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COMP-C3b as a molecular marker for inflammatory joint diseases
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Abstracts / Molecular Immunology 48 (2011) 1666–1733
alternative pathway (132.5–124.3%) (p = 0.34) comparing to low proteinuria patients, the plasma concentrations of C5b-9 and C3d/dg did not differ between groups. The number of apoptotic cells was higher in urine of patients with high proteinuria, but not statistically significant. Patients with diabetic nephropathy, who excrete increased amounts of protein, demonstrate repeatedly also high levels of uC5b-9, demonstrating complement involvement in renal tissue injury in diabetes. Since classical and alternative complement activation are not involved in diabetic nephropathy, it is feasible that glucose transforming over fructose to mannose mark renal cells and cause complement activation via mannan pathway and consequent inflammation and harm of kidney in diabetic patients. doi:10.1016/j.molimm.2011.06.391 P172 Differences of complement activation profile between type I and type II of hereditary angioedema due to C1-inhibitor deficiency Csuka a,∗ , Füst b , Temesszentandrási b , Jakab b , Farkas b , Varga b a
Semmelweis University, Budapest, Hungary 3rd Department of Internal Medicine, Semmelweis University, Budapest, Hungary b
Our aim was to investigate complement activation products in hereditary angioedema due to C1 inhibitor deficiency (HAEC1-INH), during a follow-up period and to confirm our previous findings on the relationship between these products and severity of disease. 107 HAE-C1-INH patients (96 HAE type I, 11 type II) and 113 healthy control subjects were included. C1rC1sC1-INH, C3bBbP, and SC5b-9 levels were determined using ELISA methods in single EDTA-plasma samples of controls and in 4 samples from patients taken in 4 subsequent years. Median levels of C1rC1sC1-INH level (60 U/mL [40–113] vs 8 U/mL [4–10]; p < 0.0001) and SC5b-9 (0.6 U/mL [0.4–1.2] vs 1.8 [0.9–2.8]; p < 0.0001) differed between patients and controls. Significant differences were found between HAE type I and type II as regards median C1rC1sC1-INH (54 U/mL [33–97] vs 31 U/mL [21–49], p < 0.0001), and in an opposite manner with C3bBbP median levels (6 U/mL [4–12] vs 10 U/mL [8–17], p = 0.0002); SC5b-9 exhibited a similar difference as with C3bBbP. Negative correlation was found between levels of C1rC1sC1-INH and functional C1-INH (r = −0.5095, p < 0.0001) in HAE type I, but not in type II. In accordance with our earlier findings, level of C1rC1sC1-INH correlated with the number of attacks (r = 0.3189, p = 0.0015) in HAE type I, but no correlation was found in HAE type II. The lack of correlation between attack number and the level of C1rC1sC1-INH in HAE type II can be explained by the possible differences between the functional activity of mutant C1-INH proteins against C 1s and enzymes of edema forming pathways. Further investigations are needed to confirm these novel findings. doi:10.1016/j.molimm.2011.06.392
P173 COMP-C3b as a molecular marker for inflammatory joint diseases E. Happonen a,∗ , T. Heinegård b
Saxne b , A.M.
Blom c , P.
Geborek b , D.
a
Lund University, Malmö, Sweden Lund University, Clinical Sciences, Lund, Sweden c Lund University, Laboratory Medicine, Malmö, Sweden b
Introduction: Cartilage oligomeric matrix protein (COMP) is found at elevated concentrations in sera of patients with erosive joint diseases such as rheumatoid arthritis (RA). We recently showed that COMP can activate complement via properdin and that circulating COMP-C3b complexes are present in sera of RA patients, but not healthy controls. We now set out to verify the specificity of such a disease marker in a larger patient cohort. Methods: COMP-C3b levels in sera of patients with rheumatologic diseases were measured using ELISA capturing COMP and detecting C3b. Results: COMP-C3b was significantly elevated in sera of patients with RA compared to healthy controls, but also in SLE patients, both during disease flare and remission. SLE patients with arthritis had significantly higher COMP-C3b levels than patients without arthritis. Furthermore, COMP-C3b levels were moderately elevated in patients with ankylosing spondylitis and psoriatic arthritis and highly elevated in reactive arthritis. The levels of COMP-C3b in the circulation of a subset of RA patients decreased upon treatment with TNF-alfa inhibitors. COMP-C3b did not correlate with CRP or serum COMP in any of the measured groups. Conclusion: COMP-C3b is elevated in several rheumatologic diseases and it appears to measure a process distinct from classical inflammatory markers such as CRP. doi:10.1016/j.molimm.2011.06.393 P174 Identification of epitopes on the collagen-like region of C1q recognized by serum antibodies from patients with lupus erythematosus D. Vanhecke a,∗ , H. Wan a , L. Osthoff a , M. Trendelenburg a a b
Roumenina b , M.
Schaller a , M.
University Hospital Basel, Basel, Switzerland Cordeliers Research Center, INSERM UMRS 872, 75006 Paris, France
Background and objective: Auto-antibodies against complement C1q (anti-C1q) have been shown to strongly correlate with the occurrence of severe nephritis in patients with systemic lupus erythematosus (SLE). Identification of the epitope(s) within C1q that are recognized by these auto-antibodies might lead to better diagnostic assays and/or help elucidate the putative role of C1q or anti-C1q in SLE. Method: Anti-C1q specific Fab molecules (Fabs) isolated from a phage display library of a SLE patient were used in a commercial micro-array based peptide scan to identify the peptide sequence recognized by anti-C1q. Affinity and specificity of anti-C1q Fab binding to the target peptide was further analysed using surface plasmon resonance (Biacore) and peptide-based ELISA’s. Results: A peptide scan of the A- and B-chains of the collagen-like region of C1q identified two regions that are the target of anti-C1q Fabs. Binding specificity and affinity was confirmed by surface plasmon resonance analysis. Peptide-based ELISA’s were used to detect antibody binding to one of the two identified regions. Serum antibodies from most SLE patients but not from healthy individuals
Abstracts / Molecular Immunology 48 (2011) 1666–1733
alternative pathway (132.5–124.3%) (p = 0.34) comparing to low proteinuria patients, the plasma concentrations of C5b-9 and C3d/dg did not differ between groups. The number of apoptotic cells was higher in urine of patients with high proteinuria, but not statistically significant. Patients with diabetic nephropathy, who excrete increased amounts of protein, demonstrate repeatedly also high levels of uC5b-9, demonstrating complement involvement in renal tissue injury in diabetes. Since classical and alternative complement activation are not involved in diabetic nephropathy, it is feasible that glucose transforming over fructose to mannose mark renal cells and cause complement activation via mannan pathway and consequent inflammation and harm of kidney in diabetic patients. doi:10.1016/j.molimm.2011.06.391 P172 Differences of complement activation profile between type I and type II of hereditary angioedema due to C1-inhibitor deficiency Csuka a,∗ , Füst b , Temesszentandrási b , Jakab b , Farkas b , Varga b a
Semmelweis University, Budapest, Hungary 3rd Department of Internal Medicine, Semmelweis University, Budapest, Hungary b
Our aim was to investigate complement activation products in hereditary angioedema due to C1 inhibitor deficiency (HAEC1-INH), during a follow-up period and to confirm our previous findings on the relationship between these products and severity of disease. 107 HAE-C1-INH patients (96 HAE type I, 11 type II) and 113 healthy control subjects were included. C1rC1sC1-INH, C3bBbP, and SC5b-9 levels were determined using ELISA methods in single EDTA-plasma samples of controls and in 4 samples from patients taken in 4 subsequent years. Median levels of C1rC1sC1-INH level (60 U/mL [40–113] vs 8 U/mL [4–10]; p < 0.0001) and SC5b-9 (0.6 U/mL [0.4–1.2] vs 1.8 [0.9–2.8]; p < 0.0001) differed between patients and controls. Significant differences were found between HAE type I and type II as regards median C1rC1sC1-INH (54 U/mL [33–97] vs 31 U/mL [21–49], p < 0.0001), and in an opposite manner with C3bBbP median levels (6 U/mL [4–12] vs 10 U/mL [8–17], p = 0.0002); SC5b-9 exhibited a similar difference as with C3bBbP. Negative correlation was found between levels of C1rC1sC1-INH and functional C1-INH (r = −0.5095, p < 0.0001) in HAE type I, but not in type II. In accordance with our earlier findings, level of C1rC1sC1-INH correlated with the number of attacks (r = 0.3189, p = 0.0015) in HAE type I, but no correlation was found in HAE type II. The lack of correlation between attack number and the level of C1rC1sC1-INH in HAE type II can be explained by the possible differences between the functional activity of mutant C1-INH proteins against C 1s and enzymes of edema forming pathways. Further investigations are needed to confirm these novel findings. doi:10.1016/j.molimm.2011.06.392
P173 COMP-C3b as a molecular marker for inflammatory joint diseases E. Happonen a,∗ , T. Heinegård b
Saxne b , A.M.
Blom c , P.
Geborek b , D.
a
Lund University, Malmö, Sweden Lund University, Clinical Sciences, Lund, Sweden c Lund University, Laboratory Medicine, Malmö, Sweden b
Introduction: Cartilage oligomeric matrix protein (COMP) is found at elevated concentrations in sera of patients with erosive joint diseases such as rheumatoid arthritis (RA). We recently showed that COMP can activate complement via properdin and that circulating COMP-C3b complexes are present in sera of RA patients, but not healthy controls. We now set out to verify the specificity of such a disease marker in a larger patient cohort. Methods: COMP-C3b levels in sera of patients with rheumatologic diseases were measured using ELISA capturing COMP and detecting C3b. Results: COMP-C3b was significantly elevated in sera of patients with RA compared to healthy controls, but also in SLE patients, both during disease flare and remission. SLE patients with arthritis had significantly higher COMP-C3b levels than patients without arthritis. Furthermore, COMP-C3b levels were moderately elevated in patients with ankylosing spondylitis and psoriatic arthritis and highly elevated in reactive arthritis. The levels of COMP-C3b in the circulation of a subset of RA patients decreased upon treatment with TNF-alfa inhibitors. COMP-C3b did not correlate with CRP or serum COMP in any of the measured groups. Conclusion: COMP-C3b is elevated in several rheumatologic diseases and it appears to measure a process distinct from classical inflammatory markers such as CRP. doi:10.1016/j.molimm.2011.06.393 P174 Identification of epitopes on the collagen-like region of C1q recognized by serum antibodies from patients with lupus erythematosus D. Vanhecke a,∗ , H. Wan a , L. Osthoff a , M. Trendelenburg a a b
Roumenina b , M.
Schaller a , M.
University Hospital Basel, Basel, Switzerland Cordeliers Research Center, INSERM UMRS 872, 75006 Paris, France
Background and objective: Auto-antibodies against complement C1q (anti-C1q) have been shown to strongly correlate with the occurrence of severe nephritis in patients with systemic lupus erythematosus (SLE). Identification of the epitope(s) within C1q that are recognized by these auto-antibodies might lead to better diagnostic assays and/or help elucidate the putative role of C1q or anti-C1q in SLE. Method: Anti-C1q specific Fab molecules (Fabs) isolated from a phage display library of a SLE patient were used in a commercial micro-array based peptide scan to identify the peptide sequence recognized by anti-C1q. Affinity and specificity of anti-C1q Fab binding to the target peptide was further analysed using surface plasmon resonance (Biacore) and peptide-based ELISA’s. Results: A peptide scan of the A- and B-chains of the collagen-like region of C1q identified two regions that are the target of anti-C1q Fabs. Binding specificity and affinity was confirmed by surface plasmon resonance analysis. Peptide-based ELISA’s were used to detect antibody binding to one of the two identified regions. Serum antibodies from most SLE patients but not from healthy individuals