Mannose-binding Lectin Levels Research Articles

A Nanoplasmonic Assay for Point-of-Care Detection of Mannose-Binding Lectin in Human Serum.

Mannose-binding lectin (MBL) activates the complement system lectin pathway and subsequent inflammatory mechanisms. The incidence and outcome of many human diseases, such as brain ischemia and infections, are associated with and influenced by the activity and serum concentrations of MBL in body fluids. To quantify MBL levels, tests based on ELISA are used, requiring several incubation and washing steps and lengthy turnaround times. Here, we aimed to develop a nanoplasmonic assay for direct MBL detection in human serum at the point of care. Our assay is based on gold nanorods (GNRs) functionalized with mannose (Man-GNRs) via an amphiphilic linker. We experimentally determined the effective amount of sugar linked to the nanorods' surface, resulting in an approximate grafting density of 4 molecules per nm2, and an average number of 11 to 13 MBL molecules binding to a single nanoparticle. The optimal Man-GNRs concentration to achieve the highest sensitivity in MBL detection was 15 μg·mL-1. The specificity of the assay for MBL detection both in simple buffer and in complex pooled human sera was confirmed. Our label-free biosensor is able to detect MBL concentrations as low as 160 ng·mL-1 within 15 min directly in human serum via a one-step reaction and by using a microplate reader. Hence, it forms the basis for a fast, noninvasive, point-of-care assay for diagnostic indications and monitoring of disease and therapy.

Trauma patients with type O blood exhibit unique multi-omics signature with decreased lectin pathway of complement levels.

Patients with type O blood may have an increased risk of hemorrhagic complications due to lower baseline levels of von Willebrand Factor (vWF) and factor VIII, but the transition to a mortality difference in trauma is less clear. We hypothesized that type O trauma patients will have differential proteomic and metabolomic signatures in response to trauma beyond vWF and FVIII alone. Patients meeting the highest level of trauma activation criteria were prospectively enrolled. Blood samples were collected upon arrival to the emergency department. Proteomic and metabolomic (multi-omics) analyses of these samples were performed using liquid chromatography-mass spectrometry. Demographic, clinical, and multi-omics data were compared between patients with type O blood versus all other patients. There were 288 patients with multi-omics data; 146 (51%) had type O blood. Demographics, injury patterns, and initial vital signs and laboratory measurements were not different between groups. Type O patients had increased lengths of stay (7 vs. 6 days, p = 0.041) and a trend towards decreased mortality secondary to traumatic brain injury compared to other causes (TBI, 44.4 % vs. 87.5%, p = 0.055). Type O patients had decreased levels of mannose-binding lectin (MBL) and MBL associated serine proteases 1 and 2 which are required for the initiation of the lectin pathway of complement activation. Type O patients also had metabolite differences signifying energy metabolism and mitochondrial dysfunction. Blood type O patients have a unique multi-omics signature, including decreased levels of proteins required to activate the lectin complement pathway. This may lead to overall decreased levels of complement activation and decreased systemic inflammation in the acute phase possibly leading to a survival advantage, especially in TBI. However, this may later impair healing. Future work will need to confirm these associations, and animal studies are needed to test therapeutic targets. Retrospective Comparative Study, Level IV.

Complement activation in wasp venom-induced acute kidney injury

Previous studies have highlighted the significant role of complement activation in kidney injuries induced by rhabdomyolysis, intravascular hemolysis, sepsis, and ischemia-reperfusion. Nevertheless, the specific role and mechanism of complement activation in acute kidney injury (AKI) caused by wasp venom remain unclear. The aim of this study was to elucidate the specific complement pathway activated and investigate complement activation in AKI induced by wasp venom. In this study, a complement-depleted mouse model was used to investigate the role of complement in wasp venom-induced AKI. Mice were randomly categorized into control, cobra venom factor (CVF), AKI, and CVF + AKI groups. Compared to the AKI group, the CVF + AKI group showed improved pathological changes in kidneys and reduced blood urea nitrogen (BUN) levels. The expression levels of renal complement 3 (C3), complement 5 (C5), complement 1q (C1q), factor B (FB), mannose-binding lectin (MBL), and C5b-9 in AKI group were upregulated compared with the control group. Conversely, the renal tissue expression levels of C3, C5, C1q, FB, MBL, and C5b-9 were decreased in the CVF + AKI group compared to those in the AKI group. Complement activation occurs through all three pathways in AKI induced by wasp venom. Furthermore, complement depletion by CVF attenuates wasp venom-induced nephrotoxicity, suggesting that complement activation plays a primary role in the pathogenesis of wasp venom-induced AKI.

Mannose Binding Lectin and C3 Serum Levels in Coronary Artery Disease: A Cross-Sectional Study

ABSTRACT Background The process of tissue injury in coronary artery disease (CAD) has been associated with activation of the complement system, partly due to the action of mannose-binding lectin (MBL) and C3, which are expressed in atherosclerotic lesions. Objective The aim of this study was to evaluate the serum levels of MBL and C3 in patients with CAD and to compare them with healthy controls. Additionally, we aim to assess the correlation between MBL and C3 levels and cardiometabolic parameters. Methods MBL and C3 serum concentration were determined by ELISA and immunoturbidimetry, respectively, in up to 119 patients undergoing coronary angiography for CAD evaluation, comprising 48 individuals diagnosed with acute myocardial infarction (MI) and 71 without MI. A total of 93 paired healthy controls were included in the study. Results Individuals with CAD had MBL serum concentration higher than controls (p = .002), regardless of the presence of MI (p = .006). In addition, high concentration of MBL (>2000 ng/mL) was more frequent in patients with CAD (p = .007; OR = 2.6; 95% CI = 1.3–5.1). C3 levels were not significantly associated with any of the patient groups but were positively correlated with cardiometabolic parameters such as body mass index (BMI) and triglycerides levels. Conclusions Higher concentrations of MBL were found to be associated with CAD, whereas C3 levels were found to be associated with cardiovascular risk factors.

Augmented mannose-binding lectin levels in primary membranous nephropathy: A pilot study.

There is evidence to suggest that M-type phospholipase A2 (PLA2R) antibodies activate the mannose-binding lectin (MBL) cascade, resulting in glomerular damage and proteinuria in patients with primary membranous nephropathy (PMN). Furthermore, there are few reports indicating that aberrant MBL activation is associated with endothelial dysfunction and accelerated atherosclerosis. While PMN is a common cause of adult nephrotic syndrome, and patients are at increased risk of cardiovascular disease (CVD), there is a lack of research that explores the factors that contribute to this condition. This study aims to determine the MBL levels in PMN and their relation to the clinical activity and endothelial dysfunction in PMN. The MBL levels of 22 biopsy-confirmed PMN patients were assessed at baseline and after 6 months of immunosuppressive therapy. In order to evaluate endothelial dysfunction in PMN patients, flow-mediated vasodilation (FMD) was measured at baseline and after treatment. A total of 22 healthy controls were included in this study to measure MBL levels and FMD. A significant difference was observed between MBL levels in PMN patients and healthy controls (p < .01). MBL levels decreased significantly after immunosuppressive therapy (p = .04). The baseline MBL levels and FMD levels exhibited a strong correlation (Spearman correlation coefficient [ρ] = 0.51: p = .01). In conclusion, the study signals the activation of the MBL cascade and its association with endothelial dysfunction in PMN patients.

P139 A potential protective rule of Mannose Binding lectin (MBL) against SARS-COV2 infection in IBD patients

Abstract Background Since the beginning of the COVID-19 pandemic, IBD patients have appeared to be less susceptible to a severe form of the disease, despite undergoing immunosuppressive treatments. Mannose binding lectin (MBL) is a humoral fluid-phase pattern recognition molecule (PRM) crucial for activating the lectin complement pathway. It is capable of binding to the spike protein and blocking SARS-CoV-2 infection. Low MBL expression has been linked to poor outcomes in both SARS and SARS- CoV-2 infections. In IBD patients, the role of MBL is controversial; low concentrations seem to predispose individuals to the development of IBD, while high concentrations have been observed in severe forms of Crohn's disease. Methods Since April 2020, 104 IBD patients have been enrolled, with 20% treated with mesalazine, 50% with Anti-TNFa, 20% with Vedolizumab, and 20% receiving no treatment. Additionally, 45 healthy controls (HC) from North Italy were included. Serum samples and colon biopsies from inflamed and non- inflamed mucosa were collected. Serum samples underwent an ELISA test to quantify circulating MBL concentration, and MBL gene expression in biopsies was analyzed using qPCR. Results Both Crohn's disease and Ulcerative Colitis patients exhibited significantly higher circulating MBL levels than HC (411.6 ± 45.5 ng/ml vs. 160.9 ± 35.3 ng/ml, p &amp;lt; 0.05). Patients treated with Anti-TNFa showed significantly higher circulating MBL levels compared to those not undergoing therapy (530.1 ± 76.5 ng/ml vs. 225.4 ± 61.6 ng/ml, p &amp;lt; 0.05) and patients receiving Vedolizumab (530.1 ± 76.5 ng/ml vs. 155.3 ± 32.1 ng/ml, p &amp;lt; 0.05). MBL intestinal gene expression is higher in IBD patients than HC (5.55 ± 0.9 vs. 2.36 ± 0.6; p=0.591) and tended to be elevated at similar levels in inflamed and non-inflamed mucosa (5.14 ± 1.4 vs. 5.79 ± 1.1; p=0.337), suggesting a prevalent genetic determination of MBL concentration regardless of the inflammatory background. Conclusion MBL appears to play a key role in SARS-CoV-2 infection. We demonstrate that IBD patients have, on average, higher circulating MBL levels than HC independently of their inflammatory status. The highest MBL levels were observed in patients treated with Anti-TNFa. These findings contribute to understanding the reported low mortality and hospitalization for COVID-19 among IBD patients treated with Anti-TNFa.

High production MBL2 polymorphisms protect against COVID-19 complications in critically ill patients: A retrospective cohort study

Mannose-binding lectin (MBL) binds to SARS-CoV-2, inhibits infection of susceptible cells, and activates the complement system via the lectin pathway. In this study, we investigated the association of MBL2 polymorphisms with the risk of hospitalization and clinical worsening in patients with COVID-19. A total of 550 patients with COVID-19 were included (94 non-hospitalized and 456 hospitalized). Polymorphisms in MBL2 exon 1 (codons 52, 54 and 57) and promoter region (−550, −221, and +4) were determined by real-time PCR. MBL and complement proteins were measured by Luminex. A higher frequency of the H/H genotype and the HYPA haplotype was observed in non-hospitalized patients when compared to hospitalized. In addition, critically ill patients carrying haplotypes associated with high MBL levels (HYPA/HYPA + HYPA/LYPA + HYPA/LYQA + LYPA/LYQA + LYPA/LYPA + LYQA/LYQA + LXPA/HYPA + LXPA/LYQA + LXPA/LYPA) were protected against lower oxygen saturation levels (P = 0.02), use of invasive ventilation use (P = 0.02, OR 0.38), and shock (P = 0.01, OR 0.40), independent of other potential confounders adjusted by multivariate analysis. Our results suggest that variants in MBL2 associated with high MBL levels may play a protective role in the clinical course of COVID-19.

Patterns of Mannose-Binding Lectin (MBL) responses to &lt;i&gt;Plasmodium falciparum&lt;/i&gt; infections in hyperendemic settings

Background: malaria caused by Plasmodium falciparum remains a significant and major public health concern in Africa, particularly in hyperendemic regions. Recurrent fevers and high quantities of inflammatory mediators in the circulation define the disease's blood stages. By binding to non-self-pathogen oligosaccharide surfaces, Mannose-Binding Lectin (MBL) and lectin complement pathways trigger innate immune processes and contribute to the formation of adaptive immune responses. Methods: in Sudan, we investigated the varied immune response levels of MBL to the different phases of P. falciparum infection in White Nile and Blue Nile states endemic to malaria. And we looked at the interaction of regulatory Interleukin 6 (IL- 6) cytokines on MBL during infection. Our study was based on a total of 108 cases, in which 86 patients (62.0%) were uncomplicated and (17.6%) were severe, all met the diagnostic criteria and were clinically admitted for malaria infections. For the determination of serum MBL and IL-6 levels, a commercial ELISA kit was employed. Results: the analysis of the results revealed significantly elevated levels of MBL and IL-6 in both severe and uncomplicated cases (p&lt;0.001). And MBL average in contrast to residents, Blue Nile patients had high parasitemia (599.9 ng/mL) and this difference was statistically significant (p-value&lt;0.05). The remarkable positive correlation of IL-6 serum levels with MBL among malaria patients and healthy controls (r=0.399, p&lt;0.001) was noted too. Conclusions: according to the findings of this study, patients living in hyperendemic areas exhibit a different MBL response rate and appear to be more homogeneous in proportion to the density of P. falciparum due to parasitemia. In addition, it is also dependent on the regulatory immune mediator IL-6.

The Role of Mannose-Binding Lectin and Inflammatory Markers in Establishing the Course and Prognosis of Community-Acquired Pneumonia in Children.

Community-acquired pneumonia (CAP) is one of the most significant childhood diseases worldwide and a leading infectious cause of death in children. This study aimed to evaluate the prognostic value of the inflammatory markers-C-reactive protein (CRP) and procalcitonin (PCT)-and the polymorphic glycoprotein mannose-binding lectin (MBL), deficiency of which is associated with severe infections, in the determination of the optimal type and timing of therapeutic intervention for CAP in childhood. Retrospective evaluation was conducted on a cohort of 204 children aged 4 months-17 years hospitalized with CAP. Their levels of CRP, PCT, and MBL were assessed for their association with a variety of outcomes, including the incidence of local and systemic complications, admission to the ICU, duration of antibiotic treatment and hospital stay, and death. CRP and PCT proved to be better predictors of complications of CAP than MBL. The area under the curve (AUC) value was highest for PCT as a predictor of systemic complications (AUC = 0.931, 95%CI 0.895-0.967), while CRP (AUC = 0.674, 95%CI 0.586-0.761) performed best as a predictor of local complications (AUC = 0.674, 95%CI 0.586-0.761). Regarding admission to the ICU, CRP was the weakest predictor (AUC = 0.741), while PCT performed the best (AUC = 0.833), followed by MBL (AUC = 0.797). Sensitivity and specificity were calculated for the optimal threshold generated by receiver operating characteristic (ROC) curves, rendering sensitivity of 90% and specificity of 87% for PCT in assessing the risk of systemic complications, compared to sensitivity of 83% and specificity of 90% for CRP. MBL showed relatively high sensitivity (96%) but low specificity (25%) for predicting the need for ICU admission. Early measurement of CRP, PCT, and MBL provides clinicians with important information regarding the course and prognosis of children diagnosed with CAP, thus ensuring prompt, optimal therapeutic management.

Systemic and local complement activation in peritoneal dialysis patients via conceivably distinct pathways.

Despite several advantages compared to haemodialysis (HD), peritoneal dialysis (PD) remains an underused dialysis technique due to its high technique failure rate related to membrane fibrosis and peritonitis events. Previous work has suggested a harmful role for the complement system in these processes, highlighting the need for a more comprehensive examination in PD. Plasma levels of C1q, mannose-binding lectin (MBL), Properdin, Factor D, C3d/C3-ratio and soluble membrane attack complex (sC5b-9) were determined in PD patients (n = 55), HD patients (n = 41), non-dialysis chronic kidney disease (CKD) patients (n = 15) and healthy controls (n = 14). Additionally, C1q, MBL, Properdin, Factor D and sC5b-9 levels were assessed in the peritoneal dialysis fluid (PDF). In a subgroup, interleukin-6, matrix metalloproteinase-2 (MMP-2), myeloperoxidase (MPO) and elastase were measured in the PDF. PD patients had significantly higher systemic levels of sC5b-9 compared to healthy controls, CKD and HD patients (p < 0.001). Plasma levels of C1q and C3d/C3-ratios were significantly associated with systemic sC5b-9 levels (p < 0.001). Locally, sC5b-9 was detected in the PDF of all PD patients, and levels were approximately 33% of those in matched plasma, but they did not correlate. In the PDF, only Properdin levels remained significantly associated with PDF sC5b-9 levels in multivariate analysis (p < 0.001). Additionally, PDF levels of sC5b-9 positively correlated with elastase, MPO and MMP-2 levels in the PDF (p < 0.01). Our data reveal both systemic and local complement activation in PD patients. Furthermore, these two processes seem independent considering the involvement of different pathways and the lack of correlation.

115 The mannose-binding lectin (MBL) in MIS-C: relationship between MBL genotype, levels, and functional activity against SARS-CoV-2

115 The mannose-binding lectin (MBL) in MIS-C: relationship between MBL genotype, levels, and functional activity against SARS-CoV-2

Molecular characterization of complete coding sequence of the MBL1 gene in the Indian Buffalo (Bubalus bubalis) breed

Mannose-binding lectin (MBL) is a member of the collectin protein family that binds a broad range of microorganisms and activates the lectin-complement pathway of innate immunity. A number of mutations have been found in both the coding as well as the non-coding regions of the MBL1 gene in various species, of which several variations affected the assembly of MBL1, thus leading to a low level of plasmic MBL and innate immune dysfunctions. In the present study, we have reported molecular cloning and characterization of the complete coding sequence of the MBL1 gene in the Indian buffalo breed Murrah. A 951 bp fragment of the MBL1 gene was amplified, cloned and sequenced. Multiple sequence alignment with other buffalo and cattle breeds revealed that the Murrah buffalo MBL1 CDS was 98.1-99.6% homologous to other buffalo breeds, and 98.3-98.5% similar to cattle breeds at nucleotide level. It was 96.8-98.8% homologous to buffalo breeds and 96.8-97.2% similar to cattle breeds at amino acid level. The amino acid sequence of the Murrah buffalo MBL1 contained two non-synonymous amino acid substitutions (L204P and S180P). Further, PCR-RFLP was performed to screen 50 Murrah buffalo for the presence of SNPs, g.855G&gt;A in intron I and g.2686T&gt;C, as well as g.2651G&gt;A in exon 2 region of the MBL1 gene. The ApaI/intron I PCR-RFLP assay revealed a polymorphic pattern with three genotypes viz., AG (90%), GG (8%) and AA (2%), with allelic frequencies 0.94 for G and 0.06 for A. HaeIII/exon 2 PCR-RFLP assay exhibited the presence of three genotypes, namely, TC (66%), TT (32%) and CC (2%) with allelic frequencies 0.15 for T and 0.85 for C. StyI/exon 2. PCR-RFLP assay showed a monomorphic pattern for g.2651G&gt;A with GG genotype only. We further examined the association of these SNPs with milk production traits and somatic cell score (SCS), and found no significant difference for any of the traits. Since the present study has formulated the results on the basis of a relatively small sample size, further studies with a larger sample size are required to validate the effects of polymorphisms.

The complement system and endometriosis: what's new?

The objective of this literature review was to reveal new noninvasive markers of the complement system for improvement of endometriosis (EM) diagnostics. To analyze scientific literature, the international database was used.&#x0D; Among women with EM, a significant increase in the blood serum С1, С1-INH, C3c and С4 levels and elevated concentrations in the peritoneal fluid was observed. However, iC3b level in EM women was significantly lower in the peritoneal fluid and blood serum compared with healthy women. The levels of C4A/B gene expression were higher in the ectopic tissues than in the eutopic endometrium. The membrane attack complex (MAC) concentration was higher in the peritoneal fluid and blood serum among women with disseminated stage of EM compared to the control group. In women with EM, an increased level of mannose-binding lectin (MBL) in the peritoneal fluid was noted; a higher concentration was observed at the early stage of EM (stages I and II AFS) in comparison with the disseminated one (stages III and IV AFS). The development of new and improvement of the existing noninvasive markers of the complement system can be perspective for noninvasive diagnostics of EM and determination of the degree of its severity.

Association between mannose binding lectin gene polymorphisms and clinical severity of COVID-19 in children.

Mannose-binding lectin (MBL) is a member of innate immunity and acts with MASP (MBL-associated serine protease) to activate the lectin pathway of the complement system. MBL gene polymorphisms are associated with susceptibility to infectious diseases. This study investigated whether MBL2 genotype, serum MBL levels, and serum MASP-2 levels affect the course of SARS-CoV-2 infection. Pediatric patients diagnosed with COVID-19 by positive real-time polymerase chain reaction (PCR) were included in the study. Single nucleotide polymorphisms in the promoter and exon 1 in the MBL2 gene (rs11003125, rs7096206, rs1800450, rs1800451, rs5030737) were identified by a PCR and restriction fragment length polymorphisms analysis. Serum MBL and MASP-2 levels were measured by ELISA. COVID-19 patients were divided into asymptomatic and symptomatic. Variables were compared between these two groups. A total of 100 children were included in the study. The mean age of the patients was 130 ± 67.2 months. Of the patients, 68 (68%) were symptomatic, and 32 (32%) were asymptomatic. The polymorphisms in the - 221nt and - 550nt promoter regions did not differ between groups (p > 0.05). All codon 52 and codon 57 genotypes were determined as wild-type AA. AB genotypes were found 45.6% in symptomatic patients while 23.5% in asymptomatics. Moreover, BB genotype was detected 9.4% in symptomatic and 6.3% in asymptomatic patients (p < 0.001). B allele was more frequent in symptomatic patients (46.3%) compared to asymptomatic patients (10.9%). (p < 0.001). Serum MBL and MASP-2 levels did not differ statistically between the groups (p = 0.295, p = 0.073). These findings suggest that codon 54 polymorphism in the MBL2 gene exon-1 region can be associated with the symptomatic course of COVID-19.

Mannose-binding lectin gene 2 variant DD (rs 5030737) is associated with susceptibility to COVID-19 infection in the urban population of Patna City (India).

The study aimed to measure plasma levels of Mannose-Binding Lectin (MBL) and MBL-associated serine protease-2 (MASP-2) and theirpolymorphisms in COVID-19 patients and controls to detect association. As MBL is a protein of immunological importance, it may contribute to the first-line host defence against SARS-CoV-2. MBL initiates the lectin pathway of complement activation with help of MASP-1 and MASP-2. Hence, appropriate serum levels of MBL and MASPs are crucial in getting protection from the disease. The polymorphisms of MBL and MASP genes affect their plasma levels, impacting their protective function and thus may manifest susceptibility, extreme variability in the clinical symptoms and progression of COVID-19 disease. The present study was conducted to find plasma levels and genetic variations in MBL and MASP-2 in COVID-19 patients and controls using PCR-RFLP and ELISA, respectively.The present study was conducted to find plasma levels and genetic variations in MBL and MASP-2 in COVID-19 patients and controls using PCR-RFLP and ELISA, respectively. Our results indicate that median serum levels of MBL and MASP-2 were significantly low in diseased cases but attained normal levels on recovery. Only genotypeDD was found to be associated with COVID-19 cases in the urban population of Patna city.

Characterization of Mannose Binding Lectin (MBL) Levels in Type-2 Diabetes Mellitus Patients Amongst Pakistani Population

Introduction: Mannose Binding Lectin (MBL) is a pattern recognizing molecule in the Lectin complement pathway and acts by activating the complement cascade via binding with ligands. There is evidence of increased autoreactivity of Mannose Binding Lectin in various diseases especially diabetes. MBL deficiency can reduce pathogen clearance and impair atherogenic lipoprotein removal whereas higher levels are associated with exaggerated immune response due to complement activation in the presence of hyperglycemia.&#x0D; Aims &amp; Objectives: This study aims to find out the association of MBL (Mannose Binding Lectin) with different clinical parameters in healthy controls and type 2 DM patients to predict disease outcome in type 2 diabetics. Mean level of MBL in type 2 diabetics and healthy population will be compared to characterize MBL levels amongst diabetics helping the clinicians to stratify patients according to disease severity.&#x0D; Place and duration of study: It was a cross sectional analytical study conducted at Chughtai Institute of Pathology from July 2019 to January 2020 on samples collected nationwide at Chughtai Lab collection centres.&#x0D; Material &amp; Methods: We selected 300 adult male and females in this study after taking informed consent based on strict inclusion and exclusion criteria. Of these 200 were known cases of type 2 diabetes mellitus and 100 healthy controls. .Fasting blood samples were drawn from both groups were analyzed for hs-CRP, HbA1c, creatinine, Total Cholesterol, Alanine amino transfer as (ALT), HDL-Cholesterol, LDL-Cholesterol, Glucose, Triglyceride, and Mannose Binding lectin. eGFR (Estimated Glomerular Filtration rate) was calculated for each patient and control. Data was analyzed via Graph Pad Prism 5 and SPSS version 23.0, p value ? 0.05 was taken as significant.&#x0D; Results: Mean age of the participants was 47.9 years in diabetic group and 39.3 years in healthy controls. The healthy population had a mean MBL level of 110.1 (SD±3.94) pg/ml and mean MBL level of diabetic group was 197.9 (SD±12.84) pg/ml (p&lt;0.05). No differences in MBL levels were detected based on gender distribution. There was a significant difference among HbA1c, LDL-C, HDL-C, Fasting Glucose, TG, creatinine and eGFR amongst the diabetic and the healthy group (p&lt;0.05). There was a negative correlation between MBL levels and plasma glucose and a positive correlation between the former and HDL-C in the healthy controls. In diabetic patients having MBL above 178pg/ml, a positive correlation of HbA1C with MBL was found. CRP in the healthy population resembled levels in patients with elevated MBL and the ratio Trig/HDL was higher in this subgroup having a positive correlation with MBL.&#x0D; Conclusion: MBL plays a role in pathophysiology of diabetes mellitus and elevated MBL having positive correlation with HbA1c might show association of glycemic control with the biomarker levels. A direct relationship of MBL with development of cardiovascular complications in type 2 diabetics was suggested by a positive association of MBL with TG to HDL-C ratio.

Polymorphisms in the MBL2 gene are associated with the plasma levels of MBL and the cytokines IL-6 and TNF-α in severe COVID-19.

Mannose-binding lectin (MBL) promotes opsonization, favoring phagocytosis and activation of the complement system in response to different microorganisms, and may influence the synthesis of inflammatory cytokines. This study investigated the association of MBL2 gene polymorphisms with the plasma levels of MBL and inflammatory cytokines in COVID-19. Blood samples from 385 individuals (208 with acute COVID-19 and 117 post-COVID-19) were subjected to real-time PCR genotyping. Plasma measurements of MBL and cytokines were performed by enzyme-linked immunosorbent assay and flow cytometry, respectively. The frequencies of the polymorphic MBL2 genotype (OO) and allele (O) were higher in patients with severe COVID-19 (p< 0.05). The polymorphic genotypes (AO and OO) were associated with lower MBL levels (p< 0.05). IL-6 and TNF-α were higher in patients with low MBL and severe COVID-19 (p< 0.05). No association of polymorphisms, MBL levels, or cytokine levels with long COVID was observed. The results suggest that, besides MBL2 polymorphisms promoting a reduction in MBL levels and therefore in its function, they may also contribute to the development of a more intense inflammatory process responsible for the severity of COVID-19.

5588568 ASSOCIATION OF MANNOSE-BINDING LECTIN SERUM LEVEL AND PROMOTER GENE VARIANTS RS7096206 AND RS10031251 WITH FREQUENCY OF VASO-OCCLUSIVE EVENTS IN SICKLE CELL DISEASE PATIENTS; AN EGYPTIAN CROSS-SECTIONAL STUDY

Background: Sickle cell disease (SCD) is a genetic blood disorder involving hemoglobin alterations, in addition to endothelial adhesion, thrombosis and inflammation. Low serum Mannose-binding lectin (MBL) levels can enhance SCD-related blood vessel inflammation as well as reduction of phagocytic activity, leading to sickled erythrocyte accumulation on vessel walls and impaired ability to combat infections. This may contribute to the vaso-occlusive (VOC) episodes. Aim: This work aimed to investigate serum MBL level and MBL promoter gene variants distribution among a cohort of Egyptian SCD patients and to describe their association with VOC events frequencies in the studied patients. Methods: This cross-sectional study included 88 steady-state Egyptian SCD patients aged 6-18 years diagnosed and followed up at Pediatric Hematology Unit, Cairo University Children Hospital. Informed consent was obtained willingly from all subjects or their guardians before enrolment in the study. MBL promoter (-221) (rs7096206) X/Y and (-550) (rs10031251) H/L gene variants were studied by Polymerase Chain Reaction- Restriction Fragment Length Polymorphism (PCR-RFLP) technique. Serum MBL level was assayed by ELISA technique with values <500ng/ml considered deficient. Results: The median serum MBL level in SCD patients was 130.9 ng/ml (IQR 71.2-323.9 ng/ml). Patients with serum MBL levels <500ng/ml were significantly older, had longer disease duration and higher rate of VOCs per year, VOCs per lifetime and a higher VOC index (p= 0.039, 0.034, 0.047, 0.040 and 0.008 respectively). Levels <500ng/ml predominated in SS (89.4%) than Sβ groups (70%) (p= 0.023) and in patients with high frequency of VOCs (91.4%) (p=0.008). Serum MBL level correlated negatively with patients’ age, disease duration, hydroxyurea total treatment duration, blood transfusions per lifetime and steady-state HbS level (p= <0.001, <0.001, 0.011, 0.014, 0.031 respectively) but correlated positively with steady-state HbF level (p=0.002). MBL (-221) X/Y both alleles were more associated with (H) allele of MBL (-550) than with L allele (p=0.048), however, with no statistically significant genotype distribution between the studied variants. There was no statistically significant difference in genotype distribution or allele frequencies between MBL (-221) and MBL (-550) in SCD patients regarding serum MBL level, sickle cell type (SS and Sβ), VOCs frequencies or disease severity classes. Conclusion: Serum MBL level rather than studied MBL gene variants is more likely to contribute to the clinical outcomes of SCD; patients with lower MBL levels had a higher rate of VOC per year, per lifetime and a higher VOC index. Meanwhile, the variant genotypes and alleles of the studied MBL promotor gene variants were not associated with MBL deficiency, VOCs, infection events, and disease severity.Further studies to investigate other polymorphisms in MBL gene; MBL exon-1 (codons 52,54 and 57) are recommended. Keywords: MBL, Polymorphism, Sickle cell disease, Vaso-occlusive crises, Egypt

Levels of Complement Components in Children With Acute COVID-19 or Multisystem Inflammatory Syndrome

Multisystem inflammatory syndrome in children (MIS-C) is a severe and unrestrained inflammatory response with multiorgan involvement, which occurs within a few weeks following the resolution of acute SARS-CoV-2 infection. The complement system is a vital part of the innate immune system and plays a role in COVID-19 pathogenesis. To examine and compare the levels of complement components and regulators along with complement activation products in the different clinical spectrum of children with SARS-CoV-2 and a control group. This cross-sectional study analyzed children with MIS-C admitted to a single hospital in India from June through September 2020. Eligible participants were children who were hospitalized of either sex, aged 1 to 18 years. Data were analyzed August 2022. Levels of complement components and regulators along with complement activation products in all the groups of children. Mann-Whitney U test and Kruskal-Wallis analysis were used to compare the complement component levels, and Spearman rank correlation analysis was used to describe the association between complement components and laboratory and biochemical parameters. A total 145 children were included (median age, 5 years [range, 1 month-17 years); 84 [58%] male): 44 children with MIS-C, 33 with acute COVID-19 (reverse transcriptase-polymerase chain reaction [RT-PCR] positive), 47 with convalescent COVID-19 (immunoglobulin G-positive non-MIS-C) and 21 children for a control group (both serology and RT-PCR negative). Children with MIS-C and COVID-19 had higher levels of C1q (geometric mean [SD]: MIS-C, 61.5 [18.5] ng/mL; acute COVID-19, 56.9 [18.6] ng/mL; controls, 24.1 [3.3] ng/mL), C2 (MIS-C, 605.8 [219.7] ng/mL; acute COVID-19, 606.4 [167.7] ng/mL; controls, 255.9 [73.3] ng/mL), C3 (MIS-C, 318.2 [70.7] ng/mL; acute COVID-19, 237.7 [61.8] ng/mL; controls, 123.4 [15.7] ng/mL), C4b (MIS-C, 712.4 ng/mL; acute COVID-19, 640.7 ng/mL; controls, 351.5 ng/mL), C5 (MIS-C, 1487 ng/mL; acute COVID-19, 1364 ng/mL; controls, 561.9 ng/mL), C5a, (MIS-C, 2614.0 [336.2] ng/mL; acute COVID-19, 1826.0 [541.0] ng/mL; controls, 462.5 [132.4] ng/mL), C3b/iC3b (MIS-C, 3971.0 [635.1] ng/mL; acute COVID-19, 3702.0 [653.9] ng/mL; controls, 2039.0 [344.5] ng/mL), and factor B (MIS-C, 47.6 [7.8] ng/mL; acute COVID-19, 44.6 [6.3] ng/mL; controls, 27.5 [5.0] ng/mL), factor D (MIS-C, 44.0 [17.2] ng/mL; acute COVID-19, 33.8 [18.4] ng/mL; controls, 21.3 [6.1] ng/mL), and factor H (MIS-C, 53.1 [4.0] ng/mL; acute COVID-19, 50.8 [5.7] ng/mL; controls, 43.6 [3.8] ng/mL) in comparison with convalescent and control children. In addition, children with MIS-C had significantly elevated levels of C3 (318.2 [70.7] ng/mL vs 237.7 [61.8] ng/mL), C5a (2614 [336.2] ng/mL vs 1826 [541.0] ng/mL), and mannose-binding lectin (79.4 [12.4] ng/mL vs 69.6 [14.7] ng/mL) in comparison to children with acute COVID-19. Levels of some of these analytes at admission (ie, pretreatment) were more elevated in children with MIS-C who needed pediatric intensive care unit (PICU) support as compared with those who did not require PICU support, and in children with COVID-19 who developed moderate to severe disease compared with those who developed mild disease. Overall, MIS-C and acute COVID-19 were associated with the hyperactivation of complement components and complement regulators. In this cross-sectional study, the complement system was associated with the pathogenesis of MIS-C and COVID-19 in children; complement inhibition could be further explored as a potential treatment option.

The relationship between COVID-19 and the complement system: mannose-binding lectin.

Mannose-binding lectin (MBL) is one of the important parts of the complement system. In our study, we aimed to determine serum MBL levels and their relationship with intensive care hospitalization. Ninety COVID-19-positive patients from outpatient clinics and clinics were included in this study. The patients were evaluated in three groups as mild, moderate, and severe groups. Each group consisted of 30 patients. A venous blood sample was taken once from each patient. Serum MBL, C-reactive protein (CRP), lactate dehydrogenase (LDH), fibrinogen, D-dimer, and ferritin levels were measured. The mean serum MBL levels of all patients were 695.46±324.42 ng/mL. One-way ANOVA test resulted in significant differences in serum CRP, LDH, fibrinogen, D-dimer, ferritin, and MBL levels between groups (p<0.05 for all comparisons). Post-hoc Tukey analysis showed significant differences in serum MBL levels between mild and severe groups and moderate and severe groups. MBL may be used as a prognostic biomarker in COVID-19 patients. Further studies are needed to determine MBL in treatment strategies.