Human lymphocyte antigen (HLA) class I proteins of the major histocompatibility complex are largely dependent for expression on small peptides supplied to them by transporter associated with antigen processing (TAP) protein. An inherited human deficiency in the TAP transporter was identified in two siblings suffering from recurrent respiratory bacterial infections. The expression on the cell surface of class I proteins was very low, whereas that of CD1a was normal, and the cytotoxicity of natural killer cells was affected. In addition, CD8+ alpha beta T cells were present in low but significant numbers and were cytotoxic in the most severely affected sibling, who also showed an increase in CD4+CD8+ T cells and gamma delta T cells.
Immunophenotyping is a major tool to assign acute leukemia blast cells to the myeloid lineage. However, because of the large heterogeneity of myeloid-related lineages, no clinically relevant immunological classification of acute myeloblastic leukemia (AML) has been devised so far. To attempt at formulating such a classification, we analyzed the pattern of expression of selected antigens, on blast cells collected at AML diagnosis. Patients were eligible if they had a first diagnosis of de novo AML and a sufficient number of blast cells for proper immunophenotyping. The relative expression of CD7, CD13, CD14, CD15, CD33, CD34, CD35, CD36, CD65, CD117, and HLA-DR were analyzed by cytometry in a test series of 176 consecutive AML cases. Statistical tools of clusterization allowed to remove antigens with overlapping distribution, leading us to propose an AML classification that was validated in a second AML cohort of 733 patients. We identified five AML subsets (MA to ME) based on the expression of seven antigens within four groups (CD13/CD33/CD117, CD7, CD35/CD36, CD15).-MA and MB-AML have exclusively myeloid features with seldom extramedullary disease and rare expression of lymphoid antigens. No cases of acute promyelocytic leukemia (APL) were observed within MB AML. MC AML have either myeloid or erythroblastic features. MD AML have more frequently high WBC counts than other subsets, which were related to the expression of CD35/CD36 and CD14 and to monoblastic differentiation. ME AML lack CD13, CD33, and CD117 but display signs of terminal myeloid differentiation. Specific independent prognostic factors were related to poor overall survival in each immunological subset: CD34+ (Po3 Â 10 À4 ) in MA AML, CD7+ in MB AML, non-APL cases (Po0.03) in MC AML, CD34+ (Po0.002) and CD14+ (Po0.03) in MD AML, CD14+ in ME AML (Po0.01). The inclusion of seven key markers in the immunophenotyping of AML allows a stratification into clinically relevant subsets with individual prognostic factors, which should be considered to define highrisk AML populations.
The pore-forming activity of leukocidin (PVL) secreted by Staphylococcus aureus has been investigated on human white cells by flow cytometry techniques. This two-component toxin induced morphological modifications of neutrophils and monocytes as detected by forward light scattering measurements, but was inactive on lymphocytes. These modifications were the consequence of pore formation through the cell membrane leading to its permeabilization. In the absence of calcium, PVL formed pores large enough to allow ethidium ions to penetrate the cells and become fluorescent by intercalating nucleic acids. In the presence of calcium, the pores were too small for ethidium entry but Key terms: Staphylococcus aureus, polymorphonuclear neutrophil, monocyte, HL-60, leukocidin, pore-forming toxin, cell activation, flow cytometry Many bacterial toxins provoke lesions in the plasma membrane and modify its permeability to ions or even to proteins. These toxins are called "pore-forming toxins" and 102 have been isolated and characterized to date ( 1). Among these, several are synthesized and excreted by Staphylococcus aureus: alpha-toxin (2), delta toxin (10) and synergohymenotropic toxins (1 2). Amid the latter, the so-called Panton-Valentine leukocidin (PVL) consisting of two synergic proteins S (32,000 da) and F (38,000 da) has been purified (8) and sequenced (12). The PVL is toxic for polymorphonuclear neutrophils (PMNs) but is not hemolytic. Pore formation requires the presence of the two components of the toxin and the events sequence consists of the initial binding of S followed by binding of F ( 5 ) . The pores formed by the toxin through the membrane of PMNs are ion-sized in the presence of extracellular divalent cations which enter the cells (7). When calcium is present, the calcium influx is responsible for the secretion of the granule contents of PMNs (5).The aim of the present study was to show that flow cytometry is a suitable technique to obtain a simultaneous evaluation of these different parameters and determine the cell specificity of PVL. Moreover, flow cytometry allowed us to determine the morphological modifications of the PMNs consecutive to the membrane permeability variations appearing after PVL binding. MATERIALS AND METHODS Toxin ProductionThe two components S and F of the PVL were purified, as described previously (S), by chromatography of the supernatant of S aureu V8 strain (ATCC 49775). Preparation of White CellsWhite cells were prepared from buffy-coats of healthy donors, or from blood collected from patients with This investigation was supported in part by a grant (CRE 900316) from the
for the Groupe Ouest Est Leucé mies Aiguë s Myé loblastiques (GOELAMS)Based on our previous demonstration that quinine could be used clinically to reverse P-glycoprotein-mediated resistance, we designed a multicenter, randomized trial aiming to determine whether quinine would improve the survival of adult patients (15-60 years old) with de novo acute myelogenous leukemia (AML). These patients randomly received (n ؍ 213) or did not receive (n ؍ 212) a 30 mg/kg/day continuous intravenous infusion of quinine in combination with induction chemotherapy combining idarubicine and cytarabine and, depending on bone marrow examination at day 20, an additional course of cytarabine and mitoxantrone. The mean steady-state quinine concentration was 7.8 mg/L and the mean multidrug resistance reversing activity of serum was 1.96. Complete remission (CR) was obtained in 344 patients (80.9%) without significant influence of quinine. Of the patients in complete remission, 82 were assigned to receive HLA-matched bone marrow transplants, whereas 262 were assigned to 2 courses of intensive consolidation chemotherapy, with or without quinine, depending on initial randomization. The 4-year actuarial overall survival (OS) of the 425 eligible patients was 42.0% ؎ 2.5%, without significant influence of quinine. Of 160 patients who could be studied, 54 demonstrated rhodamine 123 efflux. In these patients, quinine significantly improved the CR rate from 12 of 25 (48.0%) to 24 of 29 (82.8%) (P ؍ .01). However, there was no significant difference in OS. Neither mdr1 gene nor P-glycoprotein expression influenced the outcome. We conclude that quinine does not improve the survival of adult patients with de novo AML, even though it improves CR rate in a small subgroup of patients defined by rhodamine 123 efflux.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.