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P Garred

Publications and source records attributed to P Garred.

At least 19 recordsLinked to original sources
PubMed2006

Mannose-binding lectin and its genetic variants.

Mannose-binding lectin (MBL) is a collagen-like serum protein that mediates activation of the complement system and is of importance for host defence. Common variant alleles situated both in the promoter and structural region of the human MBL gene (MBL2) influence the stability and the serum concentration of the protein. Epidemiological studies have suggested that genetically determined variation in MBL serum concentration influences the susceptibility to and the course of different types of infections, autoimmune, metabolic and cardiovascular diseases, but this is still a subject of debate. The fact that these genetic variations are very frequent indicates a dual role for MBL in host defence. In this survey, we summarize the current molecular understanding of human MBL genetics.

Alleles↗
PubMed2006

Design of a complement mannose-binding lectin pathway-specific activation system applicable at low serum dilutions.

Recently we showed that alternative pathway (AP) amplification was responsible for more than 80% of specific classical pathway-induced terminal pathway activation under physiological conditions. The present study aimed to design a system for specific lectin pathway (LP) activation applicable at low serum dilutions with a fully functional AP. Comparison between activation of normal human serum (NHS), a mannose-binding lectin (MBL) homozygous D/D-deficient serum, and sera deficient in C1q and C2, all diluted 1 : 2, was essential to document optimal conditions for LP specificity. Mannan on the solid phase of enzyme-linked immunosorbent assay (ELISA) plates was used for activation, showing 0.5 microg mannan/well to give optimal conditions because at this concentration a good signal was preserved for C4 and TCC deposition in NHS, whereas the C3 deposition observed in C2-deficient serum at higher mannan concentrations reached nadir at 0.5 microg/well, indicating a lack of direct AP activation under these conditions. Pooled NHS and C1q-deficient serum gave the same degree of C4 and terminal complement complex (TCC) deposition, whereas deposition of these products was not obtained with MBL-deficient serum. Reconstitution with purified MBL, however, restored the depositions. A blocking anti-MBL monoclonal antibody (mAb) completely abolished the complement deposition, in contrast to a non-inhibiting anti-MBL mAb. Activation of C2-deficient serum induced C4 deposition similar to NHS, but negligible deposition of C3 and TCC, confirming the lack of direct activation of AP. Thus, this assay is unique in being LP-specific at low serum dilution and thus particularly suitable to study LP activation mechanisms and the role of AP amplification under physiological conditions.

Antibodies, Monoclonal↗
PubMed2005

Mannose binding lectin and C3 act as recognition molecules for infectious agents in the vagina.

In our study we examined the early complement components in patients with bacterial vaginosis (BV), vulvovaginal candidiasis (VVC) and in healthy controls. The levels of C1q, mannose-binding lectin (MBL) and C3 were measured by ELISA in the cervicovaginal lavage (CVL) from gynaecological patients and controls. No significant differences were observed in the levels of these proteins in the three study groups. Immunofluorescence analysis of the clue cells and Candida hyphae from BV and VVC patients for surface-bound complement components showed the presence of C3, while C1q was undetectable. MBL was revealed on clue cells but not on Candida. Binding of MBL to Candida, grown or cytocentrifuged from the CVL of VVC patients, was found to be pH dependent and occurred between pH 4.5 and pH 5.5. In conclusion, we demonstrated that MBL and C3 present in the vaginal cavity act as recognition molecules for infectious agents that colonize the cervicovaginal mucosa. Our finding that MBL, but not C1q, binds to bacteria and fungi in vagina suggests that the lectin and classical pathways of complement activation may play a different role in immune defence in the female genital tract.

Adolescent↗
PubMed2004

Functional analysis of the classical, alternative, and MBL pathways of the complement system: standardization and validation of a simple ELISA.

Primary defence against invading microorganisms depends on a functional innate immune system and the complement system plays a major role in such immunity. Deficiencies in one of the components of the complement system can cause severe and recurrent infections, systemic diseases, such as systemic lupus erythematosus (SLE) and renal disease. Screening for complement deficiencies in the classical or alternative complement pathways has mainly been performed by haemolytic assays. Here, we describe a simple ELISA-based format for the evaluation of three pathways of complement activation. The assays are based on specific coatings for each pathway in combination with specific buffer systems. We have standardized these assays and defined cut off values to detect complement deficiencies at the different levels of the complement system. The results demonstrate the value of these ELISA-based procedures for the functional assessment of complement deficiencies in clinical practice. The assay is now available commercially in kit form.

Complement Activation↗
PubMed2003

Three new alleles of IGHG2 and their prevalence in Danish Caucasians, Mozambican Blacks and Japanese.

The human IGHG2 gene locus is polymorphic, encoding two known allotypes of IgG2: G2m(n-) and G2m(n+). The allele prevalence varies greatly between different ethnic groups and individual genotypes correlate with the level of plasma IgG2 and with antibody responses to certain polysaccharide antigens. In this study, we present three new alleles of IGHG2 (IGHG2*03, 04, and 05), and a complete sequence specific PCR typing system allowing discrimination between the different allotypes of IgG2. A hitherto unknown allotype, which we name G2m(ny), is encoded by IGHG2*04 and differs from G2m(n-) by asparagine rather than serine in CH1 residue 75 and by phenylalanine rather than leucine in CH1 residue 76 (EU numbering 192 and 193). The polymorphic residues are probably surface exposed near the hinge region. The same residues are also found in IgG1, IgG3, and IgG4, and G2m(ny) is therefore an isoallotype that probably arises by gene conversion within the heavy chain locus. The IGHG2*04 allele is present among Danish Caucasians with a low prevalence (2.5%), but was not found in Japanese or Mozambicans. The two other new alleles (IGHG2*03 and IGHG2*05) both encode the G2m(n-) allotype. The IGHG2*03 allele encodes most of the IgG2 of the G2m(n-) allotype in Danish Caucasians.

Alleles↗
PubMed2003

Ascites fluid and plasma calprotectin concentrations in liver disease.

BACKGROUND: Calprotectin, a marker of neutrophil activation, has been associated with a poor prognosis in alcohol-induced cirrhosis. The aims were to study concentrations of calprotectin in patients with various liver diseases, and to further investigate the prognostic value of calprotectin in cirrhosis. METHODS: Plasma calprotectin concentrations were determined in 84 patients with alcohol-induced liver disease, 32 hepatitis B or C infected patients, 33 patients with liver disease of other aetiologies, 7 patients with combined aetiologies and in 24 patients with malignant disease. Thirty healthy individuals were included as controls. Ascites calprotectin concentrations were determined in patients with ascites (n = 75). Follow-up for survival was performed after a median observation period of 10 months. RESULTS: Increased plasma and ascites calprotectin concentrations were observed in malignant disease compared to non-malignant disease (P < 0.0001). Plasma calprotectin concentrations were low in viral liver disease compared to patients with non-viral liver disease (P = 0.02) and to controls (P = 0.0002). Plasma calprotectin (>median) was a highly significant marker of poor survival in alcohol-induced cirrhosis (P = 0.001), but was of no prognostic value in non-alcohol-induced cirrhosis (P = 0.88). In decompensated cirrhosis high (>upper quartile) ascites calprotectin concentrations were associated with an increased mortality (P = 0.002), as were high (>median) plasma calprotectin levels (P = 0.009). CONCLUSION: The prognostic importance of calprotectin in alcohol-induced cirrhosis is confirmed and demonstrated as specific for alcohol-induced liver disease. Low calprotectin levels are indicated in viral liver disease, and an association between high ascites calprotectin levels and malignant ascites was observed.

Ascitic Fluid↗
PubMed2002

Cerebrospinal fluid levels of nitric oxide metabolites predict response to methylprednisolone treatment in multiple sclerosis and optic neuritis.

The role of nitric oxide (NO) in multiple sclerosis (MS) is not clear. We found increased cerebrospinal fluid concentrations of the NO degradation products nitrate (NO(x)) in clinically definite MS but not in clinically isolated syndromes. High CSF concentrations of NO(x) correlated with long attack duration. Patients carrying the truncated CC chemokine receptor allele CCR5 Delta32 had lower serum concentration of NO(x) at later attack stages. NO(x) concentrations did not change after methylprednisolone treatment but high concentrations were associated with more pronounced treatment responses. These findings suggest an association of high CSF levels of NO(x) with more severe disease activity in relapsing-remitting MS.

Adult↗
PubMed2002

Autoantibodies against interleukin 1alpha in rheumatoid arthritis: association with long term radiographic outcome.

OBJECTIVES: To investigate the possible association of interleukin 1alpha autoantibodies (IL1alpha aAb) with the long term course of joint erosion in patients with rheumatoid arthritis (RA). METHODS: Serum samples from 176 patients with RA included in a prospective study over 30 years were analysed for IL1alpha aAb by binding to human [(125)I]IL1alpha. Erosions of 19 diarthrodial joints were radiographically scored by the Larsen method. RESULTS: The relative risk (RR) of early IL1alpha aAb positive patients developing at least 30% of maximum radiographic joint destruction was significantly lower than for IL1alpha aAb negative patients, RR=0.29 (p=0.04). In rheumatoid factor positive patients RR was only 0.18 (p=0.02). Patients who seroconverted more than two years after the onset of RA showed the most aggressive development of joint erosion, with a relative risk of at least 40% of maximum radiographic joint destruction of 2.56 (p=0.048) CONCLUSIONS: The progression of radiographic joint destruction in patients with RA is associated with, and perhaps modified by, circulating IL1alpha aAb, suggesting that IL1alpha or IL1alpha aAb, or both, have a role in the erosive processes. IL1alpha aAb appear to be of prognostic significance in RA.

Adolescent↗
PubMed2001

Acute respiratory tract infections and mannose-binding lectin insufficiency during early childhood.

CONTEXT: Hospital-based studies have found that increased susceptibility to certain infections is associated with low serum levels of mannose-binding lectin (MBL) due to MBL variant alleles. However, the contribution of MBL insufficiency to incidence of common childhood infections at a population level is unknown. OBJECTIVE: To investigate the effect of MBL insufficiency on risk for acute respiratory tract infection (ARI) in unselected children younger than 2 years. DESIGN AND SETTING: Population-based, prospective, cohort study conducted in Sisimiut, Greenland. PARTICIPANTS: Two hundred fifty-two children younger than 2 years who were followed up weekly between August 1996 and August 1998 for morbidity surveillance. MAIN OUTCOME MEASURE: Risk of ARI, based on medical history and clinical examination, compared by MBL genotype, determined from blood samples based on presence of structural and promoter alleles. RESULTS: A 2.08-fold (95% confidence interval [CI], 1.41-3.06) increased relative risk (RR) of ARI was found in MBL-insufficient children (n = 13) compared with MBL-sufficient children (n = 239; P<.001). The risk association was largely restricted to children aged 6 to 17 months (RR, 2.92; 95% CI, 1.78-4.79) while less effect (RR, 1.47; 95% CI, 0.45-4.82) and no effect (RR, 1.00; 95% CI, 0.42-2.37) was shown among children aged 0 to 5 months and 18 to 23 months, respectively. CONCLUSION: These data suggest that genetic factors such as MBL insufficiency play an important role in host defense, particularly during the vulnerable period of childhood from age 6 through 17 months, when the adaptive immune system is immature.

Acute Disease↗
PubMed2001

Association of mannose-binding lectin gene variation with disease severity and infections in a population-based cohort of systemic lupus erythematosus patients.

This study describes the importance of mannose-binding lectin (MBL) variant alleles for systemic lupus erythematosus (SLE) and accompanying infections in a population-based cohort. MBL alleles were determined in 99 SLE patients recruited from a representative Danish region. Patients were classified according to the 1982 revised ACR criteria as definite SLE (D-SLE) (n = 77) fulfilling > or =4 criteria and incomplete SLE (I-SLE) (n = 22) with 0.99, respectively). A meta-analysis of eight previously published studies suggested that the presence of MBL variant alleles confer a 1.6 times overall increased risk for D-SLE (P < 0.00001). MBL variant allele carriers had higher disease activity (SLEDAI-index) in a 2-year follow-up period (P = 0.02) and had an increased risk of acquiring complicating infections in general (P = 0.03) and respiratory infections in particular (P = 0.0006). Only in SLE patients fulfilling > or =4 ACR criteria an increased frequency of MBL variant alleles was found. MBL variant alleles were also associated with increased risk of disease activity and of complicating infections indicating that the MBL gene is an SLE disease modifier locus.

Adolescent↗
PubMed2001

The influence of mannose binding lectin polymorphisms on disease outcome in early polyarthritis. TIRA Group.

OBJECTIVE: To determine whether variant alleles of the mannose binding lectin (MBL) gene causing low serum concentrations of MBL are associated with increased susceptibility to rheumatoid arthritis (RA) and erosive outcome in an inception cohort of patients with early polyarthritis. METHODS: MBL and HLA-DRB1 alleles were determined by polymerase chain reaction in 68 Danish patients with incident early polyarthritis observed for one year. The associations between MBL and specific HLA-DRB1 genotypes and disease outcomes were analyzed. RESULTS: Among the patients with early polyarthritis 7.4% (5/68) and 41.2% (28/68) were homozygous and heterozygous for MBL variant alleles, compared with 2.8% (7/250) and 34.4% (86/250) of healthy controls (p = 0.09), while the corresponding figures in the patients with RA were 10% (5/50) and 42% (21/50) (p = 0.03), and in the patients with erosive RA 18.8% (3/16) and 35.3% (6/16), respectively (p = 0.004). Patients with early polyarthritis homozygous for MBL variant alleles had an increased risk of having erosive RA at inclusion by a factor of 4.7 (p = 0.02) and after one year by a factor of 3.6 (p = 0.04). MBL deficiency was associated with increased levels of C-reactive protein (CRP) and IgM rheumatoid factor (RF) at inclusion (p < 0.05). HLA-DRB1 alleles were not found to be associated with disease outcome. CONCLUSION: MBL variant alleles appear to be weak susceptibility markers for RA, and patients with early polyarthritis and homozygous for MBL structural variant alleles have a higher risk of developing early erosive RA. These findings, together with the positive association between MBL variant alleles and the increased serum levels of IgM RF and CRP, point at the MBL gene as a relevant locus in the pathophysiology of RA.

Adult↗
PubMed2000

CCR5 delta32, matrix metalloproteinase-9 and disease activity in multiple sclerosis.

Chemokines and matrix metalloproteinases (MMPs) appear to be crucial in leukocyte recruitment to the central nervous system in multiple sclerosis (MS). CCR5 delta32, a truncated allele of the CC chemokine receptor CCR5 gene encoding a non-functional receptor, did not confer protection from MS. CCR5 delta32 was, however, associated with a lower risk of recurrent clinical disease activity. High CSF levels of MMP-9 activity were also associated with recurrent disease activity. These results directly link intrathecal inflammation to disease activity in patients with MS, suggesting that treatments targeting CCR5 or treatment with MMP inhibitors may attenuate disease activity in MS.

Adult↗
PubMed2000

The association of variant mannose-binding lectin genotypes with radiographic outcome in rheumatoid arthritis.

OBJECTIVE: To investigate the possible association of mannose-binding lectin (MBL) genotypes with the outcome of rheumatoid arthritis (RA). METHODS: MBL genotypes and plasma concentrations were retrospectively determined in 140 RA patients who were selected from a major cohort followed up prospectively for up to 32 years. RESULTS: MBL-insufficient patients (those with 2 defective structural MBL alleles or with 1 defective allele combined with a low-expression variant of the normal allele) had unfavorable outcomes. The relative risk of a severe radiographic outcome event (30% of maximum radiographic destruction, or an RE30) was 3.1 (95% confidence interval 1.8-5.1) in the MBL-insufficient group versus the MBL-competent group (P < 0.0001). An RE30 occurred in 50% of MBL-competent patients within 17 years, while such an event occurred 9 years earlier in MBL-insufficient patients (i.e., within 8 years) (P < 0.0001). During the first 15 years, there was a significant trend toward lower hemoglobin levels (P < 0.04), higher erythrocyte sedimentation rates (P < 0.02), and a higher number of swollen joints (P < 0.05) in the MBL-insufficient group. CONCLUSION: MBL genotypes giving rise to MBL insufficiency are highly significant risk factors for fast progression of radiographic joint destruction.

Adolescent↗