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The DNAJB1-PRKACA fusion transcript was identified as the oncogenic driver of tumor pathogenesis in fibrolamellar hepatocellular carcinoma (FL-HCC), also known as fibrolamellar carcinoma (FLC), as well as in other tumor entities, thus representing a broad target for novel treatment in multiple cancer entities. FL-HCC is a rare primary liver tumor with a 5-year survival rate of only 45%, which typically affects young patients with no underlying primary liver disease. Surgical resection is the only curative treatment option if no metastases are present at diagnosis. There is no standard of care for systemic therapy. Peptide-based vaccines represent a low side-effect approach relying on specific immune recognition of tumor-associated human leucocyte antigen (HLA) presented peptides. The induction (priming) of tumor-specific T-cell responses against neoepitopes derived from gene fusion transcripts by peptide-vaccination combined with expansion of the immune response and optimization of immune function within the tumor microenvironment achieved by immune-checkpoint-inhibition (ICI) has the potential to improve response rates and durability of responses in malignant diseases. The phase I clinical trial FusionVAC22_01 will enroll patients with FL-HCC or other cancer entities carrying the DNAJB1-PRKACA fusion transcript that are locally advanced or metastatic. Two doses of the DNAJB1-PRKACA fusion-based neoepitope vaccine Fusion-VAC-XS15 will be applied subcutaneously (s.c.) with a 4-week interval in combination with the anti-programmed cell death-ligand 1 (PD-L1) antibody atezolizumab starting at day 15 after the first vaccination. Anti-PD-L1 will be applied every 4 weeks until end of the 54-week treatment phase or until disease progression or other reason for study termination. Thereafter, patients will enter a 6 months follow-up period. The clinical trial reported here was approved by the Ethics Committee II of the University of Heidelberg (Medical faculty of Mannheim) and the Paul-Ehrlich-Institute (P-00540). Clinical trial results will be published in peer-reviewed journals., Trial Registration Numbers: EU CT Number: 2022-502869-17-01 and ClinicalTrials.gov Registry (NCT05937295)., Competing Interests: JB, YM and JW are listed as inventors on a patent related to the DNAJB1-PRKACA T cell epitopes and TCRs Peptides and antigen binding proteins for use in immunotherapy against fibrolamellar HCC and other cancers, Application number: EP21214728.4. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer BJ declared a past co-authorship with the author JW to the handling editor., (Copyright © 2024 Hackenbruch, Bauer, Heitmann, Maringer, Nelde, Denk, Zieschang, Kammer, Federmann, Jung, Martus, Malek, Nikolaou, Salih, Bitzer and Walz.)

Differential diagnosis of clonal versus reactive cytopenia and monocytosis, respectively, frequently presents a diagnostic challenge. With the two recent classifications of myeloid disorders, mutational analysis has gained importance as a diagnostic tool. However, reports on its utility on trephine bone marrow biopsies (BMB) are sparse. The aim of our proof of principle study was to determine the suitability of targeted sequencing for the longitudinal evaluation of cytopenia and monocytosis and demonstration of clonal evolution on sequential BMB. Seventy-seven EDTA-decalcified BMB of 33 patients with peripheral cytopenia and/or monocytosis, including at least one follow-up biopsy/patient, were included. Initial morphological diagnoses were idiopathic cytopenia of undetermined significance (ICUS, 8 cases), MDS (without blast increase, 7 cases), MDS with increased blasts/excess blasts (MDS-IB/EB) (11 cases), and CMML (7 cases). Thirty-one genes relevant for myeloid disorders were examined using two custom AmpliSeq NGS panels. Mutations were found in the initial BMB of 5/8 cases of ICUS, thus changing the diagnosis to clonal cytopenia of unknown significance (CCUS), 5/7 MDS, 10/11 MDS-IB/EB, and 7/7 CMML. Clonal evolution was observed in 14/33 (42%) cases, mostly associated with disease progression. None of the wild-type patients acquired mutations during follow-up. NGS-based mutation profiling is a robust diagnostic tool for BMB and provides valuable additional information, especially for cases with no/minimal dysplasia, and for better risk stratification of MDS. Tracking variant allele frequency and appearance of mutations over time allows for observing clonal evolution or relapse., (© 2023. The Author(s).)

Despite high cure rates in classic Hodgkin lymphoma (cHL), relapses are observed. Whether relapsed cHL represents second primary lymphoma or an underlying T-cell lymphoma (TCL) mimicking cHL is underinvestigated. To analyze the nature of cHL recurrences, in-depth clonality testing of immunoglobulin (Ig) and T-cell receptor (TCR) rearrangements was performed in paired cHL diagnoses and recurrences among 60 patients, supported by targeted mutation analysis of lymphoma-associated genes. Clonal Ig rearrangements were detected by next-generation sequencing (NGS) in 69 of 120 (58%) diagnoses and recurrence samples. The clonal relationship could be established in 34 cases, identifying clonally related relapsed cHL in 24 of 34 patients (71%). Clonally unrelated cHL was observed in 10 of 34 patients (29%) as determined by IG-NGS clonality assessment and confirmed by the identification of predominantly mutually exclusive gene mutations in the paired cHL samples. In recurrences of >2 years, ∼60% of patients with cHL for whom the clonal relationship could be established showed a second primary cHL. Clonal TCR gene rearrangements were identified in 14 of 125 samples (11%), and TCL-associated gene mutations were detected in 7 of 14 samples. Retrospective pathology review with integration of the molecular findings were consistent with an underlying TCL in 5 patients aged >50 years. This study shows that cHL recurrences, especially after 2 years, sometimes represent a new primary cHL or TCL mimicking cHL, as uncovered by NGS-based Ig/TCR clonality testing and gene mutation analysis. Given the significant therapeutic consequences, molecular testing of a presumed relapse in cHL is crucial for subsequent appropriate treatment strategies adapted to the specific lymphoma presentation., (© 2023 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Immune cell reconstitution after stem cell transplantation is allocated over several stages. Whereas cells mediating innate immunity recover rapidly, adaptive immune cells, including T and B cells, recover slowly over several months. In this study we investigated kinetics and reconstitution of de novo B cell formation in patients receiving CD3 and CD19 depleted haploidentical stem cell transplantation with additional in vivo T cell depletion with monoclonal anti-CD3 antibody. This model enables a detailed in vivo evaluation of hierarchy and attribution of defined lymphocyte populations without skewing by mTOR- or NFAT-inhibitors. As expected CD3 + T cells and their subsets had delayed reconstitution (<100 cells/μL at day +90). Well defined CD19 + B lymphocytes of naïve and memory phenotype were detected at day +60. Remarkably, we observed a very early reconstitution of antibody-secreting cells (ASC) at day +14. These ASC carried the HLA-haplotype of the donor and secreted the isotypes IgM and IgA more prevalent than IgG. They correlated with a population of CD19 - CD27 - CD38 low/+ CD138 - cells. Of note, reconstitution of this ASC occurred without detectable circulating T cells and before increase of BAFF or other B cell stimulating factors. In summary, we describe a rapid reconstitution of peripheral blood ASC after CD3 and CD19 depleted haploidentical stem cell transplantation, far preceding detection of naïve and memory type B cells. Incidence before T cell reconstitution and spontaneous secretion of immunoglobulins allocate these early ASC to innate immunity, eventually maintaining natural antibody levels.

Background: In situ follicular neoplasia (ISFN) is a t(14;18)(q32;q21) + precursor lesion of follicular lymphoma (FL), which in turn can transform into diffuse large B‑cell lymphoma (DLBCL). For DLBCL that arise de novo, no precursor lesion is known. Given the high frequency of the t(14;18) translocation in de novo DLBCL as well, we investigated whether they can also arise from ISFN without FL as an intermediate step., Objectives: To investigate the clonal evolution of ISFN to DLBCL - transformed from FL and de novo., Materials and Methods: Identification of ISFN lesions in patients with DLBCL was performed by BCL2 staining of reactive lymphoid tissues. ISFN and DLBCL were subsequently analyzed by fluorescence in situ hybridization, clonality analyses, sequencing of the t(14;18) breakpoint, and targeted next-generation sequencing., Results: 10 cases with paired ISFN and DLBCL samples were identified, 6 of which were de novo DLBCL and 4 transformed from FL. 3 DLBCL carried MYC-rearrangements in addition to the t(14;18) and were classified as high-grade B‑cell lymphoma (HGBL). The clonal relationship of ISFN and DLBCL/HGBL was confirmed for all cases. CREBBP, KMT2D, EZH2, TNFRSF14, and BCL2 were the genes most frequently mutated, with the distribution of private and shared mutations pointing to 2 different scenarios of clonal evolution. In most cases, DLBCL/HGBL, ISFN, and, if also present, FL had evolved divergently from a common progenitor, whereas linear evolution was less frequent., Conclusion: We show for the first time that t(14;18) + DLBCL/HGBL can arise directly from ISFN without FL as an intermediate step and that during this progression, divergent evolution is common., (© 2021. Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Myeloproliferative neoplasms (MPN) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN) both harbor the potential to undergo myelodysplastic progression or acceleration and can transform into blast-phase MPN or MDS/MPN, a form of secondary acute myeloid leukemia (AML). Although the initiating transforming events are yet to be determined, current concepts suggest a stepwise acquisition of (additional) somatic mutations-apart from the initial driver mutations-that trigger disease evolution. In this study we molecularly analyzed paired bone marrow samples of MPN and MDS/MPN patients with known progression and compared them to a control cohort of patients with stable disease course. Cases with progression displayed from the very beginning a higher number of mutations compared to stable ones, of which mutations in five ( ASXL1 , DNMT3A , NRAS , SRSF2 and TP53 ) strongly correlated with progression and/or transformation, even if only one of these genes was mutated, and this particularly applied to MPN. TET2 mutations were found to have a higher allelic frequency than the putative driver mutation in three progressing cases (" TET2 -first"), whereas two stable cases displayed a TET2 -positive subclone (" TET2 -second"), supporting the hypothesis that not only the sum of mutations but also their order of appearance matters in the course of disease. Our data emphasize the importance of genetic testing in MPN and MDS/MPN patients in terms of risk stratification and identification of imminent disease progression.

In situ follicular neoplasia (ISFN) is the earliest morphologically identifiable precursor of follicular lymphoma (FL). Although it is genetically less complex than FL and has low risk for progression, ISFN already harbors secondary genetic alterations, in addition to the defining t(14;18)(q32;q21) translocation. FL, in turn, frequently progresses to diffuse large B-cell lymphoma (DLBCL) or high-grade B-cell lymphoma (HGBL). By BCL2 staining of available reactive lymphoid tissue obtained at any time point in patients with aggressive B-cell lymphoma (BCL), we identified ten paired cases of ISFN and DLBCL/HGBL, including six de novo tumors and four tumors transformed from FL as an intermediate step, and investigated their clonal evolution using microdissection and next-generation sequencing. A clonal relationship between ISFN and aggressive BCL was established by immunoglobulin and/or BCL2 rearrangements and/or the demonstration of shared somatic mutations for all ten cases. Targeted sequencing revealed CREBBP, KMT2D, EZH2, TNFRSF14 and BCL2 as the genes most frequently mutated already in ISFN. Based on the distribution of private and shared mutations, two patterns of clonal evolution were evident. In most cases, the aggressive lymphoma, ISFN and, when present, FL revealed divergent evolution from a common progenitor, whereas linear evolution with sequential accumulation of mutations was less frequent. In conclusion, we demonstrate for the first time that t(14;18)+ aggressive BCL can arise from ISFN without clinically evident FL as an intermediate step and that during this progression, branched evolution is common.

Post-transplant lymphoproliferative disorders (PTLD) occur after solid organ transplantation (SOT) or hematopoietic stem cell transplantation (HCT) and are frequently associated with Epstein-Barr virus (EBV). Because of the complex immune setup in PTLD patients, the tumor microenvironment (TME) is of particular interest to understand PTLD pathogenesis and elucidate predictive factors and possible treatment options. We present a comparative study of clinicopathological features of 48 PTLD after HCT (n = 26) or SOT (n = 22), including non-destructive (n = 6), polymorphic (n = 23), and monomorphic (n = 18) PTLD and classic Hodgkin lymphoma (n = 1). EBV was positive in 35 cases (73%). A detailed examination of the TME with image analysis-based quantification in 22 cases revealed an inflammatory TME despite underlying immunosuppression and significant differences in its density and composition depending on type of transplant, PTLD subtypes, and EBV status. Tumor-associated macrophages (TAMs) expressing CD163 (p = 0.0022) and Mannose (p = 0.0016) were enriched in PTLD after HCT. Double stains also showed differences in macrophage polarization, with more frequent M1 polarization after HCT (p = 0.0321). Higher counts for TAMs (CD163 (p = 0.0008) and cMaf (p = 0.0035)) as well as in the T cell compartment (Granzyme B (p = 0.0028), CD8 (p = 0.01), and for PD-L1 (p = 0.0305)) were observed depending on EBV status. In conclusion, despite the presence of immunosuppression, PTLD predominantly contains an inflammatory TME characterized by mostly M1-polarized macrophages and cytotoxic T cells. Status post HCT, EBV positivity, and polymorphic subtype are associated with an actively inflamed TME, indicating a specific response of the immune system. Further studies need to elucidate prognostic significance and potential therapeutic implications of the TME in PTLD.

SOX11 is a valuable marker to identify biologically and clinically relevant groups of mantle cell lymphoma such as cyclin D1 negative and leukemic non-nodal mantle cell lymphoma (MCL). We aimed to establish a sensitive in situ hybridization analysis of SOX11 mRNA allowing its quantification within the histopathological context and compare it with immunohistochemistry and real-time quantitative reverse transcription-PCR (RT-qPCR). Furthermore, TP53 status was correlated with SOX11 mRNA levels. Sixty-six cases were investigated; 58 conventional mantle cell lymphomas (cMCL), including six cyclin D1 negative (46 classic, 12 blas-toid) and eight leukemic non-nodal mantle cell lymphomas (nnMCL). RNAscope was used for the in situ hybridization and the results scored as 0 to 4. MCL cases with SOX11 positivity by immunohistochemistry (IHC) were positive by RNA in situ hybridization (RNAscope) but with different scores. RT-qPCR showed a good correlation with the median of the grouped scores but had a wide variation in individual cases. The SOX11 negative leukemic non-nodal mantle cell lymphomas were also negative by RNAscope. TP53 was mutated in 13/63 (21%) cases, including 5/7 (71%) leukemic non-nodal and 8/56 (14%) cMCL. Interestingly, of the TP53 mutated cases, nine were in the RNAscope negative/low SOX11 group (9/15; 60%) and four in the high SOX11 group (4/36; 11%) ( P =0.0007). In conclusion, RNAscope is a reliable method to evaluate SOX11 mRNA levels. This study demonstrates the broad range of SOX11 mRNA levels in MCL. An important finding is the significant correlation of TP53 mutations with negative/low SOX11 mRNA level both in leukemic nnMCL and cMCL., (Copyright© 2020 Ferrata Storti Foundation.)

The aim of this study was to test the hypothesis that computed tomography texture analysis (CTTA) is accurate for response assessment of Hodgkin lymphoma (HL).A total of 100 patients with HL were identified. CTTA in baseline and interim staging was performed generating volume of interests in lymphoma tissue from which CTTA features including 1st, 2nd, and higher order textural features were extracted. Baseline and interim 2-deoxy-fluor-glucose positron emission tomography results were used to determine therapy response and compared to CTTA in terms of patient outcome.At interim, 1st-order features yielded a significant drop (e.g., entropy of heterogeneity, P = .01) or a significant rise (deviation, P < .001), whereas 2nd and higher order features decreased (e.g., entropy of co-occurrence matrix, P < .001). Patients achieving complete remission at end of treatment had a significantly lower entropy of heterogeneity at baseline and interim compared to patients achieving partial remission (P < .05).CT textural features change in parallel to metabolic therapy response, and are therefore a feasible diagnostic tool for a more accurate response assessment of HL.

Objective: To test the hypothesis that both indolent and aggressive chronic lymphocytic leukemia (CLL) can be differentiated from diffuse large B cell lymphoma (DLBCL) of Richter syndrome (RS) by CT texture analysis (CTTA) of involved lymph nodes., Material and Methods: We retrospectively included 52 patients with indolent CLL (26/52), aggressive CLL (8/52), and DLBCL of RS (18/52), who underwent standardized contrast-enhanced CT. In main lymphoma tissue, VOIs were generated from which CTTA features including first-, second-, and higher-order textural features were extracted. CTTA features were compared between the entire CLL group, the indolent CLL subtype, the aggressive CLL subtype, and DLBCL using a Kruskal-Wallis test. All p values were adjusted after the Bonferroni correction. ROC analyses for significant CTTA features were performed to determine cut-off values for differentiation between the groups., Results: Compared with DLBCL of RS, CTTA of the entire CLL group showed significant differences of entropy heterogeneity (p < 0.001), mean intensity (p < 0.001), mean average (p = 0.02), and number non-uniformity gray-level dependence matrix (NGLDM) (p = 0.03). Indolent CLL significantly differed for entropy (p < 0.001), uniformity of heterogeneity (p = 0.02), mean intensity (p < 0.001), and mean average (p = 0.01). Aggressive CLL showed significant differences in mean intensity (p = 0.04). For differentiation between CLL and DLBCL of RS, cut-off values for mean intensity and entropy of heterogeneity were defined (e.g., 6.63 for entropy heterogeneity [aggressive CLL vs. DLBCL]; sensitivity 0.78; specificity 0.63)., Conclusions: CTTA features of ultrastructure and vascularization significantly differ in CLL compared with that in DLBCL of Richter syndrome, allowing complementary to visual features for noninvasive differentiation by contrast-enhanced CT., Key Points: • Richter transformation of CLL into DLBCL results in structural changes in lymph node architecture and vascularization that can be detected by CTTA. • First-order CT textural features including intensity and heterogeneity significantly differ between both indolent CLL and aggressive CLL and DLBCL of Richter syndrome. • CT texture analysis allows for noninvasive detection of Richter syndrome which is of prognostic value.

The traditional concept of unidirectional maturation of hematopoietic cells has been called into question due to the recognition of lineage plasticity, which is increasingly found also in the clonal evolution of hematopoietic and lymphoid malignancies. Here we present an unusual case of a patient with TP53-mutated chronic lymphocytic leukemia (CLL) treated with a PI3Kδ inhibitor evolving to clonally related Langerhans cell histiocytosis (LCH) with acquired BRAF V600E and STK11 mutations and loss of expression of PAX-5 and other examined B cell markers. In indolent B cell lymphoma, transformation to a more aggressive high-grade lymphoma occurs frequently during the course of disease and is thought to be caused by clonal evolution. Our case further supports the concept of significant lineage plasticity in lymphomas and raises the question of a potential role of novel pharmacologic agents in clonal evolution.

Purpose: Peripheral T cell lymphomas (PTCL) are a rare and heterogeneous group of aggressive non-Hodgkin lymphomas, showing a generally poor prognosis. In this retrospective analysis, we aimed to investigate the impact of autologous stem cell transplantation (autoSCT) in PTCL., Methods: A retrospective analysis of 58 consecutive unselected PTCL patients aged 21-71 years undergoing autoSCT as first-line consolidation as well as in the relapse setting was performed., Results: The median follow-up time was 67 months. A 5-year overall survival (OS) of 53% and a 5-year progression-free survival (PFS) after autoSCT of 44% was achieved. The overall relapse rate after autoSCT was 50%. On multivariate analysis, standard baseline characteristics such as age, disease stage and international prognostic index (IPI) score failed to predict outcome in our cohort. First-line treatment with autoSCT was not associated with a benefit in OS when compared to patients receiving autoSCT at relapse. Notably, autoSCT seemed to be a suitable approach even for older transplant-eligible patients (aged ≥ 60 years), with a similar 5-year OS of 49% when compared to younger patients., Conclusions: Our study suggests that autoSCT can achieve long-term survival in PTCL patients even after relapse and should also be considered for eligible older patients.

Background: Apoptosis-stimulating Protein of TP53-2 (ASPP2) is a tumor suppressor enhancing TP53-mediated apoptosis via binding to the TP53 core domain. TP53 mutations found in cancers disrupt ASPP2 binding, arguing for an important role of ASPP2 in TP53-mediated tumor suppression. We now identify an oncogenic splicing variant, ASPP2κ, with high prevalence in acute leukemia., Methods: An mRNA screen to detect ASPP2 splicing variants was performed and ASPP2κ was validated using isoform-specific PCR approaches. Translation into a genuine protein isoform was evaluated after establishing epitope-specific antibodies. For functional studies cell models with forced expression of ASPP2κ or isoform-specific ASPP2κ-interference were created to evaluate proliferative, apoptotic and oncogenic characteristics of ASPP2κ., Findings: Exon skipping generates a premature stop codon, leading to a truncated C-terminus, omitting the TP53-binding sites. ASPP2κ translates into a dominant-negative protein variant impairing TP53-dependent induction of apoptosis. ASPP2κ is expressed in CD34+ leukemic progenitor cells and functional studies argue for a role in early oncogenesis, resulting in perturbed proliferation and impaired induction of apoptosis, mitotic failure and chromosomal instability (CIN) - similar to TP53 mutations. Importantly, as expression of ASPP2κ is stress-inducible it defines a novel class of dynamic oncogenes not represented by genomic mutations., Interpretation: Our data demonstrates that ASPP2κ plays a distinctive role as an antiapoptotic regulator of the TP53 checkpoint, rendering cells to a more aggressive phenotype as evidenced by proliferation and apoptosis rates - and ASPP2κ expression results in acquisition of genomic mutations, a first initiating step in leukemogenesis. We provide proof-of-concept to establish ASPP2κ as a clinically relevant biomarker and a target for molecule-defined therapy. FUND: Unrestricted grant support from the Wilhelm Sander Foundation for Cancer Research, the IZKF Program of the Medical Faculty Tübingen, the Brigitte Schlieben-Lange Program and the Margarete von Wrangell Program of the State Ministry Baden-Wuerttemberg for Science, Research and Arts and the Athene Program of the excellence initiative of the Eberhard-Karls University, Tübingen., (Copyright © 2019. Published by Elsevier B.V.)

Development of diffuse large B-cell lymphoma in chronic lymphocytic leukemia, so-called Richter transformation (RT), occurs in 2-5% of patients and is associated with poor outcome. The clinical features of RT are fairly non-specific and unable to discriminate transformation from other mimics. In case of clinically suspected RT, a CT/MRT is recommended, and FDG-PET/CT may help to select the site of biopsy. Radiological features suggestive of RT have been defined, but there are only limited data about their predictive value, and histological confirmation is still considered the gold standard for RT diagnosis. We retrospectively analyzed 34 patients with clinically suspected RT and available radiological and histological data. A histopathological diagnosis of RT with concordant clinical and radiological findings was obtained in 13 patients. In 18 patients, CT did not show features of transformation, concordant with lack of RT in the biopsy. Of interest, a distinct lymphoma other than DLBCL was identified in two of these cases. A false-positive radiological diagnosis of RT was rendered in two patients, including a case of Herpes simplex virus lymphadenitis. In conclusion, our findings confirm the central role of tissue biopsy in the diagnostic work up in case of clinically suspected RT.

The TNF receptor family member OX40 promotes activation and proliferation of T cells, which fuels efforts to modulate this immune checkpoint to reinforce antitumor immunity. Besides T cells, NK cells are a second cytotoxic lymphocyte subset that contributes to antitumor immunity, particularly in leukemia. Accordingly, these cells are being clinically evaluated for cancer treatment through multiple approaches, such as adoptive transfer of ex vivo expanded polyclonal NK cells (pNKC). Here, we analyzed whether and how OX40 and its ligand (OX40L) influence NK-cell function and antileukemia reactivity. We report that OX40 is expressed on leukemic blasts in a substantial percentage of patients with acute myeloid leukemia (AML) and that OX40 can, after stimulation with agonistic OX40 antibodies, mediate proliferation and release of cytokines that act as growth and survival factors for the leukemic cells. We also demonstrate that pNKC differentially express OX40L, depending on the protocol used for their generation. OX40L signaling promoted NK-cell activation, cytokine production, and cytotoxicity, and disruption of OX40-OX40L interaction impaired pNKC reactivity against primary AML cells. Together, our data implicate OX40/OX40L in disease pathophysiology of AML and in NK-cell immunosurveillance. Our findings indicate that effects of the OX40-OX40L receptor-ligand system in other immune cell subsets and also malignant cells should be taken into account when developing OX40-targeted approaches for cancer immunotherapy. Cancer Immunol Res; 6(2); 209-21. ©2018 AACR ., (©2018 American Association for Cancer Research.)

The facts that cancer represents tissues consisting of heterogeneous neoplastic, as well as reactive, cell populations and that cancers of the same histotype may show profound differences in clinical behavior have long been recognized. With the advent of new technologies and the demands of precision medicine, the investigation of tumor heterogeneity has gained much interest. An understanding of intertumoral heterogeneity in patients with the same disease entity is necessary to optimally guide personalized treatment. In addition, increasing evidence indicates that different tumor areas or primary tumors and metastases in an individual patient can show significant intratumoral heterogeneity on different levels. This phenomenon can be driven by genomic instability, epigenetic events, the tumor microenvironment, and stochastic variations in cellular function and antitumoral therapies. These mechanisms may lead to branched subclonal evolution from a common progenitor clone, resulting in spatial variation between different tumor sites, disease progression, and treatment resistance. This review addresses tumor heterogeneity in lymphomas from a pathologist's viewpoint. The relationship between morphologic, immunophenotypic, and genetic heterogeneity is exemplified in different lymphoma entities and reviewed in the context of high-grade transformation and transdifferentiation. In addition, factors driving heterogeneity, as well as clinical and therapeutic implications of lymphoma heterogeneity, will be discussed., (© 2017 S. Karger AG, Basel.)

Palisaded neutrophilic and granulomatous dermatitis (PNGD) is characterized by erythematous papules or plaques on trunk or limbs and is frequently associated with rheumatologic, autoimmune, or hematologic malignancies. Histopathology shows interstitial granulomas composed of epitheloid histiocytes in the reticular dermis with surrounding foci of collagen degeneration and variable neutrophilic inflammation. We report 3 cases of generalized PNGD associated with chronic myelomonocytic leukemia (CMML), a myelodysplastic/myeloproliferative neoplasm, which may show a variety of cutaneous manifestations. SRSF2 P95 hotspot mutations, found in 40%-50% of CMML cases, were retrospectively detected in skin and bone marrow biopsies of all 3 patients, in 1 of them already 5 years before CMML diagnosis. Generalized PNGD may represent a type of cutaneous manifestation of CMML. Because diagnosis of CMML is frequently difficult in cases with isolated persistent monocytosis and minimal dysplasia in the bone marrow, patients with a generalized PNGD should be evaluated for the presence of hematologic disorders including CMML, ideally supported by mutational analyses., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Disease relapse after one or more allogeneic hematopoietic cell transplantations (HCT) represents a therapeutic challenge with all options bearing a significant morbidity and mortality. Haploidentical HCT may induce more pronounced anti-leukemic effects and was evaluated at our center in 25 consecutive patients with disease relapse after preceding HCT receiving haploidentical grafts after in vitro T cell depletion. Overall survival at 1 and 2 years was 32 and 14%, respectively. Of note, patients with complete remission (CR) before haploidentical HCT had a very favorable overall survival of 41.7% at 2 years. Cumulative incidence of non-relapse mortality was 36 and 40% at 1 and 2 years, respectively. With a cumulative incidence for relapse of 36 and 45.6% at 1 and 2 years, disease-free survival (DFS) was 28 and 14.4%, respectively. Here also, patients with CR before haploidentical HCT had a favorable DFS of 42% at 2 years. Only very limited acute (11 patients (44%) with a median grade 1) and chronic graft versus host disease (GvHD) (5 patients (11%), limited grade only) was observed. The main complications and causes of death comprised-besides relapse-infections and bleeding complications. Hence, haploidentical HCT can achieve long-term survival comparable to second transplantation with matched or mismatched donors for patients with otherwise deleterious prognosis and should be considered as a treatment option for patients experiencing disease relapse after previous allogeneic HCT.

Post-transplant lymphoproliferative disorders (PTLD) develop as a consequence of iatrogenic immunosuppression, and the majority is associated with EBV. PTLD after allogeneic hematopoietic stem cell transplantation (allo-HCT) are rare. Most cases are donor-derived, reflecting immune reconstitution by malignant transformed donor cells, and are EBV-positive. We report three unusual cases of aggressive EBV-negative PTLD of monomorphic type after allo-HCT. All cases were of donor origin and arose with long latency, 4-12 years after HCT. The patients had a history of severe graft-versus-host disease (GVHD) resulting in prolonged immunosuppression before the diagnosis of lymphoma. In one case, the temporal evolution of the malignant clone was analyzed by clone-specific PCR targeting the immunoglobulin heavy chain rearrangement. A tumor-specific product was already detected 3 years before lymphoma development. This indicates that chronic antigenic stimulation and reduced immune surveillance, may promote the outgrowth of premalignant donor-derived clones after acquisition of additional genetic alterations.

We report a retrospective single-center analysis of 112 consecutive patients that underwent allogeneic hematopoietic cell transplantation (HCT) after reduced-intensity conditioning (RIC) with fludarabine (FLU) and busulfan (BU) for the treatment of acute myeloid leukemia (AML), myelodysplastic syndrome (MDS) and myeloproliferative syndrome (MPS) from 2005 to 2014. Three-year event-free survival (EFS) and overall survival (OS) were 46 and 58 %, respectively. Patients ≥60 years of age showed a similar outcome compared to younger patients (3-year OS 55 vs. 61 %, p = 0.96; 3-year EFS 46 vs. 46 %, p = 0.82). Cumulative incidence of non-relapse mortality (NRM) at 3 years adjusted for relapse as competing risk was 25 % for patients aged <60 years and 15 % for older patients (p = 0.15). Infusions of higher CD34(+) blood stem cell doses were associated with a significantly better outcome in the elderly subgroup (3-year OS 82 vs. 39 %, p = 0.007). Moreover, complete donor chimerism at day +100 was associated with a significantly improved survival (3-year OS 69 vs. 23 %, p = 0.003). In conclusion, our data suggest that RIC with FLU/BU enables long-term disease-free survival even in an elderly patient population. Age has no negative impact on the outcome of allogeneic HCT, and decision for transplant should be based on disease risk and performance status rather than age alone.

A 72-year-old male patient presented with multiple erythematous plaques on the lower arms, lower legs and feet. The patient suffered from rheumatoid arthritis and accompanying interstitial granulomatous dermatitis under treatment with tocilizumab. Several months prior to presentation a chronic myelomonocytic leukemia (CMML) had been diagnosed. The skin biopsy showed a perivascular infiltration of medium-sized cells with positivity for CD123, CD303 and CD4 with a low proliferation activity so that a diagnosis of a CMML-associated proliferation of plasmacytoid dendritic cells was made. The differential diagnosis of specific cutaneous infiltrates in CMML is discussed.

Vitreoretinal diffuse large B-cell lymphoma is a rare disorder, occurring as primary ocular disease or as secondary involvement by primary central nervous system lymphoma. It is usually diagnosed by cytologic, immunocytochemical, and molecular examination of vitreous aspirates. However, distinguishing vitreoretinal diffuse large B-cell lymphoma from uveitis remains difficult, and clonality analysis may be either unsuccessful or misleading. Diffuse large B-cell lymphoma arising in immune-privileged sites (eg, the central nervous system) shows a high frequency of MYD88 mutations. Therefore, we retrospectively assessed the frequency of MYD88 mutations in vitreoretinal lymphoma (VRL) and their diagnostic potential in 75 vitrectomy samples of 69 patients, and validated our results in a separate cohort (n = 21). MYD88 mutations were identified in 20 of 29 (69%) clinically, histologically, and molecularly confirmed VRL, including 6 cases of the test cohort initially diagnosed as reactive (3/6) or suspicious (3/6) for lymphoma. MYD88 mutations, especially L265P, are very frequent in VRL and their detection significantly improves the diagnostic yield of vitrectomy specimens., (© 2015 by The American Society of Hematology.)

Recurrent mutations in MYD88 have been identified in >90% of lymphoplasmacytic lymphoma (LPL). Recently, WHIM (warts, hypogammaglobulinaemia, infections, myelokathexis) syndrome-like mutations in CXCR4 have been described in 28% of LPL cases, and seem to impact clinical presentation and response to therapy. We investigated the presence of the MYD88 L265P mutation in 90 decalcified, formalin-fixed, paraffin-embedded (FFPE) bone marrow (BM) biopsies, including 51 cases of LPL, 14 cases of B-cell chronic lymphocytic leukaemia (CLL), 13 cases of marginal zone lymphoma (MZL) and 12 normal controls. In addition, the C-terminal domain of CXCR4 was sequenced in LPL cases. MYD88 L265P was found in 49/51 (96%) LPL cases and in 1/13 (7·6%) MZL (splenic type), whereas all CLL samples remained negative. The two MYD88 wild type LPL cases were associated with cold agglutinin disease. Mutations in CXCR4 were detected in 17/47 (36·2%) LPL cases, which showed a higher extent of BM infiltration and lower leucocyte counts (P = 0·02), haemoglobin (P = 0·05) and platelet counts (P = 0·01). In conclusion the detection of MYD88 L265P mutation in FFPE samples is reliable and useful for subtyping small B-cell lymphomas in BM biopsies. In addition, the presence of CXCR4 mutations identifies a subgroup of LPL patients with higher disease activity., (© 2015 John Wiley & Sons Ltd.)

Reduced intensity conditioning regimens lead to an increasing use of allogeneic hematopoietic cell transplantation (HCT) in elderly patients. We retrospectively analyzed 151 patients aged ⩾60 receiving allogeneic HCT 2000-2012 at our center. Median age was 66 years. Kaplan-Meier estimated 3-year OS was 42% with a median follow-up of 38 months. Cumulative incidences of progression and non-relapse mortality after 3 years were 38 and 24%. OS was better in the group of patients >65 years with a Kaplan-Meier estimated OS of 50% vs 34%, P=0.060. We observed a significant influence of donor age (<50 years: 53% vs >50 years: 30%, P=0.017) and gender match (matched: 57% vs mismatched: 32%, P=0.007) on outcome. The use of a matched related donor was inferior compared with a matched or mismatched unrelated donor (19% vs 47%, P=0.015). On multivariate analysis there was an increased hazard ratio for a non-gender-matched HLA-matched-related donor (hazard ratio 3.23, 95% confidence interval 1.55-6.74, P=0.002). Age had no significant impact on OS (P=0.414). In conclusion, the data suggest that older age alone has no negative impact on the outcome of allogeneic HCT. Transplant decision should be tailored to disease risk and patient performance status rather than age.

Diagnosis of chronic myelomonocytic leukemia (CMML) is based on a combination of clinical, laboratory, and morphological parameters, including persistent peripheral blood monocytosis. Recently, mutations of serine/arginine-rich splicing factor 2 (SRSF2) have been identified in 40% to 50% of CMMLs and occasionally in other myeloid disorders. In this study, we established a robust assay for the detection of SRSF2 mutations in decalcified, paraffin-embedded bone marrow (BM) biopsies and investigated its diagnostic utility. BM biopsies of 78 patients with myeloid neoplasms, including 36 CMMLs, 22 myelodysplastic syndromes (MDS), and 20 Ph- myeloproliferative neoplasms (MPN) were analyzed. The region around hot spot P95 in exon 1 of SRSF2 was amplified and bidirectionally sequenced. In addition, a restriction fragment length polymorphism analysis was established. The JAK2 V617F mutation was investigated by allele-specific polymerase chain reaction. SRSF2 mutations were identified in 16 (44%) of 36 CMMLs, including 1 of 3 cases with associated systemic mastocytosis, 4 (20%) of 20 Ph- MPN, and 1 (4.5%) of 22 MDS. Restriction fragment length polymorphism analysis detected all mutations with the exception of a single P95A. Of note, 2 cases of JAK2 V617F+ primary myelofibrosis with SRSF2 mutation initially were diagnosed as CMML based on significant peripheral blood monocytosis. In CMML, no correlation with histopathology and/or clinical parameters was observed, but SRSF2 mutations were associated with normal karyotype (P < .001). In summary, SRSF2 mutations are frequent in CMML and a useful diagnostic feature demonstrable in BM biopsies, allowing a definitive diagnosis for cases with minimal dysplasia and normal karyotype. The role of SRSF2 mutations in cases with hybrid features between primary myelofibrosis and CMML needs further investigation., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Graft-versus-host disease (GvHD) is a major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation. However, the pathophysiology of GvHD remains poorly understood. In this study, we analyzed the induction of Th17 cells by monocytes of patients with GvHD in vitro, demonstrating that monocytes isolated from patients with acute skin and intestinal GvHD stage I-IV and chronic GvHD induce significantly increased levels of Th17 cells compared with patients without GvHD. S100 proteins are known to act as innate amplifier of inflammation. We therefore investigated the presence of S100 proteins in the stool, serum, and bowel tissue of patients with GvHD and the influence of S100 proteins on the induction of Th17 cells. Elevated levels of S100 proteins could be detected in patients with acute GvHD, demonstrating the release of these phagocyte-specific proteins during GvHD. Furthermore, stimulation of monocytes with S100 proteins was found to promote Th17 development, emphasizing the role of S100 proteins in Th17-triggered inflammation. Altogether, our results indicate that induction of Th17 cells by activated monocytes and the stimulatory effects of proinflammatory S100 proteins might play a relevant role in the pathogenesis of acute GvHD. Regarding our data, S100 proteins might be novel markers for the diagnosis and follow-up of GvHD., (Copyright © 2014 by The American Association of Immunologists, Inc.)

Natural killer (NK)-cell alloreactivity after allogeneic hematopoietic cell transplantation (HCT) is influenced by the interaction of killer-cell immunoglobulin-like receptors (KIRs) on donor NK cells and human leukocyte antigen (HLA) class I ligands on recipient cells. We investigated the influence of donor KIR haplotype and KIR-ligand mismatch (MM) on relapse in 57 patients with hematologic malignancies receiving haploidentical HCT after reduced intensity conditioning and graft CD3/CD19 depletion. Of the 57 donors, 17 had KIR haplotype A (29.8 %) and 40 had KIR haplotype B (70.2 %). A KIR-ligand MM was found in 34 of 57 patients (59.6 %). There was no difference between donor KIR haplotypes in non-relapse mortality (NRM, p = 0.200) but had a significantly reduced incidence of relapse for patients with a haplotype B donor (p = 0.001). In particular, patients in partial remission (PR) benefited more from a haplotype B graft (p = 0.008) than patients in complete remission (CR, p = 0.297). Evaluating KIR-ligand MM cumulative incidences of relapse (p = 0.680) or NRM (p = 0.579), we found no significant difference. In conclusion, in the setting of reduced intensity conditioning (RIC) and CD3/CD19-depleted haploidentical HCT, we could not confirm the positive data with KIR-ligand MM but observed a significant lower risk of relapse with a KIR haplotype B donor.

After allogeneic hematopoietic cell transplantation (alloHCT) liver biopsy is performed for enigmatic liver disorders when noninvasive diagnostic steps have failed in establishing a definitive diagnosis. This document provides an updated consensus on the prerequisites for proper evaluation of liver biopsies in alloHCT patients and the histological diagnostic criteria for liver graft-versus-host disease (GvHD). The Working Group's recommendations for the histological diagnosis of liver GvHD were derived from the peer-reviewed literature and from the consensus diagnosis of a total of 30 coded liver biopsies. Acceptance of the recommendations was tested by a survey distributed to all HCT centers in Austria, Germany and Switzerland. Consensus was achieved for biopsy indications, methods of sample acquisition and processing, reporting and interpretation of biopsy findings. As GvHD is variably treated and the treatment modalities have changed over time, the panel endorses the use of more frequent biopsies in clinical studies in order to improve the present challenging clinical and diagnostic situation.

Patients with primary refractory or relapsed acute myeloid leukemia (AML) have a dismal prognosis. We report a retrospective single center analysis of aplasia-inducing chemotherapy using fludarabine, cytarabine, and amsacrine (FLAMSA) followed by reduced-intensity conditioning (RIC) for allogeneic hematopoietic cell transplantation (HCT) in 62 consecutive primary refractory or relapsed AML patients. Two-year event-free survival and overall survival (OS) were 26 and 39%, respectively. Risk stratification according to cytogenetic and molecular genetic markers showed superior survival in patients in the intermediate-1 risk group (2-year OS 70%) compared to the intermediate-2 risk (2-year OS 34%, p = 0.03) and adverse risk (2-year OS 38%, p = 0.06) group. The use of HLA-matched versus HLA-mismatched donors had no significant influence on survival (p = 0.98). Two-year OS in the elderly subgroup defined by age ≥60 years was 31% compared to 46% in the group of younger patients <60 years (p = 0.19). Cumulative incidence of non-relapse mortality at 2 years adjusted for relapse as competing risk was 20% for patients <60 years and 26% for older patients (p = 0.55). Chronic graft-versus-host disease was associated with a statistically significant superior survival (p < 0.01). FLAMSA-RIC followed by allogeneic HCT enables long-term disease-free survival in primary refractory or relapsed AML even in the elderly patient population.

Purpose: Our objective was a multifunctional imaging approach of chronic sclerodermatous graft-versus-host disease (ScGVHD) and its course during therapy using PET/MRI., Methods: We performed partial-body PET/CT and PET/MRI of the calf in 6 consecutively recruited patients presenting with severe ScGVHD. The patients were treated with different immunosuppressive regimens and supportive therapies. PET/CT scanning started 60.5 ± 3.3 minutes, PET/MRI imaging 139.5 ± 16.7 minutes after (18)F-FDG application. MRI acquisition included T1- (precontrast and postcontrast) and T2-weighted sequences. SUV(mean), T1 contrast enhancement, and T2 signal intensity from region-of-interest analysis were calculated for different fascial and muscular compartments. In addition, musculoskeletal MRI findings and the modified Rodnan skin score were assessed. All patients underwent imaging follow-up., Results: At baseline PET/MRI, ScGVHD-related musculoskeletal abnormalities consisted of increased signal and/or thickening of involved anatomical structures on T2-weighted and T1 postcontrast images as well as an increased FDG uptake. At follow-up, ScGVHD-related imaging findings decreased (SUV(mean) n = 4, mean T1 contrast enhancement n = 5, mean T2 signal intensity n = 3) or progressed (SUV(mean) n = 3, mean T1 contrast enhancement n = 2, mean T2 signal intensity n = 4). Clinically modified Rodnan skin score improved for 5 follow-ups and progressed for 2. SUV(mean) values correlated between PET/CT and PET/MRI acquisition (r = 0.660, P = 0.014), T1 contrast enhancement, and T2 signal (r = 0.668, P = 0.012), but not between the SUV(mean) values and the MRI parameters., Conclusions: PET/MRI as a combined morphological and functional technique seems to assess the inflammatory processes from different points of view and provides therefore in part complementary information.

A total of 20 patients enrolled in a multicenter phase II dose escalation study of radioimmunotherapy (RIT) using yttrium-90-ibritumomab tiuxetan at two dose levels (22 and 30 MBq/kg) in 10 patients, combined with reduced intensity conditioning (RIC) using fludarabine, melphalan and alemtuzumab followed by allogeneic hematopoietic cell transplantation (HCT) from either matched-related (n=5) or matched-unrelated donors (n=15). Postgrafting immunosuppression with cyclosporine was administered. Diagnoses were diffuse large B-cell lymphoma (n=13), transformed CLL (n=4), blastic mantle cell lymphoma (n=2) and follicular lymphoma grade 3 (n=1). Median age was 51 (range, 29-69) years. All patients were high risk with relapsed/refractory disease or relapse after preceding autologous HCT. Median follow-up of patients alive was 1115 (range, 1006-1252) days. No directly RIT-related toxicities were observed. The cumulative incidence of non-relapse mortality was 30%. Incidences of grade II-IV acute and chronic GvHD was 45% and 70%, respectively. Kaplan-Meier estimated 3-year OS and EFS were 20% for both dose levels. In conclusion, dose escalation of RIT and combined use with RIC is feasible with no additional toxicity due to dose escalation. This study is registered on http://clinicaltrials.gov as NCT00302757.

Background: We report a prospective multicenter phase II study of haploidentical hematopoietic stem cell transplantation using CD3/CD19-depleted grafts after reduced intensity conditioning with fludarabine, thiotepa, melphalan and OKT-3., Design and Methods: Sixty-one adults with a median age of 46 years (range 19-65 years) have been enrolled. Diagnoses were acute myeloid leukemia (n=38), acute lymphoblastic leukemia (n=8), non-Hodgkin's lymphoma (n=6), myeloma (n=4), chronic myeloid leukemia (n=3), chronic lymphatic leukemia (n=1) and myelodysplastic syndrome (n=1). Patients were considered high risk because of refractory disease (n=18), cytogenetics (n=6), complete remission (≥ 2) (n=9), chemosensitive relapse in partial remission (n=4) or relapse after prior hematopoietic stem cell transplantation (n=15 allogeneic, n=8 autologous, n=1 both). At haploidentical hematopoietic stem cell transplantation, 30 patients were in complete remission and 31 in partial remission. Grafts contained a median of 7.0 × 10(6) (range 3.2-22) CD34(+) cells/kg, 4.2 × 10(4) (range 0.6-44) CD3(+) T cells/kg and 2.7 × 10(7) (range 0.00-37.3) CD56(+) cells/kg., Results: Engraftment was rapid with a median of 12 days to granulocytes more than 0.5 × 10(9)/L (range 9-50 days) and 11 days to platelets more than 20 × 10(9) (range 7-38 days). Incidence of grade IIIV acute graft-versus-host-disease and chronic graft-versus-host-disease was 46% and 18%, respectively. Non-relapse mortality on Day 100 was 23% and 42% at two years. Cumulative incidence of relapse/progression at two years was 31%. Kaplan-Meier estimated 1-year and 2-year overall survival with median follow up of 869 days (range 181-1932) is 41% and 28%, respectively., Conclusions: This regimen allows successful haploidentical hematopoietic stem cell transplantation with reduced intensity conditioning in high-risk patients lacking a suitable donor. (clinicaltrials.gov identifier:NCT00202917).

History and Admission Findings: A 42-year-old woman was referred with a bleeding in the upper gastrointestinal tract, varices in the fundus of the stomach and portal hypertension of unknown primary., Investigations: Ultrasound examinations showed splenomegaly as well as portal hypertension. Blood examinations revealed low levels of haemoglobin. CT imaging showed multiple arteriovenous malformations with arterioportal shunts within the liver which led to a volume-induced portal hypertension. The genetic analysis revealed no mutations in the activin receptor-like kinase (ALK) 1 or endoglin genes., Diagnosis, Treatment and Course: The patient was clinically diagnosed with hereditary hemorrhagic teleangiectasia, also known as Osler-Weber-Rendu disease. Because of the multiple arterioportal shunts within the liver and the resulting portal hypertension with live-threatening gastrointestinal bleeding, the only therapeutic option for the patient is liver transplantation. Therefore, an application for a standard exception was made at Eurotransplant and the patient is going to be liver transplantated within the next months., Conclusions: Osler-Weber-Rendu disease is an autosomal dominant hereditary disease which leads to arteriovenous malformations and which can affect different organ systems. The course of the disease can be rather benign, but it can also lead to live-threatening complications requiring fast interventions., (© Georg Thieme Verlag KG Stuttgart · New York.)

Haploidentical hematopoietic cell transplantation (HHCT) using CD34 selected grafts is complicated by slow engraftment and immune reconstitution. Engraftment and immune reconstitution might be improved using CD3/CD19-depleted grafts and reduced intensity conditioning (RIC). We report on 28 patients after HHCT with CD3/CD19-depleted grafts using RIC, which were prospectively evaluated for engraftment and immune reconstitution. Engraftment was rapid with full chimerism reached on day +15 after HHCT. T-cell reconstitution was delayed with a median of 205 CD3+ cells/μl, 70 CD3+CD4+ cells/μl and 66 CD3+ CD8+ cells/μl on day +100, respectively. A skewed T-cell receptor-Vβ repertoire with oligoclonal T-cell expansions to day +100 and normalization after day +200 was observed. B-cell reconstitution was slow with a median of 100 CD19+ CD20+ cells/μl on day +150. Natural killer (NK) cell engraftment was fast reaching normal values on day +20. An increased natural cytotoxicity receptor and NKG2A, but decreased NKG2D and KIR expressions were observed on NK cells until day +100. We observed a positive impact of donor lymphocyte infusions on immune reconstitution. In conclusion, after HHCT, using CD3/CD19-depleted grafts and RIC, T- and B-cell reconstitution is delayed, whereas NK-cell reconstitution occurs early and fast.

Forty patients were enrolled in this phase 2 study combining radioimmunotherapy (RIT) using yttrium-90-ibritumomab-tiuxetan (15 MBq [0.4 mCi]/kg) with reduced-intensity conditioning (RIC) using fludarabine (90 mg/m(2)) and 2 Gy total body irradiation followed by allogeneic hematopoietic cell transplantation (HCT) from related (n = 13) or unrelated (n = 27) donors for the treatment of advanced non-Hodgkin lymphoma. Diagnoses were follicular lymphoma (n = 17), chronic lymphocytic leukemia (n = 13), mantle cell lymphoma (n = 8), marginal zone lymphoma (n = 1), and lymphoplasmacytic lymphoma (n = 1). Median age was 55 years (range, 34-68 years). All patients were high risk with refractory disease or relapse after preceding autologous HCT. No additional toxicities attributable to RIT were observed. Engraftment was rapid and sustained. Incidences of acute graft-versus-host disease 2-4 and chronic graft-versus-host disease were 43% and 53%, respectively. Kaplan-Meier-estimated nonrelapse mortality was 45% at 2 years. Twenty-two of 40 patients (55%) are alive, resulting in a Kaplan-Meier-estimated 2-year survival of 51% for all, 67% for follicular lymphoma, 49% for chronic lymphocytic leukemia, and 37% for mantle cell lymphoma patients. The combined use of RIT with RIC is feasible with acceptable toxicity, even in elderly and heavily pretreated patients. This study is registered at www.clinicaltrials.gov as #NCT00302757.