Search

The addition of rituximab to chemotherapy has substantially improved outcomes for patients with B-cell malignancies. The mechanisms of action of rituximab include activation of natural killer cells. Killer-cell immunoglobulin-like receptors (KIRs) mediate natural killer cell function through interaction with HLA. We evaluated the clinical impact of KIR–HLA genotypes on rituximab-containing therapy.

Patients undergoing intensive chemotherapy are usually in need for central venous catheters (CVC). Due to contradictory study results, relation of insertion site and CVC-associated complication rate in these patients is not clear. We therefore retrospectively analyzed CVC-related data of all patients undergoing intensive chemotherapy with high risk of febrile neutropenia according to NCCN criteria, who received a CVC at our bone marrow transplantation unit between May 2016 and December 2019. In total, 210 patients received 281 CVC. CVC were placed via either the subclavian-vein (SCV, n?=?58; 20%) or the internal-jugular-vein (IJV, n?=?223; 80%). Median duration of CVC-lifetime and neutropenic days per CVC were comparable between the two groups (IJV vs SCV: 23 days vs 21 days (p?=?0.16) and 12 days vs 11 days (p?=?0.65)). Both, time to CVC removal due to local inflammation and time to central line-associated bloodstream infection was significantly shorter in patients with SCV catheters (p?=?0.013 and p?=?0.045). CVC placed in the IJV were associated with significantly less catheter-related infectious events compared with CVC placed in the SCV. This difference was consistent across different subgroups including 88 patients undergoing allogeneic stem cell transplantation.

Fcγ receptor (FcγR) polymorphisms have been shown to affect rituximab-mediated antibody-dependent cellular cytotoxicity. Of 512 patients with diffuse large B-cell lymphoma treated in the RICOVER-60 trial, carriers of FcγRIII 158 valine homozygous receptors (V/V) presented with a slightly decreased incidence of B-symptoms (158 V/V: 26%, V/F: 35%, phenylalanine receptors [F/F]: 42%; P = .037). Survival curves of all FcγR single nucleotide polymorphisms were superimposable after cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP); but after CHOP with rituximab (R-CHOP), event-free survival (EFS) and progression-free survival (PFS), but not overall survival, of FcγRIIIa 158 F/F had a trend to be lower than those of 158 V/F and 158 V/V: 3-year EFS: FcγRIIIa 158 F/F: 64.5%, 158 V/F: 70.2%, 158 V/V: 76.9% (log-rank test: P = .224 F/F vs V/V; P = .285 F/F vs V/F + V/V); 3-year PFS: FcγRIIIa 158 F/F: 68.3%, V/F: 76.1%, V/V: 80.5% (log-rank test: P = .233 for F/F vs V/V; P = .185 for F/F vs V/F + V/V). By multivariate analysis adjusting for International Prognostic Index factors, relative risk of F/F compared with V/F plus V/V was 1.80 (P = .052) for PFS and 1.55 (P = .120) for EFS. The interaction of R-CHOP, but not CHOP with FcγRIIIa polymorphisms, indicates a window of opportunity for CD20 antibodies designed to mediate enhanced antibody-dependent cellular cytotoxicity.

Paratarg-7, a frequent autoantigenic target, and all other autoantigenic targets of human paraproteins molecularly defined to date are hyperphosphorylated in the respective patients compared with healthy controls, suggesting that hyperphosphorylation of autoantigenic paraprotein targets is a general mechanism underlying the pathogenesis of these paraproteins. We now show that hyperphosphorylation of paratarg-7 occurs because of an additional phosphorylation of Ser17, which is located within the paraprotein-binding epitope. Coimmunoprecipitation identified phosphokinase C ζ (PKCζ) as the kinase responsible for the phosphorylation of most, and phosphatase 2A (PP2A) as the phosphatase responsible for the dephosphorylation of all hyperphosphorylated autoantigenic targets of paraproteins. Single-nucleotide polymorphisms (SNPs) or mutations of PKCζ and PP2A were excluded. However, PP2A was inactivated by phosphorylation of its catalytic subunit at Y307. Stimulation of T cells from healthy carriers of wild-type paratarg-7 induced a partial and transient hyperphosphorylation between days 4 and 18, which was maintained by incubation with inhibitors of PP2A, again indicating that an inactivation of PP2A is responsible for the hyperphosphorylation of autoantigenic paraprotein targets. We conclude that the genetic defect underlying the dominantly inherited hyperphosphorylation of autoantigenic paraprotein targets is not in the PP2A itself, but in genes or proteins controlling PP2A activity by phosphorylation of its catalytic subunit.

Paratarg-7, a frequent autoantigenic target, and all other autoantigenic targets of human paraproteins molecularly defined to date are hyperphosphorylated in the respective patients compared with healthy controls, suggesting that hyperphosphorylation of autoantigenic paraprotein targets is a general mechanism underlying the pathogenesis of these paraproteins. We now show that hyperphosphorylation of paratarg-7 occurs because of an additional phosphorylation of Ser17, which is located within the paraprotein-binding epitope. Coimmunoprecipitation identified phosphokinase C ζ (PKCζ) as the kinase responsible for the phosphorylation of most, and phosphatase 2A (PP2A) as the phosphatase responsible for the dephosphorylation of all hyperphosphorylated autoantigenic targets of paraproteins. Single-nucleotide polymorphisms (SNPs) or mutations of PKCζ and PP2A were excluded. However, PP2A was inactivated by phosphorylation of its catalytic subunit at Y307. Stimulation of T cells from healthy carriers of wild-type paratarg-7 induced a partial and transient hyperphosphorylation between days 4 and 18, which was maintained by incubation with inhibitors of PP2A, again indicating that an inactivation of PP2A is responsible for the hyperphosphorylation of autoantigenic paraprotein targets. We conclude that the genetic defect underlying the dominantly inherited hyperphosphorylation of autoantigenic paraprotein targets is not in the PP2A itself, but in genes or proteins controlling PP2A activity by phosphorylation of its catalytic subunit.

Mantle cell lymphoma (MCL) is a distinct subtype of lymphoma and is characterized by an aggressive clinical course in the majority of cases. In older patients, commonly used induction regimens are either anthracycline-containing CHOP-like regimens or bendamustine, both in combination with rituximab, followed by rituximab maintenance [Dreyling, 2017]. Data on efficacy and safety of rituximab in MCL are mainly derived from the randomized GLSG2000 trial, showing higher remission rates and longer FFS with R-CHOP vs. CHOP, but no significant differences in PFS in remission and OS due to limited statistical power [Lenz, 2005]. We now performed a long-term ITT analysis of CHOP vs. R-CHOP from all GLSG2000 patients pooled with the CHOP patients of the preceding GLSG1996 trial.

Bittenbring: Gilead: Consultancy; Pfizer: Consultancy. Hübel: Gilead: Consultancy, Speakers Bureau; Incyte: Consultancy, Speakers Bureau; Servier: Consultancy, Speakers Bureau; Celgene: Consultancy; EUSA: Consultancy, Speakers Bureau. Schmidt: Novartis: Consultancy, Honoraria, Other: Travel support; Kite/Gilead: Consultancy, Honoraria, Other: Travel support, Research Funding; Takeda: Consultancy, Other: Travel support; BMS: Consultancy, Other: Travel support; Janssen: Other: Travel support. Glass: Kite: Consultancy; Roche: Consultancy, Research Funding, Speakers Bureau; Riemser: Research Funding; Novartis: Consultancy; Helios Klinik Berlin-Buch: Current Employment; BMS: Consultancy. Hüttmann: Gilead: Honoraria; Celgene: Honoraria; Lead Discovery Center GmbH: Consultancy; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Klapper: Takeda: Consultancy, Research Funding; Roche: Consultancy, Research Funding; Regeneron: Consultancy, Research Funding; Amgen: Research Funding. Hiddemann: Janssen: Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding. Unterhalt: Roche: Research Funding. Dreyling: Genmab: Consultancy; BeiGene: Consultancy; Celgene: Consultancy, Research Funding, Speakers Bureau; Amgen: Speakers Bureau; Astra Zeneca: Consultancy, Speakers Bureau; Abbvie: Research Funding; Novartis: Consultancy, Speakers Bureau; Roche: Consultancy, Research Funding, Speakers Bureau; Incyte: Consultancy, Speakers Bureau; Janssen: Consultancy, Research Funding, Speakers Bureau; Gilead/Kite: Consultancy, Research Funding, Speakers Bureau; Bayer HealthCare Pharmaceuticals: Consultancy, Research Funding, Speakers Bureau.

Poeschel: Roche:Other: Travel, Accommodations, Expenses;Amgen:Other: Travel, Accommodations, Expenses;Abbvie:Other: Travel, Accommodations, Expenses.Habersang:Rheinlandklinikum Neuss:Current Employment.Mahlberg:Janssen:Other: Travel, Accommodations, Expenses;Mutterhaus der Borromaeerinnen, Trier:Current Employment;Novartis:Honoraria, Other: Travel, Accommodations, Expenses;Labor Synlab:Ended employment in the past 24 months;Abbvie:Other: Travel, Accommodations, Expenses;Roche:Honoraria;Amgen:Honoraria, Other: Travel, Accommodations, Expenses;Merck:Honoraria, Other: Travel, Accommodations, Expenses.Keller:Janssen-Cilag:Consultancy, Other: Travel, Accommodations, Expenses;Takeda:Consultancy, Other: Travel, Accommodations, Expenses;Celgene:Consultancy, Other: Travel, Accommodations, Expenses;BMS:Consultancy, Other: Travel, Accommodations, Expenses;Roche:Consultancy, Other: Travel, Accommodations, Expenses;Hexal:Consultancy;Novartis:Consultancy;MSD:Consultancy;Pfizer:Consultancy;Astra-Zeneca:Consultancy;Pentixapharm:Consultancy.Viardot:Kite/Gilead:Honoraria, Other: advisory board;Roche:Honoraria, Other: advisory board;Amgen:Honoraria, Other: advisory board;Novartis:Honoraria, Other: advisory board.Stilgenbauer:Novartis:Consultancy, Honoraria, Other, Research Funding;Pharmacyclics:Consultancy, Honoraria, Other, Research Funding;GlaxoSmithKline:Consultancy, Honoraria, Other: travel support, Research Funding;Janssen-Cilag:Consultancy, Honoraria, Other: travel support, Research Funding;Mundipharma:Consultancy, Honoraria, Other, Research Funding;Genzyme:Consultancy, Honoraria, Other: travel support, Research Funding;Genentech:Consultancy, Honoraria, Other: travel support, Research Funding;F. Hoffmann-LaRoche:Consultancy, Honoraria, Other: travel support, Research Funding;Celgene:Consultancy, Honoraria, Other: travel support, Research Funding;Gilead:Consultancy, Honoraria, Other: travel support, Research Funding;AbbVie:Consultancy, Honoraria, Other: travel support, Research Funding;Boehringer-Ingelheim:Consultancy, Honoraria, Other: travel support, Research Funding;Amgen:Consultancy, Honoraria, Other: travel support, Research Funding.Held:Roche:Consultancy, Other: Travel, Accommodations, Expenses, Research Funding;BMS:Consultancy, Other: Travel, Accommodations, Expenses, Research Funding;MSD:Consultancy;Acrotech:Research Funding;Spectrum:Research Funding;Amgen:Research Funding.Bittenbring:Gilead:Honoraria, Other: Travel, Accommodations, Expenses;Bluebird Bio:Honoraria, Other: Travel, Accommodations, Expenses;Roche:Honoraria, Other: Travel, Accommodations, Expenses, Advisory board;Celgene:Honoraria, Other: Travel, Accommodations, Expenses, Advisory Board;Pfizer:Honoraria, Other: Travel, Accommodations, Expenses.

Vitamin D deficient patients suffering from diffuse large B-cell lymphoma (DLBCL) treated with R-CHOP have lower overall survival. This especially applies for patients with vitamin D levels ≤8 ng/ml (Bittenbring et al. J Clin Oncol. 2014; 32:3242-8). Vitamin D up to 65 ng/ml may be necessary for optimal efficacy of R-CHOP (Neumann et al. Cancer Immunol Immunother. 2018; 67:1709-18). To study the clinical benefit of vitamin D substitution, we established a fast-track schedule to appropriately substitute patients to these vitamin D levels.

Krämer: Gilead: Other: Travel grants; MSD: Honoraria. Stilgenbauer:AbbVie: Consultancy, Honoraria, Other: Travel grants, Research Funding; Hoffmann-La Roche: Consultancy, Honoraria, Other: Travel grants , Research Funding; Janssen: Consultancy, Honoraria, Other: Travel grants , Research Funding; Novartis: Consultancy, Honoraria, Other: Travel grants , Research Funding; Genzyme: Consultancy, Honoraria, Other: Travel grants , Research Funding; Pharmacyclics: Consultancy, Honoraria, Other: Travel grants , Research Funding; Boehringer Ingelheim: Consultancy, Honoraria, Other: Travel grants , Research Funding; Amgen: Consultancy, Honoraria, Other: Travel grants, Research Funding; Genentech: Consultancy, Honoraria, Other: Travel grants , Research Funding; Gilead: Consultancy, Honoraria, Other: Travel grants , Research Funding; Mundipharma: Consultancy, Honoraria, Other: Travel grants , Research Funding; GSK: Consultancy, Honoraria, Other: Travel grants , Research Funding; Celgene: Consultancy, Honoraria, Other: Travel grants , Research Funding; Sanofi: Consultancy, Honoraria, Other: Travel grants , Research Funding. Böttcher:Hoffmann-LaRoche: Honoraria, Other: Travel grants, Research Funding; Celgene: Research Funding; AbbVie: Honoraria, Research Funding. Ritgen:Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding. Hegenbart:Jansen Cilag: Honoraria, Other: financial support of conference participation. Hallek:F. Hoffmann-LaRoche: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Janssen-Cilag: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Gilead: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Mundipharma: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; AbbVie: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau. Kneba:Amgen: Research Funding; Gilead: Consultancy, Honoraria, Other: Travel grants, Research Funding; Glaxo-SmithKline: Other: Travel grants; Roche: Consultancy, Honoraria, Other: Travel grants, Research Funding; AbbVie: Consultancy, Honoraria, Other: Travel grants; Janssen-Cilag: Consultancy, Honoraria, Other: Travel grants. Dreger:Gilead: Consultancy; Novartis: Consultancy; Gilead: Speakers Bureau; Novartis: Speakers Bureau; Janssen: Consultancy; Roche: Consultancy.

Ciceri: MolMed SpA: Consultancy. Foà:Ariad: Speakers Bureau; Pfizer: Speakers Bureau; BMS: Consultancy; Celgene: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Gilead: Consultancy, Speakers Bureau; Janssen-Cilag: Consultancy, Speakers Bureau; Genetech: Consultancy; Roche: Consultancy, Speakers Bureau. Hallek:Mundipharma: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; F. Hoffmann-LaRoche: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; AbbVie: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Janssen-Cilag: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Gilead: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau. Schetelig:Sanofi: Honoraria. Kröger:Sanofi: Honoraria, Research Funding; Neovii: Honoraria, Research Funding; Riemser: Honoraria, Research Funding; Novartis: Honoraria, Research Funding.

Background:Refractory or early relapsed (<1 year) diffuse large B-cell lymphoma has a dismal prognosis especially for those not responding to salvage chemotherapy (Van den Neste; Bone Marrow Transplant. 2016 Jan;51(1):51-7). Allogeneic stem cell transplantation is potentially curative (Glass et al; Lancet Oncology 2014 Jun;15(7):757-66). Even though this is less likely in those not responding or having frank progression pre-transplantation.

Introduction:

No relevant conflicts of interest to declare.

No relevant conflicts of interest to declare.

PURPOSEof this analysis was to provide 10-year follow-up of the GCLLSG CLL3X trial which aimed at evaluating reduced-intensity conditioning (RIC) HSCT in patients with poor-risk CLL.

In addition to antimicrobial activity, macrophages regulate tissue development, remodeling, and repair. In terms of neoplastic growth, tumor-associated macrophages (TAMs) are even considered pro-tumorigenic based on their angiogenic and T-cell suppressive properties. In multiple myeloma (MM) macrophages represent an abundant component of the stromal cell compartment and are believed to support proliferation, survival, and drug resistance of MM cells. Those pro-tumorigenic functions are partly instructed by T-helper (TH)-2 cytokines such as interleukin-4 (IL-4) and IL-10, which skew TAM differentiation towards an alternatively activated, or so-called M2-like, phenotype. In contrast, M1 macrophages generally considered as potent effectors in response to microbial products or interferon-γ (IFN-γ), are characterized by superior antigen-presentation, abundant production of pro-inflammatory cytokines such as interleukin-12 (IL-12), and consequently, promote a polarized type I immune response against infections as well as malignant cells. Transcriptional regulation is a key determinant for macrophage polarization. The Ikaros (IKZF1) transcription factor is critical for lymphoid development and is found in all hematopoietic progenitors as well as in T-, B-, NK-cells and macrophages. Interestingly, IKZF1 is overexpressed in MM and selectively degraded by lenalidomide, which is approved in MM therapy. The potential role of IKZF1 in modulating macrophage polarization has not been elucidated yet.

Pfreundschuh: Roche, Janssen, Celgene: Honoraria, Research Funding.

Off Label Use: off-label drug use: antithymocyte globulin (ATG) for allo-SCT conditioning. Tischer:Sanofi-Aventis: Other: advisory board. Schmid:Neovii: Consultancy; Janssen Cilag: Other: Travel grand. Mayer:Janssen: Research Funding. Hallek:Pharmacyclics: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding; Janssen: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding; Boehringher Ingelheim: Honoraria, Other: Speakers Bureau and/or Advisory Boards; Mundipharma: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding; Celgene: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding; Gilead: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding; Roche: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding; AbbVie: Honoraria, Other: Speakers Bureau and/or Advisory Boards, Research Funding.

Bruns: Morphosys: Research Funding; Celgene: Research Funding.

Introduction.Allogeneic hematopoietic cell transplant (HCT) is an established treatment modality that is potentially curative for many patients with acute myeloid leukemia (AML). The development of reduced intensity conditioning (RIC) allows performing HCT in elderly and/or in heavily pretreated patients and in those with comorbidities precluding the use of standard myeloablative conditioning. Post-transplant relapse remains a challenge after RIC, particularly in patients with adverse prognosis factors.The so-called "sequential" transplant approach (e.g. FLAMSA regimen combining both intensive chemotherapy and RIC HCT within the same procedure) initially developed in patients with refractory AML, could be a promising strategy to improve disease control and decrease the risk of relapse in high-risk AML patients in complete remission (CR).

Multiple myeloma (MM) is considered a chronic and incurable disease due to its highly complex and heterogeneous molecular abnormalities and the support from myeloma microenvironment factors. Macrophages are an abundant component of the stromal cell compartment and are believed to support proliferation, survival, and drug resistance of MM cells. Conversely, macrophages are key immune effector cells for the therapeutic effect of monoclonal antibodies and can directly eliminate tumor cells. However, myeloma-associated macrophages (MAMs) regularly fail to exert direct effector functions. Given their abundance in MM, an attractive therapeutic approach would be to stimulate their tumoricidal activity in order to promote antitumor immunity. Lenalidomide, an immunomodulatory agent that enhances antibody dependent cell mediated cytotoxicity (ADCC), has the potential to synergize with MOR202, an anti-CD38 monoclonal IgG1 antibody currently in phase I/IIa for the treatment of MM. Furthermore, vitamin D plays a key role in regulating effector functions of human macrophages. This is closely linked to the expression of the vitamin D-1-hydroxylase CYP27B1, which catalyzes the conversion of 25-hydroxy-vitamin D (25D) to the bioactive form 1,25-di-hydroxy-vitamin D (1,25D). We have previously shown, that vitamin D promotes tumoricidal activity of macrophages and improves the efficacy of rituximab-dependent cytotoxicity (Bruns et al., Sci. Transl. Med., 2015; Bittenbring et al., JCO, 2014). Therefore, we hypothesized that the combination of MOR202 with lenalidomide and MOR202 with 1,25D would enhance the MOR202- dependent macrophage-mediated effector functions against myeloma cells.

Background:Vitamin D3 deficiency impairs the rituximab-mediated antibody-dependent cellular cytotoxicity (ADCC) and the outcome of elderly patients with diffuse large B-cell lymphoma (Bittenbring et al., J Clin Oncol. 2014 Oct 10; 32(29):3242-8) treated with R-CHOP and of patients with follicular lymphoma (Kelly et al., J Clin Oncol. 2015 May 1; 33(1):1482-90. The aim of this study was to determine the optimal 25-OH-vitamin D3 (VD3) level for rituximab- and obinutuzumab-mediated ADCC.

No relevant conflicts of interest to declare.

Infiltration by macrophages represents a characteristic morphological hallmark in high grade lymphatic malignancies such as Burkitt’s lymphoma (BL). Although macrophages can in principle target neoplastic cells and mediate antibody-dependent cytotoxicity (ADCC), tumor associated macrophages (TAMs) regularly fail to exert direct cytotoxic functions. The underlying mechanisms responsible for this observation remain unclear. Here we demonstrate that inflammatory M1 macrophages kill proliferating high grade B-cell lymphoma cells by releasing the antimicrobial peptide cathelicidin in a vitamin D-dependent fashion. Moreover, we show that cathelicidin directly induces cell death by targeting mitochondria of BL-cells. In contrast, anti-inflammatory M2 macrophages and M2-like TAMs in BL exhibit an altered vitamin D metabolism resulting in a reduced production of cathelicidin and consequently in inability to lyse BL cells. However, treatment of M2 macrophages with the bioactive form of vitamin D, 1,25D, or a vitamin D receptor agonist effectively induces cathelicidin production and triggers tumoricidal activity against BL cells. Furthermore, rituximab-mediated cytotoxicity of M2 macrophages is cathelicidin dependent and vitamin D treatment of 25D deficient volunteers improves rituximab-mediated ADCC against BL cells. These data indicate that activation of the vitamin D signaling pathway may activate antitumor activity of TAMs and improve the efficacy of ADCC.

To investigate the impact and underlying mechanisms of vitamin-D-deficiency (VDD) on outcome of elderly (61 to 80 year-old) DLBCL patients.Pretreatment 25-OH-vitamin-D serum levels from 359 patients treated in the prospective multicenter RICOVER-60 trial with 6 or 8 cycles of CHOP-14 with and without 8 cycles rituximab and 63 patients in the RICOVER-noRT study treated with 6xCHOP-14 + 8xR were determined determined by LIASION®, a commercially available chemoluminescent immunoassay.RICOVER-60 patients with VDD (defined as serum levels ≤8 ng/m l) and treated with rituximab had a 3-year event-free survival of 59% compared to 79% in patients with >8 ng/ml; 3-year overall survival was 70% and 82%, respectively. These differences were significant in a multivariable analysis adjusting for IPI risk factors with a hazard ratio of 2.1 [p=0.008] for event-free survival and 1.9 [p=0.040] for overall survival. In patients treated without rituximab 3-year EFS was not significantly different in patients with vitamin-D levels ≤8 and >8 ng/ml (HR 1.2; p=0.388). These results were confirmed in an independent validation set of 63 patients treated within the RICOVER-noRT study. Rituximab-mediated cellular toxicity (RMCC) against the CD20+ cell line Daudi as determined by LDH release assay increased significantly (p<0.005) in 5/5 vitamin-D-deficient individuals after vitamin-D substitution and normalization of their vitamin-D levels.VDD is a significant risk factor for elderly DLBCL patients treated with rituximab. Our results show that VDD impairs RMCC and that RMCC can be improved by vitamin-D substitution. This together with the differential effect of VDD in patients treated with and without rituximab suggests that vitamin-D substitution might result in a better outcome of these patients when treated with CHOP plus rituximab. Supported by a grant from Deutsche Krebshilfe.No relevant conflicts of interest to declare.

To investigate the impact and underlying mechanisms of vitamin-D-deficiency (VDD) on outcome of elderly (61 to 80 year-old) DLBCL patients.

Background: Minor histocompatibility antigens are antigenic peptides derived from normal cellular molecules which are presented in the context of major histocompatibility antigens (MHC class I and MHC class II). After an allogeneic hematopoietic stem cell transplantation (aHSCT) recipient-derived mHags can be recognized by T-cells of the transplanted immune system an mediate both a graft-versus-host disease and graft-versus- leukemia reaction. All mHags known to date have been identified by allo-reactive T-cells. Due to complex logistics needed for the establishment of such T-cell clones only a few mHags have been molecularly defined to date. Since patients with GvH develop antibodies against mHags and the presence of mHag antibodies has been shown to correlate with GvH and maintenance of remission [Miklos et al. (2005) Blood 105:2973-9] we set out to identify new mHags using SEREX the serological identification of antigens using recombinant expression cloning [Sahin et al. (1995) PNAS 92:11810-3]. Methods: Fibroblasts obtained by skin biopsies from patients with chronic GvH were propagated in vivo and used as a source to establish a cDNA library. cDNA was expressed by lambda phage in E.coli and expressed clones were screened for reactivity with antibodies in the serum of patients with chronic GvH. Positive clones were monoclonized and sequenced. The sequences were compared with known sequences using BLAST data bank. Reactive sera were compared with patient’s pre transplant serum and the serum from the donor to exclude pre-existing antibodies against (auto-)antigens expressed by the fibroblasts. Only neo-antigens recognized by the transplanted immune system were analyzed further. Results: cDNA libraries obtained from 7 patients with chronic GvH after HLA-identical stem cell transplantation were screened with the sera of these 7 patients by SEREX. Antibodies from one patient with chronic GvH were absent in the donor and the patients pre-transplant serum, reacted with c1ORF107. This constellation proves that the c1ORF107 antibodies in the patient’s serum developed after transplant and recognized c1ORF as a neo-antigen. The immunogenic c1ORF107 of the patient differed at previously described polymorphic position 275 (rs585627) with G in the recipient leading to glutamate and C in the donor leading to glutamine. The definition of the c1ORF107 epitopes eliciting a T-cell response by “reverse T-cell immunology” is currently underway. Conclusion: This study proves the principle that the analysis of the humoral immune response in patients with chronic GvH by SEREX allows for the definition of new mHags. SEREX in combination and followed by reverse T-cell immunology is a straight-forward approach which will expand considerably the number of molecularly defined mHags causing GvH in patients after allogeneic stem cell transplantation. Supported by Jose Carreras Foundation Germany

Background: Minor histocompatibility antigens are antigenic peptides derived from normal cellular molecules which are presented in the context of major histocompatibility antigens (MHC class I and MHC class II). After an allogeneic hematopoietic stem cell transplantation (aHSCT) recipient-derived mHags can be recognized by T-cells of the transplanted immune system an mediate both a graft-versus-host disease and graft-versus- leukemia reaction. All mHags known to date have been identified by allo-reactive T-cells. Due to complex logistics needed for the establishment of such T-cell clones only a few mHags have been molecularly defined to date. Since patients with GvH develop antibodies against mHags and the presence of mHag antibodies has been shown to correlate with GvH and maintenance of remission [Miklos et al. (2005) Blood 105:2973-9] we set out to identify new mHags using SEREX the serological identification of antigens using recombinant expression cloning [Sahin et al. (1995) PNAS 92:11810-3].