Increase of HLA-DRB1*0408 and -DQB1*0301 in HLA-B27 positive reactive arthritis

OBJECTIVE

To study HLA class II association in reactive arthritis.

METHODS

63 patients with reactive arthritis and 46 with rheumatoid arthritis were included in the study. HLA-DR alleles were determined by using a sequence specific PCR method. Oligonucleotide hybridisation was used for definition of DRB1*04 subtypes and DQB1 alleles. HLA-B27 was determined by standard microcytotoxity test or by PCR. HLA-B27 subtyping was made by sequencing.

RESULTS

46 (73%) of 63 patients with reactive arthritis were HLA-B27 positive and 24 (38%) were HLA-DRB1*04 positive. When haplotypes were inferred according to the known associations between DRB1 and DQB1 alleles, the frequency of DRB1*04-DQB1*0301 haplotype was found to be 13% (12/92) in HLA-B27 positive reactive arthritis patients, in contrast to 0% in HLA-B27 negative reactive arthritis (P = 0.04) and 1% in random controls (P = 0.0009). However, this combination was also found in 5% of 84 HLA-B27 positive control haplotypes, showing a linkage disequilibrium between B27 and this particular class II haplotype. HLA-DRB1*0408 subtype was found in 8/24 (33%) of the HLA-DRB1*04 alleles in patients with reactive arthritis, accounting for most DQB1*0301 haplotypes, but only in 5/55 (9%) of the DRB1*04 alleles in random controls (P = 0.017). All reactive arthritis patients with this subtype were positive for HLA-B27. DRB1*04-DQB1*0302 haplotype was increased in patients with rheumatoid arthritis (28/92, 30%) compared with reactive arthritis (12/126, 10%) or with the controls (12/100, 12%; P = 0.003). HLA-B*2705 was by far the dominant B27 subtype both in reactive arthritis patients with the particular DRB1*0408-DQB1*0301 haplotype and in controls. It was found in 11 out of 12 DR analysed patients, as well as in 10 out of 11 randomly selected B27 positive controls.

CONCLUSIONS

Although no single class II allele was found to be increased among patients with reactive arthritis, HLA-B27, DRB1*0408, and DQB1*0301 might exert a haplotypic effect in the pathogenesis of reactive arthritis, or they may be markers of a subset of B27 haplotypes conferring susceptibility.

High frequency of Yersinia antibodies in healthy populations in Finland and Germany

Sera from 94 healthy Finnish and 100 healthy German blood donors were studied for Yersinia enterocolitica antibodies by two different techniques, enzyme immunoassay and immunoblotting, to compare the frequency of Yersinia infections in Finnish and German populations. The prevalence of Yersinia antibodies in Finland (19% and 31% by enzyme immunoassay and immunoblotting, respectively) and in Germany (33%, 43%) is relatively high and may indicate many subclinical Yersinia infections in healthy populations. Postinfectious complications, such as reactive arthritis, may follow also such subclinical infection; sensitive serological tests are important in their diagnosis.

Oncoprotein expression in human synovial tissue: an immunohistochemical study of different types of arthritis

Based on the fact that synovial lining cells have some properties of transformed-appearing cells, we have examined the expression of Myc, Myb, Fos, Jun and Ras oncoproteins in synovial tissues from patients with different types of arthritis. Formalin-fixed and paraffin-embedded sections of synovial tissue from 12 patients with rheumatoid arthritis (RA), 14 with reactive arthritis (ReA), nine with other seronegative arthritis (OSA), seven with bacterial arthritis (BA), eight with probable bacterial arthritis (PBA) and eight with osteoarthritis (OA) were studied using the immunoperoxidase staining technique. The oncoproteins studied were expressed both in the synovial lining layer and in the sublining layer, consisting of lymphocytes, other inflammatory cells and blood vessels. Among the six disease entities, RA and OA appeared to be the most distinct, whereas the results obtained for ReA and OSA, and on the other hand for BA and PBA, closely resembled each other. The expression of Myc, Myb, Fos and Jun was significantly correlated both to the degree of synovial hypercellularity and the synovial lymphocytic infiltration. For Ras, such a correlation could not be seen. We conclude that we find no evidence of a cell lineage-specific or a disease-specific abnormality of proto-oncogene products in RA, and the expression of these oncoproteins is consistent with inflammation rather than with any primary abnormality of cell growth.

Reactive arthritis

During the past year, new information has been obtained regarding the pathogenetic process in reactive arthritis. Characterization of the triggering microbes as well as of their interaction with T cells and other host components has brought us closer to achieving a comprehensive picture of the events leading from infection to reactive arthritis. Efforts are ongoing to define clinically applicable diagnostic criteria. It is becoming apparent that chronic forms of the disease are not uncommon.

Antibiotic prophylaxis and treatment of reactive arthritis. Lessons from an animal model

OBJECTIVE

To study the effect of antibiotic prophylaxis and treatment of reactive arthritis (ReA), using an experimental model.

METHODS

Yersinia enterocolitica O:8, when injected intravenously into Lewis rats, causes a sterile arthritis closely resembling human ReA in 70% of the animals. Arthritis develops in 1-2 weeks; in some of the animals it remains chronic, and exacerbations occur. This model was applied to study the effect of a 7-day treatment with ciprofloxacin, using 2 different dosages (20 or 100 mg/kg/day) and 4 different schedules for initiation of treatment. The effects were evaluated by determining the daily arthritis score, the number of rats developing arthritis, and fecal excretion of Yersinia. In addition, weight gain was monitored. At autopsy (35 or 60 days after inoculation with bacteria), samples were obtained for determination of Yersinia-specific antibodies in the serum. At the same time, samples were collected from mesenteric lymph nodes, lung, spleen, and liver for bacterial cultures, and from the ankle joints for histologic evaluation. In a separate experiment, ciprofloxacin concentrations in samples from serum and mesenteric lymph nodes were analyzed by high performance liquid chromatography.

RESULTS

A 7-day course with 100 mg/kg/day of ciprofloxacin, started on day 3 after bacterial inoculation, completely prevented the development of ReA and eliminated Yersinia during the 60-day experiment. If a dosage of 20 mg/kg/day was used, development of acute arthritis was prevented, but some of the animals had positive fecal cultures at the end of experiment. If antibiotic treatment was started on day 5, the preventive effect was still observed, but was less pronounced. If the treatment was started at the peak of the development of arthritis, no effect on arthritis was observed.

CONCLUSION

These results indicate that if any effect of antibiotic treatment in Yersinia-triggered ReA is to be expected, the treatment must be started early and given in sufficient dosage. However, antibiotic treatment has no effect on fully developed arthritis.

HLA frequencies in HLA-B27 negative patients with reactive arthritis

The purpose of the present work was to find out whether there is an HLA type common to the patients who, in spite of being B27 negative, have developed reactive arthritis (ReA). We compared the HLA-antigens of 25 HLA-B27 negative ReA patients to those of healthy control persons. No statistically significant differences were observed in the HLA-A, B, C, DR and DQ antigen frequencies between the patients and the control group. The frequency of DR4 was slightly lower in the patients than in the controls, although this difference was not statistically significant. On the other hand, 18/25 (72%) of the B27-negative ReA patients experienced a chronic or prolonged course of the disease. These findings indicate that DR4 does not contribute to the chronicity of ReA in the same way that it is known to do in rheumatoid arthritis (RA) or Lyme arthritis. They do not support the hypothesis that some other HLA-antigen, in addition to HLA-B27, could have a predisposing or protective effect in ReA.

Epidemiologic, clinical, and therapeutic aspects of reactive arthritis and ankylosing spondylitis

The role of microbes in the pathogenesis of various arthritides continues to be the focus of keen interest. In the study of genetic factors that predispose to spondyloarthropathies, HLA-B27 transgenic animal models present exciting new research possibilities. The basic principles in the management of these arthritides have not changed, but an increasing number of patients are being treated with disease-modifying antirheumatic drugs when the response to nonsteroidal anti-inflammatory drugs is inadequate.

Ten-year follow up study of patients from a Yersinia pseudotuberculosis III outbreak

A Yersinia pseudotuberculosis serotype III outbreak in 1982 was characterized by a high frequency of post-infectious complications. Ten years later 16 out of the 19 patients originally included in the outbreak were reached for a follow up evaluation. Altogether nine patients suffered from chronic joint symptoms. Four of them were HLA B27-positive. Two of these had ankylosing spondylitis; one with severe erosive polyarthritis and secondary amyloidosis which led to uremia requiring haemodialysis and eventually to death, the other with ankylosis of the lumbar spine and sacroiliitis. None of the patients any longer had detectable anti-Yersinia antibodies. The long-term prognosis of Yersinia-triggered reactive arthritis is discussed.

Yersinia-associated arthritis in rats: effect of 65 kDa heat shock protein, bovine serum albumin and incomplete Freund's adjuvant

OBJECTIVE

We have previously shown that the microbial load of rats has a significant effect on their susceptibility to Yersinia-associated arthritis. In this study our aim was to see whether mycobacterial 65 kDa heat shock protein (hsp) could induce the same suppressive effect in experimental Yersinia-associated arthritis as has been reported for arthritides induced by adjuvant, pristane, or streptococcal cell walls (SCW).

METHODS

Arthritis was induced by the intravenous injection of Yersinia enterocolitica 0:8 into Lewis rats. Hsp, bovine serum albumin (BSA) or NaCl, administered in incomplete Freund's adjuvant (IFA), was given subcutaneously on day -5 or +5 with regard to the bacterial inoculation.

RESULTS

Mycobacterial hsp given in IFA on day -5 significantly suppressed the development of arthritis. However, a similar suppression was observed with BSA or NaCl given in IFA.

CONCLUSION

These results, together with those known from the effect of microbial load, suggest that susceptibility to Yersinia-associated arthritis is easily affected by external factors.

Synovial fluid L-lactic acid in acute arthritis of the adult knee joint

Determination of synovial fluid (SF) lactic acid has been suggested to be an unspecific indicator of SF leukocytosis, and it is not recommended for differential diagnosis of bacterial arthritis. We analyzed the L-lactic acid content by enzymatic UV-method in 65 SF samples obtained from adult patients with acute knee arthritides. The concentration of L-lactic acid was not high in any SFs with intensive leukocytosis. The mean concentration of L-lactic acid was 13.5 mmol/l (95% confidence intervals 9.4; 17.6 mmol/l) in the synovial-fluid samples from culture-positive arthritis and 5.5 mmol/l (4.9; 6.2 mmol/l) in the synovial-fluid samples from culture-negative arthritis. Determination of SF L-lactic acid is an important part of the diagnostic setup for acute arthritis. Values > 9 mmol/l strongly support occurrence of bacterial arthritis and indicates an immediate onset of the treatment.

Synovial fluid muramic acid in acute inflammatory arthritis

Presence of muramic acid, a bacterial cell wall component, was analysed by gas chromatography-mass spectrometry in synovial fluid (SF) of 40 patients with acute inflammatory arthritis. SF muramic acid was observed in 4/14 patients with acute, culture negative inflammatory arthritis of unclear origin. Each of these four patients had a history of a recent bacterial disease (pansinuitis, purulent leg ulcer, erysipelas, unexplained fever with suspicion of cholecystitis and urinary tract infection). In the bacterial arthritis, SF muramic acid was detected in 6/12 patients (in 2/6 culture negative cases). In the reactive arthritis due to Salmonella or Yersinia, the rate of positivity was 2/14. Nineteen samples of traumatic SF effusion were muramic acid negative. These findings indicate that several cases of undefined acute inflammatory arthritis are of bacterial origin.

When is an autoimmune disease not an autoimmune disease?

What are the environmental triggers and genetic susceptibilities underlying the development of autoimmune diseases? These and other questions were addressed at a recent meeting in Finland.

Yersinia-specific antibodies in serum and synovial fluid in patients with Yersinia triggered reactive arthritis

OBJECTIVES

To further evaluate the role of bacterial antigens in triggering inflammation in the joint in patients with reactive arthritis by studying local antibody synthesis in the joint.

METHODS

Yersinia-specific antibodies in paired serum and synovial fluid samples from 29 patients with yersinia triggered reactive arthritis were studied using an enzyme linked immunosorbent assay (ELISA), an inhibition ELISA with six monoclonal antibodies against lipopolysaccharide or released proteins of yersinia and immunoblotting. Antibodies of IgM, IgG and IgA classes, as well as antibodies of IgA subclasses and those containing secretory component were measured against the lipopolysaccharide and the sodium dodecyl sulphate extract of whole Yersinia enterocolitica O:3 bacteria.

RESULTS

It was shown that yersinia-specific antibodies, as well as antibodies against other microbial antigens (rubella, measles, Bordetella pertussis, tetanus toxoid and Candida albicans) in synovial fluid mirror those in serum by concentration, by specificity and by distribution in classes and subclasses.

CONCLUSION

These results do not suggest any strong local antibody production, but indicate that the majority of yersinia antibodies in the synovial fluid are derived from the circulation.

A statistical analysis system macro for age-standardized incidence rates

The Statistical Analysis System (SAS) is a commercial software system for data analysis. We designed a SAS macro that produces age-specific rates of any given disease directly from the basic patient data on SAS files. The macro conforms to the statistical methods of the World Health Organization's MONICA project, which is a multinational project for MONItoring of trends and determinants in CArdiovascular disease. The data of the Coronary Register of the City of Turku, Finland, was used to test this macro. The data consists of both men and women between the ages of 35 and 64 years. Acute coronary events leading to hospitalization and acute coronary death events outside hospital have been registered since 1972. For age-standardization Segi's world population was used as the standard. The weights were then calculated for five consecutive years. Individual weights related to the population size of the reporting unit and the standard population were calculated for each subject in the population using the population size of the reporting unit and the standard population. This yielded the age-standardized rates of the acute myocardial infarction and the corresponding standard deviations. The macro permits standardization of the incidence rates of any disease. It will present the required figures instantly.

Infection and arthritis

Reactive arthritis is caused by an infection, and components of the triggering agent can be demonstrated at the site of inflammation. This fact has opened new views in studies regarding other rheumatic diseases, such as rheumatoid arthritis and ankylosing spondylitis. The possible role of infectious agents in their etiology and pathogenesis is being re-evaluated.

Epidemiologic aspects, clinical features, and management of ankylosing spondylitis and reactive arthritis

The generally reported prevalence of 0.1% to 0.2% for ankylosing spondylitis in the white population is probably too low, because it is based almost entirely on hospital records. The incidence and clinical presentation of ankylosing spondylitis have not changed during the past few decades. For reactive arthritis, the list of microbes recognized as triggering agents is continuously increasing. Reactive arthritis is divided into urogenic, enterogenic, respiratory tract-associated, and idiopathic arthritides. In addition, several microbial diseases may be accompanied by reactive arthritis, even though the identity of the causative agent is not always known. In the diagnosis of the spondyloarthropathies, definite progress has been made in developing classification criteria. Intensive research is going on to evaluate new therapies, with special attention to the use of antimicrobial agents for the treatment of reactive arthritis.

Electron microscopy and immunolabeling of Yersinia antigens in human synovial fluid cells

Recent findings have emphasized the involvement of bacterial antigens in synovitis in reactive arthritis. It is still unclear, however, in what form the microbial material exists in the joint. Both antigen-containing cells and intact bacteria have been proposed as candidates on the basis of immunohistochemical studies of the synovial membrane. This study addresses that question by electron microscopy and peroxidase immunolabeling of synovial fluid cells from three patients with reactive arthritis triggered by Yersinia enterocolitica O:3. For all three patients a diffuse reaction in the cytoplasm of phagocytes was interpreted as bacterial material in a degraded form. These results are consistent with our proposal that intact bacteria rarely, if ever, enter the joints of Yersinia-triggered reactive arthritis patients.

Synovial-fluid D-lactic acid in bacterial and other acute joint effusions

The use of D-lactic acid in differential diagnosis of bacterial arthritis was evaluated in a prospective study. The concentration of D-lactic acid was determined by the enzymatic UV-method in sixty-eight synovial fluids (SF) and in twenty four sera from adult patients with acute knee effusion. High concentrations of D-lactic acid (> 0.15 mmol/l) were measured most frequently in SF from bacterial arthritis, but also in individual culture-negative SF samples from patients with inflammatory culture-negative joint effusions with and without identified history of infections. Determination of SF D-lactic acid is not useful in differential diagnosis of bacterial arthritis.

Does Yersinia induce autoimmunity?

Yersinia enterocolitica O:3 and the human thyrotropin receptor share a structural similarity, revealed by their serological cross-reactivity. The exact molecular basis of the similarity is open. In spite of this cross-reactivity, Yersinia seems not to be a major inducer of thyroid autoimmunity. Yersinia infections or avirulent Yersinia strains in the intestinal flora may rather contribute to the development of thyroid autoimmunity arising for other reasons in genetically susceptible individuals. Regarding Yersinia and spondyloarthropathies, it is undetermined whether the chronic sequelae of acute Yersinia-triggered reactive arthritis are due to the persistence of phlogistic microbial components or to autoimmunity, or to both. No convincing evidence exists for a role of molecular mimicry between Yersinia and HLA B27 or other host structures. Cytotoxic T-cell clones derived from synovial fluid, and capable of killing Yersinia-infected and uninfected autologous targets in an HLA B27-restricted fashion have recently been described. Evaluation of their significance for the potential Yersinia-induced autoimmunity is waiting for characterization of the bacterial and host peptides involved.