Phlogistic properties of bacterial debris

Peptidoglycan in osteoarthritis synovial tissue is associated with joint inflammation

OBJECTIVES

Peptidoglycan (PG) is an arthritogenic bacterial cell wall component whose role in human osteoarthritis is poorly understood. The purpose of this study was to determine if PG is present in synovial tissue of osteoarthritis patients at the time of primary total knee arthroplasty (TKA), and if its presence is associated with inflammation and patient reported outcomes.

METHODS

Intraoperative synovial tissue and synovial fluid samples were obtained from 56 patients undergoing primary TKA, none of whom had history of infection. PG in synovial tissue was detected by immunohistochemistry (IHC) and immunofluorescence microscopy (IFM). Synovial tissue inflammation and fibrosis were assessed by histopathology and synovial fluid cytokine quantification. Primary human fibroblasts isolated from arthritis synovial tissue were stimulated with PG to determine inflammatory cytokine response.

RESULTS

A total of 33/56 (59%) of primary TKA synovial tissue samples were positive for PG by IHC, and PG staining colocalized with markers of synovial macrophages and fibroblasts by IFM. Synovial tissue inflammation and elevated IL-6 in synovial fluid positively correlated with PG positivity. Primary human fibroblasts stimulated with PG secreted high levels of IL-6, consistent with ex vivo findings. Interestingly, we observed a significant inverse correlation between PG and age at time of TKA, indicating younger age at time of TKA was associated with higher PG levels.

CONCLUSION

Peptidoglycan is commonly found in synovial tissue from patients undergoing TKA. Our data indicate that PG may play an important role in inflammatory synovitis, particularly in patients who undergo TKA at a relatively younger age.

Peptidoglycan in osteoarthritis synovial tissue is associated with joint inflammation

Objectives

Peptidoglycan (PG) is an arthritogenic bacterial cell wall component whose role in human osteoarthritis is poorly understood. The purpose of this study was to determine if PG is present in synovial tissue of osteoarthritis patients at the time of primary total knee arthroplasty (TKA), and if its presence is associated with inflammation and patient reported outcomes.

Methods

Intraoperative synovial tissue and synovial fluid samples were obtained from 56 patients undergoing primary TKA, none of whom had history of infection. PG in synovial tissue was detected by immunohistochemistry (IHC). Synovial tissue inflammation and fibrosis were assessed by histopathology and synovial fluid cytokine quantification. Primary human fibroblasts isolated from arthritis synovial tissue were stimulated with PG to determine inflammatory cytokine response.

Results

A total of 33/56 (59%) of primary TKA synovial tissue samples were positive for PG by IHC, with mean 8 PG occurrences per 10 mm2 of tissue in PG-positive samples. Synovial tissue inflammation and elevated IL-6 in synovial fluid positively correlated with PG positivity. Primary human fibroblasts stimulated with PG secreted high levels of IL-6, consistent with ex vivo findings. Interestingly, we observed a significant inverse correlation between PG and age at time of TKA, indicating younger age at time of TKA was associated with higher PG levels.

Conclusion

Peptidoglycan is commonly found in synovial tissue from patients undergoing TKA. Our data indicate that PG may play an important role in inflammatory synovitis, particularly in patients who undergo TKA at a relatively younger age.

The amber theory of Lyme arthritis: initial description and clinical implications

Lyme arthritis differs in many respects from other bacterial causes of arthritis. Based on an observation made for a patient with Lyme arthritis, we propose that the pathogenesis of joint swelling in Lyme arthritis is due to the introduction into the joint space of non-viable spirochetes or more likely spirochetal debris enmeshed in a host-derived fibrinous or collagenous matrix. This "amber" hypothesis can account for the clinical and laboratory features of Lyme arthritis and is amenable to experimental validation. Validation would directly impact the clinical management of patients with Lyme arthritis.

Arthroscopically assisted treatment of acute septic knees in infants using the Micro-Joint Arthroscope

Five infants with an acute hematogenous septic arthritis of the knee were treated with arthroscopically assisted drainage using the Micro-Joint Arthroscope (MJA; Linvatec, Largo, FL) combined with antibiotic therapy and early postoperative motion. The average patient age was 16 months (range, 4 to 24 months). No surgical or anesthetic complications occurred. All knees were clinically and radiologically normal at an average follow-up of 26 months.

Reiter's syndrome and reactive arthritis: a current view

This paper reviews advances in the understanding of the pathogenesis of reactive arthritis that have occurred over the last decade. Inflammatory aseptic joint disease has been linked with prior infection initiated by many different species of microorganisms. The presence of intra-articular bacterial antigens has now been firmly established with the demonstration of bacteria, bacterial fragments, DNA, RNA, and bacterial lipopolysaccharide in joints of patients with reactive arthritis. Chlamydia trachomatis, Salmonella enteritidis, and Shigella flexneri have all been detected in the joint by immunological techniques, although there is still some doubt as to the form in which they reach the joint and whether or not they persist. A number of phlogistic bacterial components could be acting as arthritogens. Negative joint culture results from patients with reactive arthritis make it unlikely that bacteria in the joint are viable, although chlamydial DNA has been shown in the joints of patients with sexually acquired reactive arthritis using the polymerase chain reaction. The use of antimicrobial therapy in the treatment of reactive arthritis is under review; data suggests that long-term antibiotic treatment warrants further study. The role of HLA-B27 in disease pathogenesis is discussed as are possible mechanisms of interplay between germ and gene. HLA-B27 might confer disease susceptibility by affecting immune mechanisms other than classical antigen presentation. The immunopathogenesis of joint inflammation in reactive arthritis is explored with reference to studies of humoral and cellular immune responses. Serological evidence to support the concept of molecular mimicry is far from conclusive; the results of relevant studies are summarized. Lymphocyte proliferation experiments suggest that antigen presenting cells play an important role. Finally, our views on reactive arthritis in the 1990s, and areas of new and potentially fruitful future research are presented.

Monoclonal antibodies preventing the development of polyarthritis in rats induced by experimental infection with erysipelas bacteria

Monoclonal IgM-antibodies specific for arthritogenic erysipelas bacteria (Erysipelothrix rhusiopathiae, serovar 2, strain T28) were isolated from rats suffering from erysipelas polyarthritis. Four of them (C52, D9, E51, R117) were administered to syngeneic Lewis rats. While D9 and an unrelated rat-IgM-antibody showed no effect, C52 protected partially and R117 as well as E51 fully from all symptoms of erysipelas polyarthritis. Prevention of the disease was associated with a lack of antibody-formation against the erysipelas bacteria. There is evidence that prevention is not due to classical passive immunization, but rather to induction of host mechanisms efficiently activated by "inductive" monoclonal antibodies.

Antibiotic treatment insufficient for established septic arthritis. Staphylococcus aureus experiments in rabbits

We treated septic arthritis of the knee in 38 rabbits with cloxacillin i.m. once and twice daily combined with probenecid for 7 or 21 days, respectively, or with only cloxacillin i.m. thrice daily for 7 days. The animals were killed weekly in groups up to 5 weeks after inoculation. Aspirated cultures obtained after 4 days of treatment were always negative. Histologic specimens revealed progressive joint destruction, but at a slower rate after frequent treatment independent of the period. We concluded that antibiotic therapy alone could not prevent destruction of articular cartilage once bacterial arthritis was established.

Solubilization and characterization of surface antigenic components of Erysipelothrix rhusiopathiae T28

The antigenicity of Erysipelothrix rhusiopathiae T28 (serotype 2) was investigated. Antigens were solubilized from the cell surface with detergents. By means of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting it was shown that the molecular weight of the main antigenic component--a nonprotein--was 14,000 to 22,000. This major antigen was shown to be a polydisperse anionic polysaccharide located on the surface of E. rhusiopathiae. Affinity chromatography also revealed a number of immunologically active proteins with molecular weights of 78,000, 72,000, 68,000, and 48,000.

Granulomatous enterocolitis induced in rats by purified bacterial cell wall fragments

This study was designed to determine if poorly biodegradable bacterial cell wall components can produce chronic intestinal inflammation. A sterile aqueous suspension of sonically disrupted group A or group D streptococcal cell wall fragments was injected intramurally into the small intestine and cecum of 100 rats. Gross findings in rats killed at intervals of 1 day to 6 mo included intestinal thickening, adhesions, and mesenteric contraction. Acute histologic inflammation subsided by 2 wk, but chronic granulomatous inflammation persisted for 6 mo in the rats injected with group A streptococcal cell wall fragments and 3 mo in the rats injected with group D streptococcal cell wall fragments. Ninety-six control rats identically injected with human serum albumin or phosphate-buffered saline demonstrated mild acute inflammation that resolved, with only 1 rat having chronic intestinal inflammation. Granulomas in the intestine, mesentery, and mesenteric lymph nodes developed in 46% of the rats injected with group A fragments and 45% of the rats injected with group D streptococcal cell wall fragments, compared with 20% of the controls injected with albumin and 4% of the controls injected with phosphate-buffered saline. Group A streptococcal antigen was detected by immunofluorescence at the site of inflammation for 4 mo, and possible reactivation of acute inflammation was seen up to 6 mo after injection. We conclude that bacterial cell wall fragments are capable of producing chronic granulomatous inflammation in the intestinal wall if present in appropriate particle size and concentration. We speculate that cell walls from the enteric microflora may leak across a permeable mucosa in chronic inflammatory bowel disease to initiate and sustain local and systemic inflammation.

Isolation of an interleukin-1-like factor from human joint effusions

Interleukin-1 (IL-1) is a macrophage derived mediator whose properties suggest that it could play a role in the pathology of arthritis. To test this hypothesis, joint fluids from patients with serveral different arthritides were tested. Small amounts of IL-1-like activity were recovered from many of these joint fluids after affinity chromatography over a column of rabbit anti-human IL-1. Positive fluids were obtained from patients with rheumatoid arthritis, psoriatic arthritis, Reiter's syndrome, osteoarthritis, gout, and traumatic arthritis. Upon gel filtration, the joint derived factor displayed a molecular weight distribution similar to that of IL-1 derived from human monocytes stimulated in vitro. These results suggest that IL-1 is present in joint effusions and, therefore, might contribute to joint destruction.

Reactive arthritis--infectious agents and genetic susceptibility in the pathogenesis of sero-negative arthritis

In this review we discuss the role of genetic and infectious factors in the aetiology of ‘reactive’ arthritis. Two broad categories of reactive arthritis are considered—the sero-negative HLA B27 related spondarthritides, and a miscellaneous group of reactive arthritides occuring after bacterial infection but which are not HLA B27 related.

Strain and sex variation in the susceptibility to streptococcal cell wall-induced polyarthritis in the rat

Sixteen inbred rat strains were examined for susceptibility and resistance to group A streptococcal cell wall-induced polyarthritis. The findings indicated that 2 or more genetic loci, as well as sex-related factors, played a major role in determining susceptibility to arthritis in this model. Breeding studies demonstrated that susceptibility was a dominant or codominant trait. A positive association between the severity of arthritis and the development of chronic inflammation in multiple tissues was also observed. In strains that were relatively resistant to arthritis, chronic inflammation was generally limited to the spleen. Since translocation of the poorly degradable and phlogogenic streptococcal cell walls to the synovium and other tissues appears to initiate inflammation, these studies suggested that susceptibility might be the result of a defect in host mechanisms limiting cell wall dissemination.

Distribution of lysozyme in synovial tissue of patients with osteoarthritis and rheumatoid arthritis demonstrated by different enzyme histochemical methods

Lysozyme-producing cells were analysed by enzyme histochemistry in paraffin sections of synovial tissue of 60 patients with rheumatoid arthritis (RA) and 20 patients with osteoarthritis (OA). For lysozyme detection three enzyme histochemical systems - peroxidase-anti-peroxidase, alkaline phosphatase and biotin-avidin - were used in parallel experiments. Lysozyme was found to be produced by polymorphonuclear cells, mononuclear phagocytes and part of synovial lining cells. All types of lysozyme-producing cells were increased in RA compared with OA. Subgrouping of RA synovitis according to histomorphological criteria allowed the demonstration of an inverse relationship between the number of lysozyme-producing cells and the grade of proliferation of fibroblasts, called mesenchymoid transformation by Fassbender [19]. The different methods of lysozyme detection differed in specificity and sensitivity. The immunoenzymatic staining of lysozyme allows specific and quantitative evaluation of phagocytizing cells in RA and OA.

The spectrum of inflammatory skin disease following jejuno-ileal bypass for morbid obesity

From a series of 105 patients who had undergone jejuno-ileal bypass for morbid obesity, seven developed an episodic illness featuring inflammatory skin lesions, usually associated with a non-destructive polyarthritis. Tenosynovitis, myalgia and fever had also occurred. The illness abated spontaneously in four patients. The most characteristic skin lesion was an erythematous macule which developed a central vesicle or pustule. Erythema nodosum-like lesions and liquefying nodules were also seen. Early lesions were characterised by a dense accumulation of neutrophils. Changes is dermal vessels were less destructive than is usually seen in immune complex mediated vasculitis. Circulating immune complexes could be demonstrated in patients actively developing skin lesions. They were also found in some patients long after activity had ceased and in jejuno-ileal bypass subjects who had never developed inflammatory lesions. Dapsone was effective in suppressing the skin and joint symptoms when metronidazole and/or tetracycline had failed.

The intestinal bypass: arthritis-dermatitis syndrome

Of the 31 patients who developed polyarthritis following jejunoileal bypass for obesity, 24 had cutaneous vasculitis (urticarial, pustular, and nodular), 11 paresthesias, 10 Raynaud's phenomenon, and 1 pericarditis. Blind loop symptoms (14 of 26 patients), cryoglobulinemia (10 of 28), and immune deposits in biopsied skin lesions (5 of 7) support the theory of a relationship between bowel bacteria and immune complexes. Treating the blind loop with antibiotics and sphincteroplasty to prevent bacterial reflux into the blind loop helped 5 of 10 and 6 of 9 patients, respectively. A comparison is made to other bowel associated arthritides.

Association of inflammation with raised serum IgA in ankylosing spondylitis

Serum immunoglobulins were measured in 122 patients with ankylosing spondylitis (AS) during various phases of disease activity and compared to those in 58 healthy subjects. The mean serum IgA was 38% higher in patients (306.9 mg/dl) than in controls (222.7 mg/dl) (P < 0.005), but there was no significant difference in IgG and IgM levels. Increased IgA was associated with laboratory parameters of active inflammatory disease. The mean IgA in patients having an erythrocyte sedimentation rate (ESR) equal to or greater than 15 mm/h was 369 mg/dl, 65% higher than in controls (P < 0.001), whereas there was no significant difference between controls and patients with an ESR of less than 15 mm/h. The mean IgA in patients having a C-reactive protein (CRP) level equal to greater than 15 micrograms/ml (15 mg/l) was 387.8 mg/dl, 74% higher than in controls (P < 0.001), and again there was no significant difference between controls and patients with CRP levels less than 15 micrograms/ml. (SI conversion: g/l = mg/dl x 0.01). It is suggested that selective increase of serum IgA occurs predominantly during phases of active inflammatory disease in AS, and this finding is compatible with the concept of a microbial triggering agent acting across an IgA secreting organ such as the gut.

Search for Klebsiella cell wall components cross-reactive with lymphocytes of B27+ AS+ individuals

It has been suggested that some Klebsiella sp may cross-react with a cell surface determinant on the lymphocytes of B27+AS+ individuals. Studies were undertaken to identify culture filtrates capable of rendering the lymphocytes of B27-positive healthy controls susceptible to lysis by the anti-Klebsiella antiserum. Polyacrylamide gel electrophoresis of cell wall material of Klebsiella K43 prepared by sonication, high-speed centrifugation, and nonidet solubilization, demonstrated the presence of four major protein bands. When antisera raised in rabbits to each of these were tested for their cytotoxic effect on the lymphocytes of B27+AS+ individuals, an antiserum to one component only, of 40-52 K daltons molecular weight, reproduced the activity of the whole serum. Studies on the K43 filtrate indicated that the 'modifying' factor appeared to reside in a 25-50 K dalton component. Immunoelectrophoresis against anti-K43 serum demonstrated overlapping bands in the culture filtrate and the 40-52 K dalton cell wall fraction and these appeared to be identical on immunodiffusion. Antibody to the cell wall component removed both the 'modifying' activity and the appropriate protein band from the filtrate. The results suggest that a 40-52 K dalton component of the Klebsiella K43 cell wall is cross-reactive with a determinant on the lymphocytes of B27+AS+ individuals and is similar to or identical with a modifying factor in K43 culture filtrate which renders the lymphocytes of B27-positive healthy controls susceptible to lysis by anti-Klebsiella antiserum.

The bowel bypass syndrome: a response to bacterial peptidoglycans

A characteristic intermittent neutrophilic dermatosis, associated with polyarthritis, tenosynovitis, malaise, fever, and cryoglobulinemia, occurs in 20% of patients who undergo ileojejunal bypass surgery for the treatment of morbid obesity. The clinical syndrome may mimic gonococcal sepsis. The histologic changes in the skin are those of Sweet's syndrome. The syndrome remits spontaneously in most cases, but it may recur intermittently over a period of years. Treatment with low-dose steroids, tetracycline, or metronidazole suppresses symptoms in most cases, and restoration of normal bowel anatomy is curative. Skin testing with Streptococcus pyogenes antigen causes an excerbation of symptoms, or may provoke the entire syndrome de novo. Bacterial peptidoglycans, especially those of group A streptococci, produce similar arthritis and skin lesions in animal models. Peptidoglycans from numerous intestinal bacteria share common structural and antigenic features with S. pyrogenes peptidoglycan and are suggested as causative of the toxic and immunologic features of this syndrome.

Systemic immune complex disease following intestinal bypass surgery: bypass disease

Twenty-one patients with arthritis and dermatitis following intestinal bypass surgery were studied. The arthritis was polyarticular, remittent, and intermittent. Typically, the synovial fluid was inflammatory. The commonest inflammatory skin lesion was a vesiculopustular dermatitis. Nineteen patients and serum immmune complexes using the Raji cell technic. Seventeen patients had serum cryoproteins, primarily consisting of IgG 1, IgG 3, C3, and C4. Three patients had both Escherichia coli antigens and anti-E. coli antibody in their cryoprotein. Five patients had granular and one had linear deposits of immunoglobulin and complement at the dermoepidermal junction. Further evidence that bacterial antigens play a role in tissue injury was provided by detection of granular deposits of E. coli antigen at the dermoepidermal junctions in two patients, and at the glomerular capillary basement membrane in one patient.

Antigenic bacterial polysaccharide in rheumatoid synovial effusions

Phenol-water extracted rheumatoid synovial fluids and synovial fluid leukocytes contain an antigen immunologically identical to the Proprionibacterium group bacteria. The antigen was identified by counter-immunoelectrophoresis in 70% of rheumatoid synovial fluid leukocyte pellets and in 60% of rheumatoid synovial fluids. It was also present in 6% of nonrheumatoid fluids and in 22% of nonrheumatoid inflammatory fluid leukocytes. Antigen was not detectable in synovial samples before extraction. Synovial and bacterial antigens were further purified by proteolytic digestion and Sepharose 4B column chromatography. Biochemical and enzymatic studies of bacterial and synovial antigens were similar and consistent with a high molecular weight polysaccharide. Serum antibody to bacterial and synovial antigens was significantly less frequent in rheumatoid sera than in normal controls. The significance of demonstrating a bacterial polysaccharide primarily in rheumatoid synovial effusions is discussed.