Background Phenotypic characterization of immune cells in the bone marrow (BM) of patients with acute myeloid leukemia (AML) is lacking. Methods T‐cell infiltration was quantified on BM biopsies from 13 patients with AML, and flow cytometry was performed on BM aspirates (BMAs) from 107 patients with AML who received treatment at The University of Texas MD Anderson Cancer Center. The authors evaluated the expression of inhibitory receptors (programmed cell death protein 1 [PD1], cytotoxic T‐lymphocyte antigen 4 [CTLA4], lymphocyte‐activation gene 3 [LAG3], T‐cell immunoglobulin and mucin‐domain containing‐3 [TIM3]) and stimulatory receptors (glucocorticoid‐induced tumor necrosis factor receptor‐related protein [GITR], OX40, 41BB [a type 2 transmembrane glycoprotein receptor], inducible T‐cell costimulatory [ICOS]) on T‐cell subsets and the expression of their ligands (41BBL, B7‐1, B7‐2, ICOSL, PD‐L1, PD‐L2, and OX40L) on AML blasts. Expression of these markers was correlated with patient age, karyotype, baseline next‐generation sequencing for 28 myeloid‐associated genes (including P53), and DNA methylation proteins (DNA methyltransferase 3α, isocitrate dehydrogenase 1[IDH1], IDH2, Tet methylcytosine dioxygenase 2 [TET2], and Fms‐related tyrosine kinase 3 [FLT3]). Results On histochemistry evaluation, the T‐cell population in BM appeared to be preserved in patients who had AML compared with healthy donors. The proportion of T‐regulatory cells (Tregs) in BMAs was higher in patients with AML than in healthy donors. PD1‐positive/OX40‐positive T cells were more frequent in AML BMAs, and a higher frequency of PD1‐positive/cluster of differentiation 8 (CD8)‐positive T cells coexpressed TIM3 or LAG3. PD1‐positive/CD8‐positive T cells were more frequent in BMAs from patients who had multiply relapsed AML than in BMAs from those who had first relapsed or newly diagnosed AML. Blasts in BMAs from patients who had TP53‐mutated AML were more frequently positive for PD‐L1. Conclusions The preserved T‐cell population, the increased frequency of regulatory T cells, and the expression of targetable immune receptors in AML BMAs suggest a role for T‐cell–harnessing therapies in AML.
Pediatric large B-cell lymphomas (LBCLs) share morphological and phenotypic features with adult types but have better prognosis. The higher frequency of some subtypes such as LBCL with IRF4 rearrangement (LBCL-IRF4) in children suggests that some age-related biological differences may exist. To characterize the genetic and molecular heterogeneity of these tumors, we studied 31 diffuse LBCLs (DLBCLs), not otherwise specified (NOS); 20 LBCL-IRF4 cases; and 12 cases of high-grade B-cell lymphoma (HGBCL), NOS in patients ≤25 years using an integrated approach, including targeted gene sequencing, copy-number arrays, and gene expression profiling. Each subgroup displayed different molecular profiles. LBCL-IRF4 had frequent mutations in IRF4 and NF-κB pathway genes (CARD11, CD79B, and MYD88), losses of 17p13 and gains of chromosome 7, 11q12.3-q25, whereas DLBCL, NOS was predominantly of germinal center B-cell (GCB) subtype and carried gene mutations similar to the adult counterpart (eg, SOCS1 and KMT2D), gains of 2p16/REL, and losses of 19p13/CD70. A subset of HGBCL, NOS displayed recurrent alterations of Burkitt lymphoma–related genes such as MYC, ID3, and DDX3X and homozygous deletions of 9p21/CDKN2A, whereas other cases were genetically closer to GCB DLBCL. Factors related to unfavorable outcome were age >18 years; activated B-cell (ABC) DLBCL profile, HGBCL, NOS, high genetic complexity, 1q21-q44 gains, 2p16/REL gains/amplifications, 19p13/CD70 homozygous deletions, and TP53 and MYC mutations. In conclusion, these findings further unravel the molecular heterogeneity of pediatric and young adult LBCL, improve the classification of this group of tumors, and provide new parameters for risk stratification.
Signaling through immune checkpoint receptors may lead to T-cell exhaustion and function as immune escape mechanisms in cancer. For diffuse large B-cell lymphoma (DLBCL), the mechanistic and prognostic importance of these markers on tumor cells and the tumor microenvironment remains unclear. We determined the immunohistochemical expression of PD-1, PD-L1, TIM-3, and LAG-3 on tumor cells and on tumor infiltrating lymphocytes (TILs) among 123 DLBCL patients. TIM-3 showed positive staining on tumor cells in 39% of DLBCL cases and PD-L1 expression was noted in 15% of cases. Both PD-1 and LAG-3 were positive on tumor cells in a minority of DLBCL cases (8.3% and 7.5%, respectively), but were more widely expressed on TILs in a correlated manner. With median follow-up of 44 months ( n = 70, range 5–85), 4-year progression-free survival (PFS) and overall survival (OS) rates were significantly inferior among DLBCL patients with high vs low/negative TIM-3 expression (PFS: 23% [95% CI 7% to 46%] vs 60% [95% CI 43% to 74%], respectively, P = 0.008; OS: 30% [95% CI 10% to 53%] vs 74% [95% CI 58% to 85%], respectively, P = 0.006). Differences in OS remained significant when controlling for International Prognostic Index in Cox regression analyses (HR 3.49 [95% CI 1.40–6.15], P = 0.007). In addition, we observed that co-culture of DLBCL cell lines with primed T cells in the presence of anti-LAG-3 and anti-TIM-3 induced potent dose-dependent increases in in vitro cell death via AcellaTox and IL-2 ELISA assays, suggesting potent anti-tumor activity of these compounds.
Advances in molecular genetic sequencing techniques have contributed to the elucidation of previously unknown germline mutations responsible for inherited thrombocytopenia (IT). Regardless of age of presentation and severity of symptoms related to thrombocytopenia and/or platelet dysfunction, a subset of patients with IT are at increased risk of developing myeloid neoplasms during their life time, particularly those with germline autosomal dominant mutations in RUNX1, ANKRD26, and ETV6. Patients may present with isolated thrombocytopenia and megakaryocytic dysmorphia or atypia on baseline bone marrow evaluation, without constituting myelodysplasia (MDS). Bone marrow features may overlap with idiopathic thrombocytopenic purpura (ITP) or sporadic MDS leading to misdiagnosis. Progression to myelodysplastic syndrome/ acute myeloid leukemia (MDS/AML) may be accompanied by progressive bi‐ or pancytopenia, multilineage dysplasia, increased blasts, cytogenetic abnormalities, acquisition of bi‐allelic mutations in the underlying gene with germline mutation, or additional somatic mutations in genes associated with myeloid malignancy. A subset of patients may present with MDS/AML at a young age, underscoring the growing concern for evaluating young patients with MDS/AML for germline mutations predisposing to myeloid neoplasm. Early recognition of germline mutation and predisposition to myeloid malignancy permits appropriate treatment, adequate monitoring for disease progression, proper donor selection for hematopoietic stem cell transplantation, as well as genetic counseling of the affected patients and their family members. Herein, we describe the clinical and diagnostic features of IT with germline mutations predisposing to myeloid neoplasms focusing on mutations involving RUNX1, ANKRD26, and ETV6.
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