The Importance of Platelet Glycoside Residues in the Haemostasis of Patients with Immune Thrombocytopaenia

Loss of sialic acid from the carbohydrate side chains of platelet glycoproteins can affect platelet clearance, a proposed mechanism involved in the etiopathogenesis of immune thrombocytopaenia (ITP). We aimed to assess whether changes in platelet glycosylation in patients with ITP affected platelet counts, function, and apoptosis. This observational, prospective, and transversal study included 82 patients with chronic primary ITP and 115 healthy controls. We measured platelet activation markers and assayed platelet glycosylation and caspase activity, analysing samples using flow cytometry. Platelets from patients with ITP with a platelet count <30 × 103/µL presented less sialic acid. Levels of α1,6-fucose (a glycan residue that can directly regulate antibody-dependent cellular cytotoxicity) and α-mannose (which can be recognised by mannose-binding-lectin and activate the complement pathway) were increased in the platelets from these patients. Platelet surface exposure of other glycoside residues due to sialic acid loss inversely correlated with platelet count and the ability to be activated. Moreover, loss of sialic acid induced the ingestion of platelets by human hepatome HepG2 cells. Changes in glycoside composition of glycoproteins on the platelets’ surface impaired their functional capacity and increased their apoptosis. These changes in platelet glycoside residues appeared to be related to ITP severity.

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Glycoside Residues on Platelet's Surface Regulate Platelet Function, Apoptosis and Binding of Coagulation Complexes in Patients with Immune Thrombocytopaenia

Blood ◽

10.1182/blood-2020-141299 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 10-11

Author(s):

Nora V. Butta ◽

María Teresa Alvarez Román ◽

Elena Monzón Manzano ◽

Paula Acuña ◽

Mónica Martín ◽

...

Keyword(s):

Platelet Count ◽

Sialic Acid ◽

Platelet Function ◽

Research Funding ◽

Platelet Rich Plasma ◽

University Hospital ◽

Activation Markers ◽

Platelet Surface ◽

Prothrombinase Complex ◽

Platelet Disorder

Introduction: Platelet surface glycoproteins (GPs) are highly glycosylated and are key elements for platelet function since most of them constitute receptors for adhesion ligands. However, exact role of their glycan composition is not clear. Under normal conditions, platelets contain sialic acid in the carbohydrate side chains of their GPs, and it has been described that alterations in the degree of their sialinization can affect the clearance of platelets. This mechanism has been proposed as involved in etiopathogenesis of immune thrombocytopaenia (ITP), mainly in those patients who do not respond to treatments. Thus, after the loss of sialic acid, there would be a greater exposure of galactose and of N-acetyl-glucosamine residues on the surface of circulating platelets to hepatic Ashwell-Morell receptors, which could induce their phagocytosis and platelet clearance. On the other hand, procoagulant platelets, defined as the platelet subpopulation that binds functional prothrombinase, exposed on their surface increased levels of P-selectin and GPIb, two glycan rich GPs. So, it is tempting to speculate that changes in glycan residues on platelet surface may induce changes in their function. Aim: We aimed to assess in ITP patients whether changes in platelet glycosylation, mainly the loss of sialic acid, may condition platelet function, apoptosis and binding of prothrombinase complex. Methods: This is an observational, prospective and transversal study approved by Ethics Committee from La Paz University Hospital. One hundred and eight patients with chronic primary ITP (68 with a platelet count ≥30x103 platelets/µL and 40 with a platelet count <30x103 platelets/µL) and 132 healthy controls were included after signing the informed consent. Platelet activation markers were determined in platelet rich plasma; whereas platelet glycosylation, binding of prothrombinase, annexin V and caspase's activities were assayed in washed platelets. Samples were analyzed by flow cytometry. Table 1 shows lectins tested and their sugar-binding specificity. Data were analyzed with GraphPad Prism 6.0 software. Results: Platelets from ITP patients with a platelet count <30x103/µL exposed less sialic acid in correspondence to an enhanced binding of lectins to non-sialylated residues. Moreover, levels of α1,6-Fucose, a glycan residue which could directly regulate antibody-dependent cellular cytotoxicity, and of α-Mannose, which could be recognized by the mannose binding lectin and activate complement pathway, were increased in platelets from these ITP patients. In accordance, sialic acid loss and consequent platelet surface exposure of other glycoside residues were inversely related to platelet count and ability to be activated (Table 1). These differences in glycosylation observed in ITP patients with a platelet count <30x103/µL were accompanied by a less ability of platelets to be activated (Figure 1), an increased exposure of phosphatidylserine and higher caspase activites (Figure 2). Moreover, increased exposure of phosphatidylserine and of N-acetyl-glucosamine residues (measured through the binding of WGA) enhanced binding of prothrombinase complex (Figure 3). Conclusion: Changes in glycoside composition of GPs on platelet's surface impaired their functional capacity, increases their apoptosis and modifies conditions for the binding of coagulation proteins. These modifications in platelet's glycoside residues seem to be related to severity of ITP. This work was supported by grants from FIS-FONDOS FEDER (PI19/00772) and and Platelet Disorder Support Association. EMM holds a predoctoral fellowship from Fundación Española de Trombosis y Hemostasia (FETH-SETH). Disclosures Butta: Grifols: Research Funding; Novartis: Speakers Bureau; ROCHE: Research Funding, Speakers Bureau; Pfizer: Speakers Bureau; SOBI: Speakers Bureau; Takeda: Research Funding, Speakers Bureau; NovoNordisk: Speakers Bureau. Alvarez Román:Grifols: Research Funding; Bayer: Consultancy; Novartis: Speakers Bureau; Roche: Speakers Bureau; Pfizer,: Research Funding, Speakers Bureau; SOBI,: Consultancy, Research Funding, Speakers Bureau; Takeda: Research Funding, Speakers Bureau; NovoNordisk,: Research Funding, Speakers Bureau. Martín:SOBI: Research Funding; Pfizer: Research Funding, Speakers Bureau; Roche: Speakers Bureau; Novartis: Speakers Bureau; NovoNordisk: Speakers Bureau. Rivas Pollmar:Novartis: Speakers Bureau; Roche: Speakers Bureau; Pfizer: Speakers Bureau. Justo Sanz:Takeda: Current Employment. García Barcenilla:NovoNordisk: Research Funding, Speakers Bureau; Takeda: Research Funding, Speakers Bureau; Pfizer,: Speakers Bureau; Roche: Speakers Bureau; Bayer: Speakers Bureau; Novartis: Speakers Bureau. Canales:Celgene: Honoraria; Janssen: Speakers Bureau; Novartis: Honoraria; Roche: Honoraria; Gilead: Honoraria; Sandoz: Honoraria; iQone: Honoraria; Takeda: Speakers Bureau; Sandoz: Speakers Bureau; Roche: Speakers Bureau; Janssen: Speakers Bureau; Sandoz: Honoraria; Roche: Honoraria; Takeda: Speakers Bureau; Novartis: Honoraria; Sandoz: Speakers Bureau; Karyopharm: Honoraria; Roche: Speakers Bureau; Janssen: Honoraria; Karyopharm: Honoraria; Janssen: Honoraria. Jimenez-Yuste:F. Hoffman-La Roche Ltd, Novo Nordisk, Takeda, Sobi, Pfizer, Grifols, Octapharma, CSL Behring, Bayer: Honoraria; F. Hoffman-La Roche Ltd, Novo Nordisk, Takeda, Sobi, Pfizer: Consultancy; Grifols, Novo Nordisk, Takeda, Sobi, Pfizer: Research Funding.

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High Mannose Glycans and Sialic Acid on gp120 Regulate Binding of Mannose-Binding Lectin (MBL) to HIV Type 1

AIDS Research and Human Retroviruses ◽

10.1089/088922202320886352 ◽

2002 ◽

Vol 18 (17) ◽

pp. 1311-1317 ◽

Cited By ~ 45

Author(s):

Melanie L. Hart ◽

Mohammed Saifuddin ◽

Kazuhide Uemura ◽

Eric G. Bremer ◽

Brad Hooker ◽

...

Keyword(s):

Sialic Acid ◽

Mannose Binding Lectin ◽

Mannose Binding ◽

High Mannose ◽

Hiv Type 1 ◽

Binding Lectin

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Platelet Function in Paroxysmal Nocturnal Haemoglobinuria

Blood ◽

10.1182/blood-2019-130291 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 4884-4884

Author(s):

Fathima Mohiyaddin Ayyalil ◽

Samantha J Montague ◽

Sarah Hicks ◽

Amandeep Kaur ◽

Anila Jahangiri ◽

...

Keyword(s):

Platelet Count ◽

Platelet Function ◽

Whole Blood ◽

Clinical Characteristics ◽

Paroxysmal Nocturnal Haemoglobinuria ◽

Clot Formation ◽

Haematopoietic Stem Cell ◽

Activation Markers ◽

Platelet Surface ◽

The Impact

Introduction Paroxysmal nocturnal haemoglobinuria (PNH) is a rare acquired clonal haematopoietic stem cell disorder characterised by haemolytic anaemia, thrombosis and bone marrow failure. Thrombosis is considered a major cause for high morbidity and mortality in PNH patients (Hillmen P et al N Eng J Med 1995). However, the underlying mechanisms of thrombosis in PNH are still poorly understood. Various factors including defective interactions between the complement system, platelets and coagulation systems have been proposed (Peacock-Young B et al Haematologica 2017). Platelet function and clot formation in this disorder have not been comprehensively evaluated. Here we describe standard and novel techniques to evaluate platelet function in blood from PNH patients, to elucidate the underlying pro-thrombotic mechanisms. Methods Whole blood was collected from five PNH patients and compared to same-day healthy donor (HD) controls. The samples were collected at trough for those patients who were on eculizumab (Complement C5 inhibitor used in the treatment of PNH). Surface levels of platelet adhesion proteins and activation markers P-selectin and phosphatidylserine (PS) were assessed using flow cytometry. Plasma soluble GPVI (a platelet-specific activation marker) and cytokine levels were measured by ELISA. Clot formation was assessed by viscoelastic testing (ROTEM). Adhesion of platelets to collagen under flow in a whole blood assay was evaluated by Digital Holographic Microscopy (DHM) and thrombus height, surface area and volume quantified using custom-built MatLab-based software. Results Clinical characteristics of PNH patients were highly variable: two patients had history of thrombosis, three patients were on eculizumab, four patients were thrombocytopenic (<150x109/L) and three were haemolysing. Platelet surface levels of adhesion/signalling receptor proteins including glycoproteins (GP) Iba, GPVI, aIIbb3, and ADAM10 (membrane expressed enzyme responsible for shedding GPVI from the surface) were all at lower ends of HD ranges. P-selectin and PS levels under resting and activated conditions and plasma soluble GPVI levels were comparable to same day HD. There were no differences between HD and PNH groups for levels of interleukin (IL) -6, IL-1β, tumour necrosis factor α, IL-17A, interferon γ or monocyte chemoattractant protein-1 (MCP-1). ROTEM analysis revealed slower formation of smaller clots in PNH patients, which correlated with their platelet count. Peak thrombus height and volume analysed by DHM were not different from data obtained with HD blood at both venous and arterial shear rates. However, both parameters were increased in PNH samples at arterial shearrate, when adjusted for platelet count (p<0.01). Conclusion Analysis of these PNH patients with highly variable clinical characteristics did not identify a unifying platelet lesion. DHM could detect and quantify parameters of small thrombi in real time, in PNH patient samples and these data were consistent with enhanced thrombogenic potential in PNH patients. Mechanisms beyond platelet activation that contribute to increased thrombosis in these patients and the impact of eculizumab therapy on thrombotic propensity need to be explored further. Disclosures D'Rozario: Alexion: Honoraria, Membership on an entity's Board of Directors or advisory committees.

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Evaluation of Platelet Function Defects in Patients with Immune Thrombocytopenia

Blood ◽

10.1182/blood-2021-153425 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 1021-1021

Author(s):

Elena Monzón Manzano ◽

María Teresa Alvarez Román ◽

Andres Ramirez Lopez ◽

Elena G Arias-Salgado ◽

Paula Acuña ◽

...

Keyword(s):

Flow Cytometry ◽

Sialic Acid ◽

Platelet Function ◽

Research Funding ◽

Immune Thrombocytopenia ◽

Healthy Controls ◽

Activation Markers ◽

Platelet Production ◽

Neuraminidase Activity ◽

Fibrinogen Receptor

Abstract Background: Primary immune thrombocytopenia (ITP) is a megakaryocytic (MK)/platelet-specific autoimmune disorder characterized by platelet count <100×10 9/L with or without bleeding manifestations, and diagnosed by exclusion of other causes of thrombocytopenia. It is widely accepted the involvement of platelet autoantibodies on deterioration of platelets from patients with ITP. Moreover, an enhanced activity of neuraminidase may also reduce sialic acid from glycoside residues on platelet surface, especially from the highly glycosylated von Willebrand factor (vWF) receptor. Because controversial results regarding the functionality of platelets from ITP patients can be found in literature, we aimed to determine platelet ability to be stimulated by agonists. Moreover, we aimed to determine the way anti-platelet auto- antibodies (abs) and neuraminidase activity may affect the function of platelets derived from MKs of healthy controls. Methods: This observational, prospective and transversal study included 42 patients with chronic primary ITP and 55 healthy controls. Platelet fibrinogen and vWF receptors and activation markers (PAC1 binding to activated fibrinogen receptor and exposure of P-selectin after agonists treatment), were evaluated by flow cytometry. Presence of Antibodies (abs) against platelet's glycoproteins in ITP serum was analysed with a Luminex based assay (LifecodesPak Lx). Neuraminidase (NEU) activity in serum was determined with the substrate 20-(4-methylumbelliferyl)-a-D-N-(MUNANA). Human CD34 + cell-enriched population was obtained with CliniMACS (MiltenyiBiotec) from G-CSF mobilized peripheral blood of a healthy donor. For MK differentiation, CD34 + cells were cultured 12 days in StemSpan™ Serum-Free Expansion Medium II (SFEM II) with 50ng/ml of recombinant human thrompoietin. Then, 10% of serum from healthy controls (4) or ITP patients (4) were added to the culture of mature MKs and incubated for 3 days. Phenotypic analysis of MKs and culture derived-platelets was carried out using abs against CD34, CD41, CD42a and CD42b.Platelet-like particles were considered as CD41-positive events with a size (FSC) and granularity (SSC) scatter properties similar to blood platelets. Culture-derived platelets were stimulated with 100 µM TRAP and 10 µM ADP and activation markers were analyzed by flow cytometry. Results: Expression of fibrinogen receptor on platelets from ITP patients were similar to those from healthy controls but showed a reduced capacity to be activated. Impairment in platelet degranulation measured as exposition of P-selectin after agonist's stimulation was also observed in platelets from these patients (Figure 1). Of note, surface content of CD42b subunit of vWF receptor was reduced (Figure 1). To determine whether diminished platelet function might be due to a plasma component, we induced platelet production from MK of healthy controls as referred in Methods. Abs against platelets and neuraminidase activity were determined in serum samples. Serum from 4 healthy controls or from 4 ITP patients (1 with anti-CD42b, 1 with anti-GPIa-IIa and 2 with undetectable abs) were added to MKs culture. No differences existed in MK differentiation and platelet production between MKs incubated with serum from healthy controls or from ITP patients, but similarly as observed in platelets from ITP patients, MK-derived platelets had an impaired ability to be activated (Table 1). Platelets derived from MKs incubated with ITP serum with anti-platelet abs had also a diminished exposure of CD42b (73±8% of controls). Moreover, neuraminidase content of these samples was slightly higher than that from ITP samples without abs (130 vs 100 % of controls). Conclusion: Platelets from ITP patients had a diminished ability to be stimulated. In vitro study showed that megakaryopoiesis was normal in presence of ITP serum, but released platelets had a lower ability to be activated. Involvement of abs in this effect cannot be ruled out despite we detected abs only in 2 of the tested sera because efficiency of method to detect these abs is ~ 50%. On the other hand, reduced levels of CD42b might be due to the increased activity of neuraminidase. Reduction of sialic acid from CD42b might initiate its metalloproteinase-mediated cleavage or change affinity of the ab used for its detection. Research funded by ISCIII-Fondos FEDER PI19/00772 and Platelet Disorder Support Association Figure 1 Figure 1. Disclosures Alvarez Román: Pfizer: Consultancy, Honoraria, Research Funding; Octapharma: Consultancy, Honoraria, Research Funding; Sobi: Consultancy, Honoraria, Research Funding; Grifols: Consultancy, Honoraria, Research Funding; Biomarin: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Bayer: Consultancy, Honoraria, Research Funding; CSL-Behring: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Novo-Nordisk: Consultancy, Honoraria, Research Funding. García Barcenilla: Roche: Speakers Bureau; Takeda: Speakers Bureau; Bayer: Speakers Bureau; SOBI: Speakers Bureau. Canales: Janssen: Consultancy, Honoraria, Speakers Bureau; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria; Gilead/Kite: Consultancy, Honoraria; Eusa Pharma: Consultancy, Honoraria; Incyte: Consultancy; Karyopharm: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Sanofi: Consultancy; iQone: Honoraria; Sandoz: Honoraria, Speakers Bureau; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Speakers Bureau. Jiménez-Yuste: Grifols: Consultancy, Honoraria, Research Funding; NovoNordisk: Consultancy, Honoraria, Research Funding; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Bayer: Consultancy, Honoraria, Research Funding; CSL Behring: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; BioMarin: Consultancy; Sobi: Consultancy, Honoraria, Research Funding; Octapharma: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Research Funding. Butta: Novo-Nordisk: Speakers Bureau; Takeda: Research Funding, Speakers Bureau; Roche: Speakers Bureau; CSL-Behring: Research Funding.

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Structural Polymorphisms in the Mannose-Binding Lectin Gene Are Associated with Juvenile Idiopathic Arthritis

The Journal of Rheumatology ◽

10.3899/jrheum.080681 ◽

2009 ◽

Vol 36 (4) ◽

pp. 843-847 ◽

Cited By ~ 10

Author(s):

PÉTER GERGELY ◽

BORBÁLA PAZÁR ◽

ZSOLT B. NAGY ◽

TÍMEA GOMBOS ◽

KATALIN RAJCZY ◽

...

Keyword(s):

Juvenile Idiopathic Arthritis ◽

Mannose Binding Lectin ◽

Healthy Controls ◽

Promoter Polymorphisms ◽

Allelic Discrimination ◽

Lectin Gene ◽

Mannose Binding ◽

Exon 1 ◽

Control Association ◽

Binding Lectin

Objective.To investigate the possible association between polymorphisms of the mannose-binding lectin gene (MBL2) and susceptibility to juvenile idiopathic arthritis (JIA).Methods.We performed a case-control association study including 118 Hungarian patients with JIA and 118 sex-matched healthy controls. MBL genotyping for the 3 mutant structural alleles at codons 54 (B), 57 (C), and 52 (D) in exon 1 and the promoter polymorphisms at position −550 (HL) and −221 (YX) were carried out by real-time PCR allelic discrimination. Serum level of MBL was determined by ELISA.Results.Variant allele frequencies of both codon 52 and 57 polymorphisms in the MBL2 gene were significantly overrepresented in JIA (p = 0.001 and p = 0.004, respectively). The frequency of low MBL genotypes (XA/XA, YA/YO, XA/YO, and YO/YO) in JIA was higher than that in healthy controls (p = 0.001). Serum MBL concentrations were found to be significantly lower in JIA patients versus control subjects (p = 0.001). The 2 promoter polymorphisms and codon 54 SNP of the MBL2 gene were not associated with JIA.Conclusion.Our findings suggest that genetically determined low MBL levels may predispose children to JIA in a Hungarian population. These data warrant further research to investigate the role of the lectin-dependent complement system in the pathogenesis of JIA.

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A New Approach to Predict the Chance of Infectious Complications Following Autologous Hematopoietic Stem Cell Transplantation: Mannose-Binding Lectin ELISA

Blood ◽

10.1182/blood.v118.21.4492.4492 ◽

2011 ◽

Vol 118 (21) ◽

pp. 4492-4492

Author(s):

Zita Radnay ◽

Miklos Udvardy ◽

Attila Kiss ◽

Maria Papp ◽

Laszlo Rejto ◽

...

Keyword(s):

Stem Cell ◽

Stem Cell Transplantation ◽

Cell Transplantation ◽

Infectious Complications ◽

Mannose Binding Lectin ◽

Healthy Controls ◽

Hematological Diseases ◽

Mannose Binding ◽

Binding Lectin ◽

Mbl Deficiency

Abstract Abstract 4492 Introduction: Haematopoietic stem cell transplantation associated immuncompromised state carries high risk of infectious complications. Gram-positive cocci are responsible for the majority of the post-transplant bloodstream infections. Viral and invasive fungal infections can be significant causes of morbidity. Mannose-binding lectin (MBL) is involved in innate immune response. MBL is an acute phase protein, synthesized in the liver. MBL binds microbial surface carbohydrates and mediates opsonophagocytosis directly and by activation of the lectin complement pathway. MBL also functions as co-receptor of Toll-like receptor. Serum MBL level is genetically determined and quite stable. MBL deficiency is a result of impaired assembly or stability of multimers. In patients who received high dose chemotherapy/transplantation, the innate immunodeficiency is an additive risk factor for infectious complications. According to literature, significant association was shown between low concentrations of MBL and serious infections. MBL is a potential modifier of susceptibility to infection in patients who have chemotherapy-induced neutropenia. Furthermore, infections might also compromise the engraftment of stem cells and the development of cell-lines might be prolonged. Patients and methods: The association between serum MBL level and frequency, severity and occurrence of infections has been studied in 127 patients following autologous stem cell transplantation (ASCT). Subgroups, i.e. multiple myeloma, non-Hodgkin and Hodgkin lymphoma were formed and the infectious complications have been compared. A double-monoclonal antibody sandwich ELISA system (BioPorto, Denmark) was used, which is a sensitive method for determining the MBL antigen levels in the sera. The range of MBL level in healthy population varies between 5 and 5000 ng/ml, <100 ng/ml is defined as MBL deficiency. MBL antigen levels were measured following transplantation, in a period without the presence of active infection. Results: 18 patients (out of 127) proved to be MBL deficient. The median time of the onset of first infection was day +5 in MBL deficient, while day +15 among non-MBL deficient patients following transplantation. More infections were found among MBL deficient patients (2.44 vs 2.28 infectious episodes/patient). When patients with more and less than 500 ng/ml serum MBL level were compared, similar trends were seen, but the difference was not significant. The occurrence of absolute MBL deficiency was not different between patients with malignant hematological diseases and the 294 healthy controls (14.5% vs 14%). Interestingly, MBL serum levels were significantly higher in the examined patients with malignant hematological diseases compared to healthy controls. Conclusions: MBL deficiency may predispose to infections. To our best knowledge, this is one of the first reports regarding MBL deficiency in bone marrow transplant settings. Our MBL deficient patients had a greater number of severe infections and experienced their first severe infection earlier, compared to nondeficient patients following ASCT. The measuring of MBL may be helpful in antibiotic treatment, in case of MBL deficiency earlier and more intensive treatment may be indicated. Disclosures: No relevant conflicts of interest to declare.

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Genotypes Coding for Low Serum Levels of Mannose-Binding Lectin Are Underrepresented among Individuals Suffering from Noninfectious Systemic Inflammatory Response Syndrome

Clinical and Vaccine Immunology ◽

10.1128/cvi.00375-09 ◽

2009 ◽

Vol 17 (3) ◽

pp. 447-453 ◽

Cited By ~ 7

Author(s):

Alex Smithson ◽

Rafael Perello ◽

Jesus Aibar ◽

Gerard Espinosa ◽

Dolors Tassies ◽

...

Keyword(s):

Systemic Inflammatory Response Syndrome ◽

Inflammatory Response ◽

Gene Polymorphisms ◽

Serum Levels ◽

Systemic Inflammatory Response ◽

Healthy Controls ◽

Icu Patients ◽

Mannose Binding ◽

Binding Lectin ◽

Low Serum

ABSTRACT Gene polymorphisms, giving rise to low serum levels of mannose-binding lectin (MBL) or MBL-associated protease 2 (MASP2), have been associated with an increased risk of infections. The objective of this study was to assess the outcome of intensive care unit (ICU) patients with systemic inflammatory response syndrome (SIRS) regarding the existence of functionally relevant MBL2 and MASP2 gene polymorphisms. The study included 243 ICU patients with SIRS admitted to our hospital, as well as 104 healthy control subjects. MBL2 and MASP2 single nucleotide polymorphisms were genotyped using a sequence-based typing technique. No differences were observed regarding the frequencies of low-MBL genotypes (O/O and XA/O) and MASP2 polymorphisms between patients with SIRS and healthy controls. Interestingly, ICU patients with a noninfectious SIRS had a lower frequency for low-MBL genotypes and a higher frequency for high-MBL genotypes (A/A and A/XA) than either ICU patients with an infectious SIRS or healthy controls. The existence of low- or /high-MBL genotypes or a MASP2 polymorphism had no impact on the mortality rates of the included patients. The presence of high-MBL-producing genotypes in patients with a noninfectious insult is a risk factor for SIRS and ICU admission.

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