TP53/NPM1-mutated acute myeloid leukemia as a molecularly distinct disease entity.

7030 Background: TP53-mutated acute myeloid leukemia (AML) is a distinct disease entity associated with a dismal prognosis. This disease group is distinguishable by its low frequency of SNVs, unremarkable transcriptional signatures, and lower leukocyte and myeloblast counts compared to TP53 wildtype disease. Response to gold-standard hypomethylating agents is typically transient. NPM1 mutations in this disease subset are rare despite the fact that NPM1c has been shown to negatively regulate the tumor suppressive functions of p53 .Methods: Bone marrow, peripheral blood, or FFPE tissue samples from 10,118 patients with suspected myeloid disease were sequenced using a dual DNA/RNA 297 gene myeloid panel. Results were validated in a separate independent dataset using a 54 gene TruSight myeloid panel (N = 2463). FISH/cytogenetic data was analyzed across myeloid disease. Patients with confirmed AML (n = 460) were included in the NGS portion of this study. Statistics were performed using Fisher’s exact test for categorical variables and two-tailed T-test for continuous variables. Results: All TP53-mutated myeloid disease (n = 1282 / 10,118) was associated with fewer co-mutations except DNMT3A (13.4%; n = 172), and complex cytogenetics (36.4%; n = 134/381). TP53+/NPM1+ status across all myeloid disease was not associated with a complex karyotype (7.6% vs 38.5%; 1/13 vs. 133/368, p = 0.02). Among AML patients, NPM1+/TP53+ patients (n = 18) were more co-mutated with DNMT3A (33.3% vs. 10.3%, P = 0.01), FLT3 (33.33% vs. 2.5%, P < 0.0001), IDH1 (27.8% vs. 4.4%, P = 0.002), IDH2 (22.2% vs. 6.4%, P = 0.03); and PTPN11 (22.2% vs. 2.5%, P = 0.003) when compared to TP53+/NPM1- patients. NPM1+/TP53+ AML had more mutations in recurrently mutated genes (4.5 vs 2.1; P < 0.0001) than TP53+/NPM1- AML. Conclusions: TP53+/NPM1+ AML harbors molecular signatures which clearly distinguish it from ordinary TP53-mutated AML, and is more reflective of de novo and NPM1+ AML. Further clinical outcome studies are needed to determine the therapeutic and prognostic implications of this subset, and whether other TP53-mutated patients can be better risk stratified.[Table: see text]

Baseline Characteristics and Survival of an Australian Interstitial Pneumonia with Autoimmune Features Cohort

<b><i>Background and objective:</i></b> The research term “interstitial pneumonia with autoimmune features” (IPAF) encompasses interstitial lung disease (ILD) patients with autoimmune features not meeting diagnostic criteria for a defined connective tissue disease (CTD). It remains unclear if IPAF is a distinct disease entity with implications for management and prognosis. We describe an Australian IPAF population and compare their baseline characteristics and outcomes with distinct cohorts of idiopathic interstitial pneumonia (IIP), CTD-ILD, and unclassifiable ILD. <b><i>Methods:</i></b> Review of 291 consecutive patients attending a specialist ILD clinic was performed. Patients with a diagnosis of IIP, CTD-ILD, and unclassifiable ILD by ILD-multidisciplinary meeting (ILD-MDM) were included. Patients meeting the IPAF criteria were identified. Baseline clinical data, survival, and progression were compared between ILD groups. <b><i>Results:</i></b> 226 patients were included, 36 meeting the IPAF criteria. IPAF patients demonstrated a high prevalence of autoantibodies to tRNA synthetase (35.3%), Ro52 (27.8%), and neutrophilic cytoplasmic antigens (ANCA; 20.0%). IPAF and CTD-ILD patients demonstrated similar clinical characteristics (mean age 66.6 and 63.7 years, respectively, female predominant, frequent CTD-manifestations). Lung function did not differ between ILD groups. Disease severity, pulmonary hypertension (PH), and ILD-MDM diagnosis were strong predictors of worse transplant-free survival (TFS). Meeting the IPAF criteria was not associated with TFS. <b><i>Conclusions:</i></b> We identified IPAF as a heterogeneous phenotype that overlaps considerably with CTD-ILD. Disease severity, PH, and ILD-MDM diagnosis were more powerful predictors of survival outcomes than meeting the IPAF criteria.

Thinking outside the cavity: effusion lymphoma primary to bone marrow

Primary effusion lymphoma (PEL) is a distinct disease entity of large B-cell lymphomas most often occurring in immunocompromised patients. We present a rare case of extracavitary PEL primary to the bone marrow in a HIV-positive patient.

New ‘Antigens’ in Membranous Nephropathy

Membranous nephropathy (MN) occurs due to deposition of immune complexes along the subepithelial region of glomerular basement membrane. Two previously identified target antigens for the immune complexes, PLA2R (identified in 2009) and THSD7A (in 2014), account for approximately 60% of all MN, both primary and secondary. In the remaining MN, target antigens were unknown. Use of laser microdissection and mass spectrometry enabled identification of new “antigens.” This approach led to the identification of four novel types of MN: exotosin 1 (EXT1)– and exotosin 2 (EXT2)–associated MN, NELL1-associated MN, Sema3B-associated MN, and PCDH7-associated MN. Each of these represents a distinct disease entity, with different clinical and pathologic findings. In this review, the structure of the proteins and the clinical and pathologic findings of the new types of MN are discussed. The role of mass spectrometry for accurate diagnosis of MN cannot be overemphasized. Finally, any classification of MN should be made on the basis of the antigens that are detected. Further studies are required to understand the pathophysiology, response to treatment, and outcomes of these new MNs.

The Role of Autoantibodies in Arrhythmogenesis

Purpose of Review The role of autoantibodies in arrhythmogenesis has been the subject of research in recent times. This review focuses on the rapidly expanding field of autoantibody-mediated cardiac arrhythmias. Recent Findings Since the discovery of cardiac autoantibodies more than three decades ago, a great deal of effort has been devoted to understanding their contribution to arrhythmias. Different cardiac receptors and ion channels were identified as targets for autoantibodies, the binding of which either initiates a signaling cascade or serves as a biomarker of underlying remodeling process. Consequently, the wide spectrum of heart rhythm disturbances may emerge, ranging from atrial to ventricular arrhythmias as well as conduction diseases, irrespective of concomitant structural heart disease or manifest autoimmune disorder. Summary The time has come to acknowledge autoimmune cardiac arrhythmias as a distinct disease entity. Establishing the autoantibody profile of patients will help to develop novel treatment approaches for patients.