Clinical aspects, outcome assessment, and management of ankylosing spondylitis and postenteric reactive arthritis

Clinical Implications of Shared Epitope and Anti-citrullinated Peptide Antibody in Patients With Rheumatoid Arthritis

Objective

The shared epitope (SE) and anti-citrullinated peptide antibody (ACPA) are involved in the pathogenesis of rheumatoid arthritis (RA). This study evaluated the clinical implications of SE and ACPA in terms of disease manifestation and response to biologic disease modifying anti-rheumatic drugs (DMARDs).

Methods

Patients with identified human leukocyte antigen (HLA)-DRB1 alleles were included to compare the clinical characteristics and drug survival rate of tumor necrosis factor (TNF) inhibitors or abatacept based on the presence of SE and ACPA.

Results

Of the 533 patients with identified HLA-DRB1 alleles, 329 patients (61.7%) with SE alleles showed higher disease activity and erosive changes compared to patients without SE alleles. SE-positive patients were more likely to start biologic (b-) or targeted synthetic DMARDs (tsDMARDs) within the first 5 years (p=0.020). The presence of SE, smoking, dyslipidemia, and higher erythrocyte sedimentation rate were independently associated with the initiation of b- or tsDMARDs (p=0.016, 0.028, 0.031, and 0.001, respectively). The presence of SE and ACPA did not affect the drug survival rate of TNF inhibitors, whereas the abatacept retention rate was higher in ACPA-positive patients (p=0.024).

Conclusion

The presence of SE affected disease characteristics and prognosis in Korean patients with RA without a significant impact on drug survival rate of TNF inhibitors and abatacept. ACPA positivity was associated with abatacept drug retention, suggesting that abatacept may be helpful in ACPA-positive patients than in ACPA-negative patients.

Time-integrated Cumulative Parameters Predictive of Radiographic Progression of Rheumatoid Arthritis: Real-world Data From a Prospective Single-center Cohort

Objective

With many chronic inflammatory diseases, outcomes are determined by assessing both disease activity at presentation and cumulative activity over time. Here, we investigated whether cumulative activity better reflects the radiographic progression (RP) of rheumatoid arthritis (RA) than measurement of activity at a single time point.

Methods

From a prospective cohort of RA patients, most of whom were treated with anti-rheumatic drugs, we selected 117 subjects for whom laboratory, clinical, and radiographic parameters potentially influencing RP were monitored serially for more than 1 year. X-ray images of both hands and both feet were scored using the van der Heijde modified total Sharp score (mTSS). In addition to cross-sectional values at baseline, longitudinal and cumulative values for each parameter were calculated in a time-integrated and averaged manner.

Results

Among the values measured at baseline, mTSS, but not the baseline erythrocyte sedimentation rate (ESR) or C-reactive protein level, was associated with RP. By contrast, multivariate analyses identified cumulative values such as the cumulative ESR, cumulative tender joint count, cumulative swollen joint count (SJC), and cumulative Disease Activity Score 28-ESR as major determinants of RP. In particular, the cumulative SJC showed the best predictive performance for RP.

Conclusion

This study highlights the importance of cumulative indices for predicting progression of RA. Specifically, dynamic and cumulative values of RA activity-related factors, particularly the cumulative SJC, may be the major determinants of RP in the current practice.

Putative Pathobionts in HLA-B27-Associated Spondyloarthropathy

Spondyloarthritis (SpA) is a group of immune mediated inflammatory diseases with a strong association to the major histocompatibility (MHC) class I molecule, HLA-B27. Although the association between HLA-B27 and AS has been known for almost 50 years, the mechanisms underlying disease pathogenesis are elusive. Over the years, three hypotheses have been proposed to explain HLA-B27 and disease association: 1) HLA B27 presents arthritogenic peptides and thus creates a pathological immune response; 2) HLA-B27 misfolding causes endoplasmic reticulum (ER) stress which activates the unfolded protein response (UPR); 3) HLA-B27 dimerizes on the cell surface and acts as a target for natural killer (NK) cells. None of these hypotheses explains SpA pathogenesis completely. Evidence supports the hypothesis that HLA-B27-related diseases have a microbial pathogenesis. In animal models of various SpAs, a germ-free environment abrogates disease development and colonizing these animals with gut commensal microbes can restore disease manifestations. The depth of microbial influence on SpA development has been realized due to our ability to characterize microbial communities in the gut using next-generation sequencing approaches. In this review, we will discuss various putative pathobionts in the pathogenesis of HLA-B27-associated diseases. We pursue whether a single pathobiont or a disruption of microbial community and function is associated with HLA-B27-related diseases. Furthermore, rather than a specific pathobiont, metabolic functions of various disease-associated microbes might be key. While the use of germ-free models of SpA have facilitated understanding the role of microbes in disease development, future studies with animal models that mimic diverse microbial communities instead of mono-colonization are indispensable. We discuss the causal mechanisms underlying disease pathogenesis including the role of these pathobionts on mucin degradation, mucosal adherence, and gut epithelial barrier disruption and inflammation. Finally, we review the various uses of microbes as therapeutic modalities including pre/probiotics, diet, microbial metabolites and fecal microbiota transplant. Unravelling these complex host-microbe interactions will lead to the development of new targets/therapies for alleviation of SpA and other HLA-B27 associated diseases.

Chinese Herbal Formula Huayu-Qiangshen-Tongbi Decoction Compared With Leflunomide in Combination With Methotrexate in Patients With Active Rheumatoid Arthritis: An Open-Label, Randomized, Controlled, Pilot Study

Background: Traditional Chinese Medicine is complementary and an alternative to modern medicine. The combination therapies of herbal products with disease-modifying anti-rheumatic drugs are gradually and widely adopted in the management of rheumatoid arthritis (RA) in China. Purpose: To evaluate the efficacy and safety of Huayu-Qiangshen-Tongbi (HQT) decoction, a Chinese medicine formula, combined with methotrexate (MTX) in the treatment of patients with active RA, in comparison with the combination therapy of MTX with leflunomide (LEF). Methods: This pilot study was a monocenter, open-label, randomized controlled trial with two parallel arms. Ninety patients with active RA were randomly allocated to receive either HQT at a dose of 250 ml twice daily or LEF at a dose of 20 mg once daily, and all participants received MTX at a dose of 10-15 mg once weekly. The primary efficacy endpoint was the proportion of patients who achieved a 20% improvement in the American College of Rheumatology criteria (ACR20) after a 24-week treatment. Results: 84.4% (76/90) patients completed the 24-week observation. In the intention-to-treat analysis, the percentage values of patients achieving the ACR20 response criteria were 72.1% (31/43) in MTX + HQT group and 74.4% (32/43) in MTX + LEF group (p = 0.808). No significant difference was observed in other parameters, including ACR50, ACR70, clinical disease activity index good responses, European League Against Rheumatism good response, remission rate, and low disease activity rate. The results of the per-protocol analysis showed consistency with those of the intention-to-treat analysis. The mean change from baseline at week 24 for the van der Heijde modified total sharp score had no significant difference between two groups (3.59 ± 4.75 and 1.34 ± 8.67 in the MTX + HQT group and MTX + LEF group, respectively, p = 0.613). The frequency of adverse events was similar in both groups (11 cases in the MTX + HQT and 17 cases in the MTX + LEF, p > 0.05). Conclusions: In patients with active RA, treatment with the combination of HQT and MTX was associated with improvement in signs, symptoms, and physical function. With a beneficial clinical response and acceptable tolerability, HQT or other Chinese medicine formula may be a good therapeutic option in combination with MTX for RA treatment. Trial registration: Chinese Clinical Trails Registry, ChiCTR-INR-16009031, Registered on 15th August 2016, http://www.chictr.org.cn/enindex.aspx.

High-Resolution Peripheral Quantitative Computed Tomography for Bone Evaluation in Inflammatory Rheumatic Disease

High resolution peripheral quantitative computed tomography (HR-pQCT) is a 3-dimensional imaging modality with superior sensitivity for bone changes and abnormalities. Recent advances have led to increased use of HR-pQCT in inflammatory arthritis to report quantitative volumetric measures of bone density, microstructure, local anabolic (e.g., osteophytes, enthesiophytes) and catabolic (e.g., erosions) bone changes and joint space width. These features may be useful for monitoring disease progression, response to therapy, and are responsive to differentiating between those with inflammatory arthritis conditions and healthy controls. We reviewed 69 publications utilizing HR-pQCT imaging of the metacarpophalangeal (MCP) and/or wrist joints to investigate arthritis conditions. Erosions are a marker of early inflammatory arthritis progression, and recent work has focused on improvement and application of techniques to sensitively identify erosions, as well as quantifying erosion volume changes longitudinally using manual, semi-automated and automated methods. As a research tool, HR-pQCT may be used to detect treatment effects through changes in erosion volume in as little as 3 months. Studies with 1-year follow-up have demonstrated progression or repair of erosions depending on the treatment strategy applied. HR-pQCT presents several advantages. Combined with advances in image processing and image registration, individual changes can be monitored with high sensitivity and reliability. Thus, a major strength of HR-pQCT is its applicability in instances where subtle changes are anticipated, such as early erosive progression in the presence of subclinical inflammation. HR-pQCT imaging results could ultimately impact decision making to uptake aggressive treatment strategies and prevent progression of joint damage. There are several potential areas where HR-pQCT evaluation of inflammatory arthritis still requires development. As a highly sensitive imaging technique, one of the major challenges has been motion artifacts; motion compensation algorithms should be implemented for HR-pQCT. New research developments will improve the current disadvantages including, wider availability of scanners, the field of view, as well as the versatility for measuring tissues other than only bone. The challenge remains to disseminate these analysis approaches for broader clinical use and in research.

Mean platelet volume, red cell distribution width, platelet-to-lymphocyte and neutrophil-to-lymphocyte ratios in patients with ankylosing spondylitis and their relationships with high-frequency hearing thresholds

The mean platelet volume (MPV), red cell distribution width (RDW) and neutrophil-to-lymphocyte ratio (NLR) comprise laboratory markers in ankylosing spondylitis (AS). There is a controversy in the literature regarding which type of ear involvement is characteristic of AS. The aim of this study was to simultaneously investigate the MPV, RDW, platelet to lymphocyte (PLR) and NLR in patients with AS and their relationships with high-frequency hearing thresholds. Thirty patients with AS and 35 age-matched healthy subjects were included. Each subject was tested with low- (250, 500, 1000 and 2000 Hz) and high- (4000, 8000, 10,000, 12,000, 14,000 and 16,000 Hz) frequency audiometry. Additionally, the case and control groups were evaluated regarding the average hearing thresholds in bone conduction. The erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels were measured. The RDW, MPV, neutrophils, lymphocytes and platelet counts were evaluated with the complete blood count. Furthermore, the NLR and PLR were calculated. The complete blood count, platelet numbers, ESR, CRP and NLR levels were significantly increased in the AS patients compared with the healthy controls (p < 0.001, p = 0.007, p < 0.001, p < 0.001 and p = 0.047, respectively). There was no statistically significant difference in the RDW, PLR or MPV levels (p > 0.05) in the AS patients compared with the healthy controls. The BASDAI score and disease duration were not correlated with the ESR, CRP levels, MPV, PLR, RDW or NLR in patients with AS (all; p > 0.05). The AS patients had increased average measurement values for the hearing threshold in both ears at frequencies of 250, 500, 1000 and 2000 Hz; however, there was no statistically significant difference (p > 0.05). The average values of the hearing threshold in both ears at the high frequencies of 4000, 6000, 8000, 10,000, 12,000 and 14,000 Hz were significantly increased in the case group; however, it was not significantly increased at 16,000 Hz. The current study is the first to investigate the PLR, NLR, MPV and RDW levels in acute AS. We identified a significantly increased NLR, leukocyte count, ESR and CRP in AS patients. Sensorineural hearing loss, especially at extended high frequencies, is common in patients with AS and may represent an extra-articular feature of the disease. The combined use of NLR with the leukocyte count and other clinical assessments may facilitate the diagnostic process of ankylosing spondylitis.

Is There Any Relationship between Joint Destruction and Carotid Intima-media Thickness in Patients with Rheumatoid Arthritis?

[Purpose] The purpose of this study was to investigate the possible relationship between joint destruction and carotid intima-media thickness in patients with rheumatoid arthritis. [Subjects and Methods] Thirty-four RA patients and 31 healthy controls were enrolled in this study. The disease activity for 28 joints was recorded for each patient using the erythrocyte sedimentation rate (DAS28ESR), a visual analog scale (VAS0-10 cm), and a disability index, the health assessment questionnaire (HAQ). X-ray imagesof the patients were scored according to the modified Sharp/van der Heijde method, and the common carotid intimal medial thickness (CIMT) was automatically measured with software using high-resolution Doppler ultrasound. [Results] Contrary to our hypothesis, the modified total Sharp score (mTSS) and CIMT were not significantly associated. The erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels of the RA patients and the right CIMT, left CIMT, and mean CIMT scores were significantly elevated. Positive correlation was detected between the mean CIMT score and age, CRP levels, LDL concentration and triglycerides (TG) level. In the regression model, where the mean CIMT was the independent variable and age, CRP, LDL, and TG were dependent variables, age was found to be an independent predictor of CIMT. [Conclusions] Patients suffering from RA require close monitoring for cardiovascular risks, and the comorbidity of age-related cardiovascular disease should not be overlooked.

Hearing and cochlear function of patients with ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic systemic inflammatory disorder that primarily affects the spine and sacroiliac joints. Recent studies described audiovestibular impairment in AS patients. The aim of this study was to evaluate the hearing and function of the cochlear system in patients with AS. Thirty-seven AS patients and 20 healthy controls were evaluated prospectively. Otorhinolaryngologic examinations were performed in all patients together with pure tone audiometry, speech discrimination test, tympanometry, and distortion product otoacoustic emission (DPOE). Disease duration, Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) scores, and hematologic findings (CRP and ESR) were also collected. Pure tone audiometry findings of the patients and controls were significantly different in all frequencies (p < 0.01). Speech discrimination scores were also significantly different (p < 0.01). No significant difference was found between DPOE responses of the patients and controls (p > 0.05). There was no correlation between disease duration, BASDAI scores, hematological findings, and audiometry findings (p > 0.05). This study demonstrated that there is an association between AS and hearing loss, but the cochlea is not the main source of hearing loss.

Immunogenetics of drug-induced skin blistering disorders. Part II: Synthesis

The overall immunopathogenesis relevant to a large series of disorders caused by a drug or its associated hyperimmune condition is discussed based upon examining the genetics of severe drug-induced bullous skin problems (sporadic idiosyncratic adverse events including Stevens–Johnson syndrome and Toxic epidermal necrolysis). New results from an exemplar study on shared precipitating and perpetuating inner causes with other related disease phenotypes including aphtous stomatitis, Behçets, erythema multiforme, Hashimoto’s thyroiditis, pemphigus, periodic fevers, Sweet’s syndrome and drug-induced multisystem hypersensitivity are presented. A call for a collaborative, wider demographic profiling and deeper immunotyping in suggested future work is made.

Serum amyloid a as a useful indicator of disease activity in patients with ankylosing spondylitis

PURPOSE

To investigate whether serum amyloid A (SAA) levels are increased in patients with ankylosing spondylitis (AS) and whether its levels correlate well with AS disease activity.

MATERIALS AND METHODS

Thirty-eight patients with AS and 38 age- and sex-matched control subjects were enrolled in this cross-sectional study. Their SAA levels were quantitatively measured by immunonephelometry. An established, self-administered instrument for evaluating disease activity (Bath Ankylosing Spondylitis Disease Activity Index, BASDAI) was used to measure and acute phase reactants, including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), in patients with AS.

RESULTS

Patients with AS had a significantly higher mean SAA level than controls (9.52 +/- 7.49mg/L versus 2.73 +/- 1.57mg/L, p < 0.05), and the mean BASDAI score of patients with elevated SAA levels was significantly higher than that of patients with normal SAA levels (5.6 +/- 1.3 versus 4.4 +/- 1.5, p < 0.05). SAA levels showed significant correlations with BASDAI scores (r=0.431, p=0.007), ESR (r=0.521, p=0.001) and CRP levels (r=0.648, p < 0.001). Additionally, the correlation between ESR and CRP levels also appeared significant (r=0.703, p < 0.001). In those with normal ESR or CRP levels, SAA levels and BASDAI scores were elevated (p < 0.05) and showed a trend of positive correlation with one another.

CONCLUSION

Our data showed that SAA levels were increased in patients with AS and correlated well with disease activity. These findings suggest that SAA can be used as a valuable indicator of disease activity in AS.

Pharmacogenetic of antirheumatic treatments: clinical implications

Preliminary pharmacogenetic data suggest that germline genetic informations might be of value in individualizing disease-modifying antirheumatic drugs (DMARDs) therapy in various autoimmune chronic inflammatory diseases. Either DMARDs small molecules (DMARDs-SM) or DMARDs biological therapies (DMARDs-BT) might be selected for their lower toxicity or better efficacy based on single-nucleotide polymorphisms (SNPs) of genes governing the metabolism of drugs, or the response of immune cells to proinflammatory molecules, or the proinflammatory molecular activity of immune cells. Data available for one DMARDs-SM, methotrexate, suggest that a careful assessment of the SNPs of four enzymes involved in the folate metabolism allow one to construct a genetic index of toxicity (toxicogenetic index) that might be employed in daily practice to find the patient's most at risk. Only the full knowledge of the various gene polymorphisms controlling the phenotypic manifestations of the inflammatory-immunological milieu of each rheumatic disease will allow one to obtain the clear definition of a personalized medicine. Few different cytokine gene SNPs seem to be of importance in determining the susceptibility to diseases, or the aggressiveness of diseases. The role of genetics in affecting a possible clinical response to DMARDs-BT targeting specific inflammatory molecules or their receptors still has to be defined. However, the available data suggest that cytokine (and/or receptors) gene SNPs might indeed play a role in determining the biological effects, hence the clinical effectiveness of DMARDs-BT. Crucial to this aim will be the prospective analysis of clinical benefits and safety on the basis of the at baseline stratification of gene SNPs in each chronic inflammatory rheumatic disease before starting any new DMARDs-SM or DMARDs-BT.

Survival of TNF antagonists in spondylarthritis is better than in rheumatoid arthritis. Data from the Spanish registry BIOBADASER

The aim of the present work is to compare drug survival and safety of infliximab, etanercept, and adalimumab (tumor necrosis factor [TNF] antagonists) in spondylarthritis (SpA) with those of rheumatoid arthritis (RA). To this purpose, we analysed the data in BIOBADASER (2000–2005), a drug registry launched in 2000 for long-term follow-up of the safety of these biologics in rheumatic diseases. The rates of drug discontinuation and adverse events (AEs) in SpA (n = 1,524) were estimated and compared with those of RA (n = 4,006). Cox regression analyses were used to adjust for independent factors. Total exposure to TNF antagonists for SpA was 2,430 patient-years and 7,865 for RA. Drug survival in SpA was significantly greater than in RA at 1, 2, and 3 years. The hazard ratio (HR) for discontinuation in SpA compared with RA was 0.66 (95% confidence interval [CI], 0.57–0.76) after adjustment for age, gender, and use of infliximab. The difference remained after controlling for the individual medication and its place in the sequence of treatment. There were fewer SpA patients with AEs (17%) than RA patients (26%; p < 0.001). The HR for AEs in SpA was 0.80 (95% CI, 0.70–0.91) compared with RA after adjustment for age, disease duration, and use of infliximab. In conclusion, due in part to a better safety profile, survival of TNF antagonists in SpA is better than in RA. TNF antagonists are at present a safe and effective therapeutic option for long-term treatment of patients with SpA failing to respond to traditional drugs. Because chronic therapy is necessary, continual review of this issue is necessary.

Recent advances in the treatment of the spondyloarthropathies

PURPOSE OF REVIEW

Recently, there has been renewed interest in the spondyloarthropathy family of chronic inflammatory rheumatic conditions, which has been fueled to a large extent by the biologic era. Over the period of the past 2 years in particular, there have been several notable advances. First, there have been a number of large, high-quality randomized controlled trials evaluating the tumor necrosis factor (TNF) blockers and conservative treatments such as physiotherapy and nonsteroidal anti-inflammatory drugs for use in spondyloarthropathy. This has paved the way for the development of better tools to assess outcome in these patients both in daily practice and in the context of clinical trials. This review uses a systematic approach to outline the most recent (within the last 2 years) and the most pertinent advances in the treatments of the spondyloarthropathies, with particular emphasis on ankylosing spondylitis and psoriatic arthritis.

RECENT FINDINGS

Supervised group exercise programs maintain flexibility and posture in patients with ankylosing spondylitis, and spa therapy is a cost-effective treatment option in ankylosing spondylitis. Nonsteroidal anti-inflammatory drugs have a role in symptom modification and, more importantly, may prevent structural disease progression in patients with ankylosing spondylitis when administered continuously at a fixed dose. TNF blockers have been evaluated in a number of randomized controlled trials in ankylosing spondylitis and psoriatic arthritis and have been demonstrated to be safe and effective in the short-term management of these diseases. Longer-term trials are awaited with radiographic outcomes to comment on their disease-modifying properties and their long-term safety and efficacy profiles.

SUMMARY

There has been renewed interest in the spondyloarthropathy family of disorders, with an explosion in the number of trials evaluating outcome with the TNF blockers. To date, no cure has been found for the disease, but these agents are emerging as the best therapeutic option available for patients with ankylosing spondylitis and psoriatic arthritis to date.

HLA-B27-associated reactive arthritis: pathogenetic and clinical considerations

Current evidence supports the concept that reactive arthritis (ReA) is an immune-mediated synovitis resulting from slow bacterial infections and showing intra-articular persistence of viable, non-culturable bacteria and/or immunogenetic bacterial antigens synthesized by metabolically active bacteria residing in the joint and/or elsewhere in the body. The mechanisms that lead to the development of ReA are complex and basically involve an interaction between an arthritogenic agent and a predisposed host. The way in which a host accommodates to invasive facultative intracellular bacteria is the key to the development of ReA. The details of the molecular pathways that explain the articular and extra-articular manifestations of the disease are still under investigation. Several studies have been done to gain a better understanding of the pathogenesis of ReA; these constitute the basis for a more rational therapeutic approach to this disease.

The effect of chiropractic care for a 30-year-old male with advanced ankylosing spondylitis: a time series case report

BACKGROUND

Manipulative treatment for ankylosing spondylitis is a controversial subject, and no literature on using this therapy for advanced cases with fusion of the spine could be found.

OBJECTIVE

To discuss the case presentation of a patient with advanced ankylosing spondylitis who was treated with chiropractic manipulation and mobilization. Clinical features The patient was a 30-year-old Asian male who was first diagnosed with ankylosing spondylitis at age 12. Despite medical intervention, a series of exacerbations had fused his sacroiliac joints and the facet joints in his lumbar and cervical spine. He presented with local moderate-to-severe pain in his low back and neck and lack of mobility. Intervention and outcome The patient was treated with grade 5 manipulation of his thoracic spine and grade 3 mobilization of his lumbar and cervical spine, along with physical therapy and stretches for a period of 12 weeks. He reported some improvement of his condition as measured by the SF-36 Health Survey and several measures of spinal flexibility.

CONCLUSIONS

This case shows that even advanced cases of ankylosing spondylitis may show a favorable response to chiropractic manipulative therapy.

New pathogenic hypotheses for spondyloarthropathies

Pathogenic hypotheses for spondyloarthropathies are evolving. Several candidates have been added to the list of inciting microorganisms, and genes other than HLA-B27 are under scrutiny. Above all, the chiefly 'immunological' theory of spondyloarthropathies incriminating a cross-reaction between self-proteins and bacterial peptides is giving way to a more 'microbiological' concept in which latent bacteria residing within macrophagic or dendritic cells undergo reactivation through a process facilitated by HLA-B27. This molecule is prone to misfolding, which decreases the presentation of bacterial peptides to the immune system and stimulates the Nf-KB inflammation pathway within infected macrophages and/or dendritic cells. Migration of these infected cells from the mucous membranes to the tissues targeted by spondyloarthropathies, particularly the bone marrow located near entheses, may facilitate transient reactivation of dormant intracellular bacteria by creating a favorable cytokine environment. This environment may include high levels of TGFbeta and IL-10, noted also at other sites that enjoy immune privilege, such as the eye. The reactivation may be stopped by a local response of CD4+ and/or CD8+ T cells at the expense of local inflammation responsible for clinical manifestations. This scenario seems consistent with results from studies of murine models transgenic for the HLA-B27 antigen: exposure to bacteria is necessary to the development of spondyloarthropathy, but the disease occurs even when only the heavy chain of HLA-B27 is present (i.e., beta2-microgloblin is not indispensable). Improved understanding of the mechanisms that confer to some bacterial strains a strong potential for persisting within cells, including macrophagic cells, may open the way toward new treatment approaches capable of complementing antagonists of TNF-alpha and other monokines, which merely suspend the disease process, and antibiotic therapy, which fails to kill dormant bacteria located within cells. Pathogenic hypotheses for spondyloarthropathies are evolving. This review presents the most recent concepts. These concepts have not all received confirmation from experimental data. However, the high degree of consistency among them prompted us to consolidate them into a single picture. Although this approach may yield a motley composite of fact and speculation, it may open up new avenues of thought for rheumatologists interested in the links between chronic intracellular infections and inflammatory joint disease.

Clinical aspects and pathophysiology of inflammatory bowel disease

The chronic inflammatory bowel diseases (IBD), Crohn's disease and ulcerative colitis, are recognized as important causes of gastrointestinal disease in children and adults. In this review we delineate the clinical manifestations and diagnostic features of IBD. In addition, we summarize important recent advances in our understanding of the immune mediators of intestinal inflammation. This information has led to new therapeutic approaches in IBD. Further, we discuss the considerable data that point to the significance of genetic factors in the development of IBD and the genetic loci which have been implicated through genome-wide searches. The commensal bacterial flora also appears to be a critical element, particularly in regards to Crohn's disease, although the precise role of the bacteria in the disease manifestations remains unclear. Current investigations promise to yield fresh insights in these areas.