Background: Dendritic cell (DC) vaccines can induce antitumor immune responses in patients with malignant diseases, while the most suitable DC culture conditions have not been established yet. In this study we compared monocyte derived human DC from conventional cultures containing GM-CSF and IL-4/TNF-α (IL-4/TNF-DC) with DC generated by the novel protocol using GM-CSF and IFN-α (IFN-DC).

The prognostic relevance of minimal residual disease (MRD) in patients with multiple myeloma is still an open question. In bone marrow, the level of residual myeloma cells is associated with treatment outcome, but the role of clonotypic cells in the peripheral blood (PB) for the prognosis of patients is not identified yet. In this study, we retrospectively analyzed MRD by quantitative real-time IgH-PCR (IgH-qPCR) in the PB of 42 patients undergoing high-dose therapy followed by autologous PB stem cell transplantation as first-line therapy for multiple myeloma. The MRD level of PB samples was in median 40-fold lower than in bone marrow samples, collected on the same day, with a wide intra- and interindividual variation (range, .4- to 4628-fold). The presence or absence of detectable MRD levels in PB did not correlate with the serological remission status. Still, patients with negative PCR results in PB 3 months after high-dose therapy and PB stem cell transplantation had lower International Staging System stage (P = .01), lower levels of β2-microglobulin (P = .02), higher hemoglobin levels (P = .01), and a prolonged event-free (median, 15 versus 4 months; P = .004) and overall (median, 52 versus 17 months; P = .03) survival. Importantly, by sequential monitoring of clonotypic cells in PB, in 19 of 29 patients (66%) with progressive disease, an increase of the 2IgH/β-actin ratio of at least 1 log step could be detected in median 4 months (range, .8 to 13 months) before the relapse was diagnosed on the basis of the European Group for Blood and Marrow Transplantation criteria. These patients with a molecular relapse in PB before a serological relapse had a significantly shorter overall survival than other patients (median, 17 months versus median not reached, P = .02). In conclusion, IgH-qPCR is a sensitive technique for the detection of clonotypic cells in PB, which precede clinical relapse. Future studies are needed to evaluate whether these circulating tumor cells play a role in promoting disease recurrence.

The outcome of T cell activation is determined by mechanisms that balance Ca2+ influx and clearance. Here we report that murine CD4 T cells lacking Neuroplastin (Nptn −/−), an immunoglobulin superfamily protein, display elevated cytosolic Ca2+ and impaired post-stimulation Ca2+ clearance, along with increased nuclear levels of NFAT transcription factor and enhanced T cell receptor-induced cytokine production. On the molecular level, we identified plasma membrane Ca2+ ATPases (PMCAs) as the main interaction partners of Neuroplastin. PMCA levels were reduced by over 70% in Nptn −/− T cells, suggesting an explanation for altered Ca2+ handling. Supporting this, Ca2+ extrusion was impaired while Ca2+ levels in internal stores were increased. T cells heterozygous for PMCA1 mimicked the phenotype of Nptn −/− T cells. Consistent with sustained Ca2+ levels, differentiation of Nptn −/− T helper cells was biased towards the Th1 versus Th2 subset. Our study thus establishes Neuroplastin-PMCA modules as important regulators of T cell activation.

The prognostic relevance of minimal residual disease (MRD) in patients with multiple myeloma is still an open question. We measured MRD levels in bone marrow (BM) samples of 53 patients treated with high-dose therapy (HDT) and autologous peripheral blood stem cell transplantation using real-time quantitative (RQ)-IgH-PCR with allel-specific oligonucleotide probes. We identified a prognostically relevant threshold level of 0.2% 2IgH/β-actin ratio in the BM before HDT. Twenty-six patients with MRD levels below this value were termed as the "low-MRD group," whereas 27 patients with levels above this threshold were allocated to the "high-MRD group." Median event-free-survival (EFS) in the low-MRD group was significantly (P = .001) longer than in the high-MRD group with 35 versus 20 months, respectively. Overall survival (OS) within the low-MRD group was also significantly longer with 70 versus 45 months (P = .04). Using multivariate analysis, we found that the pretransplantation MRD level was an independent prognostic factor for EFS (P = .003) and OS (P = .05). Further, EFS of patients in the high-MRD could be improved (P = .005) when they achieved a low MRD level after HDT. In conclusion, measuring MRD is of prognostic relevance in patients with MM, and low MRD levels should be a goal of treatment.

Splenic marginal zone B cells (MZB) shuttle between the blood-filled marginal zone for antigen collection and the follicle for antigen delivery. However, it is unclear how MZBs migrate directionally from the marginal zone to the follicle. Here, we show that murine MZBs migrate up shear flow via the LFA-1 (αLβ2) integrin ligand ICAM-1, but adhere or migrate down the flow via the VLA-4 integrin (α4β1) ligand VCAM-1. MZBs lacking Arhgef6 (Pak-interacting exchange factor (αPIX)) or functional LFA-1 are impaired in shuttling due to mislocalization toward the VCAM-1-rich red pulp. Sphingosine-1-phosphate (S1P) signaling through the S1PR3 receptor inhibits MZB migration up the flow, and deletion of S1pr3 in Arhgef6 −/− mice rescues mislocalized MZBs. These findings establish shear flow as a directional cue for MZB migration to the follicle, and define S1PR3 and VCAM-1 as counteracting forces that inhibit this migration.

Thymocytes mature in a series of stages by migrating through specific areas of the thymus and interacting with other cells to receive the necessary developmental signals; however, little is known about the molecular mechanisms governing this migration. We report that murine thymocytes with a knockout mutation in α-PAK (p21-activated kinase)-interacting exchange factor (PIX; Arhgef6), an activator of Rho GTPases, showed greatly increased motility and altered morphology in two-dimensional migration on ICAM-1. αPIX was also required for efficient positive selection, but not negative selection, of thymocytes. TCR signaling was normal in αPix− thymocytes, indicating that the effects of αPIX on positive selection are largely independent of TCR signaling. αPix− thymocytes also paused less during migration in the thymic cortex, interacted less with ICAM-1 coated beads, and could overcome TCR stop signals, consistent with defective scanning behavior. These results identify αPIX as a regulator of thymocyte migration and subsequent arrest that is linked to positive selection.

The amplitude and duration of Ca2+ signaling is crucial for B‐cell development and self‐tolerance; however, the mechanisms for terminating Ca2+ signals in B cells have not been determined. In lymphocytes, plasma membrane Ca2+ ATPase (PMCA) isoforms 1 and 4 (PMCA1 and PMCA4, aka ATP2B1 and ATP2B4) are the main candidates for expelling Ca2+ from the cell through the plasma membrane. We report here that Pmca4 (Atp2b4) KO mice had normal B‐cell development, while mice with a conditional KO of Pmca1 (Atp2b1) had greatly reduced numbers of B cells, particularly splenic follicular B cells, marginal zone B cells, and peritoneal B‐1a cells. Mouse and naïve human B cells showed only PMCA1 expression and no PMCA4 by western blot, in contrast to T cells, which did express PMCA4. Calcium handling was normal in Pmca4−/− B cells, but Pmca1 KO B cells had elevated basal levels of Ca2+, elevated levels in ER stores, and reduced Ca2+ clearance. These findings show that the PMCA1 isoform alone is required to ensure normal B‐cell Ca2+ signaling and development, which may have implications for therapeutic targeting of PMCAs and Ca2+ in B cells.

Background: High-dose chemotherapy with autologous stem cell transplantation has improved outcome and survival of patients with multiple myeloma. However, the majority of patients suffer from relapse. Using real-time quantitative (RQ) PCR we have shown before (Haematologica 89,2004) that the amount of residual tumor cells in the bone marrow of patients before transplantation is of prognostic relevance. In this study we evaluated in a larger group of patients with multiple myeloma whether a pre-transplantation level of clonotypic cells in the bone marrow is predictive for time-to-progression (TTP) and overall survival (OS). Further, we compared results with known prognostic factors. Patients and Methods: Bone marrow samples of 19 patients with stage II/III multiple myeloma were obtained after induction therapy but before transplantation. Immunoglobulin heavy chain (IgH) RQ-PCR using patient-specific Taqman probes was performed to quantify pre-transplantation tumor levels. The proportion of clonotypic cells was assessed as IgH/2 beta-actin ratio in percent. Medical records of patients were reviewed for prognostic factors and outcome. Results: The median level of residual tumor cells in bone marrow of all patients at the time before transplantation was 0.3 %. At 23 month median follow-up after transplantation the median TTP and OS in our study were 14 and 36 month, respectively. The threshold level of 0.03% clonotypic cells identified two prognostic groups (p<0.0001, log rank). Twelve patients in the bad prognostic group had an early relapse with a median TTP of 9 month (range: 3 – 17 month). All patients in the good prognostic group (n=7) had ongoing remissions after a median follow-up of 24 month (range: 13–44 month). Univariat analysis was performed including other prognostic factors at the time before transplantation such as cytogenetic abnormalities, beta2-microglobulin, hemoglobulin, platelet count, LDH, CRP, serum albumine and age. Besides the pre-transplant level of minimal residual disease, CRP level was predictive for TTP. In multivariat analysis using a step-wise cox regression model grouping by pre-transplantation tumor level was the only prognostic factor for TTP (p = 0.05). Moreover, low pre-transplantation tumor levels also showed a trend for a better OS, but in multivariat analysis only normal cytogenetics were predictive for a superior outcome (p = 0.03). Conclusion: Quantitative molecular assessment of pre-transplantation tumor level in the bone marrow is an independent prognostic parameter for the progression-free survival of patients with multiple myeloma and thus helps to guide therapeutic interventions