOP-like chemotherapy increases response rate and EFS to the same extent as other DLBCL. The combination of rituximab with CHOP chemotherapy is an effective treatment in PMBCL with good prognosis features.

Autoantigens are translocated into small apoptotic bodies during early stages of apoptosis.

A dysregulation of apoptosis or an ineffective clearance of apoptotic material is suspected to be involved in the pathogenesis of systemic lupus erythematodes. Subcellular fragments such as apoptotic bodies (ABs) have been recognized as modulators of intercellular communication and immune function. In this context, we have been interested whether nuclear and cytoplasmic antigens are relocated into ABs. In the present study, we characterized ABs isolated from apoptozing lymphoblasts. We found an accumulation of the linker-histone (histone 1) as well as the core-histones (histone 2A, histone 2B, histone 3, histone 4) in ABs. Further, they contained DNA, RNA and the ribonuclear protein La/SSB. Proteins such as cytochrome c, HSP 70, prohibitin, p53, nuclear matrix antigen or lamin B were excluded from ABs. The content of ABs differed from that observed in membrane microparticles isolated from viable cells. Formation of ABs occurred early during apoptosis. It was observed before DNA-degradation or phosphatidylserine exposure was detected. ABs were engulfed by monocyte-derived phagocytes. These findings suggest that immunogenic molecules are actively translocated into ABs followed by a rapid engulfment of the latter by environmental phagocytes. In autoimmune diseases, a defect in the clearance of ABs or AB formation may contribute to the development of autoimmunity.

Characteristics of relapse after autologous stem-cell transplantation for follicular lymphoma: a long-term follow-up.

BACKGROUND: Pattern and outcome of disease recurrence after autologous stem-cell transplantation (autoSCT) for follicular lymphoma (FL) is not well known. PATIENTS AND METHODS: Relapse cases were identified from 241 consecutive patients autografted for disseminated untransformed FL from 1990 to 2002 in three institutions. Prognostic factors for relapse and outcome after relapse were analyzed by log-rank comparisons and Cox regression analyses. RESULTS: One hundred and three relapses occurred. The 10-year relapse probability was 47%. Median time from autoSCT to relapse was 20 (2-128) months. Only three relapses were observed later than 6 years posttransplant. Median survival after relapse was 8.3 years. Patients with disease recurrence within 1 year from transplant and those who had received autoSCT as second-line treatment had significantly reduced survival by multivariate analysis, whereas Follicular Lymphoma International Prognostic Index score, age, remission status at autoSCT, high-dose regimen, and ex vivo purging had no impact. CONCLUSIONS: FL recurrence after autoSCT follows a biphasic pattern with continuing relapse during the first 6 years and only few events thereafter. The prognosis after relapse is relatively good and appears to be comparable to that of disease recurrence after standard treatment. The situation is less favorable for patients who relapse within the first posttransplant year.

Commercial LightCycler-based quantitative real-time PCR compared to nested PCR for monitoring of Bcl-2/IgH rearrangement in patients with follicular lymphoma.

Translocation of chromosomes 14 and 18 [t(14;18)] for detection of minimal residual disease in follicular lymphoma patients can be analyzed by nested polymerase chain reaction (PCR) or by quantitative PCR like LightCycler-based assays. We have compared both methods in blood and bone marrow samples of 28 patients enrolled in a clinical study on immunochemotherapy. In 42% of samples, the bcl2-IgH rearrangement was detectable by nested PCR, but not by LightCycler PCR. Nested PCR was able to reveal a significant drop in positive bone marrow or peripheral blood samples after therapy. In contrast, with LightCycler PCR, the detected drop in t(14;18)-positive cells did not reach statistical significance. The majority of patients showed positive results with nested PCR of peripheral blood or bone marrow without any associations to presence or absence of histological bone marrow (BM) infiltration by lymphoma cells. With LightCycler PCR, the numbers of positive cells were higher in samples from patients with BM infiltration of lymphoma cells (1.9 x 10(-2)) compared to samples from patients without involvement (4.08 x 10(-5)). A similar trend was seen in samples derived from the peripheral blood. Positivity for t(14;18) after therapy in two patients correlated with clinical relapse 6 months later. The data shown here demonstrate a lower sensitivity of LightCycler vs. nested PCR for detection of t(14;18). The usefulness of nested PCR for t(14;18) for risk stratification after primary therapy has to be validated in larger trials.

[Current diagnostic and therapy of light chain amyloidosis]. / Aktuelle Diagnostik und Therapie der Leichtkettenamyloidose.

Amyloidoses are protein-folding disorders in which soluble proteins are deposited as insoluble fibrillar aggregates due to a change in protein conformation. This might occur intra- or extracellularly, systemically or in a localized manner. The light chain type is the most common form of systemic amyloidoses and has the worst prognosis. The underlying disease is a monoclonal, mostly non-malignant plasma cell disorder. The causative treatment is the reduction of the amyloidogenic light chains with conventional or high-dose chemotherapy. Meanwhile, the"new drugs" used in multiple myeloma are also successfully applied. Early diagnosis is important to be able to treat patients effectively and to avoid further deterioration of organ function. Patients with newly diagnosed amyloidosis should be referred to a specialized center for consultation, diagnosis and treatment recommendation.

VEGF expression by mesenchymal stem cells contributes to angiogenesis in pancreatic carcinoma.

Little is known about the factors that enable the mobilisation of human mesenchymal stem cells (MSC) from the bone marrow into the blood stream and their recruitment to and retention in the tumour. We found specific migration of MSC towards growth factors present in pancreatic tumours, such as PDGF, EGF, VEGF and specific inhibitors Glivec, Erbitux and Avastin interfered with migration. Within a few hours, MSC migrated into spheroids consisting of pancreatic cancer cells, fibroblasts and endothelial cells as measured by time-lapse microscopy. Supernatant from subconfluent MSC increased sprouting of HUVEC due to VEGF production by MSC itself as demonstrated by RT-PCR and ELISA. Only few MSCs were differentiated into endothelial cells in vitro, whereas in vivo differentiation was not observed. Lentiviral GFP-marked MSCs, injected in nude mice xenografted with orthotopic pancreatic tumours, preferentially migrated into the tumours as observed by FACS analysis of green fluorescent cells. By immunofluorescence and intravital microscopic studies, we found the interaction of MSC with the endothelium of blood vessels. Mesenchymal stem cells supported tumour angiogenesis in vivo, that is CD31(+) vessel density was increased after the transfer of MSC compared with siVEGF-MSC. Our data demonstrate the migration of MSC toward tumour vessels and suggest a supportive role in angiogenesis.

Heterogeneity of mesenchymal stromal cell preparations.

As an archetype of human adult stem cells that can readily be harvested, enriched and expanded in vitro, mesenchymal stromal cells (MSC) have been reported to be of significance for regenerative medicine. The literature is replete with reports on their developmental potentials in pre-clinical model systems. Different preparative protocols have been shown to yield MSC-like cell cultures or even cell lines, from starting materials as diverse as bone marrow, fat tissue, fetal cord blood and peripheral blood. However, MSC are still ill-defined by physical, phenotypic and functional properties. The quality of preparations from different laboratories varies tremendously and the cell products are notoriously heterogeneous. The source and freshness of the starting material, culture media used, presence of animal sera, cytokines, cell density, number of passages upon culture, etc., all have a significant impact on the (1) cell type components and heterogeneity of the initial population, (2) differential expansion of specific subsets, with different potentials of the end products, and (3) long-term functional fate of MSC as well as other types of progenitor cells that are co-cultivated with them. Consequently, there is an urgent need for the development of reliable reagents, common guidelines and standards for MSC preparations and of precise molecular and cellular markers to define subpopulations with diverse pathways of differentiation and divergent potentials.

Isolation of human mesenchymal stromal cells is more efficient by red blood cell lysis.

BACKGROUND: Human mesenchymal stromal cells (MSC) have raised high hopes for tissue engineering and clinical therapy. Their isolation usually involves density fractionation of mononuclear cells (MNC) but this is difficult to standardize, especially under good manufacturing practice (GMP) conditions. MSC represent a heterogeneous mixture of cell types and the composition of subpopulations is affected by the initial steps of cell preparation. METHODS: This study describes a straightforward method for isolation of human MSC based on red blood cell (RBC) lysis with ammonium chloride. Colony formation was compared directly with Ficoll density fractionation and culture of an untreated whole bone marrow (BM) aspirate. RESULTS: After 7 days the number of fibroblastic colony-forming units (CFU-F) per milliliter of BM aspirate was slightly higher upon RBC lysis and the colonies were significantly larger compared with density fractionation, possibly because of maintenance of platelets. In contrast, colony formation was much lower in untreated BM. The heterogeneous composition of subpopulations was reflected by differences between the initial colonies with regard to growth pattern (tight or disperse) and cell morphology (round or elongated). This heterogeneous composition was not affected by the three different isolation methods. Furthermore, enrichment of CD271(+) cells resulted in the same morphologic heterogeneity. All cell preparations demonstrated the same immunophenotype using a panel of surface markers and displayed adipogenic and osteogenic differentiation potential. DISCUSSION: This study demonstrates that human MSC can be efficiently isolated by RBC lysis. This technique is faster and can be standardized more easily for clinical application of MSC.