Natural killer cell receptor expression reflects the role of human cytomegalovirus in the pathogenesis of a subset of CD4(+) T-cell large granular lymphocytosis

A high frequency of CD4(+) T-cell large granular lymphocyte (T-LGL) lymphocytosis occurs in human leukocyte antigen (HLA) -DRB1*0701 individuals displaying monoclonal expansions of V beta 13.1+ CD4(+) T-cell clones, which specifically respond to human cytomegalovirus (HCMV) antigens. We previously reported the expression of natural killer (NK)- cell associated receptors (NKR) by HCMV-specific cytolytic CD4(+) T cells from healthy donors. In the present study a high expression of different NKR (i.e., NKG2D, killer Ig-like receptors (KIR), CD94, ILT2) was observed in CD4(+) T cells from both V beta 13.1- and V beta 13.1+ CD4(+) T-LGL cases. Remarkably, elevated numbers of CD94/NKG2C+ NK cells, previously shown to expand in association to HCMV infection, were preferentially found in V beta 13.1+ T-LGL, further supporting its role in the pathogenesis of a subset of CD4(+) T-LGL (C) 2011 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved

Multicolor Flowcytometric Immunophenotyping Is a Valuable Tool for Detection of Intraocular Lymphoma

<p>Objective: Intraocular lymphoma (IOL) is a rare condition and frequently difficult to distinguish from uveitis or other uveitis-masquerading syndromes. The diagnosis is confirmed by cytologic examination of ocular fluid specimens and more recently by molecular-immunoglobulin heavy chain (IGH) translocation or cytokine analysis. However, some of these more recent methods have not been validated by follow-up studies.</p><p>Design: Evaluation of a diagnostic test.</p><p>Participants: In a cohort of 51 consecutive patients with a clinical suspicion of IOL, vitreous analysis was performed via multicolor flowcytometric immunophenotyping.</p><p>Methods: Multicolor flowcytometric immunophenotyping was performed with CD45, CD3, CD19, CD20, anti-SmIg kappa, and anti-SmIg lambda antibodies. The presence of a clear B-cell population showing a disequilibrium of Ig kappa versus Ig lambda expression was used to confirm the diagnosis of non-Hodgkin lymphoma (NHL). Patients were followed for a minimum of 2 years (mean, 5.9 +/- 2.0 years) to validate the accuracy of the method.</p><p>Main Outcome Measures: The presence or absence of IOL during follow-up.</p><p>Results: In 14 of 51 patients, a clinical diagnosis of IOL was confirmed using flowcytometric analysis. Of these 14 patients, 11 had primary IOL and 3 had metastasized secondary lymphomas. In 3 of 51 patients who were diagnosed with (central nervous system) NHL during follow-up, the test failed to confirm the presence of a clonal B-cell population. In 18 of the 34 other patients, an infectious or well-defined immunologic disorder was established during follow-up. The remaining 16 patients, with a minimal follow-up of 2 years, were diagnosed with idiopathic uveitis.</p><p>Conclusions: Multicolor flowcytometric analysis had 82.4% sensitivity and 100% specificity in patients with suspected IOL. This is comparable to the reported vitreous interleukin (IL)-6/IL-10 testing sensitivity of 0.8 and sensitivity of 0.65 to 0.95 by immunoglobulin heavy chain (IGH) gene arrangement testing in clinical cohorts. Because flowcytometric tests are readily performed in hematologic laboratories, this can be regarded as a useful method for confirming the clinical diagnosis of IOL.</p>

Distinct gene expression profiles of acute myeloid/T-lymphoid leukemia with silenced CEBPA and mutations in NOTCH1

Gene expression profiling of acute myeloid leukemia (AML) allows the discovery of previously unrecognized molecular entities. Here, we identified a specific subgroup of AML, defined by an expression profile resembling that of AMLs with mutations in the myeloid transcription factor CCAAT/enhancer-binding protein alpha (C/EBPα), while lacking such mutations. We found that in these leukemias, the CEBPA gene was silenced, which was associated with frequent promoter hypermethylation. The leukemias phenotypically showed aberrant expression of T-cell genes, of which CD7 was most consistent. We identified 2 mechanisms that may contribute to this phenotype. First, absence of Cebpa led to up-regulation of specific T-cell transcripts (ie, Cd7 and Lck) in hematopoietic stem cells isolated from conditional Cebpa knockout mice. Second, the enhanced expression of TRIB2, which we identify here as a direct target of the T-cell commitment factor NOTCH1, suggested aberrantly activated Notch signaling. Putatively activating NOTCH1 mutations were found in several specimens of the newly identified subgroup, while a large set of control AMLs was mutation negative. A gene expression prediction signature allowed the detection of similar cases of leukemia in independent series of AML