Total hemolytic complement (CH50) and second component of complement (C′2hu) activity in serum and synovial fluid

Physiological and transcriptional analysis of Chinese soft-shelled turtle (Pelodiscus sinensis) in response to acute nitrite stress

Nitrite is a harmful substance in aquaculture, and has a serious impact on the survival of the Chinese soft-shelled turtle, Pelodiscus sinensis. However, the cellular responses of P. sinensis to nitrite stress have not yet been investigated. The present study showed that nitrite led to a decrease in hemoglobin content and an increase in methemoglobin content in the blood, thus reducing the oxygen-carrying capacity of blood in P. sinensis. Nitrite also affects the antioxidant system of the liver and leads to lipid peroxidation. In addition, nitrite caused immune responses, including a decrease in lysozyme content and an increase in total complement activity, interleukin-6, and heme oxygenase concentrations in the serum. Additionally, the terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) assay showed that apoptosis occurred in liver cells. Finally, a comparative transcriptome analysis was conducted. A total of 573 differentially expressed genes and 15 significantly enriched KEGG pathways were identified. Among them, the glutathione S-transferase omega 1 (GSTO1) gene may relieve nitrite-induced oxidative damage in P. sinensis by participating in a variety of redox-related pathways, while the PPAR signaling pathway has been proposed to play an important regulatory role in lipid metabolism and immune responses. The present study comprehensively explored the cellular responses of P. sinensis to nitrite stress and provided guidance for future studies.

A novel anti-inflammatory role for secretory phospholipase A2 in immune complex-mediated arthritis

Phospholipase A₂ (PLA₂) catalyses the release of arachidonic acid for generation of lipid mediators of inflammation and is crucial in diverse inflammatory processes. The functions of the secretory PLA₂ enzymes (sPLA₂), numbering nine members in humans, are poorly understood, though they have been shown to participate in lipid mediator generation and the associated inflammation. To further understand the roles of sPLA₂ in disease, we quantified the expression of these enzymes in the synovial fluid in rheumatoid arthritis and used gene-deleted mice to examine their contribution in a mouse model of autoimmune erosive inflammatory arthritis. Contrary to expectation, we find that the group V sPLA₂ isoform plays a novel anti-inflammatory role that opposes the pro-inflammatory activity of group IIA sPLA₂. Mechanistically, group V sPLA₂ counter-regulation includes promotion of immune complex clearance by regulating cysteinyl leukotriene synthesis. These observations identify a novel anti-inflammatory function for a PLA₂ and identify group V sPLA₂ as a potential biotherapeutic for treatment of immune-complex-mediated inflammation.

An analysis of the levels of complement components in the synovial fluid in rheumatic diseases

A linear relationship between the synovial fluid to serum concentration ratios and log molecular weight was found for six plasma proteins, which are largely synthesized by the liver. Production or utilization of a given protein in the joint can, therefore, be determined by its deviation from the calculated diffusion line. Based on this diffusion model the role of the complement system was investigated in the joint effusions of 48 patients with rheumatoid arthritis (RA), 6 patients with osteoarthritis (OA) and 7 patients with meniscus lesions (ML). Among these three groups quantitative differences were found in the metabolism or utilization of several complement components, based on the fact that the ratios were lower than expected for diffusion of proteins of similar molecular weight. The ratios for the RA group were the lowest. In the three patient groups, results showed increased consumption mainly of C3 and C4 locally in the joint. The existence of a real complement activation in the joints of the three different patient groups was further proved by the elevated levels of C3 breakdown products (C3d). Overall this kind of calculation provides us with a method for studying the role of other proteins which may be important in the inflammatory process of the joint.

Glucocorticosteroids and oral medicine

The article deals with the use of glucocorticosteroids in the treatment of the oral manifestations of Systemic Lupus Erythematosus (SLE), Discoid Lupus Erythematosus (DLE), Rheumatoid Arthritis (RA) in the temporomandibular joint, Pemphigus Vulgaris, Pemphigoid, Erythema Multiforme Exudativum (EME), Lichen Planus (LP), and Recurrent Aphthous Ulcerations (RAU). The benefit from steroids is discussed on the basis of current knowledge of etiology and pathogenesis of the various disorders. All of them are characterized by inflammation which appears secondary to a hypersensitivity reaction against autocomponents. Glucocorticoids do not interfere with the primary disease mechanisms. But it is concluded from the literature, that because of anti-inflammatory and immunosuppressive effects of the hormones, it seems reasonable to profit from steroids as palliatives in acute phases of the diseases and/or as long-term suppressors of the general host defense.

Protein synthesis in rheumatoid synovial tissue

1. Function of synoviocytes and other cells in the synovium A. Histologic Considerations 1. Electron microscopic studies 2. In vivo and in vitro phagocytosis studies 3. Fluorescent antibody staining B. Culture techniques 1. Problems posed by study of isolated cells 2. Long-term explant cultures 3. Advantages of short-term incubations of synovial fragments 4. Isolation of immunoglobulins C. Non-Immunoglobulin Products of the Synovium 1. Products of normal synovium 2. Alterations induced by rheumatoid arthritis II. The Local Immune response in Rheumatoid Synovitis A. Evidence for Active Immune Stimulation 1. Meditators of cellular immunity in synovial fluid 2. Effect of synovectomy 3. Type and amount of immunoglobulin produced B. Local Commitment of Antibody Response 1. Effect of exogenous immunization 2. Rheumatoid factors. 3. Pepsin agglutinators C. 1. Relative enrichment for IgG-3 subclass 2. Increase in lambda-light chain composition III. Pathogenetic Considerations in Rheumatoid Arthritis A. Comparison of Rheumatoid versus Experimental Immune Synovitis 1. Chronic synovitis as a local immune response. 2. Role of cartilage complexes in substaining chronic synovitis B. Significance of the Restriction in the Immunoglobulin Response in Rheumatoid Arthritis 1. Analogy with other disease states in man 2. Common antigen in RA?

Immunoelectrophoretic assay for synovial fluid C3 with correction for synovial fluid globulin

Synovial fluid C3 was measured by electroimmunoassay. When C3 was expressed as mg/ml, the amounts found in Reiter's disease, psoriatic arthritis, gout, and systemic lupus erythematosus were significantly different from degenerative arthritis. When C3 was corrected for total protein, the levels for rheumatoid arthritis, Reiter's disease, psoriatic arthritis, and systemic lupus were significantly different from degenerative arthritis. When C3 was corrected for synovial fluid globulin, only rheumatoid arthritis and systemic lupus were significantly different from degenerative arthritis. Correction of C3 for globulin increases the difference between rheumatoid arthritis and degenerative arthritis. A proportion of gouty fluids with a relative decrease in C3 is demonstrated. It is argued that correction of C3 for globulin is more meaningful than correction for total protein. While many nonrheumatoid inflammatory effusions demonstrate split products of C3, the majority of fluids from patients with systemic lupus have none.

Antinuclear antibodies (ANA): immunologic and clinical significance

The methods currently used for the detection of ANA have been analyzed, with emphasis on their practical application to the diagnosis of the CTD. The use of the indirect IF-ANA test was recommended as a screening procedure to detect ANA. The need to standardize the technique using a single substrate and fluorescent conjugates with uniform F/P ratios was stressed. Most importantly, the value of titrating ANA for the diagnosis of the CTD was discussed. ANA titers higher than 1/500 are usually very significant clinically, often found in spontaneous or drug-induced SLE and few other CTD. The immunologic aspects of ANA and their potential value as aids in the diagnosis and management of the CTD were discussed. Anti-nDNA antibodies have been found to have a high degree of specificity for SLE and high titers of these antibodies correlate well with low levels of serum complement and severity of kidney involvement. The spectrum of ANA in the sera from patients with SLE has been expanded with the finding of anti-Sm antibodies which, when detected by gel precipitation with prototype serum, have been found so far only in SLE. Some of these antibodies have been found to have prognostic significance. Patients with MCTD and a group of patients with SLE have high titers of serum ANA with specificity for an RNase-sensitive component of ENA. The group of SLE patients defined by the presence of these antibodies (anti-Mo) have a better prognosis and in general develop only mild nephritis or have no kidney involvement at all. High titers of pure antinucleolar antibodies probably are found almost exclusively in the sera of patients with scleroderma. Some ANA have organ specificity, and GS-ANA have been found in all patients with Felty's syndrome and in a large proportion of patients with RA. One of the great advances in the field has been the recognition that ANA can be induced in the human and in experimental animals by the use of a number of therapeutic agents. Some of these agents can also induce a clinical picture resembling spontaneous SLE, though kidney involvement does not occur or is extremely mild. It is interesting that the whole spectrum of ANA can be found in drug-induced LE except anti-nDNA antibodies which have been associated to the pathogenesis of immune complex nephritis in spontaneous SLE. There is no doubt that research on ANA has contributed a great deal to the understanding of the CTD and will continue to be a valuable tool for the clinician and the investigator.

C3b inactivator in the rheumatic diseases. Measurement by radial immunodiffusion and by inhibition of formation of properdin pathway C3 convertase

C3b inactivator (C3bINA) has been measured in biologic fluids by radial immunodiffusion using a monospecific antiserum prepared in rabbits, and by a hemolytic assay which measures the reduction in the capacity of EAC43 cells bearing limited C3b sites to form C3B, the alternative pathway C3 convertase. The radial immunodiffusion and hemolytic assays show a good correlation (r = 0.86 P less than 0.001). Measurement of C3bINA concentrations in the sera of patients with systemic lupus erythematosus showed that during exacerbations of disease activity C3bINA concentrations tended to be lower, usually in association with reductions in C4, C3, factor B, and properdin, and sometimes with reductions of the alternative pathway proteins, factor B, and properdin alone. Supranormal values for C3bINA were found in the sera of 14 of 20 patients with seropositive rheumatoid arthritis and 3 of 9 seronegative patients, but none of 7 patients with degenerative joint disease. Synovial fluid concentrations of C3bINA, after correction for total synovial fluid protein and serum concentration of the enzyme, were significantly reduced in patients with rheumatoid arthritis compared to patients with degenerative joint disease (P less than 0.05). In both serum and synovial fluid from patients with rheumatoid arthritis, there was a good correlation between the concentrations of C3bINA and those of C3, factor B, and properdin, but not that of C4, suggesting that levels of C3bINA may serve to modulate recruitment of the properdin amplification loop in this disease.

Intraarticular activation of the complement system in patients with juvenile rheumatoid arthritis

Analyses of CH50, complement components, properdin factors, and kininogen in synovial fluid of patients with juvenile rheumatoid arthritis revealed evidence of activation of the classic complement pathway in all clinical subgroups. Juveniles with the adult pattern of disease had the greatest incidence of complement abnormalities. Evaluation of individual components by both activity determination and protein measurement showed decreased synovial fluid specific functional activity (activity per microgram protein) to the more marked in synovial fluids with profound depressions of complement activity. These findings provide further evidence that nonfunctional, antigenically intact component protein may remain after complement activation. Radial immunodiffusion measurements of properdin factors and kininogen failed to support their involvement in joint inflammation. Serum complement component measurements by activity but not protein concentration correlated with other parameters or inflammation. Four patients had isolated depressions of serum C2 activity. Immunoglobulin levels, particularly IgA, correlated with some complement measurements and with the sedimentation rate.

Immunoglobulins and complement components in synovial fluid of patients with acute rheumatic fever

Three components of complement and six other serum proteins were assayed in synovial fluid and serum samples from 25 patients with acute rheumatic fever in Trinidad. The resulting data indicate a relative decrease in both early and late components of complement within the synovial fluids which suggests local activation by immune complexes. Such activation of complement within the joint spaces may play a primary role in development of the inflammatory arthritis of acute rheumatic fever.

Depressed synovial fluid levels of properdin and properdin factor B in patients with rheumatoid arthritis

Two proteins in the properdin system, properdin and factor B, and complement components C4 and C3 were measured by radial immunodiffusion in serums and synovial fluids from 21 patients with rheumatoid arthritis (RA) and positive tests for rheumatoid factor, 9 patients with seronegative RA, and 10 with degenerative joint disease. In addition to depressions of synovial fluid C4 which correlated with lowered C3 in seropositive RA, consistent with activation of the classic pathway, low synovial fluid levels of factor B and properdin in seropositive RA indicate intraarticular activation of the properdin pathway as well.

Activation of the complement and properdin systems in rheumatoid arthritis

The classic (C1, C4, and C2) and properdin factors (D, C3b, and B) of complement generate C3 convertases that are capable of cleaving C3 and subsequently activating C5-C9. Both C1 and factor D are serine esterases, and both convertases undergo decay and regeneration. In seropositive rheumatoid arthritis, where intraarticular activation of the classic early components (C1, C4, and C2) by immunoglobulin complexes appears to predominate, findings of relative depressions in synovial fluid levels of factor B indicate recruitment of the amplification loop (D, C3b, and B), and relative declines in properdin levels suggest activation of the properdin pathway as well. Quantitative analysis of the complement system in disease states requires several different approaches: measurement of function and antigenic concentration to assess the functional integrity of the protein; determination of component metabolism to appreciate the relative contributions of hypercatabolism and hyper- or hyposynthesis to the plasma level; and for compartmentalized disease, measurement of the component in the appropriate biologic fluid and determination of local tissue synthesis.

Studies of the action of some anti-inflammatory drugs on complement mediated immune haemolysis

1 The effects of various anti-inflammatory and non-anti-inflammatory drugs on complement mediated haemolysis have been studied. Drugs which were significantly protein bound were found to inhibit this form of immune lysis, but only at greater concentrations than achieved therapeutically. 2 Removal of the drugs by prolonged dialysis resulted in restoration of complement activity with the exceptions of phenylbutazone and warfarin sodium. 3 Reconstitution experiments indicated that C2 and some of the later components especially C7 were affected by the drugs. 4 Intra-articular injections of prednisolone (100 mg) in patients with rheumatoid arthritis, failed to produce significant changes in the synovial fluid complement system. 5 None of the drugs affected the binding of antibody to antigen, or the ability of sensitized sheep cells to fix complement.

Current concepts of the mechanism of acute inflammation in gouty arthritis

The acute gouty attack develops after free crystalline monosodium urate crystals appear in the joint cavity (1). Recent developments in the investigation of urate crystal-induced inflammation have led to a better understanding of the pathogenesis of acute gouty arthritis. The purpose of this review is to summarize present concepts concerning the mechanism of the acute gouty attack.

Complement system in synovial fluids from patients with rheumatoid arthritis

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Distribution of the anti-gamma globulin factors in the synovial membrane and other tissues in various diseases

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In vitro synthesis of immunoglobulin by rheumatoid synovial membrane

A technique for the in vitro culture of rheumatoid synovial tissue with (14)C-amino acids and isolation and quantitation of the newly synthesized immunoglobulins has been developed. This technique has been used to compare immunoglobulin synthesis of 12 rheumatoid synovia with that of synovia from nonarthritic patients and with that of normal human lymph nodes and spleen. In addition, the spleen of a patient with Felty's syndrome has also been examined. Immunoglobulin synthesis in rheumatoid synovia has been shown to be quantitatively and qualitatively similar to that of normal human spleen and lymph nodes although somewhat less active than the Felty's syndrome spleen examined. 79% of the immunoglobulin produced in rheumatoid synovia was of the IgG type, whereas IgM comprised 10% and IgA, 11% of the total. Less than 10% of the IgM synthesized was found to be rheumatoid factor. A fraction containing approximately 90% of its radioactivity in the form of IgG has been obtained for further studies.

Comparative morphology, respiration, and phagocytic function of leukocytes from blood and joint fluid in rheumatoid arthritis

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