Comprehensive genetic profiling reveals frequent alterations of driver genes on the X chromosome in extranodal NK/T-cell lymphoma.

Extranodal NK/T-cell lymphoma (ENKTCL) is an Epstein-Barr virus (EBV)-related neoplasm with male dominance and a poor prognosis. A better understanding of the genetic alterations and their functional roles in ENKTCL could help improve patient stratification and treatments. Here, we performed comprehensive genetic analysis of 177 ENKTCL cases to delineate the landscape of mutations, copy number alterations (CNAs), and structural variations, identifying 34 driver genes including six previously unappreciated ones, namely HLA-B, HLA-C, ROBO1, CD58, POT1, and MAP2K1. Among them, CD274 (24%) was the most frequently altered, followed by TP53 (20%), CDKN2A (19%), ARID1A (15%), HLA-A (15%), BCOR (14%), and MSN (14%). Chromosome X (chrX) losses were the most common arm-level CNAs in females (~40%), and alterations of four X-linked driver genes (MSN, BCOR, DDX3X, and KDM6A) were more frequent in males and females harboring chrX losses. Among X-linked drivers, MSN was the most recurrently altered, and its expression was lost in approximately one-third of cases using immunohistochemical analysis. Functional studies of human cell lines demonstrated that MSN disruption promoted cell proliferation and NF-κB activation. Moreover, MSN inactivation increased sensitivity to NF-κB inhibition in vitro and in vivo. In addition, recurrent deletions were observed at the origin of replication in the EBV genome (6%). Finally, by integrating the 34 drivers and 19 significant arm-level CNAs, non-negative matrix factorization and consensus clustering identified two molecular groups with different genetic features and prognosis irrespective of clinical prognostic factors. Together, these findings could help improve diagnostic and therapeutic strategies in ENKTCL.

Unmasking Bartonella henselae infection in the shadows of long COVID thanks to clinical metagenomics.

The diagnosis of long COVID often relies on symptoms post-COVID-19, occasionally lacking biological evidence. This case study illustrates how investigating long COVID uncovered an underlying bartonellosis through clinical metagenomics. Following mild COVID-19, a 26-year-old woman experienced persistent symptoms during 5 months, including axillary adenopathy. Pathological examination, 16 S rRNA PCR, and clinical metagenomic analysis were done on an adenopathy biopsy. The latter revealed Bartonella henselae DNA and RNA. Treatment with clarithromycin improved symptoms. This case underscores the relevance of clinical metagenomics in diagnosing hidden infections. Post-COVID symptoms warrant thorough investigation, and bartonellosis should be considered in polyadenopathy cases, regardless of a recent history of cat or flea exposures.

Low-dose non-steroidal anti-inflammatory drugs: a promising approach for the treatment of symptomatic bone marrow failure in Ghosal hematodiaphyseal dysplasia.

Not available.

Genomic and functional impact of Trp53 inactivation in JAK2V617F myeloproliferative neoplasms.

Classical myeloproliferative neoplasms (MPNs) are characterized by the proliferation of myeloid cells and the risk of transformation into myelofibrosis or acute myeloid leukemia (AML) and TP53 mutations in MPN patients are linked to AML. However, JAK2V617F has been reported to impact the TP53 response to DNA damage, suggesting potential overlapping role of TP53 inactivation in MPN. We established a mouse model showing that JAK2V617F/Vav-Cre/Trp53-/- mice displayed a similar phenotype to JAK2V617F/Vav-Cre mice, but their proliferation was outcompeted in competitive grafts. RNA-Seq revealed that half of the genes affected by JAK2V617F were affected by p53-inactivation, including the interferon pathway. To validate this finding, mice were repopulated with a mixture of wild-type and JAK2V617F (or JAK2V617F/Vav-Cre/Trp53-/-) cells and treated with pegylated interferonα. JAK2V617F-reconstituted mice entered complete hematological remission, while JAK2V617F/Vav-Cre /Trp53-/--reconstituted mice did not, confirming that p53 loss induced interferon-α resistance. KEGG and Gene Ontology analyses of common deregulated genes showed that these genes were mainly implicated in cytokine response, proliferation, and leukemia evolution, illustrating that in this mouse model, the development of MPN is not affected by TP53 inactivation. Taken together, our results show that many genetic modifications induced by JAK2V617F are influenced by TP53, the MPN phenotype may not be. Trp53 loss alone is insufficient to induce rapid leukemic transformation in steady-state hematopoiesis in JAK2V617F MPN, and Trp53 loss may contribute to interferon resistance in MPN.

Higher rate of progression in HIV- than in HIV+ patients after rituximab for HHV8+ multicentric Castleman disease.

Rituximab has revolutionized the treatment of Kaposi sarcoma-associated herpesvirus/human herpesvirus 8-associated multicentric Castleman disease (HHV8+ MCD), converting a rapidly fatal illness into a relapsing disease. HHV8+ MCD mainly affects patients with HIV infection but can also be observed in patients without HIV infection. We retrospectively analyzed a cohort of 99 patients (73 who tested HIV+ and 26 who tested HIV-), with HHV8+ MCD treated with rituximab-based therapy. Baseline characteristics were similar in patients who had HIV- and HIV+ results, although those who tested HIV- were older (65 vs 42 years) and presented less frequently with Kaposi sarcoma (15% vs 40%). Ninety-five patients (70 HIV+ and 25 HIV-) achieved complete remission (CR) after rituximab-based therapy. After a median follow-up of 51 months, 36 patients (12 HIV- and 24 HIV+) experienced disease progression. The 5-year progression-free survival (PFS) was 54%. The 5-year PFS was lower in HIV- patients than in HIV+ patients : 26% and 62%, respectively (P = .02). A multivariate prognostic factors analysis including time-dependent covariates revealed that HIV- status, reoccurrence of HHV8 DNA >3 log copies per mL, and serum C-reactive protein (CRP) >20 mg/mL were independently associated with an increased risk of progression after rituximab-induced CR (P = .001; P = .01; and P = .01, respectively). The lower rate of progression observed in the population with HIV+ results despite a longer follow-up period might have resulted from the possible immune restoration upon antiretroviral therapy. HHV8 viral load and serum CRP monitoring after rituximab therapy provide information on the progression risk and may help in the decision to resume specific therapy.

Paraneoplastic pemphigus uncovers distinct clinical and biological phenotypes of western unicentric Castleman disease.

Unicentric Castleman disease (UCD) is a lymphoproliferative disease of unknown cause. Paraneoplastic pemphigus (PNP) is a major complication shown to be associated with a poor prognosis, with particular severity in patients with bronchiolitis obliterans (BO). This study describes the clinical and biological characteristics of UCD-PNP patients in a large Western cohort. A total of 148 patients diagnosed with UCD were identified, including 14 patients with a defined PNP. PNP was significantly associated with myasthenia gravis (MG) and FDC sarcoma during follow-up (FDCS). PNP was also significantly associated with reduced survival. These data, together with a multivariate analysis by principal components, led to the identification of UCD-PNP as a group at risk of MG, FDCS and death. PDGFRB sequencing performed on UCD lesions from six patients found the gain-of-function p.N666S variant in two. Interestingly, both patients had hyaline-vascular UCD subtype, were in the UCD-PNP subgroup and had FDCS. Sera from 25 UCD-PNP patients and 6 PNP patients without UCD were tested for PNP-associated autoantibodies. Sera from UCD-PNP patients had a strong reactivity against the N-terminal domain of recombinant periplakin (rPPL, 82%) and showed reactivity against at least two domains of rPPL. These features were not found in patients with UCD alone or in the PNP group without UCD. These data indicate that UCD-PNP patients belong to a subgroup sharing strong clinical and biological identity that might help to decipher the different dynamics of UCD natural history.

Positron emission tomography-imaging assessment for guiding strategy in patients with relapsed/refractory large B-cell lymphoma receiving CAR T cells.

The aim of this study was to evaluate the prognostic impact of the F-fluorodeoxyglucose positron emission tomography response at 1 month (M1) and 3 months (M3) after anti-CD19 chimeric antigen receptor (CAR) T-cell therapy in a multicenter cohort of 160 patients with relapsed/refractory large B-cell lymphomas (R/R LBCL). In total, 119 (75%) patients reached M1 evaluation; 64 (53%, 64/119) had a complete response (CR); 91% were Deauville Score (DS) 1-3. Progressionfree survival (PFS) and overall survival (OS) were significantly worse in patients with DS-5 at M1, than in patients with DS 1-3 (PFS hazard ratio [HR]=6.37, 95% confidence interval [CI]: 3.5-11.5 vs. OS HR=3.79, 95% CI: 1.7-8.5) and DS-4 (PFS HR=11.99, 95% CI: 5.0-28.9 vs. OS HR=12.49, 95% CI: 2.8-55.8). The 1-year PFS rates were 78.9% (95% CI: 58.9-89.9) for DS-4 at M1, similar to 67.3% (95% CI: 51.8-78.8) for patients with DS 1-3 at M1, very different to 8.6% (95% CI: 1.8-22.4) for DS-5, respectively. Only eight of 30 (26%) patients with DS-4 progressed. Response at M3 evaluated in 90 (57%) patients was prognostic for PFS with lower discrimination (HR=3.28, 95% CI: 1.5-7.0; P=0.003) but did not predict OS (HR=0.61, 95% CI: 0.2-2.3; P=0.45). Patients with a high baseline total metabolic tumor volume (TMTV) >80 mL had worse PFS (HR=2.05, 95% CI: 1.2-3.5; P=0.009) and OS (HR=4.52, 95% CI: 2.5-8.1; P<0.001) than patients with low TMTV. Multivariable analyses identified baseline elevated lactate dehydrogenase, DS-5, CAR T cells at M1 for PFS and baseline elevated lactate dehydrogenase, TMTV >80 mL, and DS-5 at M1 for OS. In conclusion, baseline TMTV and response at M1 strongly predicts outcomes of patients with R/R LBCL undergoing CAR T-cell therapy.

Characteristics of circulating KSHV-infected viroblasts during active KSHV+ multicentric Castleman disease.

Kaposi sarcoma-associated herpesvirus (KSHV)/human herpesvirus 8-associated multicentric Castleman disease (MCD) is a polyclonal B-cell lymphoproliferative disorder that mainly occurs in immunocompromised hosts. The diagnosis relies on lymph node biopsy demonstrating KSHV-infected cells located in the mantle zone with a marked interfollicular plasma cell infiltration. Infected cells are large cells positive for immunoglobulin M (IgM), λ light chain, and CD38, described initially as infected plasmablasts. We show that IgM+λ+CD38high cells were also detectable in the peripheral blood of 14 out of 18 (78%) patients with active KSHV-MCD and absent in 40 controls. Using immunofluorescence and flow-fluorescence in situ hybridization, we demonstrate that these cells are KSHV infected and express both latent and lytic KSHV transcripts. These KSHV-infected viroblasts (KIVs) harbor a distinct phenotype compared with conventional plasmablasts. We also identified several putative mechanisms of immune escape used by KSHV, because KIVs displayed an overall decrease of costimulatory molecules, with a remarkable lack of CD40 expression and are interleukin-10-producing cells. The identification of this specific and easily accessible KSHV+ circulating population brings new elements to the understanding of KSHV-MCD but also raises new questions that need to be clarified.

Lymphoma as an Exclusion Criteria for CVID Diagnosis Revisited.

PURPOSE: Hypogammaglobulinemia in a context of lymphoma is usually considered as secondary and prior lymphoma remains an exclusion criterion for a common variable immunodeficiency (CVID) diagnosis. We hypothesized that lymphoma could be the revealing symptom of an underlying primary immunodeficiency (PID), challenging the distinction between primary and secondary hypogammaglobulinemia. METHODS: Within a French cohort of adult patients with hypogammaglobulinemia, patients who developed a lymphoma either during follow-up or before the diagnosis of hypogammaglobulinemia were identified. These two chronology groups were then compared. For patients without previous genetic diagnosis, a targeted next-generation sequencing of 300 PID-associated genes was performed. RESULTS: A total of forty-seven patients had developed 54 distinct lymphomas: non-Hodgkin B cell lymphoma (67%), Hodgkin lymphoma (26%), and T cell lymphoma (7%). In 25 patients, lymphoma developed prior to the diagnosis of hypogammaglobulinemia. In this group of patients, Hodgkin lymphoma was overrepresented compared to the group of patients in whom lymphoma occurred during follow-up (48% versus 9%), whereas MALT lymphoma was absent (0 versus 32%). Despite the histopathological differences, both groups presented with similar characteristics in terms of age at hypogammaglobulinemia diagnosis, consanguinity rate, or severe T cell defect. Overall, genetic analyses identified a molecular diagnosis in 10/47 patients (21%), distributed in both groups and without peculiar gene recurrence. Most of these patients presented with a late onset combined immunodeficiency (LOCID) phenotype. CONCLUSION: Prior or concomitant lymphoma should not be used as an exclusion criteria for CVID diagnosis, and these patients should be investigated accordingly.

[Castleman disease]. / La maladie de Castleman.

The term "Castleman disease" covers a variety of entities that have very different clinical, biological, pathological and physiopathological features. In this issue, we review the characteristics of the unicentric Castleman disease, of the HHV8 associated multicentric Castleman disease and the idiopathic multicentric Castleman disease associated or not with TAFRO syndrome ("thrombocytopenia, anasarca, fever, reticulin myelofibrosis and/or renal insufficiency, organomegaly"). We detail the differential diagnostics of these entities.

HHV-8 associated lymphoma.

PURPOSE OF REVIEW: The discovery of Kaposi sarcoma herpesvirus (KSHV) / human herpesvirus 8 (HHV-8) led to recognition of primary effusion lymphoma (PEL) as a distinct lymphoproliferative disorder. Subsequently, two other types of lymphoma have been shown to be associated with HHV-8 : HHV-8 positive diffuse large B cell lymphoma not otherwise specified and germinotropic lymphoproliferative disorder.The pathogenesis of PEL is unique as in most cases the HHV-8+ tumoral cells are coinfected with the Epstein-Barr virus (EBV), suggesting an interplay between these two herpesviruses. This article reviews advances in the field of characterization of the lymphomatous cells, pathogenesis, and targeted therapies. RECENT FINDINGS: The gene expression profile analysis of PEL cells and the experimental coinfection of peripheral B cells with HHV-8 and EBV allow dissection of the mechanisms of lymphomagenesis and of the relative contribution of both viruses. Systemic chemotherapy regimen remains poorly effective but new therapeutic perspectives are open with the use of monoclonal antibodies, immunomodulatory drugs, and immunotherapy. SUMMARY: HHV-8 associated lymphoma is a model for studying virus-induced lymphoproliferation and its relation with host immune response and PEL is a unique model to study the relative contribution of two herpesviruses to lymphomagenesis in coinfected cells.

Leg-type form of idiopathic multicentric Castleman disease associated with severe lower extremity chronic venous/lymphatic disease.

Idiopathic multicentric Castleman disease (iMCD) is a lymphoproliferative disease of unknown etiology. Deciphering mechanisms involved in CD pathogenesis may help improving patients' care. Six cases of stereotyped sub-diaphragmatic iMCD affecting lower limb-draining areas and associated with severe and often ulcerative lower extremity chronic dermatological condition were identified in our cohort. Pathological examination revealed mixed or plasma-cell type MCD. In three patients, shotgun metagenomics failed to identify any pathogen in involved lymph nodes. Antibiotics had a suspensive effect while rituximab and tocilizumab failed to improve the condition. This novel entity requires a specific approach and exclusion of potentially harmful immunomodulation.

A Comprehensive Clinicopathologic and Molecular Study of 19 Primary Effusion Lymphomas in HIV-infected Patients.

Primary effusion lymphoma (PEL) is associated with human herpesvirus 8 and frequently with Epstein-Barr virus (EBV). We report here a single-center series of 19 human immunodeficiency virus-associated PELs, including 14 EBV+ and 5 EBV- PELs. The objectives were to describe the clinicopathologic features of PELs, with a focus on programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) expression, to search for genetic alterations by targeted deep sequencing analysis, and to compare the features between EBV+ and EBV- cases. All the patients were male, and the median age at diagnosis was 47 years old (interquartile range: 40 to 56 y). Reflecting the terminal B-cell differentiation, immunophenotypic profiles showed low expression levels of B-cell markers, including CD19 (0/19), CD20 (1/19), CD79a (0/19), PAX5 (1/19), BOB1 (3/19), and OCT2 (4/19), contrasting with a common expression of CD38 (10/19), CD138 (7/19), and IRF4/MUM1 (18/19). We observed a frequent aberrant expression of T-cell markers, especially CD3 (10/19), and less frequently CD2 (2/19), CD4 (3/19), CD5 (1/19), and CD8 (0/19). Only 2 cases were PD-L1 positive on tumor cells and none PD-1 positive. With respect to immune cells, 3 samples tested positive for PD-L1 and 5 for PD-1. Our 36-gene lymphopanel revealed 7 distinct variants in 5/10 PELs, with either a single or 2 mutations per sample: B2M (n=2), CD58 (n=1), EP300 (n=1), TNFAIP3 (n=1), ARID1A (n=1), and TP53 (n=1). Finally, we did not observe any major clinical, pathologic, or immunohistochemical differences between EBV+ and EBV- PELs and the outcome was similar (2-y overall survival probability of 61.9% [95% confidence interval, 31.2-82.1] vs. 60.0% [95% confidence interval, 12.6-88.2], respectively, P=0.62).

Long-term outcomes of adult pulmonary Langerhans cell histiocytosis: a prospective cohort.

BACKGROUND: The long-term outcomes of adult pulmonary Langerhans cell histiocytosis (PLCH), particularly survival, are largely unknown. Two earlier retrospective studies reported a high rate of mortality, which contrasts with our clinical experience. METHODS: To address this issue, all patients with newly diagnosed PLCH referred to the French national reference centre for histiocytoses between 2004 and 2018 were eligible for inclusion. The primary outcome was survival, which was defined as the time from inclusion to lung transplantation or death from any cause. Secondary outcomes included the cumulative incidences of chronic respiratory failure (CRF), pulmonary hypertension (PH), malignant diseases and extrapulmonary involvement in initially isolated PLCH. Survival was estimated using the Kaplan-Meier method. RESULTS: 206 patients (mean age 39±13 years, 60% female, 95% current smokers) were prospectively followed for a median duration of 5.1 years (IQR 3.2-7.6 years). Of these, 12 patients (6%) died. The estimated rate of survival at 10 years was 93% (95% CI 89-97%). The cumulative incidences of CRF and/or PH were <5% at both 5 and 10 years, and 58% of these patients died. 27 malignancies were observed in 23 patients. The estimated standardised incidence ratio of lung carcinoma was 17.0 (95% CI 7.45-38.7) compared to an age- and sex-matched French population. Eight (5.1%) of the 157 patients with isolated PLCH developed extrapulmonary involvement. CONCLUSION: The long-term prognosis of PLCH is significantly more favourable than has previously been reported. Patients must be closely monitored after diagnosis to detect severe complications early.

Granulomatous-lymphocytic interstitial lung disease: an international research prioritisation.

The first ever research prioritisation exercise in GLILD: this survey identified areas of interest in the diagnosis, treatment and management of GLILD, which can be used as a roadmap for future research https://bit.ly/3nVuzti.

High-grade Follicular Lymphomas Exhibit Clinicopathologic, Cytogenetic, and Molecular Diversity Extending Beyond Grades 3A and 3B.

Although follicular lymphoma (FL) is usually graded as FL1-2, FL3A, and FL3B, some borderline cases can be observed and led us to investigate the clinicopathologic diversity of grade 3 FL (FL3). Among 2449 FL patients enrolled in Lymphoma Study Association (LYSA) trials, 1921 cases with sufficient material underwent a central pathologic review. The resulting diagnoses comprised 89.6% FL1-2 (n=1723), 7.2% FL3A (n=138), and 0.5% purely follicular FL3B (n=9). The remaining 51 unclassifiable cases (2.7%) exhibited high-grade features but did not meet WHO criteria for either FL3A or FL3B; and were considered as "unconventional" high-grade FL (FL3U). FL3U morphological pattern consisted of nodular proliferation of large cleaved cells or small-sized to medium-sized blast cells. Compared with FL3A, FL3U exhibited higher MUM1 and Ki67 expression, less BCL2 breaks and more BCL6 rearrangements, together with a higher number of cases without any BCL2, BCL6 or MYC rearrangement. FL3U harbored less frequent mutations in BCL2, KMT2D, KMT2B, and CREBBP than FL3A. MYC and BCL2 were less frequently mutated in FL3U than FL3B. Rituximab cyclophosphamide, doxorubicin, vincristine, and prednisone treated FL3U patients had a worse survival than FL1-2 patients with similar follicular lymphoma international prognostic index and treatment. These results suggest that high-grade FLs encompass a heterogeneous spectrum of tumors with variable morphology and genomic alterations, including FL3U cases that do not strictly fit WHO criteria for either FL3A or FL3B, and display a worse outcome than FL1-2. The distinction of FL3U may be useful to allow a better comprehension of high-grade FLs and to design clinical trials.