Chava Perry

Diagnostic accuracy of PET⁄CT in patients with extranodal marginal zone MALT lymphoma

Background:  18Fluoro‐2‐deoxyglucose (18FDG) positron emission tomography (PET) is widely used for initial staging and follow‐up in patients with malignant lymphoma. While earlier studies suggested a limited role for PET in extranodal marginal zone mucosa‐associated lymphoid tissue (MALT) lymphoma patients due to their non‐FDG avidity, more recent reports have suggested that the issue is controversial. In the present study, we evaluated the diagnostic accuracy of PET integrated with CT (PETCT) in patients with MALT lymphoma and assessed its reliability in clinical staging and monitoring response.

Complex regulation of acetylcholinesterase gene expression in human brain tumors.

To study the regulation of acetylcholinesterase (AChE) gene expression in human brain tumors, 3′ splice variants of AChE mRNA and potentially relevant transcription factor mRNAs were labeled in primary astrocytomas and melanomas. AChE-S and AChE-R mRNA, as well as Runx1/AML1 mRNA accumulated in astrocytomas in correlation with tumor aggressiveness, but neither HNF3β nor c-fos mRNA was observed in melanoma and astrocytomas. Immunohistochemistry demonstrated nuclear Runx1/AML1 and cellular AChE-S and AChE-R in melanomas, however, only AChE-S, and not the secreted AChE-R variant, was retained in astrocyte tumor cells. Runx1/AML1 revealed weak linkage with ACHE promoter sequences, yet enhanced ACHE gene expression in co-transfected COS1 cells. The p300 co-activator and the ACHE promoters distal enhancer facilitated this effect, which was independent of much of the Runx1/AML1 trans-activation domain. Surprisingly, GASP, a fusion product of green fluorescence protein (GFP) and ASP67, a peptide composed of the 67 C-terminal amino acid residues of AChE-S, localized to COS1 cell nuclei. However, GARP, the corresponding fusion product of GFP with a peptide having the 51 C-terminal residues of AChE-E or GFP alone, remained cytoplasmic. Runx1/AML1 exhibited improved nuclear retention in GASP-expressing COS1 cells, suggesting modulated nuclear localization processes. Together, these findings reveal brain tumor-specific regulation of both expression and cellular retention of variant ACHE gene products.

Endotoxin-induced changes in human working and declarative memory associate with cleavage of plasma “readthrough” acetylcholinesterase

Endotoxin stimulation of the immune system produces marked alterations in memory functioning. However, molecular links between this cognitive response and infection-responding neurotransmission pathways are still unknown. The cytokine and memory responses of volunteers injected with 0.8 ng/kg Salmonella endotoxin were compared with changes in plasma levels and integrity of the stress-induced acetylcholinesterase variant, AChE-R. Vascular endothelial cells were found to express AChE-R messenger RNA and protein both in healthy and inflamed human tissues. Plasma AChE activity was reduced after endotoxin treatment, but not placebo treatment, parallel to the decline in cortisol after the endotoxin-induced peak and inversely to the accumulation of a C-terminal immunopositive AChE-R peptide of 36 amino acid residues. AChE-R cleavage coincided with significant endotoxin-induced improvement in working memory and impairment in declarative memory. By 3 h posttreatment, working memory improvement was negatively correlated with AChE-R cleavage, which showed association to proinflammatory cytokine levels. By 9 h posttreatment, declarative memory impairment was negatively correlated with AChE-R cleavage and positively correlated with the suppressed AChE activity. Endotoxin-induced peripheral cholinergic stress responses are hence associated with greater impairment in declarative memory and lower improvement in working memory, pointing at AChE-R as a surrogate marker of psychoneuroimmunological stress.

Hydrolytic and Nonenzymatic Functions of Acetylcholinesterase Comodulate Hemopoietic Stress Responses

Glucocorticoid-initiated granulocytosis, excessive proliferation of granulocytes, persists after cortisol levels are lowered, suggesting the involvement of additional stress mediator(s). In this study, we report that the stress-induced acetylcholinesterase variant, AChE-R, and its cleavable, cell-penetrating C-terminal peptide, ARP, facilitate granulocytosis. In postdelivery patients, AChE-R-expressing granulocyte counts increased concomitantly with serum cortisol and AChE activity levels, yet persisted after cortisol had declined. Ex vivo, mononuclear cells of adult peripheral blood responded to synthetic ARP26 by overproduction of hemopoietically active proinflammatory cytokines (e.g., IL-6, IL-10, and TNF-α). Physiologically relevant ARP26 levels promoted AChE gene expression and induced the expansion of cultured CD34+ progenitors and granulocyte maturation more effectively than cortisol, suggesting autoregulatory prolongation of ARP effects. In vivo, transgenic mice overexpressing human AChE-R, unlike matched controls, showed enhanced expression of the myelopoietic transcription factor PU.1 and maintained a stable granulocytic state following bacterial LPS exposure. AChE-R accumulation and the consequent inflammatory consequences can thus modulate immune responses to stress stimuli.

Runx1/AML1 in leukemia: disrupted association with diverse protein partners

Runx1/AML1, a chromosome 21q22 hematopoietic regulator, is frequently translocated in leukemia. Its protein product, a relatively weak transcriptional activator, becomes an effective transcriptional enhancer or repressor, when co-operating with transcriptional co-activators or co-repressors. Runx1/AML1 association with its partners is disrupted in leukemia. For example, Runx1/AML1 mutations and translocations (e.g. t(8;21), t(12;21) and t(3;21)) impair binding of Runx1/AML1-CBFbeta complexes to Runt motifs in myelopoietically active promoters, preventing normal hematopoiesis. However, Runx1/AML1-associated translocations are not leukemogenic in animal models, suggesting the involvement of yet unidentified regulatory proteins. New candidates are cholinesterases, inhibition of which increases leukemic risk in a manner potentially associated with Runx1/AML1.

Early-mid treatment C-reactive protein level is a prognostic factor in aggressive non-Hodgkin's lymphoma

Background:  In the light of an emerging role for early‐mid treatment 18 F‐deoxyfluoroglucose positron emission tomography (FDG‐PET) as an important prognostic indicator in aggressive non‐Hodgkin’s lymphoma (NHL) , we attempted to determine whether a simple parameter, such as the early‐mid treatment CRP (C‐reactive protein) level, could also be utilized as a significant prognostic factor in aggressive NHL.

Highly elevated lactate dehydrogenase level in a healthy individual: A case of macro‐LDH

Macroenzymes are complexes of serum enzymes with a plasmatic protein. They have a higher molecular weight and a more prolonged serum half‐life than those of unbound enzymes. Although macroenzymes may be found in the serum of post‐myocardial infarction patients, they are not usually associated with any specific disease. Their presence, however, can use an elevation in the serum levels of an enzyme, possibly leading to errors in diagnosis. We report a patient with extremely elevated serum levels of lactate dehydrogenase (LDH) due to the formation of complexes with immunoglobulin G. She had undergone a myriad of clinical examinations until the macroenzyme responsible for this finding was detected. We also review the literature on the clinical significance of macro‐LDH. We propose that awareness of this rare and probably benign phenomenon can spare the patient from the distress of exhaustive investigations. Am. J. Hematol. 55:39‐40, 1997.

Predictive Parameters for a Diagnostic Bone Marrow Biopsy Specimen in the Work-Up of Fever of Unknown Origin

OBJECTIVE To determine the role of bone marrow biopsy (BMBX), performed in association with comprehensive blood and imaging tests, in the evaluation of patients with fever of unknown origin (FUO). PATIENTS AND METHODS We reviewed the medical records of 475 hospitalized patients who underwent BMBX in our medical center from January 1, 2005, to April 30, 2010. We identified 75 patients who fulfilled the accepted classic Petersdorf criteria for FUO. All patients underwent in-hospital investigation for fever, including chest and abdominal computed tomography. RESULTS In 20 patients (26.7%), BMBX established the final diagnosis. Sixteen patients had hematologic disorders, including 8 patients with non-Hodgkin lymphoma, 2 with acute leukemia, 1 with multiple myeloma, 1 with myelodysplastic syndrome, and 4 with myeloproliferative disorders. The remaining patients with diagnostic BMBX specimens had solid tumors (2 patients), granulomatous disease (1 patient), and hemophagocytic syndrome (1 patient). Multivariate analysis revealed the following as the significant positive predictive parameters for a diagnostic BMBX specimen: male sex (odds ratio [OR], 7.35; 95% confidence interval [CI], 1.19-45.45), clinical lymphadenopathy (OR, 21.98; 95% CI, 1.97-245.66), anemia (OR, 2.21; 95% CI, 1.28-3.80), and increased lactate dehydrogenase levels (OR, 1.003; 95% CI, 1.001-1.006). CONCLUSION Bone marrow biopsy is still a useful ancillary procedure for establishing the diagnosis of FUO, particularly if used in the appropriate clinical setting. Clinical and laboratory parameters associated with hematologic disease are predictive of a diagnostic BMBX specimen in patients with FUO.

Expansion of regulatory T cells in B chronic lymphocytic leukemia: enhanced ‘brakes’ on host immunity

The inability of the immune system to eradicate tumors has been recently appreciated as one of the fundamental hallmarks of cancer. A variety of mechanisms are employed by tumors to actively suppress host immunity, including generating an immune-subversive milieu [1]. The human CD4þCD25þ T lymphocyte population contains cells that suppress antigen-specific T-cell immune responses and these naturally occurring regulatory T cells (Tregs) function as a physiological brake by inhibiting proliferation and cytokine release from activated CD4þCD25þ T lymphocytes. Until recently, it was difficult to identify these cells with certainty in humans, because of lack of any specific cell marker. However, it is now recognised that in addition to CD4 and CD25 they express the Forkhead box P3 (FOXP3), as well as low levels of CD127, thereby acquiring a unique identification [2]. Tregs can be generated in the thymus or may also differentiate from the peripheral pool of CD4þCD257 naive T cells. Conversion of naive peripheral CD4þCD257 T cells into CD25þ, CD45RB7/low suppressor cells that are intracellular CTLA-4þ, can be achieved through co-stimulation with T cell receptors (TCRs) and transforming growth factor beta (TGFb). TGF-b2 triggers Foxp3 expression in CD4þCD257 precursors, enabling these Foxp3þ cells to function as conventional Tregs. Furthermore, TGF-b-driven Tregs inhibit innate inflammatory processes. Thus, TGF-b is a key regulator of the signalling pathways that initiates and maintains Foxp3 expression and the suppressive function in CD4þCD257 precursors. Interleukin2 (IL-2) also plays a critical role in Tregs homeostasis and has been shown to promote the suppressive function of Tregs. IL-2 is required for TGF-b to induce naive CD4(þ)CD25(7) cells to become CD25(þ), express Foxp3 and develop the characteristic properties of CD4(þ)CD25(þ) regulatory cells [3]. A vital normal function of Tregs is the suppression of autoreactive T-cell populations which limits the development of autoimmune disease, graftversus-host disease, transplant rejection and massive tissue destruction during infections. An aberrant function of Tregs is their ability to expand in malignant diseases with subsequent inhibition of anti-tumor immune responses. High percentages of TGFb-secreting Tregs have been detected in patients with non-small cell lung cancer and ovarian cancer, thereby providing evidence that Tregs contribute to immune dysfunction in cancer patients [4,5]. Increased prevalence of Tregs has been reported not only in the tumor microenvironment itself, but also in the peripheral blood of patients with invasive breast or pancreatic cancer [6,7] and a higher prevalence of Tregs closely correlated with poor prognosis and decreased survival in patients with gastric carcinoma [8]. Moreover, it was recently reported that vaccine-induced anti-tumor immunity was associated with decreased infiltration of the tumor by Foxp3þ cells, when compared with vaccine-non responsive tumors [9]. The role of Tregs and the mechanism of their expansion in chronic lymphocytic leukemia (CLL) is particularly interesting because of the immune dysregulation of both the B and T lymphocyte pools seen in this disease. Patients with CLL, like many other cancer patients, exhibit increased numbers of circulating activated CD4þ T-cells cells [10] as well as CD4þ CD25 T cells. The highest numbers of

Absolute monocyte count trichotomizes chronic lymphocytic leukemia into high risk patients with immune dysregulation, disease progression and poor survival

Peripheral absolute monocyte count (AMC) has been reported to correlate with clinical outcome in different types of cancers. This association may relate to alteration in circulating monocytic subpopulations and tumor infiltrating macrophages. In this study we evaluated the clinical significance of peripheral AMC in 80 treatment naive patients with CLL. Measurement of AMC was based on direct morphological enumeration, due to our findings that complete blood count data may yield incorrect monocytes enumeration values in CLL. The median AMC in patients with CLL was within normal limits, however the AMC range exceeded the values of healthy individuals. The AMC trichotomized patients into 3 distinct sub-groups with different characteristics and outcomes. High AMC patients were younger and had higher absolute lymphocytes count, while patients with low AMC had prominent immune dysregulation (lower serum IgA levels, susceptibility to infections and a tendency for positive direct anti-globulin test). The low and high AMC patients had a shorter time to treatment compared to the intermediates AMC subgroups, whereas low AMC was associated with increased mortality caused by infectious complications. In conclusion, AMC quantification during the disease course classifies CLL patients into subgroups with unique clinical features and outcomes.