Gut microbiome and metabolome to discover pathogenic bacteria and probiotics in ankylosing spondylitis

Objective

Previous research has partially revealed distinct gut microbiota in ankylosing spondylitis (AS). In this study, we performed non-targeted fecal metabolomics in AS in order to discover the microbiome-metabolome interface in AS. Based on prospective cohort studies, we further explored the impact of the tumor necrosis factor inhibitor (TNFi) on the gut microbiota and metabolites in AS.

Methods

To further understand the gut microbiota and metabolites in AS, along with the influence of TNFi, we initiated a prospective cohort study. Fecal samples were collected from 29 patients with AS before and after TNFi therapy and 31 healthy controls. Metagenomic and metabolomic experiments were performed on the fecal samples; moreover, validation experiments were conducted based on the association between the microbiota and metabolites.

Results

A total of 7,703 species were annotated using the metagenomic sequencing system and by profiling the microbial community taxonomic composition, while 50,046 metabolites were identified using metabolite profiling. Differential microbials and metabolites were discovered between patients with AS and healthy controls. Moreover, TNFi was confirmed to partially restore the gut microbiota and the metabolites. Multi-omics analysis of the microbiota and metabolites was performed to determine the associations between the differential microbes and metabolites, identifying compounds such as oxypurinol and biotin, which were correlated with the inhibition of the pathogenic bacteria Ruminococcus gnavus and the promotion of the probiotic bacteria Bacteroides uniformis. Through experimental studies, the relationship between microbes and metabolites was further confirmed, and the impact of these two types of microbes on the enterocytes and the inflammatory cytokine interleukin-18 (IL-18) was explored.

Conclusion

In summary, multi-omics exploration elucidated the impact of TNFi on the gut microbiota and metabolites and proposed a novel therapeutic perspective: supplementation of compounds to inhibit potential pathogenic bacteria and to promote potential probiotics, therefore controlling inflammation in AS.

Investigating the Influence of ANTXR2 Gene Mutations on Protective Antigen Binding for Heightened Anthrax Resistance

Bacillus anthracis is the bacterium responsible for causing the zoonotic disease called anthrax. The disease presents itself in different forms like gastrointestinal, inhalation, and cutaneous. Bacterial spores are tremendously adaptable, can persist for extended periods and occasionally endanger human health. The Anthrax Toxin Receptor-2 (ANTXR2) gene acts as membrane receptor and facilitates the entry of the anthrax toxin into host cells. Additionally, mutations in the ANTXR2 gene have been linked to various autoimmune diseases, including Hyaline Fibromatosis Syndrome (HFS), Ankylosing Spondylitis (AS), Juvenile Hyaline Fibromatosis (JHF), and Infantile Systemic Hyalinosis (ISH). This study delves into the genetic landscape of ANTXR2, aiming to comprehend its associations with diverse disorders, elucidate the impacts of its mutations, and pinpoint minimal non-pathogenic mutations capable of reducing the binding affinity of the ANTXR2 gene with the protective antigen. Recognizing the pivotal role of single-nucleotide polymorphisms (SNPs) in shaping genetic diversity, we conducted computational analyses to discern highly deleterious and tolerated non-synonymous SNPs (nsSNPs) in the ANTXR2 gene. The Mutpred2 server determined that the Arg465Trp alteration in the ANTXR2 gene leads to altered DNA binding (p = 0.22) with a probability of a deleterious mutation of 0.808; notably, among the identified deleterious SNPs, rs368288611 (Arg465Trp) stands out due to its significant impact on altering the DNA-binding ability of ANTXR2. We propose these SNPs as potential candidates for hypertension linked to the ANTXR2 gene, which is implicated in blood pressure regulation. Noteworthy among the tolerated substitutions is rs200536829 (Ala33Ser), recognized as less pathogenic; this highlights its potential as a valuable biomarker, potentially reducing side effects on the host while also reducing binding with the protective antigen protein. Investigating these SNPs holds the potential to correlate with several autoimmune disorders and mitigate the impact of anthrax disease in humans.

[Faecal microbiota study reveals specific dysbiosis in spondyloarthritis according to subtype, disease activity and treatment]

OBJECTIVE

To compare the diversity and composition of the gastrointestinal microbiome of patients with SpA.

METHODS

MiSeq sequencing of the V3-V4 region of the 16S ribosomal RNA gene was performed on DNA isolated from stool. Patients with concurrent SpA and IBD were excluded. Differences were assessed for richness and diversity indices by QIIME 2™. Differences between means >0,2% with a p-value<0,05 were assumed significant. Institutional Ethics Committee endorsement.

RESULTS

69 individuals included, 49 with SpA (ankylosing spondylitis-AS 72,9%, psoriatic arthritis-PsA 18,8%, reactive arthritis-ReA 8,3%) 5 positive controls-dysbiosis and 15 controls-eubiosis. Conventional treatment in 42,9%, anti-IL-17 16,3% and anti-TNF 40,8%. By subtype, statistically significant differences in favour of AS were found for the diversity indices. AS vs PsA there was a difference in favour of AS for Clostridium clostridioforme (p=0,002), Gemmiger formicilis (p=0,009), Roseburia inulivorans (p=0,008) and Lachnospira pectinoschiza. AS vs ReA there was a difference in favour of AS for L. pectinoschiza (p=0,009), Ruminococcus callidus (p=0.006), Clostridium ruminantium (p=0.031); G. formicilis (p=0,034). Diversity and richness showed differences in patients with high activity for Simpson's and Pielou's indices. In high activity, lower enrichment of Bacteroides eggerthii (p= 0,0003), C. ruminantium (p= 0,026) and Alistipes putredinis (p=0,035) was found. The number of ASV was higher in the anti-IL-17 vs conventional group (p=0.025) and a trend between anti-IL-17 vs anti-TNF (p=0.09). In anti-TNF there was a lower proportion for C. clostridioforme (p=0.023), G. formicilis (p=0.030) and R. callidus (p= 0.003). In anti IL-17, Alistipes indistinctus (p= 0.012) was decreased.

CONCLUSIONS

There are differences in microbial diversity for SpA subtypes. The level of disease activity is plausible to influence the composition of the faecal microbiota. Anti-TNFα treatment may influence the microbiome environment favouring restoration of the gut microbiota, while anti-IL-17 may maintain an inflammatory environment.

Association of anti-TNF-α treatment with gut microbiota of patients with ankylosing spondylitis

OBJECTIVE

Gut dysbiosis contributes to multiple autoimmune diseases, including ankylosing spondylitis, which is commonly treated with tumor necrosis factor (TNF)-α inhibitors (TNFis). Because host TNF-α levels are considered to interact with gut microbiota, we aimed to systematically investigate the microbiota profile of ankylosing spondylitis patients with anti-TNF-α-based treatment and identify potential key bacteria.

METHODS

Fecal samples were collected from 11 healthy controls and 24 ankylosing spondylitis patients before/after anti-TNF-α treatment, the microbiota profiles of which were evaluated by 16S ribosomal DNA amplicon sequencing and subsequent bioinformatic analysis.

RESULTS

Significantly different microbial compositions were observed in samples from ankylosing spondylitis patients compared with healthy controls, characterized by a lower abundance of short-chain fatty acid (SCFA)-producing bacteria. All patients exhibited a positive response after anti-TNF-α treatment, accompanied by a trend of restoration in the microbiota compositions and functional profile of ankylosing spondylitis patients to healthy controls. In particular, the abundance of SCFA-producing bacteria (e.g. Megamonsa and Lachnoclostridium ) was not only significantly lower in ankylosing spondylitis patients than in healthy controls and restored after anti-TNF-α treatment but also negatively correlated with disease severity (e.g. cor  = -0.52, P  = 8 × 10 -5 for Megamonsa ). In contrast, Bacilli and Haemophilus may contribute to ankylosing spondylitis onset and severity.

CONCLUSIONS

Microbiota dysbiosis in ankylosing spondylitis patients can be restored after anti-TNF-α treatment, possibly by impacting SCFA-producing bacteria.

The association between Candida infection and ankylosing spondylitis: a population-based matched cohort study

AIMS

To explore whether newly diagnosed Candida infection increases the risk of developing ankylosing spondylitis (AS).

METHODS AND MATERIALS

We investigated 61,550 patients with newly diagnosed Candida infection between 1997 and 2013 from the Taiwan National Health Insurance Research Datasets to conduct a population-based matched-cohort study. Controls were 61,550 subjects without Candida infection and propensity score matched with the Candida exposure cohort. The follow-up period was defined as month from the initial diagnosis of Candida infection (or nested index date for controls) to the date of AS, or 31 December 2013. We used Cox proportional hazards models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the occurrence of AS.

RESULTS

The incidence rates of AS in the Candida group and comparison group were respectively 4.58 and 3.88 per 100,000 person-months. The adjusted HR (95% CI) of AS for the Candida group was 1.19 (0.99-1.44) compared to the control group after adjustment for age, gender and all covariates (95% CI = 1.77-2.27). However, an adjusted hazard ratio (aHR) of 1.77-fold (95% CI = 1.26-2.53) significant increase in the risk of developing AS was observed after 6 years of follow-up, when exposure to Candida was at baseline. The effect of Candida infection was significantly time varying (p value for interaction between follow-up period and Candida infection is .018).

CONCLUSIONS

A risk of AS was found after Candida infection, and a year of follow-up acts as an effect modifier between the Candida infection and risk of AS. Key messages What is already known on this subject? Links between spondyloarthritis and fungal infections have been found in animal studies before. What does this study add? Our study demonstrated that Candida infection is an independent risk factor for developing ankylosing spondylitis in terms of gender, age and relevant variables and comorbidities. A risk of ankylosing spondylitis was found after Candida infection, and year of follow-up acts as an effect modifier between the Candida infection and risk of AS. Clinicians should be aware of possible Candida infection in managing patients with ankylosing spondylitis. Implications: Clinicians must pay greater attention to patients with newly diagnosed Candida infection. Specifically, they should conduct tests for ankylosing spondylitis. Further research is needed to examine if and how treatment of Candida infection alleviates symptoms of AS.

Metagenome-wide association study of the alterations in the intestinal microbiome composition of ankylosing spondylitis patients and the effect of traditional and herbal treatment

Introduction. Ankylosing spondylitis (AS) is a systemic progressive disease with an unknown etiology that may be related to the gut microbiome. Therefore, a more thorough understanding of its pathogenesis is necessary for directing future therapy.Aim. We aimed to determine the differences in intestinal microbial composition between healthy individuals and patients with AS who received and who did not receive treatment interventions. In parallel, the pathology of AS in each patient was analysed to better understand the link between AS treatment and the intestinal microbiota of the patients.Methodology. Sixty-six faecal DNA samples, including 37 from healthy controls (HCs), 11 from patients with untreated AS (NM), 7 from patients treated with nonsteroidal anti-inflammatory drugs (e.g. celecoxib; WM) and 11 from patients treated with Chinese herbal medicine (CHM), such as the Bushen-Qiangdu-Zhilv decoction, were collected and used in the drug effect analysis. All samples were sequenced using Illumina HiSeq 4000 and the microbial composition was determined.Results. Four species were enriched in the patients with AS: Flavonifractor plautii, Oscillibacter, Parabacteroides distasonis and Bacteroides nordii (HC vs. NM, P<0.05); only F. plautii was found to be significantly changed in the NM-HC comparison. No additional species were found in the HC vs. CHM analysis, which indicated a beneficial effect of CHM in removing the other three strains. F. plautii was found to be significantly increased in the comparison between the HC and WM groups, along with four other species (Clostridium bolteae, Clostridiales bacterium 1_7_47FAA, C. asparagiforme and C. hathewayi). The patients with AS harboured more bacterial species associated with carbohydrate metabolism and glycan biosynthesis in their faeces. They also had bacterial profiles less able to biodegrade xenobiotics or synthesize and transport vitamins.Conclusion. The gut microbiota of the patients with AS varied from that of the HCs, and the treatment had an impact on this divergence. Our data provide insight that could guide improvements in AS treatment.

Consumption of Cooked Black Beans Stimulates a Cluster of Some Clostridia Class Bacteria Decreasing Inflammatory Response and Improving Insulin Sensitivity

There is limited information on the effect of black beans (BB) as a source of protein and resistant starch on the intestinal microbiota. The purpose of the present work was to study the effect of cooked black beans with and without high fat and sugar (HF + S) in the diet on body composition, energy expenditure, gut microbiota, short-chain fatty acids, NF-κB, occluding and insulin signaling in a rat model and the area under the curve for glucose, insulin and incretins in healthy subjects. The consumption of BB reduced the percentage of body fat, the area under the curve of glucose, serum leptin, LPS, glucose and insulin concentrations and increased energy expenditure even in the presence of HF + S. These results could be mediated in part by modification of the gut microbiota, by increasing a cluster of bacteria in the Clostridia class, mainly R. bromii, C. eutactus, R. callidus, R. flavefaciens and B. pullicaecorum and by an increase in the concentration of fecal butyrate. In conclusion, the consumption of BB can be recommended to prevent insulin resistance and metabolic endotoxemia by modifying the gut microbiota. Finally, the groups fed BB showed lower abundance of hepatic FMO-3, even with a high-fat diet protecting against the production of TMAO and obesity.

Dynamic Variations in Gut Microbiota in Ankylosing Spondylitis Patients Treated with Anti-TNF-α for Six Months

Ankylosing spondylitis (AS) is known as a microbiome-driven disease; however, the current understanding of microbiota dynamics in AS is limited. In the present study, we conducted a 16S rDNA sequence-based microbiota survey of 97 fecal samples from healthy subjects and AS patients at baseline, 1, 3 and 6 months after anti-TNF-α treatment to demonstrate the dynamic characteristic variations of gut microbiota in AS patients. The goal of this experiment is to explore the values of gut microbiota as biomarkers of disease activity and therapeutic responses to anti-TNF-α. We found that the relative abundance of microbiota in AS patients treated with anti-TNF-α differed at various time points and distinguished 4 groups: the higher and lower than healthy control (HC) level groups throughout the study and the unchanged and restored to HC levels groups. The characteristic increases of microbes in AS patients were f_Prevotellaceae and f_Actinomycetaceae In HC, the characteristic increase was f_Lachnospiraceae BASDAI positively correlated with the relative abundance of g_Escherichina-Shigella and g_Klebsiella, but negatively correlated with f_Lachnospiraraceae at baseline. (r=0.544, P=0.013, r=0.509, P=0.022 and r=-0.577, P=0.008, respectively). The beta-diversity of microbiota in AS at baseline was lower than HC at the same level (P<0.01) and restored to normal values one month after treatment. In conclusion, the variation of gut microbiota is dynamic. Therefore, some microbes can be used as indicators for monitoring disease activity and therapeutic responsiveness during treatment.

The correlation between intestinal dysbiosis and the development of ankylosing spondylitis

The pathogenesis and development of ankylosing spondylitis (AS) is concealed and complicated. In recent years, alterations in gut microbiota of AS patients have been largely investigated, although the underlying mechanisms remain unclear. This article reviews the recent studies on changes of gut microbiota in AS patients, and discusses the possible correlation between intestinal dysbiosis and AS development from aspects including genetic factor HLA-B27, mucosal immune responses and the depression accompanying AS.

A Possible Role of Intestinal Microbiota in the Pathogenesis of Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory disease primarily affecting the sacroiliac joints and the spine, for which the pathogenesis is thought to be a result of the combination of host genetic factors and environmental triggers. However, the precise factors that determine one’s susceptibility to AS remain to be unraveled. With 100 trillion bacteria residing in the mammalian gut having established a symbiotic relation with their host influencing many aspects of host metabolism, physiology, and immunity, a growing body of evidence suggests that intestinal microbiota may play an important role in AS. Several mechanisms have been suggested to explain the potential role of the microbiome in the etiology of AS, such as alterations of intestinal permeability, stimulation of immune responses, and molecular mimicry. In this review, the existing evidence for the involvement of the microbiome in AS pathogenesis was discussed and the potential of intestinal microbiome-targeting strategies in the prevention and treatment of AS was evaluated.

Role of gut microbiome in ankylosing spondylitis: an analysis of studies in literature

OBJECTIVE

Gut microbiome is considered to be involved in the pathogenesis of ankylosing spondylitis (AS). We conducted a comprehensive literature review in this area to facilitate future research.

METHODS

We searched all literature in the PubMed database from inception to July 2016. Relevant articles were chosen and analyzed by three independent investigators.

RESULTS

The composition of gut microbiome in patients with AS has been identified to be different from healthy populations; however, specific profiles of gut microbiome are not yet clearly known. Through the host-bacteria dynamic interactions in general, intestinal dysbiosis impairs the gut mucosal barrier and leads to the disorder of intestinal mucosal immunity, resulting in increased pro-inflammatory cytokines and subsequent chronic inflammatory phenotype of AS. Moreover, colonization with specific AS gut microbiome could induce effective animal models, which will aid studies of pathogenesis of AS.

CONCLUSION

This analysis underscores the role of gut microbiome in chronic inflammation of AS and its possible underlying mechanisms. Intestinal dysbiosis is undoubtedly involved in the disease progression of AS, and the discovery of a specific profile of gut microbiome in AS will help reveal new therapeutic targets and diagnosis markers.

The Link Between Klebsiella and Ankylosing Spondylitis in Worldwide Geographical Locations

Ankylosing spondylitis (AS) is a world-wide chronic inflammatory disease of the axial skeleton most likely caused by a microbial factor in genetically susceptible individuals. Over the last 40 years extensive data has been produced which shows that the majority of patients with AS possess the HLA-B27 genetic marker. Significantly elevated levels of Klebsiella antibodies have been demonstrated in 1556 AS patients in 16 different countries with various geographical locations. Other evidence for the link between Klebsiella and AS include increased fecal isolation rates of Klebsiella microbes in AS patients together with shared molecular and immunological cross-reactivity features existing between Klebsiella antigens and HLA-B27 and collagens I, III and IV. Anti-Klebsiella measures could possibly be included with the currently used medical treatment in the management of patients with AS.

[Sacroiliac joint disorders in Abidjan: epidemiological, clinical, radiological and etiological characteristics]

BACKGROUND

The sacroiliac joint remains unknown in sub-Saharan Africa. Studies about the sacroiliac diseases are rare Aim : Describe the epidemiological, clinical, radiological and etiological characteristics of sacroiliac joint diseases in Abidjan Methods : Retrospective and descriptive study concerning 17 patients hospitalized from February 2003 to April 2010 in the department of rheumatology of university hospital center of Cocody (Abidjan) for buttock pain or others functional signs evoking sacroiliac joint which were attested by radiographic lesions. We were interested on the epidemiological, clinical and radiological characteristics and the etiologies in the sacroiliac disease.

RESULTS

The hospital prevalence of sacroiliac diseases was 0.55% corresponding in 17 of 3067 rheumatological diseases. The female sex predominated (82.35%) and the mean age of 25.58 years. Gyneco-obstetric events were the predominant risk factors (47.05%). Sacroiliac damage was manifested by inflammatory pain (64.7%) localized at the buttock or lumbar spine, radiating to the thigh (52.9%) and was accompanied by functional disability (82.2%) and fever was not present every time (64.7%). The physical findings were the tripod sign positive (58.8%), the monopodal backing positive (41.2%) and palpation painful of sacroiliac joint. The standard radiograph revealed a blurring aspect and widening of joint space associated with demineralization (68.4%), a joint space narrowing and erosion of articular banks (23.5%). The etiologies found were bacterial arthritis (82.3%) mainly pyogenic (70.58%), osteoarthritis (11.7%) and ankylosing spondylitis (5.9%).

CONCLUSION

Sacroiliac joint diseases are rare in rheumatology practice in Abidjan, concern younger subjects and are dominated by pyogenic sacroiliitis.

The link between ankylosing spondylitis, Crohn's disease, Klebsiella, and starch consumption

Both ankylosing spondylitis (AS) and Crohn's disease (CD) are chronic and potentially disabling interrelated conditions, which have been included under the group of spondyloarthropathies. The results of a large number of studies support the idea that an enteropathic pathogen, Klebsiella pneumoniae, is the most likely triggering factor involved in the initiation and development of these diseases. Increased starch consumptions by genetically susceptible individuals such as those possessing HLA-B27 allelotypes could trigger the disease in both AS and CD by enhancing the growth and perpetuation of the Klebsiella microbes in the bowel. Exposure to increased levels of these microbes will lead to the production of elevated levels of anti-Klebsiella antibodies as well as autoantibodies against cross-reactive self-antigens with resultant pathological lesions in the bowel and joints. Hence, a decrease of starch-containing products in the daily dietary intake could have a beneficial therapeutic effect on the disease especially when used in conjunction with the currently available medical therapies in the treatment of patients with AS and CD.

Gut-mediated and HLA-B27-associated arthritis: an emphasis on ankylosing spondylitis and Crohn's disease with a proposal for the use of new treatment

Ankylosing spondylitis (AS) and Crohn's disease (CD), especially when associated with spondylitis are interrelated conditions included within the categories of spondyloarthropathic disease entities. They share some common clinical, genetic, and microbiological findings. An extensive amount of studies which have been carried out by various independent groups throughout the world have shown that Klebsiella pneumoniae microorganisms could be suggested as the most likely etiopathogenetic triggers for AS and CD based on the molecular mimicry mechanism and the existence of the evidence for immunological, microbiological, and molecular link between Klebsiella and self antigens. It is proposed that the use of low starch diet in conjunction with the currently used treatment might help in the eradication of Klebsiella microbes from the bowel and could result in the stoppage and alleviation of the disease process in patients with AS and/or CD.

Antibodies against recombinant heat shock proteins of 60 kDa from enterobacteria in the sera and synovial fluid of HLA-B27 positive ankylosing spondylitis patients

OBJECTIVE

To study the association of HLA-B27 with IgG antibodies to different enterobacterial HSP60s in patients with ankylosing spondylitis (AS).

METHODS

IgG antibodies to 60 kDa enterobacterial HSPs were determined by ELISA in paired samples of sera and synovial fluid from 21 HLA-B27+ ankylosing spondylitis (AS) patients; and in sera from 32 HLA-B27+ AS patients, 35 HLA-B27+ healthy relatives of AS patients, and 60 HLA-B27- healthy individuals with no family members with AS.

RESULTS

HLA-B27+ patients and healthy individuals showed significantly higher IgG antibody levels to recombinant enterobacterial HSP60s than HLA-B27- healthy controls. The levels of anti-HSP60Sf and anti-HSP60Ec antibodies correlated with disease activity and anti-HSP60Ec antibodies with male gender. No association between enterobacterial HSP60 antibody levels and disease duration was observed. All groups had lower levels of IgG antibodies to rHSP60 from Streptococcus pyogenes (rHSP60 Spy). In paired samples of sera and synovial fluid from B27+ patients, IgG antibodies to enterobacterial HSP60s were detected, but in significantly higher levels in sera than in synovial fluid. The anti-rHSPSpy IgG response in these samples was lower and similar in the three groups.

CONCLUSIONS

A correlation was found between HLA-B27 and the response to recombinat enterobacterial HSP60s. This response could be associated with disease activitir and gender in some proteins and the presence eof IgG antibodies to these proteins in synovial fluid could be associated with the inflammatory process and initiation of AS.

Ankylosing spondylitis is linked to Klebsiella--the evidence

Ankylosing spondylitis (AS) is a chronic inflammatory spinal and large-joint arthritic and potentially disabling condition, mainly affecting males of young age groups. Extensive literature based on the results of various genetic, microbiological, molecular and immunological studies carried out by independent research groups suggests that Klebsiella pneumoniae is the main microbial agent being implicated as a triggering and/or perpetuating factor in the etiopathogenesis of AS. Novel diagnostic markers and criteria based on the association with high anti-Klebsiella antibodies could be used in the detection of AS patients during early stages of the disease, and together with the current treatments might help in implementing the use of new therapeutic anti-microbial measures in the management of AS. Prospective longitudinal studies with the use of anti-microbial measures in patients with AS are required to establish the therapeutic benefit of this microbe-disease association.

A possible link between Crohn's disease and ankylosing spondylitis via Klebsiella infections

Crohn's disease (CD) is an immune-mediated gastrointestinal inflammatory disease, which could arise from an interplay between genetic and environmental factors. Klebsiella microbes were suggested to have a vital role in the initiation and perpetuation of the disease through the mechanism of molecular mimicry. This proposition is based on the results of various studies where significantly elevated levels of antibodies against the whole bacteria or preparations from Klebsiella microbes and antibodies to collagen types I, III, IV, and V were detected in patients with CD and patients with ankylosing spondylitis (AS). Molecular similarities were found between Klebsiella nitrogenase and HLA-B27 genetic markers and between Klebsiella pullulanase and collagen fibers types I, III, and IV. Furthermore, significantly positive correlations and cross-reactivity binding activities were observed between anti-Klebsiella and anticollagen antibodies among patients with CD and AS. Early treatment of CD patients with anti-Klebsiella measures is proposed, which may involve the use of antibiotics and low starch diet together with other traditionally used immunomodulatory, immunosuppressive, or biologic agents.

The potential use of antibacterial peptide antibody indices in the diagnosis of rheumatoid arthritis and ankylosing spondylitis

BACKGROUND

Both rheumatoid arthritis (RA) and ankylosing spondylitis (AS) are potentially disabling arthritic disorders for which as yet no highly sensitive and reliable diagnostic laboratory markers are available.

OBJECTIVE

The objective of this study was to evaluate the levels of antibodies against Proteus and Klebsiella antigenic peptides in an endeavor to develop diagnostic indices for the identification of patients with RA and AS, respectively.

METHODS

Sera from 50 patients with RA, 34 patients with AS, and 38 healthy subjects were screened for antibodies against "ESRRAL" and "IRRET" synthetic amino acid peptides obtained from Proteus hemolysin and urease (HU) as well as against "QTDRED" and "DRDE" peptides from Klebsiella nitrogenase and pullulanase (NP) proteins, respectively. Multiplication of the 2 antibodies against each organism produced indices for RA-HU and AS-NP.

RESULTS

Significantly increased levels of anti-HU antibodies (P<0.0001) were observed in patients with RA when compared with patients with AS or with healthy control subjects. Patients with AS were found to have significantly elevated levels of anti-NP (P<0.0001) antibodies when compared with patients with RA or with healthy subjects. Furthermore, all patients with RA were found to have values of anti-HU antibody (RA-HU) index above 95% confidence limit (CL) of the mean of healthy control subjects; meanwhile, all patients with AS were having values of anti-NP antibody (AS-NP) index above the 95% CL of the mean of healthy control subjects (100% sensitivity). However, the specificity of the RA-HU index in RA and the AS-NP index in patients with AS were 92% and 95%, respectively.

CONCLUSION

The use of the RA-HU or AS-NP diagnostic index as a sole marker or in combination with other autoantibody markers could be used in the identification of patients with RA or AS, respectively. Longitudinal investigations starting with patients with early disease will be needed.

Anti-Saccharomyces cerevisiae antibodies (ASCA) in Behçet's syndrome

OBJECTIVES

Anti-Saccharomyces cerevisiae antibodies (ASCA) are found in 50-60% of patients with Crohn's disease. Increased as well as normal levels have been reported in Behçet's syndrome (BS). We reassessed the level of IgG and IgA ASCA antibodies in BS and in a group of diseased and healthy controls.

METHODS

Eighty-five patients with BS were studied along with 20 patients with ankylosing spondylitis (AS), 24 with Crohn's disease (CD), 25 with ulcerative colitis (UC) and 21 healthy volunteers. A commercial ELISA kit was used (Inova Diagnostics).

RESULTS

It was only the patients with CD who had significantly higher levels of antibodies compared with the rest of the group (ANOVA: ASCA IgG, p = 0.0001; ASCA IgA, p = 0.0001). 42% of CD, 4% of BS, 4% of UC and 15% of AS patients had a positive IgG+IgA ASCA. There was a significant trend for patients with gastrointestinal (GI) involvement with BS (n = 8) to be more positive for IgG and IgG+IgA ASCA compared to the rest of the patients with BS (n = 77) (Chi-square, IgG, p = 0.02, IgG+IgA, p = 0.001).

CONCLUSION

The rate of positivity of ASCA in BS is comparable to that observed among patients with UC and AS. Patients with BS who have GI involvement may have higher levels of ASCA and this needs to be further studied.

Delayed response to anti-tuberculosis treatment in a patient on infliximab

The introduction of infliximab, an anti-TNF-alpha agent, in the treatment of rheumatic diseases has offered important therapeutic advances in recent years. The main adverse effect from the usage of this drug is susceptibility to infections, mainly reactivation of latent tuberculosis. We present a 23 year-old male with ankylosing spondylitis, who developed endobronchial and widespread pulmonary tuberculosis, 2 years after initiation of treatment with infliximab. The patient had already been treated for a positive PPD skin test with a 9-month prophylactic course of isoniazid. He was treated with a five drug anti-tuberculosis scheme but he showed an extremely slow therapeutic response with daily high fever, even 4 months after initiation of treatment. Seven months after beginning anti-tuberculosis therapy, bronchoscopy still revealed necrotic and inflammatory tissue at the site of the original lesions. This unusual clinical course of tuberculosis infection was attributed to immunosuppression due to the long-lasting anti-TNF-alpha action of infliximab.

Relationship between disease activity and infection in patients with spondyloarthropathies

OBJECTIVE

To assess the relationship between disease activity and signs and symptoms of infection in Mexican patients with spondyloarthropathies (SpA).

METHODS

A cross sectional study of 95 non-selected patients with SpA (62 men; mean age 26.4 years), who were examined for signs and symptoms of infection and their association with disease activity. 52 had ankylosing spondylitis (AS), 32 undifferentiated SpA (uSpA), 6 chronic reactive arthritis (ReA), and 5 psoriatic arthritis (PsA). Categorical data were analysed by chi(2) or Fisher's tests.

RESULTS

53 (56%) patients had infections: 41 (43%) upper respiratory tract (URT), 34 (36%) enteric, and 20 (21%) genitourinary infections. More infections occurred in HLA-B27 positive patients as a whole (39 v 5; p = 0.003) and in uSpA (12 v 2; p = 0.005). In AS and uSpA, infections occurred in approximately 50%. 30/39 (77%) patients with active disease (group A) and 23/56 (41%) (group B) (p = 0.001) had infection. There were more enteric infections in group A (47%; p<0.001) and more URT infections in group B (52%; p = NS). 22/30 (73%) patients attributed disease activity to infection.

CONCLUSION

Enteric, and less commonly, URT infections in Mexican patients with SpA, particularly those who were HLA-B27 positive, seem to have a role in the active phase of AS and uSpA.

Antibodies to tissue transglutaminase and Saccharomyces cerevisiae in ankylosing spondylitis and psoriatic arthritis

OBJECTIVE

Subclinical gut inflammation has been described in patients with ankylosing spondylitis (AS) or psoriatic arthritis (PsA). Joint involvement has also been reported related to celiac disease. We investigated IgA antibodies to bovine tissue tranglutaminase (tTg) and IgA and IgG antibodies to human tTg and to Saccharomyces cerevisiae (ASCA) in patients with AS and PsA.

METHODS

We evaluated the frequency of IgA antibodies to bovine tTg, and of IgA and IgG antibodies to human tTg and to ASCA in 43 patients with AS and 75 with PsA. As control groups we considered 79 patients with rheumatoid arthritis (RA) and 78 healthy blood donors.

RESULTS

We detected antibodies as follows: IgA antibodies to bovine tTg in 1/43 patients with AS, 3/75 with PsA, 1/79 with RA, and in 9/78 healthy controls; IgA antibodies to human tTg in 1/43 patients with AS, 1/75 with PsA, 1/79 with RA, and in 3/78 healthy controls; IgG antibodies to human tTg in 1/43 patients with AS, 4/75 with PsA, 5/79 with RA, and in 7/78 healthy controls. IgA ASCA were confirmed in 10/43 patients with AS, 7/75 with PsA, 14/79 with RA, and in 7/78 healthy controls; IgG ASCA were present in 5/43 patients with AS, 4/75 with PsA, 8/79 with RA, and in 8/78 healthy controls. No statistically significant difference was observed in the prevalence of IgA or IgG antibodies to bovine and human tTg and in the frequency and in mean level of IgA or IgG ASCA between the studied groups or between each group and healthy controls.

CONCLUSION

Our data fail to show an increased prevalence of autoantibodies associated with celiac and Crohn's disease in patients with AS and PsA.

Comparative immune responses to candidate arthritogenic bacteria do not confirm a dominant role for Klebsiella pneumonia in the pathogenesis of familial ankylosing spondylitis

OBJECTIVE

Using humoral immune responses, Klebsiella pneumoniae has been implicated as a candidate microbial trigger in ankylosing spondylitis (AS) by several investigators but refuted by others. The objective of this case-control study was to compare the cellular (T-cell proliferation) and humoral (IgG and IgA, by ELISA) immune responses of affected individuals in multiplex AS families with those of unaffected family members and normal healthy controls in order to find out whether affected individuals exhibit a predominant immune response to K. pneumoniae.

METHODS

Twenty-five families with two or more individuals affected with AS and 34 normal healthy controls matched with the affected family members for age, sex and ethnicity were enrolled in the study. All affected (n = 57) and unaffected (n = 37) family members had a detailed clinical evaluation. Peripheral blood was drawn to determine T-lymphocyte proliferation and the IgG and IgA (by ELISA analysis) immune responses to K. pneumoniae, Salmonella typhimurium, Yersinia enterocolitica and Chlamydia trachomatis. Immune responses to each of the four candidate organisms were compared in affected and unaffected individuals. Each individual was classified by the predominant antigenic immune response that they showed when comparison was made among the same concentrations of the four candidate microbial antigens. This stratification was then used (i) to compare immune responses in affected and unaffected family members and (ii) to compare clinical characteristics of affected family members.

RESULTS

There was no difference in mean stimulation indices or antibody responses between affected and unaffected family members for each of the candidate organisms. In terms of predominant cellular immune responses to these organisms, there was no difference between affected and unaffected family members with respect to K. pneumoniae, C. trachomatis or Y. enterocolitica. However, a higher percentage of affected family members (25.9%) exhibited a predominant response to S. typhimurium compared with unaffected family members (5.9%, P < 0.02). In assessing antibody titres, K. pneumoniae was the predominant amongst these four organisms, but there was no difference between affected family members, unaffected family members and normal healthy controls. There was no relationship between immune responses and clinical characteristics.

CONCLUSION

Our analysis of affected and unaffected family members in familial AS demonstrated no significant differences with respect to cellular or humoral immune responses to K. pneumoniae and three control microbes. In addition, K. pneumoniae did not exhibit a predominant immune response in affected individuals. Thus we find no supportive evidence to implicate a causal role for K. pneumoniae in familial AS.

Lymphocytic infiltration and expression of inducible nitric oxide synthase in human duodenal and colonic mucosa is a characteristic feature of ankylosing spondylitis

OBJECTIVE

In patients with ankylosing spondylitis (AS), inflammatory processes have been detected in the ileal and colonic mucosa. The inducible isoform of nitric oxide synthase (iNOS) may be expressed early in the inflammatory process. We investigated iNOS activity and lymphocytic infiltration in the duodenum and colon in patients with AS and ulcerative colitis compared with controls.

METHODS

Gastroscopy with duodenal biopsies and/or colonoscopy with biopsies were conducted in 42 patients with AS treated or not treated with nonsteroidal antiinflammatory drugs (NSAID), in 15 with ulcerative colitis, and in 46 controls. Lymphocytic infiltration in the lamina propria and intraepithelial infiltration were quantified by histological score. iNOS expression was assessed by immunohistochemistry with monoclonal antibodies, and iNOS activity was determined by radiochemical assay.

RESULTS

Endoscopic examination of the gastroduodenal or colonic mucosa did not reveal macroscopic lesions in the AS patients. In the duodenum, mucosal lymphocytic infiltration was found in 83.3% of the AS group compared to 48.6% of controls (p = 0.02), and was independent of the NSAID intake. Intraepithelial lymphocyte infiltration was increased in both duodenum and colon in AS patients compared to controls. iNOS activity in duodenum and colon and expression of iNOS protein in lamina propria inflammatory cells was increased in AS patients compared to controls.

CONCLUSION

Lymphocytic infiltration and iNOS expression and activity were detected in duodenal and colonic mucosa from patients with AS. Such findings may indicate an inflammatory process in the small intestine and colon of patients with AS.

Microbial factors in spondyloarthropathies: insights from population studies

Infections and genetics play a role in the development of reactive arthritis. The clinical manifestations and severity of the features depend on the triggering infections and the epidemiologic setting. Reports from hospital-based series show the lowest frequency of reactive arthritis, but often, patients have severe arthritis associated with a high frequency of HLA-B27. At the population level, reactive arthritis occur in 7 to 15% of the infected subjects. The disease is usually mild, affects small joints, can be polyarticular, often rapidly disappears, and has a low association with HLA-B27. There also seems to be a change in the spectrum of triggering infections. Reports of Yersinia arthritis are less common, whereas arthritis in association with Campylobacter or Salmonella infections seems to be increasing. The role of early antimicrobial chemotherapy for the prevention of reactive arthritis needs to be studied.

Cytotoxicity responses to peptide antigens in rheumatoid arthritis and ankylosing spondylitis

OBJECTIVE

To measure levels of IgG antibodies against structurally related synthetic peptides of HLA-DRB1*0404, type XI collagen, and Proteus mirabilis in patients with rheumatoid arthritis (RA) and HLA-B*2705 and Klebsiella pneumoniae in patients with ankylosing spondylitis (AS), and to determine whether sera from RA and AS patients are cytotoxic for sheep red blood cells (SRBC) coated with HLA-DRB1*0404, type XI collagen, or HLA-B*2705.

METHODS

Sera from 51 patients with RA, 34 with AS, and 38 healthy controls were tested against synthetic EQRRAA, ESRRAL, LRREI, and IRRET peptides by ELISA. Sera from patients and controls were also tested for reactivity in complement mediated cytotoxicity with SRBC coated with EQRRAA and HLA-B*2705, LRREI peptides.

RESULTS

Antibodies to synthetic peptides containing EQRRAA, ESRRAL, LRREI, and IRRET were significantly increased in RA patients compared with AS patients (p < 0.001) and controls (p < 0.001). The percentage lysis data for SRBC coated with EQRRAA and LRREI peptides were significantly higher for RA sera (p < 0.001) compared to control sera. Percentage lysis for SRBC coated with HLA-B*2705 peptide was significantly higher for AS sera (p < 0.001) compared to control sera.

CONCLUSION

Our results suggest that antibodies against antigenic determinants of P. mirabilis in RA and K. pneumoniae in AS have cytotoxic properties on structurally related host proteins. These cytotoxic antibodies together with T cell interactions could be relevant in the etiopathogenesis of RA and AS.

Anti-saccharomyces cerevisiae IgA antibodies are raised in ankylosing spondylitis and undifferentiated spondyloarthropathy

OBJECTIVES

To investigate whether anti-Saccharomyces cerevisiae antibodies (ASCA), a marker for Crohn's disease (CD), are present in spondyloarthropathies (SpA) and in the subgroups ankylosing spondylitis (AS), undifferentiated SpA (uSpA), and psoriatic arthritis (PsA), in comparison with healthy and inflammatory controls (patients with rheumatoid arthritis (RA)).

METHODS

ASCA IgA and IgG levels were measured with an enzyme linked immunosorbent assay (ELISA) kit (Medipan, Germany) in 26 patients with CD, 108 patients with SpA (43 patients with AS, 20 patients with uSpA, 45 patients with PsA), 56 patients with RA and 45 healthy controls. Gut biopsy samples were available in 18 AS and 10 patients with uSpA, these samples were screened for the presence of inflammation.

RESULTS

Both ASCA IgG and IgA levels were raised in CD compared with healthy controls and patients with RA. ASCA IgA, but not IgG levels, were higher in SpA than in both healthy and RA controls. ASCA IgA levels were raised in AS and uSpA, but not in PsA. No significant differences in ASCA IgA levels were noted between patients with SpA with and without histological gut inflammation.

CONCLUSION

ASCA IgA levels are significantly higher in SpA, and more specifically in AS, than in healthy controls and patients with RA. This is the first serum marker associated with SpA. No correlation between the presence of subclinical bowel inflammation and ASCA IgA levels was noted. However, it remains to be evaluated whether patients with SpA with ASCA have an increased risk of developing CD.

Antibodies to ubiquitin in relation to Yersinia infection status in patients with ankylosing spondylitis

The aim of this study was to investigate IgG and IgM antibodies to ubiquitin in relation to Yersinia enterocolitica infection status in patients with AS. Twenty-eight AS patients (M:F 24:4, mean age 43.9 yrs, range 22-70 yrs, mean disease duration 15.9 yrs) and 35 healthy controls (M:F 31:4, mean age 52.1 yrs, range 22-80 yrs) were included. The levels of antibodies to ubiquitin and Yersinia O:3 and O:9 antigens were measured using specific ELISA. The results were expressed as optical density (OD) ratio. Antibody levels were assumed increased when the OD ratio was higher than mean OD ratio + 3SD in the control group. IgM antibodies to ubiquitin were found in five patients and one control ( P < 0.05, Fisher's exact test). Anti-ubiquitin antibodies of IgG class were found in two cases, one AS patient and one control (NS). IgG antibodies to Yersinia serotypes O:3 and O:9 were present in eight and five AS patients, respectively ( P < 0.001 and P < 0.05 vs. controls, Fisher's exact test). No IgM antibodies to Yersinia were found. High levels of IgG antibodies to Y. enterocolitica serotype O:3 were found in three out of five patients with high levels of IgM antibodies to ubiquitin, compared with five out of 23 patients with low levels of anti-ubiquitin antibodies ( P=0.1231, NS). Antibodies to Yersinia serotype O:9 were found in three out of five patients with IgM antibodies to ubiquitin, compared to two out of 23 patients with low serum levels of IgM antibodies to ubiquitin ( P < 0.05). The results suggest that Y. enterocolitica infection may induce antibodies to ubiquitin in a subset of patients with AS. This may be explained by the involvement of a newly discovered ubiquitin-dependent mechanism related to Y. enterocolitica virulence.

IgG antibodies to enterobacteria 60 kDa heat shock proteins in the sera of HLA-B27 positive ankylosing spondylitis patients

OBJECTIVE

To study the association of HLA-B27 and the IgG response to the 60 kDa HSPs of Klebsiella pneumoniae, Yersinia enterocolitica, Shigella flexneri, Escherichia coli and Salmonella typhi.

METHODS

IgG against the 60 kDa HSPs of enterobacteria was determined by ELISA in the sera from 49 HLA-B27+ ankylosing spondylitis (AS) patients; 41 HLA-B27+ healthy relatives of AS patients and 101 HLA-B27-unrelated healthy individuals.

RESULTS

HLA-B27+ patients and healthy individuals, showed significantly higher IgG antibody levels to the Klebsiella, Yersinia and Salmonella HSPs than HLA-B27- healthy controls. B27+ patients had a significantly higher response to E. coli HSP than the two other groups. IgG response anti-Shigella HSP was similar in the three groups.

CONCLUSIONS

There is a relationship between HLA-B27 and the response to HSPs 60 from Klebsiella, Yersinia, Escherichia and Salmonella, that may be important in the initiation of AS.

Comparison of the faecal microflora of patients with ankylosing spondylitis and controls using molecular methods of analysis

OBJECTIVES

To determine whether differences within the complex intestinal microflora can be demonstrated between patients with ankylosing spondylitis (AS) and healthy individuals.

METHODS

The composition of the faecal microflora of 15 ankylosing spondylitis patients and 15 matched controls was determined using a variety of nucleic acid-based methods, including denaturing gradient gel electrophoresis (DGGE). Concentrations of serum antibodies reactive with intestinal bacteria were determined. T-cell proliferation responses to autologous intestinal bacteria were determined using a bioluminescent assay.

RESULTS

DGGE demonstrated a unique and stable bacterial community in the faeces of each individual. No specific differences in colonization profiles were discernible between patients and controls. Analysis of individual bacterial groups using nucleic acid-based methods showed no differences in faecal colonization with Klebsiella pneumoniae or Bacteroides vulgatus. A significantly higher proportion of faecal samples from AS patients were found to contain sulphate-reducing bacteria compared with samples from controls (P=0.0004). Three out of five patients showed elevated T-cell proliferation responses to Bacteroides species cultured from their own faeces. The concentrations of serum immunoglobulin A (IgA) and IgM antibodies reactive with klebsiella or bacteroides cells were lower in the patient group relative to the controls.

CONCLUSIONS

By using DGGE, we have demonstrated the complexity and individuality of the human intestinal microflora and shown that this is a confounding factor in determining the possible significance of individual organisms in the pathogenesis of spondyloarthritis. Nevertheless, we demonstrated a higher prevalence of sulphate-reducing bacteria in the faeces of patients with AS. These organisms have been implicated in the pathogenesis of inflammatory bowel disease. We also detected a possible loss of immunological tolerance to autologous Bacteroides isolates in patients with AS.

Novel therapies in the treatment of spondyloarthritis

Spondyloarthritis represents one of the commonest groups of inflammatory arthritides with onset in the third and fourth decades and primarily affecting the axial skeleton. Current treatment is primarily symptomatic, non-steroidal anti-inflammatory drugs being used most commonly. No therapeutics have been shown to prevent structural damage. The development of validated and standardised outcome instruments and a composite criterion of response should encourage evaluation of new therapeutics. Anti-TNF- alpha -directed therapeutics have been shown to be dramatically effective in short-term (12 week) placebo-controlled trials in both ankylosing spondylitis and psoriatic arthritis whilst observational cohorts describe efficacy that is maintained for over one year. Treatment has been well-tolerated, with mycobacterial infections being the primary concern. Significant costs and the requirement for continuous therapy are likely to spur the development of orally bioavailable agents targeting TNF- alpha expression.

IgM, IgG, and IgA response to enterobacteria in patients with ankylosing spondylitis in southern India

IgM, IgA, and IgG response to three different antigenic preparations-lipopolysaccharide (LPS), culture supernatant proteins, and outer membrane protein (OMP) of Klebsiella pneumoniae, Escherichia coli and Salmonella typhi-were measured in the sera of 20 patients with primary ankylosing spondylitis (AS), 10 with enterogenic reactive arthritis (ReA) (disease controls), and 15 voluntary blood donors (healthy controls) by ELISA using biotinylated anti-human immunoglobulins M, G, and A. Serum immunoglobulin levels were measured by immunoturbidimetric assay in 20 AS patients, 20 patients with enterogenic reactive arthritis (ReA), 20 with ulcerative colitis (UC), and 20 voluntary blood donors. Student's t-test was applied for comparison. Compared to healthy controls, AS patients showed significantly elevated IgG response against culture supernatant proteins of all the three organisms (P <0.05), LPS of E. coli (P < 0.05) and Klebsiella (P < 0.005), as well as OMP only of Klebsiella pneumoniae. This was reflected as significantly elevated IgG level in AS compared to controls (P < 0.05 vs. ReA and 0.005 vs. UC and healthy controls). This suggests the involvement of outer membrane proteins of Klebsiella pneumoniae in the pathogenic mechanism of ankylosing spondylitis.

Bacterial DNA in synovial fluid cells of patients with juvenile onset spondyloarthropathies

OBJECTIVE

To identify bacterial DNA in synovial fluid cells of patients with active juvenile onset spondyloarthropathy (SpA).

METHODS

The main group of study constituted 22 patients with juvenile onset SpA. In addition, five patients with adult onset SpA and nine with rheumatoid arthritis (RA) were studied. Polymerase chain reaction (PCR) with either genus- or species-specific primers was performed on synovial fluid cells to detect DNA sequences of Chlamydia trachomatis, Yersinia enterocolitica, Salmonella sp., Shigella sp., Campylobacter sp. and Mycobacterium tuberculosis. The presence of antibacterial antibodies in sera and synovial fluid was also determined by enzyme-linked immunoassay.

RESULTS

The synovial fluid of nine patients with juvenile onset SpA, three with adult onset SpA and one with RA contained bacterial DNA. Five juvenile onset SpA samples had DNA of one single bacterium; two juvenile onset SpA and three adult onset SpA had DNA of two bacteria and two juvenile onset SpA had DNA of three bacteria. Overall, Salmonella sp. DNA was detected in seven synovial fluid samples, Shigella sp., Campylobacter sp. and M. tuberculosis were found in four samples each, and C. trachomatis was found in two. The bacterial DNA findings correlated with neither diagnosis nor disease duration. One RA synovial fluid had DNA of Campylobacter sp. Neither serum nor synovial fluid antibacterial antibodies correlated with DNA findings or clinical diagnosis.

CONCLUSION

In this study, single and several combinations of bacterial DNA were identified in the synovial fluid of patients with long-term undifferentiated and definite juvenile onset SpA and adult onset SpA. Of relevance is that bacterial DNA corresponds to bacteria producing endemic disease in our population.

Infectious agents in chronic rheumatic diseases

The possible role of infectious microorganisms in the disease process of both arthritis and autoimmunity continue to attract both basic and clinical researchers. However, proving a causal role for these suspects is a very difficult and complicated task. This article provides an update on various mechanisms in which microbes may play roles as inciting or perpetuating factors in the pathogenesis of connective tissue disease. It also focuses on current theories that specific microorganisms may play a role in rheumatoid arthritis and ankylosing spondylitis.

Germ-free mice do not develop ankylosing enthesopathy, a spontaneous joint disease

Ankylosing enthesopathy (ANKENT) is a naturally occurring joint disease in mice with numerous parallels to human ankylosing spondylitis (AS). Similarities between AS and ANKENT include not only affected tissue (joint entheses) but also association of the disease with genetic background, including MHC genes, gender, and age. Young males with the C57Bl/10 background have been described to suffer from ANKENT and, among H-2 congenic strains, high frequency of afflicted joints has been recorded in B10.BR (H-2(k)) males. Interestingly, the incidence of ANKENT is higher in conventional (CV) males that in their specific-pathogen-free (SPF) counterparts. The latter finding suggests that microbes could play a role as an ANKENT-triggering agent. To further examine this hypothesis we have established a germ-free (GF) colony of B10.BR mice and observed ANKENT incidence in both GF males and their conventionalized (ex-GF) male littermates; 20% of ex-GF males developed ANKENT before 1 year of age. In contrast, no joint disease was observed under GF conditions (p < 0.0001). Our results show that live microflora is required in ANKENT pathogenesis.

Cellular immune response to Klebsiella pneumoniae antigens in patients with HLA-B27+ ankylosing spondylitis

OBJECTIVE

To study the reactivity of peripheral blood mononuclear cells (PBMC) of patients with ankylosing spondylitis (AS) and rheumatoid arthritis (RA) and healthy controls to Klebsiella pneumoniae antigens and to the GroEL-like proteins from K. pneumoniae (HSP60Kp) and Mycobacterium leprae recombinant heat shock protein 65 (rHSP65Ml).

METHODS

PBMC of 13 patients with AS and 9 with RA and 10 controls were stimulated in vitro by heat shock induced K. pneumoniae antigens in a cell blot assay, by insolubilized HSP60Kp, by cytosolic proteins (CP) from K. pneumoniae cultivated at 37 degrees C or 45 degrees C, by soluble HSP60Kp, or by rHSP65Ml.

RESULTS

In the cell blot assay 7/13 AS and 3/9 RA patients responded to fraction 4, which contains mainly HSP60Kp, and no controls responded (AS vs. controls: p = 0.007). The response to the insolubilized HSP60Kp was positive in 6/13 AS patients but negative in RA patients and controls (p = 0.004). The response to CP45 degrees C was positive in 7/13 AS, in 2/9 RA, and no controls (AS vs controls: p<0.015). Response to the soluble HSP60Kp was found in 7/13 AS and 5/9 RA patients, but no controls (AS vs. controls: p = 0.0075). Response to rHSP65Ml was positive in 3/13 AS, 7/9 RA patients, and 1/10 controls (AS vs RA: p = 0.027; RA vs. controls: p = 0.005; AS vs. controls: nonsignificant).

CONCLUSION

In PBMC of the majority of patients with AS and in some with RA, but not in healthy controls, there are cells that proliferate in the presence of HSP60 of K. pneumoniae.

Recognition of B cells epitopes of the Klebsiella pneumoniae GroEL-like protein by HLA-B27 positive subjects

The presence of antibodies against antigens of K. pneumoniae in HLA-B27 positive patients with ankylosing spondylitis (AS), has been well documented. We have previously reported that sera from HLA-B27 positive subjects react with the K. pneumoniae GroEL-like protein (HSP60Kp) and have higher titers than HLA-B27 negative individuals. We cloned the gene that codes for this protein, determined hydrophilic regions by computer analysis of the predicted amino acid sequence and found that residues 389-397, 360-368 and 282-290, were possible B cell epitopes. To test this prediction, and to determine if the HLA-B27 positive and negative AS patients recognize the same or different epitopes, we truncated the hsp60Kp gene, from the 3; terminal nucleotide, to obtain fragments having or not the predicted epitopes. Four polypeptides of 40, 37, 30 and 18 kDa were obtained and analysed, by ELISA and inhibition of ELISA, for their reactivity with IgG antibodies from three high responders HLA-B27 positive AS patients and three HLA-B27 negative subjects who recognized the rHSP60Kp. Sera from both HLA-B27 positive and negative subjects reacted equally well with rHSP60Kp or with the 40 and 37 kDa peptides, which do not have residues 389-397 and 360-368, respectively, but reactivity was lost with the 30 kDa peptide, which also lacks residues 282-290. Contrary to what we expected, antibodies from HLA-B27 negative and positive individuals recognized the same epitope of the HSP60Kp. Our results indicate that the important epitope for B cells could be the 282-290 region and that the contribution of the two other predicted regions is minimal. We also conclude that the differences in response to the HSP60Kp in HLA-B27 positive AS patients and HLA-B27 negative individuals is not qualitative, but only quantitative.

Prevalence of Chlamydia trachomatis in urine of male patients with ankylosing spondylitis is not increased

OBJECTIVE

To compare the prevalence of Chlamydia trachomatis infections in ankylosing spondylitis (AS) patients with controls, using DNA amplification assays in urine specimens.

METHODS

The prevalence of C trachomatis infections was assessed in 32 male AS patients and 120 age and sex matched controls. Urine specimens were tested by ligase chain reaction and polymerase chain reaction. In addition, blood samples of AS patients were tested on serum antibodies to C trachomatis (IgA and IgG) by a specific peptide based solid phase enzyme immunoassay. A questionnaire was used to assess the differences in sexual behaviour and ethnic origin between the two groups. AS patients were also asked about disease characteristics.

RESULTS

No significant differences were found between cases and controls in the prevalence of C trachomatis infections. No associations were found between C trachomatis antibodies and disease characteristics, except for acute anterior uveitis (AAU). Four of eight (50%) AS men positive for IgG had a history of AAU in comparison with three of 24 (12.5%) IgG negative men (OR = 7.0; 95% confidence intervals: 1.1, 44.1).

CONCLUSION

The prevalence of Chlamydia trachomatis infections, as detected by commercially available DNA amplification assays in urine specimens, in AS patients is not higher compared with male controls of the same age. However, there seems to be an association between specific antibodies to C trachomatis and AAU.

HLA molecules, bacteria and autoimmunity

It has been well established that many diseases are linked to HLA antigens. Two of the most interesting HLA associations may provide some insight into the pathogenesis of rheumatic inflammatory conditions. In ankylosing spondylitis (AS), 96% of patients possess HLA-B27, whilst the frequency of this marker in the general population is c. 8%. In rheumatoid arthritis (RA), >90% of patients possess either HLA-DR1 or some subtypes of HLA-DR4, whilst the frequency of this marker in the general population is c. 35%. The association between HLA-B27 and reactive arthritis (ReA) has also been well established. Furthermore, it has been shown that ReA is triggered by infection via the gastrointestinal tract due to Yersinia, Salmonella or Campylobacter spp. and in the genitourinary tract due to chlamydia. In a similar way, microbiological and immunological studies have revealed an association between Klebsiella pneumoniae in AS and Proteus mirabilis in RA. This article reviews the possible pathological implications of the associations between HLA-B27, K. pneumoniae and AS, as well as HLA-DR1/DR4, P. mirabilis and RA.

Somatic serogroups, capsular types, and species of fecal Klebsiella in patients with ankylosing spondylitis

The purpose of the present study was to find out whether patients with ankylosing spondylitis (AS) carry fecal Klebsiella strains that belong to serotypes or species specific for AS. Somatic serotypes (O groups), capsular (K) serotypes, and biochemically identified species were determined for fecal klebsiellae isolated from 187 AS patients and 195 control patients. The controls were patients with fibromyalgia or rheumatoid arthritis. The 638 isolates of Klebsiella that were obtained represented 161 strains; 81 from AS patients and 80 from the controls. The average number of Klebsiella strains per patient was 1.7 for the AS group and 1.5 for the control group. The most common O group was O1, which was observed for isolates from 23 of 187 AS patients and 24 of 195 control patients. Next in frequency was group O2, which was observed for isolates from 17 AS patients and 15 control patients. Regarding the K serotypes, 59 different types were identified, revealing a heterogeneous representation of Klebsiella strains, without a predominance of any serotype. By biochemical identification, Klebsiella pneumoniae was the most frequently occurring species, being found in 45 AS patients and 45 control patients. Next in the frequency was K. oxytoca, which was observed in 26 AS patients and in 29 control patients. K. planticola and K. terrigena occurred in only a minority of patients. Altogether, when analyzed either separately or simultaneously according to O groups, K serotypes, and biochemically identified species, no evidence of the existence of AS-specific Klebsiella strains was obtained. These findings do not indicate participation of Klebsiella in the etiopathogenesis of AS.

Ankylosing spondylitis and genitourinary infection

One hundred and thirty-four male and 32 female patients with ankylosing spondylitis and 33 women with pure ileitis terminalis Crohn were examined. The study protocol included a medical-rheumatological examination and thorough investigation for genitourinary infection. Urethroadnexitis was found in 37/134 male patients (2 patients suffered from balanitis, 17 patients from urethritis, 18 patients from prostatitis, and 2 patients from epididymitis), 15/32 female patients (11 of them had urethritis and in 4 cases urethritis associated with vaginitis) and 5/33 women with ileitis terminalis (every case with urethritis). The microorganism isolated most frequently from patients with genitourinary infection was Chlamydia trachomatis. The majority of patients with genitourinary infection were HLA-B27 positive. Nevertheless, the following conclusions can be reached: (1) evidence of Chlamydia trachomatis infection is frequent in male and female patients with ankylosing spondylitis, (2) patients with genitourinary infection tend to have HLA-B27, and (3) furthermore, presence of genitourinary infection was not significantly associated with chronic illness.

Humoral immune response to Klebsiella capsular polysaccharides in HLA-B27-positive patients with acute anterior uveitis and ankylosing spondylitis

Klebsiella is suggested to trigger ankylosing spondylitis (AS) and acute anterior uveitis (AAU) in HLA-B27-positive individuals. Previous investigations showed an increased antibody response to the Klebsiella capsular types K26, K36, and K50 in sera from HLA-B27-positive AS patients. In the present study the prevalence and titers of antibodies against Klebsiella capsular antigens were measured by means of an ELISA in 32 sera from HLA-B27-positive AAU patients either with (n = 10) or without AS (n = 22) and compared with sera from HLA-B27-negative AS-patients (n = 13). Sera from either HLA-B27-positive (n = 45) or negative (n = 40) healthy individuals served as control. Sera from HLA-B27-positive AAU with or without AS showed significantly higher antibody prevalence and IgG-titers against capsular antigens of the Klebsiella serotypes K26, K36, and K50 when compared with sera from HLA-B27-negative AS patients or with healthy controls. These results might be taken to indicate the predominance of these serotypes in the HLA-B27-associated AS and AAU.

Antibodies to Klebsiella pneumoniae lipopolysaccharide in patients with ankylosing spondylitis

The role of microbial lipopolysaccharides (LPS) in the aetiopathogenesis of ankylosing spondylitis (AS) is a matter of continuing debate. In this study, class-specific IgG, IgA and IgM antibodies against Klebsiella pneumoniae, Escherichia coli, Salmonella typhimurium and Salmonella enteritidis LPS were measured by enzyme-linked immunosorbent assay (ELISA) in 100 AS patients, 50 rheumatoid arthritis (RA) patients and 50 healthy control subjects. The AS patients had significantly elevated levels of IgG and IgA antibodies against K. pneumoniae LPS (P < 0.001) and IgA antibodies against E. coli LPS (P < 0.05) compared to healthy controls. There were no significant elevations of antibody levels against S. typhimurium and S. enteritidis in the three study groups. In addition, there was a correlation between IgG and IgA anti-K. pneumoniae LPS antibody levels and the acute-phase reactant C-reactive protein (P < 0.001).