DNA In Synovial Fluid Research Articles

Detection of bacterial DNA in synovial fluid in dogs with arthritis: a comparison between bacterial culture and 16S rRNA polymerase chain reaction

BackgroundSeptic arthritis (SA) is a serious condition in dogs that requires a prompt diagnosis and treatment to minimize long-term joint pathology. Although bacterial detection in synovial fluid (SF) through culture or cytology is often performed to confirm diagnosis, the sensitivity of these tests is low. The need for a reliable diagnostic tool to confirm the presence of bacteria in SF in humans has led to the increased use of 16S rRNA (i.e., ribosomal RNA) gene sequencing by polymerase chain reaction (16S rRNA PCR). The aim of this prospective clinical study was to compare the sensitivity and specificity of 16S rRNA PCR with bacterial culture on blood agar plates after pre-incubation of SF in paediatric blood bacterial culture bottles to identify bacteria in dogs with clinical signs of SA and to investigate the usefulness of these methods as diagnostic tools.ResultsTen dogs with clinical signs of SA, nine with osteoarthritis (OA, control group) and nine with clinical signs of immune-mediated polyarthritis (IMPA, second control group) were examined. Bacterial culture was positive in seven of 10 dogs with clinical SA, of which only two were positive by 16S rRNA PCR. The sensitivity of 16S rRNA PCR and bacterial culture analysis for dogs with clinical SA were 20% and 70%, respectively. All SF samples collected from control group (n = 9) and second control group (n = 14) animals were negative on culture, and 16S rRNA PCR rendered a specificity of 100%.ConclusionsOur study showed a lower sensitivity of 16S rRNA PCR than bacterial culture for dogs with clinical SA. Our findings suggest that there is currently no advantage in using 16S rRNA PCR as a diagnostic tool for dogs with clinical SA. Furthermore, our study indicates that pre-incubation in paediatric blood bacterial culture bottles before bacterial cultivation on blood agar plates might enhance bacterial culture sensitivity compared to other culture methods.

Lyme disease: "End of the debate?"

Lyme borreliosis is a tick-borne disease that is widespread throughout the northern hemisphere. Ixodes ricinus is present throughout metropolitan France, except for the Mediterranean region. The debate revolves around whether or not a chronic form of Lyme disease exists. This controversy is not limited to France but has been reported worldwide. In France, in 2019, 24 scientific societies representing the medical disciplines most involved in Lyme disease, including the Société Française de Rhumatologie (French Rheumatology Society [SFR]) and the Société de Pathologie Infectieuse de la Langue Française (French Infectious Disease Society-SPILF), published recommendations on the management of Lyme borreliosis following a submission to the Director General of Health. These recommendations conflict with those of the Haute Autorité de Santé (HAS), a multi-specialties independent group of physician, on a key point: whether to add a new nosological entity labeled as "persistent polymorphous signs and symptoms (or syndrome) possibly due to tick bite." The creation of this new syndrome risks should increase anchoring bias, leading to the attribution of all symptoms to a possible tick bite, without considering differential diagnoses. Lyme disease has been extensively studied. Erythema migrans is the primary clinical manifestation. In the presence of nonmetabolic, nonseptic monoarthritis involving the knee or radiculitis of a lower limb during the summer, Lyme disease should be suspected. Serologic testing for Lyme disease is reliable in the case of late forms such as chronic arthritis, while the detection of Borrelia DNA in synovial fluid by PCR is inconsistent. Sometimes, the serology can be misleading in early forms such as radiculitis. Treatment is based on doxycycline for 14 days in early forms (radiculitis), or 28 days in late forms (arthritis). Arthritis can persist or recur after antibiotic therapy. The prevalence of a diffuse polyalgia syndrome (fibromyalgia) following Lyme disease does not seem to differ much from that in the general population. It is not improved by prolonged antibiotic therapy, which is therefore not recommended.

Evidence of the Immune Relevance of Prevotella copri, a Gut Microbe, in Patients With Rheumatoid Arthritis.

Prevotella copri, an intestinal microbe, may overexpand in stool samples from patients with new-onset rheumatoid arthritis (RA), but it is not yet clear whether the organism has immune relevance in RA pathogenesis. HLA-DR-presented peptides (T cell epitopes) from P copri were sought directly in the patients' synovial tissue or peripheral blood mononuclear cell (PBMC) samples using tandem mass spectrometry. The antigenicity of peptides or their source proteins was examined in samples from the RA patients or comparison groups. T cell reactivity was determined by enzyme-linked immunospot assay; antibody responses were measured by enzyme-linked immunosorbent assay, and cytokine/chemokine determinations were made by bead-based assays. Serum and synovial fluid samples were examined for 16S ribosomal DNA for P copri using nested polymerase chain reaction analysis. In PBMCs, we identified an HLA-DR-presented peptide from a 27-kd protein of P copri (Pc-p27), which stimulated Th1 responses in 42% of patients with new-onset RA. In both new-onset RA patients and chronic RA patients, 1 subgroup had IgA antibody responses to either Pc-p27 or the whole organism, which correlated with Th17 cytokine responses and frequent anti-citrullinated protein antibodies (ACPAs). The other subgroup had IgG P copri antibodies, which were associated with Prevotella DNA in synovial fluid, P copri-specific Th1 responses, and less frequent ACPAs. In contrast, P copri antibody responses were rarely found in patients with other rheumatic diseases or in healthy controls. Subgroups of RA patients have differential IgG or IgA immune reactivity with P copri, which appears to be specific for this disease. These observations provide evidence that P copri is immune-relevant in RA pathogenesis.

Juvenile idiopathic arthritis and rheumatoid arthritis: bacterial diversity in temporomandibular joint synovial fluid in comparison with immunological and clinical findings

Temporomandibular joint (TMJ) involvement in juvenile idiopathic arthritis (JIA) occurs in up to 80% of affected children. The purpose of this study was to investigate the presence of bacterial DNA in synovial fluid, and to compare this with clinical and immunological findings in children with JIA, adults with persistent JIA, and adults with rheumatoid arthritis, in order to detect whether bacteria contribute to inflammation in TMJ arthritis. Synovial fluid and skin swab samples were collected from 30 patients (54 TMJs). Bacterial detection was performed using 16S rRNA pyrosequencing. Bacterial DNA was detected in 31 TMJs (57%) in 19 patients (63%). A positive statistically significant correlation was registered between bacterial DNA detected in TMJ synovial fluid and the following factors: total protein concentration in synovial fluid, interleukin 1β, tumour necrosis factor alpha, adrenocorticotropic hormone, and adiponectin, as well as the duration of the general medical disease. Fourteen different bacterial species were detected in synovial fluid. Bacterial DNA in TMJ synovial fluid without contamination was detected in more than 50% of the patients. Studies are needed to evaluate the consequences of this bacterial DNA in synovial fluid with regard to TMJ arthritis.

AB0149 Identification and Characterization of A Synovial Fluid Microbial DNA in Rheumatoid Arthritis Patients

BackgroundThe preclinical phase of Rheumatoid Arthritis (RA) is characterized by an immunological disorder that predate the arthritis onset for several years, and is supposed to take birth in oral, respiratory...

SP0141 Immune tolerance tangled in the nets: Neutrophils as a source of auto antigens

Upon activation, in an active process known as netosis, neutrophils can release their chromatin into the extracellular space. The resulting meshwork of DNA is called Neutrophil Extracellular Traps or NETS...

Identification of Oral Bacterial DNA in Synovial Fluid of Patients With Arthritis With Native and Failed Prosthetic Joints

We examined the presence of bacterial DNA in synovial fluids of native or clinically aseptically failed prosthetic joints from patients having periodontal disease and arthritis to determine whether there is bacterial spread from the oral cavity to the joints. A total of 36 subjects were enrolled in the study. Among these, 11 were diagnosed with rheumatoid arthritis (RA) and 25 were diagnosed with osteoarthritis (OA). Eight patients with OA and 1 patient with RA had failed prostheses. Synovial fluid was aspirated from the affected hip or knee joint. Pooled subgingival plaque samples were collected, followed by clinical periodontal examination. Bacterial DNA was extracted from the collected synovial fluid and dental plaque samples were followed by polymerase chain reactions and DNA sequence analysis of the 16S-23S rRNA genes. Of the 36 patients, bacterial DNA was detected in the synovial fluid samples from 5 patients (13.9%): 2 with RA (1 native and 1 failed prosthetic joints) and 3 with OA (1 native and 2 failed prosthetic joints). Of these 5 patients, 2 were diagnosed with periodontitis and had identical bacterial clones (Fusobacterium nucleatum and Serratia proteamaculans, respectively) detected in both the synovial fluid and the dental plaque samples. Fusobacterium nucleatum was the most prevalent, detected in 4 of the 5 positive samples. No cultures were done and no patients were treated with antibiotics or developed clinical infection. The present findings of bacterial DNA in the synovial fluid suggest the possibility of organisms translocating from the periodontal tissue to the synovium. We suggest that patients with arthritis or failed prosthetic joints be examined for the presence of periodontal diseases and be treated accordingly.

Varicella Arthritis in Childhood

Nonbacterial arthritis is a rare but well-recognized complication of acute varicella in children. Reported cases usually described monoarthritis of the knee that occurs at the onset of the rash or shortly after. Herein, we describe a case of arthritis of the hip that occurred in a 4-year-old girl 6 days before the onset of rash. The presence of varicella-zoster virus DNA in synovial fluid was confirmed by real-time polymerase chain reaction. A review of the literature reported 26 previous cases of aseptic arthritis due to varicella infection among children.

Burden and viability of Borrelia burgdorferi in skin and joints of patients with erythema migrans or lyme arthritis

To determine the burden and viability of Borrelia burgdorferi in the skin and joints of patients with Lyme disease. Standard and quantitative polymerase chain reaction (PCR) techniques were used to detect B burgdorferi DNA in skin samples from 90 patients with erythema migrans (EM) and in synovial fluid (SF) from 63 patients with Lyme arthritis (LA) and in synovial tissue from 9 patients. Quantitative PCR determinations of B burgdorferi DNA, messenger RNA (mRNA), and ribosomal RNA (rRNA) were made in 10 skin samples from EM patients and 11 SF samples from LA patients. Skin lesions in most patients with EM had positive PCR results for B burgdorferi DNA. In the majority of patients with LA, a late disease manifestation, PCR results in pretreatment SF samples were positive. In patients with antibiotic-refractory arthritis, positive PCR results persisted for as long as 11 months, but positive results in samples taken during the postantibiotic period did not correlate with relapse or with the subsequent duration of arthritis, and at synovectomy, all results of PCR of synovial tissue were negative. B burgdorferi mRNA, a marker of spirochetal viability, was detected in 8 of 10 skin samples from EM patients, but in none of 11 SF samples from LA patients, even when obtained prior to antibiotic administration. Moreover, the median ratio of spirochetal rRNA to DNA, a measure of ribosomal activity, was 160 in the 10 EM skin samples, but only 0.15 in the 3 LA SF samples with positive results. B burgdorferi in the skin lesions of EM patients were active and viable, whereas those in the SF of LA patients were moribund or dead at any time point. Thus, detection of B burgdorferi DNA in SF is not a reliable test of active joint infection in Lyme disease.

P.428 Bacterial DNA in synovial fluid of patients with TMD

P.428 Bacterial DNA in synovial fluid of patients with TMD

Seronegative Lyme arthritis

We present a 10-year-old girl who had been diagnosed with juvenile idiopathic arthritis 5 years before and who experienced a flare of arthritis affecting one knee while she was off medication for almost 3 years. Seronegative Lyme arthritis had to be diagnosed based on the detection of Borrelia burgdorferi DNA in synovial fluid. No humoral immune response to Borrelia burgdorferi was detectable before, at the time of diagnosis and up to 3 years later.

High levels of inflammatory chemokines and cytokines in joint fluid and synovial tissue throughout the course of antibiotic‐refractory lyme arthritis

To investigate the possible role of chemokines and cytokines in the pathogenesis of Lyme arthritis. Using cytometric bead array and flow cytometry techniques, chemokine and cytokine levels were determined in 65 synovial fluid (SF) samples and 7 synovial tissue (ST) samples from 17 patients with antibiotic-responsive Lyme arthritis and 35 patients with antibiotic-refractory Lyme arthritis seen during the past 18 years. In the ST samples, expression of chemokine receptors was measured using immunohistochemistry. Before or during antibiotic therapy, when the majority of patients had positive polymerase chain reaction (PCR) results for Borrelia burgdorferi DNA, SF from patients with antibiotic-refractory arthritis contained exceptionally high levels of Th1 chemoattractants and cytokines, particularly CXCL9 and interferon-gamma (IFNgamma). Compared with the patients whose arthritis was responsive to antibiotic treatment, those with antibiotic-refractory arthritis had significantly higher levels of CXCL9 and CXCL10 (both P<or=0.001) and CCL3, CCL4, CXCL8, IFNgamma, tumor necrosis factor alpha, interleukin-1beta (IL-1beta), and IL-6 (all P<or=0.01). During the post-antibiotic period, when the results of PCR for B burgdorferi DNA in SF and ST were uniformly negative, patients with antibiotic-refractory arthritis continued to exhibit high SF and ST levels of these chemokines and cytokines. In addition, synovial samples showed marked expression of the receptors for T cell or macrophage chemokines, CXCR3 and CCR5. Patients with antibiotic-refractory Lyme arthritis have high synovial fluid levels of proinflammatory chemokines and cytokines, especially CXCL9 and IFNgamma, throughout the illness. Thus, even when antibiotic treatment reduces or completely clears the infection in these patients, the inflammatory response in synovium persists.

Der Stellenwert der PCR-Diagnostik bei der Lyme-Arthritis anhand von vier Fallbeispielen

We studied retrospectively four patients with Lyme arthritis of the knee, the role of PCR for the detection of B. burgdorferi DNA and its influence on further therapeutic decisions. All four patients with Lyme arthritis suffered from knee pain and effusions. None of them remembered having had a tick bite or an erythema migrans. The diagnosis was confirmed by positive serology and in three cases by detection of B. burgdorferi DNA by PCR analysis of the joint fluid. In one patient, PCR was also positive in the synovial tissue. Because of persistent symptoms after adequate antibiotic therapy, PCR was repeated in the joint fluid of two patients. In one patient a positive PCR suggested an ongoing infection. Thus, the antibiotic treatment was changed. A further PCR was negative. Symptoms resolved slowly in all patients over a time of two to seven months after the end of the antibiotic treatment. PCR to detect B. burgdorferi DNA in synovial fluid or tissue respectively is a helpful tool for the diagnosis of Lyme arthritis. Moreover, in patients with refractory Lyme arthritis PCR may be helpful in monitoring the course of the disease.

Detection of bacterial DNA in synovial fluid from horses with infectious synovitis

Standard culturing techniques are often unrewarding in confirming diagnosis of synovial infection in the equine patient. Several human studies report the use of sensitive polymerase chain reaction (PCR) techniques for the detection of bacterial involvement in acute synovitis. However, successful extraction of bacterial DNA directly from clinical samples from horses without prior culture has not been reported yet. The goal of this study was to develop a sensitive and reliable method for molecular detection and identification of bacterial species in synovial fluid from horses with infectious synovitis. Synovial fluid samples from 6 horses with culture confirmed synovial infection were used for broad range 16S rRNA gene PCR. Synovial aspirates of 2 healthy horses were used as negative controls. Following extraction and purification of synovial fluid DNA, all samples were processed by touchdown PCR. Amplicons were detected by reverse line blot hybridisation and visualised with chemiluminescence. Pathogen-specific detection of 16S rRNA gene sequences was successful in all 6 synovial fluid samples. No bacterial DNA was detected in the aspirates from the negative control horses using touchdown PCR followed by 25 additional cycles of amplification. The identity of the pathogens was confirmed by DNA sequencing of the amplicons. It can be concluded that broad range 16S rRNA gene PCR followed by reverse line blot hybridisation is a promising technique for detection of bacterial DNA in synovial fluid samples. Further research should aim at the detection of bacterial DNA in synovial fluid samples suspected of infection but having negative culture results. When the 16S PCR proves to be reliable and more sensitive than standard culturing techniques, it may become a powerful tool in the diagnosis of synovial infection.

Extracellular mitochondrial DNA and oxidatively damaged DNA in synovial fluid of patients with rheumatoid arthritis.

We investigated whether plasma and synovial fluid (SF) samples from patients with rheumatoid arthritis (RA) contained extracellular mitochondrial DNA (mtDNA) or the oxidatively damaged DNA adduct 8-hydroxy-2'-deoxyguanosine (8-oxodG). Moreover, we correlated the laboratory findings of the patients with RA with their levels of mtDNA and 8-oxodG. SF and plasma samples from 54 patients with RA, SF from 30 non-arthritic control subjects, and plasma from 22 healthy volunteers were collected. The samples were subjected to polymerase chain reaction (PCR) using mitochondrial genomic primers, and the products were analyzed by SDS-polyacrylamide-gel electrophoresis. The intensities of the PCR-amplified bands were quantified and normalized to a reference sample. Furthermore, the SF samples were assayed by enzyme-linked immunosorbent assay for 8-oxodG. Extracellular PCR-amplifiable mtDNA was detected in the SF of 38 of 54 (70%) patients with RA, but not in any of the SF controls. PCR-amplifiable mtDNA was detected in the plasma of 30 of 54 (56%) of patients with RA and in 6 of 22 (27%) of the healthy volunteers. The levels of mtDNA in the plasma and SF samples of patients with RA were significantly higher (P < 0.0001) than in the respective control samples. The presence of both mtDNA and 8-oxodG in SF was significantly correlated with the presence of rheumatoid factor in the patients with RA. Extracellular mtDNA and oxidized DNA were detected in the SF of the great majority of patients with RA, but were absent or present at low levels in the control SF. These findings indicate that endogenous nucleic acid compounds might participate in joint inflammation by activating immune cells in the joints to produce proinflammatory cytokines.

Chlamydia andBorrelia DNA in synovial fluid of patients with early undifferentiated oligoarthritis: Results of a prospective study

More than 50% of patients with synovitis involving 1-4 joints remain classified as having undifferentiated oligoarthritis (UOA) after 1 year of disease. The clinical presentation is often similar to that of reactive arthritis (ReA) and other spondylarthropathies or to Lyme arthritis. We therefore determined how often Chlamydia trachomatis (Ct) and Borrelia burgdorferi (Bb) can be identified in patients with UOA, by using an extensive laboratory approach. We prospectively studied 52 patients with UOA who presented at an early synovitis clinic in a region highly endemic for Lyme disease. Patients were examined by standardized clinical and immunoserologic procedures. Synovial fluid was screened for the presence of Ct and Bb DNA by polymerase chain reaction (PCR). Urine was tested for Ct DNA by ligase chain reaction, and serum was tested for Ct antibodies by enzyme-linked immunosorbent assay and Bb antibodies by hemagglutination test and Western blotting. PCR results in the UOA patients were compared with the results in cohorts of patients with definite rheumatoid arthritis (RA), Lyme arthritis, and Chlamydia-induced arthritis (CIA). In the synovial fluid of 9 of 52 patients with UOA (17%), we found Ct DNA, and in 6 of the 52 patients (12%), Bb DNA was found. The frequency of bacteria-specific DNA was 50% (7 of 14) in CIA patients and 69% (11 of 16) in patients with Lyme arthritis. No Bb or Ct DNA was found in the synovial fluid of the 31 RA patients. With optimized PCR protocols, it is possible to detect considerable levels of Bb and Ct DNA in the synovial fluid of patients with UOA. Although the presence of bacterial DNA does not unequivocally prove its etiologic significance, we suggest that at least one-third of patients with UOA may have a form of ReA that involves asymptomatic primary infection.

The detection of DNA from a range of bacterial species in the joints of patients with a variety of arthritides using a nested, broad-range polymerase chain reaction.

Bacteria have been implicated in the pathogenesis of many types of inflammatory arthritides. The aim of this study was to identify any bacterial DNA in synovial fluid (SF) from patients with a range of inflammatory arthritides. A highly sensitive, broad-range, nested polymerase chain reaction (PCR) protocol targeting the bacterial 16S rRNA gene was designed and applied to SF from 65 patients with a range of rheumatic diseases. Bacterial DNA was detected in 26 SF samples, including eight from patients with rheumatoid arthritis and five with juvenile arthritides. PCR products were identified by sequencing and searching of bacterial genomic databases; 'best fits' included Haemophilus influenzae, Bordetella and Yersinia. These finding suggest an association between bacterial infection and inflammatory arthritides in some patients. Further research is required to determine the role of these organisms in the pathogenesis and whether such patients might respond to prolonged antibiotic therapy.

Presence and significance of human parvovirus B19 DNA in synovial membranes and bone marrow from patients with arthritis of unknown origin

Acute rheumatologic symptoms are frequently associated with human parvovirus B19 (B19) infections. A nested PCR (nPCR) assay was used to test for the presence of parvovirus B19 DNA in synovial fluid and/or synovial membrane specimens obtained from a total of 90 patients with arthritis of unknown origin. Whereas only one out of 73 synovial fluid samples were found positive, 15 (16.7%) out of 90 patients had parvovirus B19 DNA in the synovium. B19 virus DNA was detected in nine bone marrow aspirates subsequently obtained from these 15 patients (60%). Whereas each one of the 15 corresponding blood samples contained anti-B19 IgG antibody, none contained anti-B19 IgM antibody and only one was positive for B19 virus DNA. The blood and synovial fluid samples that contained B19 virus DNA were obtained from the same patient, who also had B19 DNA in synovium and bone marrow. For one patient, two distinct synovial membrane specimens collected 10 months apart tested positive for B19 virus DNA. Parvovirus B19 DNA was also detected in synovial tissue of one out of nine nonarthritic patients serving as control group, who also had anti-B19 IgG circulating antibody. These data illustrate that human parvovirus B19 may persist in bone marrow and synovial tissues of patients with arthritis of unknown origin. In contrast, persistence of B19 virus DNA in synovial fluid is rare. The significance of parvovirus B19 DNA in synovium of healthy patients has to be established.

Lack of correlation between the detection of Chlamydia trachomatis DNA in synovial fluid from patients with a range of rheumatic diseases and the presence of an antichlamydial immune response.

To resolve how frequently Chlamydia trachomatis and Chlamydia pneumoniae DNA are present in the joints of unselected patients with reactive arthritis (ReA) and undifferentiated oligoarthritis, and to determine if there is an accompanying serologic or cellular antichlamydial immune response. Two polymerase chain reaction (PCR) protocols to detect the plasmid of C. trachomatis and the outer membrane protein 1 gene of C. pneumoniae were developed for specific use with synovial fluid (SF). Subsequently, the assays were used to detect DNA from the 2 organisms in SF from 54 adult patients with rheumatic diseases, including 4 with sexually acquired ReA and 31 with undifferentiated oligoarthritis. The presence of chlamydial antibodies and SF lymphocyte proliferation responses were determined in parallel. The PCR protocols were species-specific and highly sensitive. SF samples from 15 patients (8 with undifferentiated oligoarthritis, 3 with ReA, 1 with rheumatoid arthritis, and 1 with psoriatic arthritis) were positive for C. trachomatis. There was no significant correlation between the presence of C. trachomatis DNA in the joint and a Chlamydia-specific synovial T cell response or a serologic response. C. pneumoniae was not detected in any of the 54 patients, although it was identified in the SF from a rheumatoid arthritis patient outside this study, demonstrating that the assay was capable of detecting the organism in the joint. C. trachomatis DNA was present in ReA patients and in nearly one-third of unselected patients with undifferentiated oligoarthritis, which further supports the hypothesis that it plays an important role in disease pathogenesis. However, its presence did not correlate with evidence of an antichlamydial immune response. Despite previous anecdotal reports, C. pneumoniae does not appear to be a major cause of undifferentiated oligoarthritis or ReA.

Detection of bacterial DNA in joint samples from patients with undifferentiated arthritis and reactive arthritis, using polymerase chain reaction with universal 16S ribosomal RNA primers.

Bacteria are considered to be important in the pathogenesis of several forms of arthritis. The goal of this study was to apply the 16S ribosomal RNA (rRNA)-polymerase chain reaction method for the detection of bacterial DNA in synovial fluid (SF) and synovial tissue (ST) from inflamed joints. Samples from 5 patients with septic arthritis and from 7 with osteoarthritis or arthritis secondary to joint trauma were used as controls. Samples from 6 patients with spondylarthropathy (SpA) and from 20 with undifferentiated arthritis (UA) were analyzed for the presence of bacterial DNA using universal 16S rRNA primers. Automated sequencing and comparative data analysis were performed to identify the species. In the positive control group, the bacterial species cultured from the synovium could be identified in all cases. No bacterial DNA was detected in the SF and ST from patients in the negative control group. In 4 of 6 patients with SpA and 7 of 20 with UA, the analysis of joint samples revealed the presence of bacterial DNA. Sequence analysis indicated the presence of multiple species, which was confirmed by sequencing of cloned products. When the the above techniques were used with a stringent regimen, we were able to demonstrate that it is possible to collect and analyze joint samples without contaminating bacterial DNA. The accumulation of phagocytic cells that contain bacterial DNA of various species could play a role in the pathogenesis of both SpA and UA.