Malignant T-cell Lymphoma Research Articles

Phenotypic heterogeneity of mycosis fungoides cells leads to the difficulties in determining tumour origin.

Mycosis fungoides (MF) is a low-grade malignant cutaneous T-cell lymphoma that originates from memory T cells. It typically follows a unique and relatively indolent disease course. MF is used to be characterized by a tissue-resident memory T cell (TRM) phenotype, although recent molecular research has revealed its complexity, casting doubt on the cell of origin and the TRM-MF paradigm. Recent clonal heterogeneity studies suggest that MF may originate from immature early precursor T cells. During development, the tumour microenvironment (TME) influences tumour cell phenotype. The exact origin and development trajectory of MF remains elusive. Clarifying the origin of MF cells is vital for accurate diagnosis and effective treatment.

Signaling Pathway Mutations Cooperate with the PICALM/MLLT10 Fusion in a Knock-in AML Mouse Model

The PICALM/MLLT10 (or CALM/AF10; C/A) is a rare but recurring fusion gene detected in patients with T-cell acute lymphoblastic leukemia, malignant lymphoma and acute myeloid leukemia (AML). Our lab has previously established a C/A knock-in mouse model, where the fusion gene preceded by a loxP-flanked transcriptional stop cassette was inserted into the Rosa26 locus (the R26LSLCA strain). To achieve tissue-specific expression of C/A, R26LSLCA mice were crossed with three different Cre-inducer lines, namely the Vav-Cre, MB1-Cre and CD19-Cre. In the Vav-Cre strain, Cre recombinase is expressed in the entire hematopoietic system, while in the MB1-Cre and CD19-Cre lines, Cre is expressed in the B-cell compartment. Using this model, Dutta et al. showed that C/A leads to leukemia only when expressed in all hematopoietic cells, including hematopoietic stem cells and does not lead to induction of leukemia when expressed in B-cells alone ( Dutta et al., Leukemia 2016). To further characterise leukemias driven by the C/A fusion, we established new R26LSLCA and Vav-Cre crosses. Similar to what was found previously, the Vav-Cre/R26LSLCA mice developed leukemia with a long median latency of 1 year (366.5 days; N=24) and complete penetrance. On post-mortem analysis, the Vav-Cre/R26LSLCA mice were found to have splenomegaly and leucocytosis. Expression of the fusion gene was confirmed in these mice by RT-PCR on the cDNA from bone marrow (BM) cells. Immunophenotyping analysis of the BM cells and splenocytes of these mice revealed a predominantly myeloid phenotype. To assess the effect of expression of C/A on the transcriptome, we performed RNA-seq analysis using BM cells from 17 leukemic mice and 12 healthy controls. In accordance with reports on C/A patient samples, the Hoxa genes Hoxa7 and Hoxa9 as well as the Hox-cofactor Meis1 were significantly upregulated in our C/A expressing mice. In addition, genes involved in B-cell development, such as Cd19, Pax5 and Ikzf3, and Gata1, which is essential for the development of erythrocytes, were downregulated. To prove that the Vav-Cre/R26LSLCA mice were indeed leukemic and had the potential to propagate the disease, we serially transplanted BM cells from 4 Vav-Cre/R26LSLCA mice into congenic recipients. The secondary (N=20) and tertiary (N=19) transplanted mice developed leukemia with a significantly shorter median latency of 21 and 17 days, respectively. Our group and others have shown that a single genetic lesion is in most cases not sufficient to cause leukemia. Thus, to determine if additional somatic mutations were acquired by the C/A knock-in mice, we performed whole exome sequencing on the DNA from BM cells of the 4 knock-in mice, some of their daughter secondary and tertiary leukemias as well as the corresponding germline DNA samples (N=19). We identified between 2-32 mutations per leukemia exome, including mutations in genes and/or members of gene families that have been implicated in human leukemias. Mutations were detected in the transcription factors Sfpi1, Zeb1, and Sox9; Aff2, a member of the Af4/Fmr2 gene family; and Sf3a2, a component of the RNA-splicing machinery, among others. In addition, in two C/A sister secondary leukemias and the corresponding tertiary leukemias, we detected a missense mutation at amino acid 507 (G507A) of the Ptpn11 gene, which is homologous to G507 of human PTPN11, a known hotspot mutation site in AML and juvenile myelomonocytic leukemia. Interestingly, Dutta et al. also reported a G507 mutation (G507V) in Ptpn11 in a C/A knock-in mouse. PTPN11 regulates the RAS/MAPK signaling pathway. This finding is reminiscent of what we have previously reported in a C/A driven murine bone marrow transplantation model, where we detected somatic mutations in several AML-associated signal transduction genes, including Flt3, Cbl and Kras ( Desai et al., Leukemia 2020). Taken together, our results strongly suggest that mutations in genes involved in signaling cascades, particularly those in the RAS/MAPK pathway, cooperate with the C/A fusion and lead to complete malignant transformation. We aim to functionally validate these findings by establishing mouse models that harbor the C/A fusion as well as mutations in Ptpn11 and other signal transduction genes. These murine models will be immensely valuable for gaining a deeper insight into PICALM/MLLT10-mediated leukemogenesis, studying cooperating mutations and for testing new targeted therapies.

Discovery of Potent and Highly Selective Interleukin-2-Inducible T-Cell Kinase Degraders with In Vivo Activity.

Interleukin-2-inducible T-cell kinase (ITK) is a promising therapeutic target for human autoimmune diseases and T-cell malignant lymphomas. This paper reports the development of a series of cereblon-recruiting ITK proteolysis targeting chimeras based on a structure-based design strategy. The representative compounds 23 and 28 exhibited potent ITK degradation and IL-2 inhibition activities in Jurkat cells. Global proteomic profiling assays indicated that compounds 23 and 28 are highly selective ITK degraders. Moreover, compound 28 showed good plasma exposure levels and elicited efficient, rapid, and prolonged ITK degradation in Balb/c mice. Furthermore, it significantly suppressed IL-2 secretion stimulated by anti-CD3 antibody. Compound 28 represents the first effective and highly selective ITK degrader. Thus, 28 is a valuable tool compound for further in vitro and in vivo studies exploring the underlying biological effects and potential therapeutic utility of ITK degradation in human diseases.

34188 A case of systemic anaplastic large cell lymphoma with secondary cutaneous involvement

Systemic anaplastic large cell lymphoma (sALCL) is a rare, malignant T-cell lymphoma characterized by CD30 expression. There are 2 subtypes: ALK-positive sALCL and ALK-negative sALCL. In either condition, extranodal involvement is uncommon and secondary dissemination to the skin only occurs in about 20% of patients. We report a unique case in a 75-year-old woman who presented with multiple crops of pruritic papules in different stages of healing along her back for 3-4 weeks. Erythematous papules on her arms, as well as lymphadenopathy, were also present.

Genome-wide CRISPR screens identify CD48 defining susceptibility to NK cytotoxicity in peripheral T-cell lymphomas

AbstractAdult T-cell leukemia/lymphoma (ATLL) is one of the aggressive peripheral T-cell neoplasms with a poor prognosis. Accumulating evidence demonstrates that escape from adaptive immunity is a hallmark of ATLL pathogenesis. However, the mechanisms by which ATLL cells evade natural killer (NK)-cell–mediated immunity have been poorly understood. Here we show that CD48 expression in ATLL cells determines the sensitivity for NK-cell–mediated cytotoxicity against ATLL cells. We performed unbiased genome-wide clustered regularly interspaced short palindromic repeat (CRISPR) screening using 2 ATLL-derived cell lines and discovered CD48 as one of the best-enriched genes whose knockout conferred resistance to YT1–NK cell line-mediated cytotoxicity. The ability of CD48-knockout ATLL cells to evade NK-cell effector function was confirmed using human primary NK cells with reduced interferon-γ (IFNγ) induction and degranulation. We found that primary ATLL cells had reduced CD48 expression along with disease progression. Furthermore, other subgroups among aggressive peripheral T-cell lymphomas (PTCLs) also expressed lower concentrations of CD48 than normal T cells, suggesting that CD48 is a key molecule in malignant T-cell evasion of NK-cell surveillance. Thus, this study demonstrates that CD48 expression is likely critical for malignant T-cell lymphoma cell regulation of NK-cell–mediated immunity and provides a rationale for future evaluation of CD48 as a molecular biomarker in NK-cell–associated immunotherapies.

STING expression is an independent prognostic factor in patients with mycosis fungoides

Mycosis fungoides is recognized as an indolent cutaneous malignant T-cell lymphoma. In contrast, there are few therapeutic options for advanced forms of mycosis fungoides. Since immunotherapy is desirable as an alternative therapeutic option, identifying candidate molecules is an important goal for clinicians. Although tumor-derived negative immunomodulatory molecules, such as PD-1/PD-L1, have been identified in various malignancies, the useful positive immunological drivers of mycosis fungoides are largely unknown. We found that the stimulator of interferon (IFN) genes (STING) was highly upregulated in early-stage mycosis fungoides. Immunohistochemical examination revealed different STING staining patterns in patients with mycosis fungoides. Although there were no significant differences in clinical factors’ characteristics, STING expression was associated with the survival of patients with mycosis fungoides. The survival rate was significantly poor in patients with low STING-expressing mycosis fungoides. Univariate and multivariate analyses revealed that low STING expression was associated with an increased hazard ratio. Our results indicate that STING expression independently influences the prognosis of mycosis fungoides.

Marek’s disease virus serine/threonine kinase Us3 facilitates viral replication by targeting IRF7 to block IFN-β production

Marek’s disease virus (MDV) is a highly oncogenic alphaherpesvirus that induces malignant T-cell lymphomas in chickens, leading to great economic loss in poultry industry. The unique-short kinase 3 (Us3), a serine/threonine kinase encoded by three MDV types (MDV-1, MDV-2 and HVT), is important for MDV replication. However, the mechanism of Us3 facilitating MDV replication has not been completely elucidated. In the present study, we report that Us3 significantly facilities MDV replication via inhibition of β interferon (IFN-β) production at the late phase of MDV infection. Overexpression or interference of Us3 significantly promoted or inhibited the replication of MDV, and accordingly inhibited or promoted the expression of IFN-β. Further, Us3 was shown to suppresses interferon stimulatory DNA (ISD)-triggered IFN-β production by targeting IFN regulatory factor 7 (IRF7) rather than NF-κB signaling. Moreover, Us3 but not kinase-dead (KD) Us3 mutant K220A blocked the nuclear translocation of IRF7 by inhibiting dimerization. Importantly, Us3 phosphorylated and interacted with IRF7. Furthermore, Us3-deficient MDV weakened viral replication and increased IFN-β production in infected cells or chickens. These results indicated that Us3 interrupts the cytosolic DNA sensing pathway, thereby leading to inhibition of IFN-β production by targeting IRF7, promoting MDV replication. Our finding expands the knowledge about the role of Us3 in MDV replication.

Dosimetry, Optimization and FMEA of Total Skin Electron Irradiation (TSEI)

PurposeTotal Skin Electron Irradiation (TSEI) is a method for treating malignant cutaneous T-cell lymphomas. This work aims to implement and optimize the total skin technique established at Strahlenklinik Erlangen, Germany on two new linear accelerators and to quantify the risks using failure mode and effects (FMEA) analysis. Material and methodsTSEI is performed at a VersaHD accelerator (Elekta, Stockholm) with 6MeV in the “high dose rate mode” HDRE and a nominal field size of 40×40cm2. To reach the entire skin surface, the patients perform 6 different body positions at a distance of 330cm behind an acrylic scatter plate, with two overlapping irradiation fields being radiated at 2 gantry angles per position. The irradiation technique was commissioned according to the recommendation of AAPM report 23. With the help of a reference profile at 270°, 2 gantry angles were calculated, which in total resulted in an optimal dose distribution. This was metrologically verified with ion-chamber measurements in the patient's longitudinal axis. The influence of the shape of the acrylic scatter plate and the distance between the acrylic scatter plate and patient was determined by measurements. The dose homogeneity was verified using an anthropomorphic disc phantom equipped with GafChromic films. The workflows and failure modes of the total skin technique were described in a process map and subsequently quantified with a FMEA analysis. ResultsAn optimal dose distribution is achieved at a distance of SSD=330cm, using the gantry angles 289° and 251°. The previously used segmented acrylic scatter plate was replaced by a flat plate (200×120×0.5cm3), which is placed at a distance of 50cm in front of the patient. The densitometric evaluation of the GafChromic films in the anthropomorphic disc phantom revealed an expected dose distribution of 3Gy at a depth of up to 1.5cm below the skin surface, with a homogeneity of ±10% over the phantom's longitudinal axis. By FMEA a maximum risk priority number of 30 was determined. ConclusionBased on the calculations and measurements performed on the new accelerators as well as the risk analysis, we concluded that total skin therapy can be implemented clinically.

PLCγ1/PKCθ Downstream Signaling Controls Cutaneous T-Cell Lymphoma Development and Progression

Developing mechanistic rationales can improve the clinical management of cutaneous T-cell lymphomas. There is considerable genetic and biological evidence of a malignant network of signaling mechanisms, highly influenced by deregulated TCR/PLCγ1 activity, controlling the biology of these lesions. In addition, activated signal transducer and activator of transcription 3 is associated with clinical progression, although the alterations responsible for this have not been fully elucidated. Here, we studied PLCγ1-dependent mechanisms that can mediate STAT3 activation and control tumor growth and progression. Downstream of PLCγ1, the pharmacological inhibition and genetic knockdown of protein kinase C theta (PKCθ) inhibited signal transducer and activator of transcription 3 activation, impaired proliferation, and promoted apoptosis in cutaneous T-cell lymphoma cells. A PKCθ-dependent transcriptome in mycosis fungoides/Sézary syndrome cells revealed potential effector genes controlling cytokine signaling, TP53, and actin cytoskeleton dynamics. Consistently, an invivo chicken embryo model xenografted with mycosis fungoides cells showed that PKCθ blockage abrogates tumor growth and spread to distant organs. Finally, the expression of a number of PKCθ target genes found in mycosis fungoides cells significantly correlated with that of PRKCQ (PKCθ) in 81 human mycosis fungoides samples. In summary, PKCθ can play a central role in the activation of malignant cutaneous T-cell lymphoma mechanisms via multiple routes, including, but not restricted to, STAT3. These mechanisms may, in turn, serve as targets for specific therapies.

Tre-O2-03 - Mogamulizumab-associated rash frequently mimics cutaneous T-cell lymphoma recurrence but heralds a positive response to therapy: an updated single-center case series

Mogamulizumab is a humanized antibody that targets CCR4, a transmembrane chemokine receptor predominantly expressed on effector T helper type 2 and malignant cutaneous T-cell lymphoma (CTCL) cells. This biologic was FDA approved for relapsed/refractory mycosis fungoides (MF)/Sézary syndrome (SS) in 2018. MARs are the most common adverse events reported; however, the clinicopathologic nature of these eruptions remains unclear. To inform future management and recognition of MAR, we report an update on our retrospective case series of MF/SS patients treated with mogamulizumab since its approval as standard of care. Among 24 CTCL (16 SS, 8 MF) patients, 17 developed MAR (68%). MAR development was associated with complete (11/17) or partial (4/17) responses, for an overall response rate (ORR) of 88% to mogamulizumab among patients with MAR. A lower ORR of 28% (2/7) was observed in patients that did not develop MAR. Median MAR time to onset (TTO) was 2.1 mo. (0.7–9.0). Median time to resolution (TTR) was 6.9 mo. (3.5–9.2) in 8/17 patients with MAR resolution. Five distinct but frequently concurrent clinical patterns were identified: lichenoid papules and plaques (9/17), MF-like lesions (9/17), photodistribution (7/17), psoriasiform plaques (7/17), and SS-like erythroderma (3/17). Histopathologic patterns included spongiotic (n=21), lichenoid (n=14), psoriasiform (n=10), and interface (n=8) features across 27 skin biopsies. Eosinophils (n=15), epithelioid granulomas (n=4), and bizarre bi- and multinucleated cells (n=6) that may represent highly activated macrophages were also noted. Although mild, features associated with CTCL were noted in all suspected MAR tissue samples [epidermotropism (n=10), exocytosis (n=12), and lymphoid atypia (n=16)]. When compared to baseline studies, flow cytometry analysis for circulating Sézary cells and TCR rearrangement studies in skin and blood were most often negative during suspected MAR despite the presence of CTCL-associated histological features, emphasizing the importance of ancillary studies in distinguishing MAR from CTCL. In conclusion, MAR may be characterized by distinct clinical, histopathologic, and molecular patterns. Notably, MAR can clinically mimic CTCL lesions and may occur more often in patients with clinical responses, highlighting the need for clinicians to rule out progressive disease vs. drug eruption in treating a condition that historically suffers from poor outcomes and treatment response.

CLINICAL, IMAGING AND PATHOLOGICAL ASPECTS OF MAMMARY LYMPHOMAS SECONDARY TO MALIGNANT T- CELL CUTANEOUS LYMPHOMAS

Primary cutaneous lymphomas rank as the second most common clinical form of extranodal non-Hogdkin malignant lymphomas. Among non-Hodgkin malignant skin T-cell lymphomas, Mycosis Fungoides (MF) is the most frequent clinical occurence. The MF lymphoma originates in skin-homing helper T-cells, which express the CD4 + marker, showing chronic evolution, with recurrent lesions. In advanced stages, patients with Mycosis Fungoides may experience severe/extensive skin lesions or extracutaneous localizations of the disease. The secondary breast lymphoma is more common in non-Hodgkin malignant lymphoma than in Hodgkin lymphoma. Among the mammographic characteristics of breast lymphoma we mention: oval or round tumor mass, with well-defined or indistinct margins, absence of intratumoral calcifications, presence of intramammary lymph nodes, supra-adjacent skin thickening and lymphedema that causes diffuse increase in breast density. The ultrasound features of breast lymphoma run as follows: it is oval or round in shape, with well-defined or indistinct margins, which in Doppler ultrasound are identified as hypervascularized masses. The description of the imaging features of mammary lymphomas secondary to cutaneous T-cell lymphomas is required before performing the breast core-needle biopsy.

Lymphadenopathy Associated With Neutralizing Anti-interferon-gamma Autoantibodies Could Have Monoclonal T-cell Proliferation Indistinguishable From Malignant Lymphoma and Treatable by Antibiotics: A Clinicopathologic Study.

Early recognition of adult-onset immunodeficiency associated with neutralizing anti-interferon gamma autoantibodies (anti-IFNγ Abs) remains difficult, and misdiagnoses have been reported. Although febrile lymphadenopathy is among the most common initial manifestations of this disorder, no comprehensive clinicopathologic analysis of lymphadenopathy in patients with anti-IFNγ Abs has been reported. Here, we describe 26 lymph node biopsy specimens from 16 patients. All patients exhibited concurrent disseminated nontuberculous mycobacterial infections, and 31% received a tentative diagnosis of lymphoma at initial presentation. We found 3 distinct histomorphologic patterns: well-formed granuloma (46%), suppurative inflammation or loose histiocytic aggregates (31%), and lymphoproliferative disorder (LPD, 23%). The latter shared some of the features of malignant T-cell lymphoma, IgG4-related disease, and multicentric Castleman disease. Half of the specimens with LPD had monoclonal T cells, and 33.3% were indistinguishable from angioimmunoblastic T-cell lymphoma as per current diagnostic criteria. All lymphadenopathy with LPD features regressed with antibiotics without administration of cytotoxic chemotherapy or immunotherapy. The median follow-up time was 4.3 years. Our study highlights the substantial challenge of distinguishing between lymphoma and other benign lymphadenopathy in the setting of neutralizing anti-IFNγ Abs. Increased vigilance and multidisciplinary discussion among clinicians and pathologists are required to achieve the most appropriate diagnosis and management.

Single-Cell RNA-seq Reveals Characteristics of Malignant Cells and Immune Microenvironment in Subcutaneous Panniculitis-Like T-Cell Lymphoma.

BackgroundSubcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a malignant primary T-cell lymphoma that is challenging to distinguish from autoimmune disorders and reactive panniculitides. Delay in diagnosis and a high misdiagnosis rate affect the prognosis and survival of patients. The difficulty of diagnosis is mainly due to an incomplete understanding of disease pathogenesis.MethodsWe performed single-cell RNA sequencing of matched subcutaneous lesion tissue, peripheral blood, and bone marrow from a patient with SPTCL, as well as peripheral blood, bone marrow, lymph node, and lung tissue samples from healthy donors as normal controls. We conducted cell clustering, gene expression program identification, gene differential expression analysis, and cell-cell interaction analysis to investigate the ecosystem of SPTCL.ResultsBased on gene expression profiles in a single-cell resolution, we identified and characterized the malignant cells and immune subsets from a patient with SPTCL. Our analysis showed that SPTCL malignant cells expressed a distinct gene signature, including chemokines families, cytotoxic proteins, T cell immune checkpoint molecules, and the immunoglobulin family. By comparing with normal T cells, we identified potential novel markers for SPTCL (e.g., CYTOR, CXCL13, VCAM1, and TIMD4) specifically differentially expressed in the malignant cells. We also found that macrophages and fibroblasts dominated the cell-cell communication landscape with the SPTCL malignant cells.ConclusionsThis work offers insight into the heterogeneity of subcutaneous panniculitis-like T-cell lymphoma, providing a better understanding of the transcription characteristics and immune microenvironment of this rare tumor.

Marek's disease virus US3 protein kinase phosphorylates chicken HDAC 1 and 2 and regulates viral replication and pathogenesis.

Marek’s disease virus (MDV) is a potent oncogenic alphaherpesvirus that elicits a rapid onset of malignant T-cell lymphomas in chickens. Three MDV types, including GaHV-2 (MDV-1), GaHV-3 (MDV-2) and MeHV-1 (HVT), have been identified and all encode a US3 protein kinase. MDV-1 US3 is important for efficient virus growth in vitro. To study the role of US3 in MDV replication and pathogenicity, we generated an MDV-1 US3-null virus and chimeric viruses by replacing MDV-1 US3 with MDV-2 or HVT US3. Using MD as a natural virus-host model, we showed that both MDV-2 and HVT US3 partially rescued the growth deficiency of MDV-1 US3-null virus. In addition, deletion of MDV-1 US3 attenuated the virus resulting in higher survival rate and lower MDV specific tumor incidence, which could be partially compensated by MDV-2 and HVT US3. We also identified chicken histone deacetylase 1 (chHDAC1) as a common US3 substrate for all three MDV types while only US3 of MDV-1 and MDV-2 phosphorylate chHDAC2. We further determined that US3 of MDV-1 and HVT phosphorylate chHDAC1 at serine 406 (S406), while MDV-2 US3 phosphorylates S406, S410, and S415. In addition, MDV-1 US3 phosphorylates chHDAC2 at S407, while MDV-2 US3 targets S407 and S411. Furthermore, biochemical studies show that MDV US3 mediated phosphorylation of chHDAC1 and 2 affect their stability, transcriptional regulation activity, and interaction network. Using a class I HDAC specific inhibitor, we showed that MDV US3 mediated phosphorylation of chHDAC1 and 2 is involved in regulation of virus replication. Overall, we identified novel substrates for MDV US3 and characterized the role of MDV US3 in MDV pathogenesis.

A new immunotherapy strategy targeted CD30 in peripheral T-cell lymphomas: CAR-modified T-cell therapy based on CD30 mAb

Chimeric antigen receptor T-cell immunotherapy (CAR-T) has shown remarkable efficacy in treating tumors of lymphopoietic origin. Herein, we demonstrate an effective CAR-T cell treatment for recurrent and malignant CD30-positive peripheral T-cell lymphomas (PTCL) has been demonstrated. The extracellular fragment gene sequences of CD30 were obtained from tumor tissues of PTCL patients and cloned into a plasmid vector to express the CD30 antigen. The CD30 targeting single-chain antibody fragment (scFv) was obtained from CD30-positive monoclonal hybridoma cells, which were obtained from CD30 antigen immunized mice. After a second-generation of CAR lentiviral construction, CD30 CAR T cells were produced and used to determine the cytotoxicity of this construct toward Karpas 299 cells. The results of CD30 CAR T-mediated cell lysis show that 9C11-2 CAR T cells could significantly promote the lysis of CD30-positive Karpas 299 cells in both LDH and real-time cell electronic sensing (RTCA) assays. In vivo data show that 9C11-2 CAR T cells effectively suppress the tumor growth in a Karpas 299 cell xenograft NCG mouse model. The CD30 CAR T cells exhibited an efficient cytotoxic effect after being co-cultured with the target cells and they also exhibited a significant tumor-inhibiting ability after being intravenously injected into PTCL xenograft tumors; these observations suggest that the new CD30 CAR-T cell may be a promising therapeutic candidate for cancer therapy.

T-cell receptor antibodies expression in benign and malignant cutaneous lymphoid infiltrates in comparison with T-cell receptor gene rearrangement and its diagnostic utility in borderline cases

IntroductionCutaneous T-cell lymphoid infiltrate can represent reactive lesion or a malignant T-cell lymphoma. However, clinical and histopathological appearance can overlap in both groups with a risk of misdiagnosis. Aberrant expression of T-cell markers is not always applicable and T-cell receptor (TCR) gene rearrangement is not always accessible and diagnosis in borderline cases can be challenging. AimsSeveral types of TCR antibodies are currently available with limited knowledge of their expression in different cutaneous lymphoid infiltrates. Aim of the study is a comparison of expression of TCR antibodies in benign and malignant lymphoid infiltrates and their utility in borderline cases. MethodsRepresentative cases of reactive and malignant lymphoproliferations were collected. Separate group of lesions with borderline morphology was selected for comparison. Immunohistochemical expression of TCR-V-betaF1 (TCRBF1), TCR-C-beta1 (TCRJOVI.1), TCR gamma/delta (TCRGD) and TCR delta (TCRD) was performed in all cases. TCR gene rearrangement evaluation was performed in all cases using PCR BIOMED-2 assay. ResultsBenign lymphoid infiltrates were all negative in TCRD and TCRGD. Expression of TCRJOVI.1 was seen in 3/10 cases and TCRBF1 in one. T-cell lymphomas were positive for TCRBF1 and TCRGD in 60% and 30% of cases respectively. TCR gene rearrangement was confirmed in 90% of lymphoma cases. All benign lesions were polyclonal. Morphologically borderline lesions showed expression of TCRBF1 in 6/10 cases and TCR gene rearrangement in 4/10 cases. Re-evaluation of the cases and clinical correlation led to the change of the diagnosis and confirmation of T-cell lymphoma in 4/10 cases. ConclusionsExpression of TCRBF1 and TCR-gene rearrangement was significantly associated with malignant infiltrates. TCRBF1 positivity in borderline cutaneous lymphoproliferations can raise the suspicion of malignancy but confirmation by TCR gene rearrangement and careful clinical correlation is still advisable.

The Emergence of a vv + MDV Can Break through the Protections Provided by the Current Vaccines.

Marek’s disease (MD) is an infectious malignant T-cell lymphoma proliferative disease caused by Marek’s disease virus (MDV). In recent years, the emergence of very virulent (vv) and/or very virulent plus (vv +) strains of MDV in the field has been suggested as one of the causes of vaccination failure. The pathogenicity of the MDV strain GX18NNM4, isolated from a clinical outbreak in a broiler breeder flock that was vaccinated with CVI988/Rispens, was investigated. In the vaccination-challenge test, GX18NNM4 was able to break through the protections provided by the vaccines CVI988 and 814. It also significantly reduced body weight gain and caused marked gross lesions and a large area of infiltration of neoplastic lymphocyte cells in the heart, liver, pancreas, etc. of the infected birds. In addition, the expressions of programmed death 1 (PD-1) and its ligand, programmed death ligand 1 (PD-L1), in the spleens and cecal tonsils (CTs) of the unvaccinated challenged birds were significantly increased compared to those in the vaccinated challenged birds, indicating that the PD-1/PD-L1 pathway is related to immune evasion mechanisms. The results showed that the GX18NNM4 strain could cause severe immunosuppression and significantly decrease the protections provided by the current commercial vaccines, thus showing GX18NNM4 to be a vv + MDV strain.

Discovery of IAP-recruiting BCL-XL PROTACs as potent degraders across multiple cancer cell lines

Targeting BCL-XL via PROTACs is a promising strategy in reducing BCL-XL inhibition associated platelet toxicity. Recently, we reported potent BCL-XL PROTAC degraders that recruit VHL or CRBN E3 ligase. However, low protein expression or mutation of the responsible E3 ligase has been known to result in decreased protein degradation efficiency of the corresponding PROTACs. To overcome these mechanisms of resistance, PROTACs based on recruiting alternative E3 ligases could be generated. Thus, we designed and synthesized a series of PROTACs that recruit IAP E3 ligases for BCL-XL degradation. Among those PROTACs, compound 8a efficiently degrades BCL-XL in malignant T-cell lymphoma cell line MyLa 1929 while CRBN-based PROTACs that have high potency in other cancer cell lines show compromised potency, likely due to the low CRBN expression. Moreover, compared with the parent compound ABT-263, PROTAC 8a shows comparable cell killing effects in MyLa 1929 cells whereas the on-target platelet toxicity is significantly reduced. Our findings expand the anti-tumor spectra of BCL-XL degraders and further highlight the importance of selecting suitable E3 members to achieve effective cellular activity.

T-Cell Lymphoma Misdiagnosed as Crohn’s Disease: Case Report

Abstract For many years, there has been a concern that inflammatory bowel disease carries an increased lymphoma risk. At the same time, patients with intestinal lymphomas are occasionally misdiag-nosed as having Crohn’s disease. We report a case of T-cell lymphoma of the bowel misdiag-nosed as Crohn’s disease, which illustrates the diagnostic challenges posed by peripheral extranodal lymphomas. A 68-year old female presented with clinical symptoms (diarrhoea, abdominal pain, poor appetite and significant weight loss), and colonoscopic and initial histological findings that were similar to inflammatory bowel disease. She was diagnosed with Crohn’s disease and received treatment with sulfasalazine with subsequent improvement of symptoms. Eight months after the initial diagnosis the patient experienced sudden abdominal pain. Laparotomy revealed necrosis in the small and large intestine and ileostomy was performed. On day 10 of a complicated postoperative period the patient died. Post-mortem histopathological examination of small and large intestine revealed highly malignant peripheral T-cell lymphoma, not otherwise specified. Differentiation of intestinal T-cell lymphoma from Crohn’s disease continues to be a challenge, because clinical, colonoscopic, radiological and histopathological findings can mimic Crohn’s disease. Careful multi-disciplinary assessment and knowledge of this rare disorder is crucial for timely diagnosis.

Potential Role of Macrophage Migration Inhibitory Factor in the Pathogenesis of Marek's Disease.

IntroductionMarek’s disease virus (MDV) can cause malignant T-cell lymphomas and immunosuppression in chickens. Macrophage migration inhibitory factor (MIF) not only plays a critical role in inhibiting T-cell responses, but also contributes to multiple aspects of tumour progression. The aim of this study was to reveal the potential role of MIF in the pathogenesis of MDV infection.Material and MethodsMIF gene expression levels were measured by using real-time PCR. Expression was assayed at different times in chicken embryo fibroblast (CEF) cells and tissue samples of SPF chickens infected with different MDV strains and fold change was calculated by the 2–△△CT method.ResultsThe expression of MIF was significantly downregulated (p < 0.05 and FC > 2) in CEF cells infected with the very virulent MDV RB1B strain at 48 h post infection (hpi) and in the skin and spleen at 14 days post infection (dpi). The reduction of MIF expression was also found in CEF cells infected by reticuloendotheliosis virus (REV), avian leukosis virus subgroup J (ALV-J), and MDV vaccine strain CVI988 or in HD11 cells stimulated with TLR2, 3, 4, and 7 ligands. Interestingly, MIF expression decreased continuously from 7 to 28 dpi in the thymus after RB1B virus infection while it increased after CVI988 virus infection. Upregulated expression of MIF was found in CEF infected with RB1B at 96 hpi and in the spleen and skin at 21 and 28 dpi.ConclusionThe present study revealed the different expression pattern of MIF in response to MDV infection and indicated that MIF level may be associated with MDV pathogenesis.