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Wouters D, Voskuyl AE, Molenaar ETH, Dijkmans BAC, Hack CE. Evaluation of classical complement pathway activation in rheumatoid arthritis: measurement of C1q-C4 complexes as novel activation products. ACTA ACUST UNITED AC 2006; 54:1143-50. [PMID: 16572449 DOI: 10.1002/art.21729] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Novel activation products that are stable and minimally susceptible to in vitro artefacts have recently been described in the classical complement pathway. The present study assessed circulating levels of these products, i.e., covalent complexes between the recognition molecule of the classical pathway (C1q) and activated C4, in plasma samples from patients with rheumatoid arthritis (RA) to establish the relationship between these levels and the clinical and immunologic parameters in these patients. METHODS C1q-C4 levels were measured in plasma samples from 41 patients with active RA and 43 patients with inactive RA. These levels were related to other complement activation products and to disease activity according to the Disease Activity Score in 28 joints (DAS28), using Spearman's rank correlations. RESULTS C1q-C4 plasma levels were significantly higher in patients with active RA as compared with patients with RA in clinical remission (median 3.3 arbitrary units [AU], range 0.4-13.4 versus 1.7 AU, range 0.2-5.5; P=0.0001), suggesting that activation of the classical complement pathway reflects disease activity. This was supported by a significant correlation between C1q-C4 levels and the DAS28 (r=0.398, P=0.0002). Levels of other complement activation products, such as activated C4 (C4b/c), were also significantly elevated in patients with active disease compared with patients with inactive disease (P=0.03), and were correlated with C1q-C4 levels (r=0.329, P=0.002). Levels of C1q-C4 complexes were higher in synovial fluid samples than in plasma samples from the 4 patients tested. CONCLUSION Systemic complement activation via the classical pathway in patients with RA correlates with disease activity. These results indicate that C1q-C4 complexes may be used as a biomarker for RA.
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Affiliation(s)
- Diana Wouters
- Department of Immunopathology, Sanquin Research at CLB and Academic Medical Centre, Amsterdam, The Netherlands.
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Molenaar ET, Voskuyl AE, Familian A, van Mierlo GJ, Dijkmans BA, Hack CE. Complement activation in patients with rheumatoid arthritis mediated in part by C-reactive protein. ACTA ACUST UNITED AC 2001; 44:997-1002. [PMID: 11352263 DOI: 10.1002/1529-0131(200105)44:5<997::aid-anr178>3.0.co;2-c] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Complement activation in patients with rheumatoid arthritis (RA) is considered to be triggered by immune complexes. Recently, it was shown that C-reactive protein (CRP) can activate the complement system in vivo. We therefore hypothesized that part of the complement activation in RA is due to CRP. The aim of this study was to investigate CRP-mediated complement activation in RA, and to assess its correlation with disease activity. METHODS Complexes between CRP and the activated complement components C3d (C3d-CRP) and C4d (C4d-CRP), which reflect CRP-mediated complement activation, as well as the overall levels of activated C3 and C4 were measured in the plasma of 107 patients with active RA and 177 patients with inactive RA. Inactive RA was defined according to the American College of Rheumatology criteria for clinical remission. Disease activity was assessed by the modified Disease Activity Score (DAS28). RESULTS Plasma levels of C3d-CRP and C4d-CRP were increased in the majority of the patients, and were significantly higher in patients with active disease versus those with inactive RA (P < 0.001). In patients with active RA, the plasma concentrations of C3d-CRP and C4d-CRP correlated significantly with the DAS28 (Spearman's rho 0.61 and 0.55, respectively; P < 0.001), whereas these correlations were less pronounced in patients with inactive RA (Spearman's rho 0.28 [P < 0.001] and 0.25 [P = 0.001], respectively). Levels of activated C3 and C4 were also increased in the majority of the patients, particularly in patients with active RA. CONCLUSION Part of the activation of complement in RA is mediated by CRP and is correlated with disease activity. We suggest that this activation is involved in the pathogenesis of RA.
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Affiliation(s)
- E T Molenaar
- Vrije Universiteit Medical Center, Amsterdam, The Netherlands
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Lahita RG. Effects of gender on the immune system. Implications for neuropsychiatric systemic lupus erythematosus. Ann N Y Acad Sci 1997; 823:247-51. [PMID: 9292050 DOI: 10.1111/j.1749-6632.1997.tb48396.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- R G Lahita
- Division of Rheumatology and Connective Tissue Diseases, St. Luke's-Roosevelt Hospital Center, New York, New York 10019, USA.
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Mageed RA, Kirwan JR, Holborow EJ. Localization of circulating immune complexes from patients with rheumatoid arthritis in murine spleen germinal centres. Scand J Immunol 1991; 34:323-31. [PMID: 1882188 DOI: 10.1111/j.1365-3083.1991.tb01553.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In previous studies we have demonstrated high levels of rheumatoid factor (RF) and large-size (greater than 22S) circulating immune complexes (CIC) in the serum of rheumatoid arthritis (RA) patients with extra-articular disease. These findings were paralleled by a concurrent increase in the level of RF-associated cross-reactive idiotypes (CRI) and an apparent diversification of the RF repertoire detected in the serum of the same patients. In the present study we examine the ability of CICs to activate the complement system in vivo, and its possible influence on expanding the RF repertoire in RA patients with extra-articular disease. Activation of complement by CICs is the key for germinal centre localization and long-term retention of such complexes on the surface of follicular dendritic cells (FDC), and so provides a source for the selection of cells with high affinity receptors for IgG and leads to the establishment of immunological memory. CICs containing different immunoglobulin isotypes and from different patients localized in mouse spleen germinal centres. However, intense localization was mainly seen for IgG-containing complexes from the serum of patients with large-size (greater than 22S) IgG-IgM RF complexes. The ability of these complexes to localize in mouse spleen germinal centres was related to activation of the complement system via the classical pathway in the patients' sera. Localization of IgG complexes was significantly (P less than 0.05) higher in sera from RA patients with extra-articular disease than those with articular disease alone. This study demonstrates the ability of large-size (greater than 22S) IgG-IgM RF complexes to activate complement, and suggests a possible role for such complexes in modulating the immune response to IgG in RA patients with extra-articular disease.
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Affiliation(s)
- R A Mageed
- Bone and Joint Research Unit, London Hospital Medical College, UK
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Jacobs RJ, Mocharla R. An analysis of the fluid phase C1q binding assay. The effect of endogenous C1q on the precipitation and detection of an immune complex model. J Immunol Methods 1988; 109:265-75. [PMID: 3258897 DOI: 10.1016/0022-1759(88)90252-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We examined the effect of endogenous C1q on the sensitivity of the fluid-phase C1q binding assay (C1qBA) in detecting an immune complex (IC) model, heat-aggregated IgG (HAIgG), at concentrations of 10-10,000 micrograms/ml sample. Results in normal human serum (NHS) or plasma (NHP) were compared with those in heat-inactivated NHS (NHS/56) in which most endogenous C1q was depleted by heat denaturation. Higher HAIgG concentrations were required in NHP and NHS to produce the same 125I-C1q precipitation seen in NHS/56. This decreased sensitivity varied from 70% at low HAIgG concentrations to 0% at high concentrations, as predicted for a large pool of endogenous C1q, in equilibrium with 125I-C1q, but in excess of that which could bind to all but the highest concentrations of IC model. In serum depleted of functional C1q on an immunoadsorbant of HAIgG, the precipitation of radiolabeled HAIgG under C1qBA conditions was concentration dependent and generated a saturation curve, showing that only a fraction of IC are usually precipitated in this assay. HAIgG precipitation was enhanced 1.4-fold in NHS/56 (8 micrograms C1q/ml) and three-fold in NHS (67 micrograms C1q/ml) suggesting that IC size is increased by endogenous C1q. In dual label experiments using 131I-HAIgG, the precipitation of 125I-C1q in NHS/56 was directly proportional to IC model precipitation, but markedly discordant in NHP, showing the measurement of IC in heat-inactivated sera superior to that in native serum. A comparison of the C1q:HAIgG ratio in PEG precipitates with that in samples, indicated that equilibrium was established between C1q and IC model. Thus the precipitation of 125I-C1q in the C1qBA represents (1) the fraction of total C1q bound to IC, and (2) the fraction of IC precipitated by PEG.
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Affiliation(s)
- R J Jacobs
- Arthritis and Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City 73104
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Abstract
The composition of complexes containing C1 inactivator (C1 IA), C1r and C1s was investigated in normal serum after activation of C1 under various conditions. Analyses were performed with PAGE of eluates from Sepharose beads coated with F(ab')2 fragments of anti C1s followed by immunoblotting with anti C1 IA, anti C1s or anti C1r. Eluates obtained from serum treated with aggregated IgG (AGG) contained C1 IA in complex with C1r and C1s with both subcomponents in activated form. Eluates from serum incubated at 37 degrees C for 1, 2 or 3 days without activators showed C1 IA complexed with activated C1r and with C1s in proenzyme state associated to the complex. On analysis of serum, treated as mentioned above, by a variant of the electroimmunoassay using an intermediate gel containing anti-C1 IA and with anti-C1s in the anodal gel the two types of C1r--C1s--C1 IA complexes could be distinguished. Investigation of fresh sera and synovial fluids from patients with rheumatoid arthritis in this assay showed complexes containing C1 IA and C1r-C1s in activated form in the synovial fluids, while C1 IA-activated C1r-proenzyme C1s complexes were found in the corresponding sera.
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Lockshin MD, Qamar T, Redecha P, Harpel PC. Hypocomplementemia with low C1s-C1 inhibitor complex in systemic lupus erythematosus. ARTHRITIS AND RHEUMATISM 1986; 29:1467-72. [PMID: 3492208 DOI: 10.1002/art.1780291207] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Ninety-three serum and plasma samples from 45 patients with systemic lupus erythematosus were analyzed for the complex formed by C1s and its inhibitor, as well as for C3, C4, C4a desarginine, and staphylococcal protein A-bound immune complexes. There were statistically significant correlations between C1s-C1 inhibitor complex and CH50, between C1s-C1 inhibitor complex and C4, and between C1s-C1 inhibitor complex and C4a desarginine. Serial studies were performed on 24 patients over a period of 6 months. Seven of 21 patients with hypocomplementemia had persistently normal levels of C1s-C1 inhibitor complex, 7 had transiently abnormal levels of C1s-C1 inhibitor complex, and 7 had sustained abnormal levels of C1s-C1 inhibitor complex. Two of 3 pregnant patients with normal levels of complement had abnormal levels of C1s-C1 inhibitor complex. Staphylococcal protein A-bound immune complexes demonstrated no correlation with any of the complement assays. Complement activation, as measured by C1s-C1 inhibitor complex, is often a transient phenomenon in systemic lupus erythematosus patients with persistent hypocomplementemia.
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Truckenbrodt H, Häfner R. Methotrexate therapy in juvenile rheumatoid arthritis: a retrospective study. ARTHRITIS AND RHEUMATISM 1986; 29:801-7. [PMID: 3718568 DOI: 10.1002/art.1780290616] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Nineteen selected patients with severe, mostly systemic onset, juvenile rheumatoid arthritis were treated with methotrexate (MTX) for an average of 10.5 months. Twelve patients showed statistically significant improvement, as measured by the number of affected, swollen, tender, and functionally impaired joints, and by decreases in erythrocyte sedimentation rate and C-reactive protein and an increase in hemoglobin level. Systemic manifestations improved in 6 of 8 patients. In 10 children receiving corticosteroids, the dosage was reduced. Seven patients did not respond to MTX therapy. Six of them showed an unchanged disease course, and 1 had a relapse after 4 months of MTX treatments. Probable side effects included gastrointestinal symptoms, elevated liver enzymes, and herpes zoster infection. MTX treatment should be considered for children with life-threatening or severe disabling arthritis that is unresponsive to other therapy.
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Abstract
Rheumatoid arthritis is a disorder characterized by chronic inflammation affecting predominantly articular tissues, leading in some instances to disruption of the normal structure and function of the joint. In some patients extra-articular manifestations are also present. In the joints, the pathologic lesion consists of synovial cell proliferation with infiltration by inflammatory cells. The complex interaction among these cells is likely responsible for the connective tissue abnormalities that characterize the rheumatoid lesion. The factors responsible for inducing the inflammatory process are unknown.
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Hack CE, Belmer AJ. The IgG detected in the C1q solid-phase immune-complex assay is not always of immune-complex nature. CLINICAL IMMUNOLOGY AND IMMUNOPATHOLOGY 1986; 38:120-8. [PMID: 3484437 DOI: 10.1016/0090-1229(86)90129-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The properties of the solid-phase C1q immune-complex assay as well as the nature of the IgG detected by this assay in patients' sera were investigated. Aggregated IgG was used as a model for immune complexes. Aggregated IgG bound to solid-phase C1q was detected by 125I-anti-IgG. Fluid-phase C1q (either in normal human serum or purified) neither inhibited the binding of aggregated IgG to solid-phase C1q nor dissociated bound aggregated IgG from the solid-phase C1q. Therefore, we concluded that the solid-phase C1q has a higher affinity for aggregated IgG than the fluid-phase C1q, probably because of the polymerization of the solid-phase C1q. To get more insight into the nature of the IgG detected by the C1q solid-phase assay in patients' sera, we investigated whether C4 and/or C3 were present on it. With the use of 125I-anti-C4 and 125I-anti-C3 instead of 125I-anti-IgG, C4 and C3, respectively, were easily detected on the aggregated IgG that had bound to the solid-phase C1q. The lower limit of detection of these assays was 30 micrograms aggregated IgG/ml of normal human serum. Sera of patients suffering from rheumatoid arthritis and systemic lupus erythematosus were tested with these assays and, despite positive results with 125I-anti-IgG, no positive results were obtained with either 125I-anti-C4 or 125I-anti-C3. So, on the IgG detected by the C1q solid-phase assay in patients' sera, neither C4 nor C3 are present. Furthermore, in five of the six sera tested, this IgG sedimented as monomeric IgG. Therefore, it seems unjustified to refer to this IgG as circulating immune complexes.
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Weinstein A, Marlowe S, Korn J, Farouhar F. Low-dose methotrexate treatment of rheumatoid arthritis. Long-term observations. Am J Med 1985; 79:331-7. [PMID: 4036984 DOI: 10.1016/0002-9343(85)90312-2] [Citation(s) in RCA: 87] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Of 21 patients with rheumatoid arthritis who began to receive low-dose weekly methotrexate up to five years ago, 15 (71 percent) have continued to take this drug for a mean of 42 months and have received a mean total dose of 2,021 mg (range: 915 to 3,075). The clinical improvement noted at the first follow-up (11 months) was sustained throughout this follow-up period (42 months). Three patients (14 percent) have had complete clinical remission and nine others (43 percent) have had an excellent response. Methotrexate was discontinued in four patients between the first and second follow-up because of planned pregnancy (one), gastrointestinal toxicity (two), and fear of toxicity (one). Liver toxicity assessed in these 21 patients and four others receiving long-term methotrexate therapy revealed acute hepatitis in one and elevated transaminase levels in 12 (48 percent). Liver biopsy specimens in 17 patients after a mean of 1,950 mg of methotrexate (range: 915 to 3,125) revealed mild fibrosis in six and no cirrhosis. Methotrexate can continue to suppress rheumatoid synovitis over a prolonged period of time with minimal toxicity in most patients. Hepatic fibrosis and cirrhosis due to methotrexate may be less common in rheumatoid arthritis than has been reported in psoriasis.
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Williams HJ, Willkens RF, Samuelson CO, Alarcón GS, Guttadauria M, Yarboro C, Polisson RP, Weiner SR, Luggen ME, Billingsley LM. Comparison of low-dose oral pulse methotrexate and placebo in the treatment of rheumatoid arthritis. A controlled clinical trial. ARTHRITIS AND RHEUMATISM 1985; 28:721-30. [PMID: 3893441 DOI: 10.1002/art.1780280702] [Citation(s) in RCA: 345] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
One hundred eighty-nine patients with rheumatoid arthritis were entered into a prospective, controlled, double-blind multicenter trial comparing placebo and methotrexate (MTX). One hundred ten patients completed 18 weeks of therapy. No remissions were seen, but patients able to tolerate low-dose pulse MTX therapy were significantly improved, compared with patients receiving placebo therapy, for all clinical variables measured, including joint pain/tenderness and swelling counts, rheumatoid nodules, and patient and physician assessment of disease activity. MTX treatment demonstrated statistically significant improvement over placebo in patients with anemia, elevated erythrocyte sedimentation rate, and rheumatoid factor. However, nearly one-third of the patients receiving MTX were withdrawn for adverse drug reactions, of which elevated levels of liver enzymes was the most common. Pancytopenia occurred in 2 patients taking MTX. All adverse drug effects resolved without sequelae. MTX appears to be effective in the treatment of active rheumatoid arthritis but requires close monitoring for toxicity.
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Letendre PW, DeJong DJ, Miller DR. The use of methotrexate in rheumatoid arthritis. DRUG INTELLIGENCE & CLINICAL PHARMACY 1985; 19:349-58. [PMID: 3891280 DOI: 10.1177/106002808501900503] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The use of methotrexate in rheumatoid arthritis is reviewed. Methotrexate, a folic acid antagonist, is sometimes employed in an attempt to symptomatically control patients whose disease does not respond adequately to conventional therapies. Systemic administration of 7.5-15 mg/wk in a "pulse" fashion appears to be effective without precipitating severe adverse effects. However, concern over potentially serious side effects and a lack of well-controlled clinical trials have limited its use to severe, refractory disease. Further studies are needed before its role in rheumatoid arthritis can justifiably be expanded.
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Fiocco GP, Davis JS, Burge JJ. Ability to activate complement is not required for the detection of immune complexes by the fluid-phase C1q binding assay. ARTHRITIS AND RHEUMATISM 1985; 28:222-5. [PMID: 3871617 DOI: 10.1002/art.1780280220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Lockshin MD, Harpel PC, Druzin ML, Becker CG, Klein RF, Watson RM, Elkon KB, Reinitz E. Lupus pregnancy. II. Unusual pattern of hypocomplementemia and thrombocytopenia in the pregnant patient. ARTHRITIS AND RHEUMATISM 1985; 28:58-66. [PMID: 3917671 DOI: 10.1002/art.1780280110] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
To explore the causes of complications in pregnant women with systemic lupus erythematosus (SLE), we prospectively evaluated 34 pregnancies in 28 SLE patients, and 2 additional pregnancies in patients with lupus anticoagulant and positive antinuclear antibody, but no other manifestations of SLE. Nineteen pregnancies (55%) were complicated by marked proteinuria, thrombocytopenia, and/or lupus anticoagulant. Hypocomplementemia occurred in 18 pregnancies (52%). Neither thrombocytopenia-anticoagulant nor proteinuria was accompanied by an increase in antibody to double-stranded DNA or by clinical signs of active SLE. Antibody to Ro antigen did not predict fetal death. Both thrombocytopenia and proteinuria appeared abruptly during pregnancy and disappeared quickly after delivery. Fetal death was the result in 7 of 9 (77%) pregnancies in patients with anticoagulant, 6 of 10 (60%) in patients with thrombocytopenia, 6 of 18 (33%) in patients with hypocomplementemia, and 3 of 11 (27%) in patients with proteinuria. Twenty of 29 (68%) children were identified as male. The pathogenesis of hypocomplementemia was evaluated by a new assay, C1s-C1 inhibitor complex, which is thought to measure rate of complement activation by the classical pathway. Most pregnant patients with low CH50 levels and proteinuria had normal levels of C1s-C1 inhibitor complex, whereas nonpregnant patients with equivalent proteinuria and hypocomplementemia had high levels, as did pregnant patients with hypocomplementemia who did not have SLE. Pregnant and nonpregnant hypocomplementemic patients with proteinuria had similar levels of C3 and C4. In pregnant patients with SLE, C1s-C1 inhibitor complex was independent of CH50; in nonpregnant patients a linear relationship between C1s-C1 inhibitor complex and CH50 was seen.(ABSTRACT TRUNCATED AT 250 WORDS)
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