Correction to: Circulating T Cells of Patients with Nijmegen Breakage Syndrome Show Signs of Senescence.

The original version of the article, "Circulating T Cells of Patients with Nijmegen Breakage Syndrome Show Signs of Senescence" incorrectly listed the affiliation of the fourth author, Iwona Solarska. The correct affiliation is "Molecular Biology Laboratory, Institute of Hematology and Transfusion Medicine.

Circulating T Cells of Patients with Nijmegen Breakage Syndrome Show Signs of Senescence.

PURPOSE: The Nijmegen breakage syndrome (NBS) is an inherited genetic disorder characterized by a typical facial appearance, microcephaly, growth retardation, immunodeficiency, and a strong predisposition to malignancies, especially of lymphoid origin. NBS patients have a mutation in the NBN gene which involves the repair of DNA double-strand breaks (DSBs). Here we studied the peripheral T cell compartment of NBS patients with a focus on immunological senescence. METHODS: The absolute numbers and frequencies of the different T cell subsets were determined in NBS patients from young age till adulthood and compared to age-matched healthy individuals (HI). In addition, we determined the expression of senescent T cell markers and the signal joint T cell receptor excision circles (sjTRECs) content. RESULTS: Our results demonstrate that NBS patients have reduced T cell numbers. NBS patients showed lower numbers of αß+ T cells, but normal γδ+ T cell numbers compared to HI. Concerning the αß+ T cells, both CD4+ as well as CD8+ T cells were excessively reduced in numbers compared to aged-matched HI. In addition, NBS patients showed higher frequencies of the more differentiated T cells expressing the senescent cell marker CD57 and did not express co-stimulatory molecule CD28. These effects were already present in the youngest age group. Furthermore, NBS patients showed lower sjTREC content in their T cells possibly indicative of a lower thymic output. CONCLUSIONS: We conclude that circulating T cells from NBS patients show signs of a senescent phenotype which is already present from young age on and which might explain their T cell immune deficiency.

Multicolor flowcytometric immunophenotyping is a valuable tool for detection of intraocular lymphoma.

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. DESIGN: Evaluation of a diagnostic test. PARTICIPANTS: In a cohort of 51 consecutive patients with a clinical suspicion of IOL, vitreous analysis was performed via multicolor flowcytometric immunophenotyping. METHODS: Multicolor flowcytometric immunophenotyping was performed with CD45, CD3, CD19, CD20, anti-SmIgκ, and anti-SmIgλ antibodies. The presence of a clear B-cell population showing a disequilibrium of Igκ versus Igλ 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. MAIN OUTCOME MEASURES: The presence or absence of IOL during follow-up. 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. 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. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

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 Vß13.1+ 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 Vß13.1- and Vß13.1+ 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 Vß13.1+ T-LGL, further supporting its role in the pathogenesis of a subset of CD4(+) T-LGL.

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/EBPalpha), 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.

Apoptosis and apoptosis-related molecules in the submandibular gland of the nonobese diabetic mouse model for Sjögren's syndrome: limited role for apoptosis in the development of sialoadenitis.

Sjögren's syndrome is an autoimmune disease in which lymphocytic infiltrates develop in the exocrine glands. Pathogenetic aspects of the disease can be studied in the nonobese diabetic (NOD) mouse strain, a spontaneous model for Sjögren's syndrome. Apoptosis may play a role in the initation phase and in the effector phase of autoimmune diseases. Here, we have examined the role of apoptosis in the development of sialoadenitis in the NOD mouse. Apoptotic cells and the expression of apoptosis-related molecules were studied in submandibular glands (SMG) of NOD and NOD-scid mice before and after the onset of sialoadenitis. Numbers of apoptotic cells were not increased as compared with control mice, at any age. By immunohistochemistry, we demonstrated increased expression of Fas, Fas ligand (FasL), and bcl-2 on SMG epithelial cells of NOD and NOD-scid mice, as early as 3 days of age. mRNA expression of Fas and FasL was also examined in SMG by RQ-PCR. Low-level expression of Fas and FasL mRNA was observed in all mouse strains, from 1 day of age onward. We conclude that increased protein expression of Fas and FasL on SMG epithelial cells of NOD and NOD-scid mice probably indicates a genetically programmed abnormality in these cells that may form a trigger for the development of sialoadenitis in NOD mice. Because increased numbers of apoptotic cells were not observed, a role for actual apoptosis in the initiation or effector phase of sialoadenitis in the NOD mouse is unlikely.