The histocompatibility antigen (HL-A 27) and disease

Extraintestinal Manifestations of Inflammatory Bowel Disease

Extraintestinal manifestations (EIM) in inflammatory bowel disease (IBD) are frequent and may occur before or after IBD diagnosis. EIM may impact the quality of life for patients with IBD significantly requiring specific treatment depending on the affected organ(s). They most frequently affect joints, skin, or eyes, but can also less frequently involve other organs such as liver, lungs, or pancreas. Certain EIM, such as peripheral arthritis, oral aphthous ulcers, episcleritis, or erythema nodosum, are frequently associated with active intestinal inflammation and usually improve by treatment of the intestinal activity. Other EIM, such as uveitis or ankylosing spondylitis, usually occur independent of intestinal inflammatory activity. For other not so rare EIM, such as pyoderma gangrenosum and primary sclerosing cholangitis, the association with the activity of the underlying IBD is unclear. Successful therapy of EIM is essential for improving quality of life of patients with IBD. Besides other options, tumor necrosis factor antibody therapy is an important therapy for EIM in patients with IBD.

PSORS1C1 may be involved in rheumatoid arthritis

PSORS1C1/CDSN is a susceptibility gene for psoriasis. Both psoriasis and rheumatoid arthritis (RA) are autoimmune diseases. This study investigated whether PSORS1C1/CDSN was involved in RA. The TagSNPs rs3130983, rs3778638 and rs4959053 in the PSORS1C1/CDSN locus were shown to predict susceptibility to RA in two independent RA cohorts using a TaqMan genotyping assay and Sequenom MassARRAY. The expression of PSORS1C1/CDSN was determined with western blotting and ELISA. Cultured synovial fibroblasts from RA patients (RASF) were treated with anti-PSORS1C1 siRNA. The TaqMan genotyping assay demonstrated significant differences in the rs3130983 and rs4959053 allele frequencies (p = 0.002001 and 1.74E-07, respectively) and genotype frequencies (0.010503 and 1.07E-06, respectively) between the RA patients and controls. Sequenom MassARRAY results indicated that SNP rs3778638 allele frequency and genotype frequency were significantly associated with RA (p = 7.35E-05 and 0.000357, respectively). Western blotting revealed a significant increase in expression of PSORS1C1 in RA synovial tissues, and ELISA detected high levels of PSORS1C1 and CDSN in the blood of RA patients. PSORS1C1-siRNA treatment significantly decreased the PSORS1C1 expression, IL-17 level, Il-1β level and cell proliferation in RASF. These results suggest that PSORS1C1 might play an important role in the development of RA.

Reactive arthritis

Reactive arthritis (ReA) was known as Reiter's disease or Fiessinger-Leroy disease for nearly 100 years. However, during the past 30 years the disease has been known as reactive arthritis, a member of the spondyloarthritis family. Despite knowing the initiating event (infection) and genetic constitution (many patients have HLA-B27) of ReA, a model of interplay between environment and genetics, its pathogenesis is still incompletely known. This review covers the epidemiology, clinical features, treatment, and prognosis of ReA.

Infliximab in two patients with juvenile ankylosing spondylitis

Infliximab, a monoclonal chimeric anti-tumor necrosis factor alpha (anti-TNF-alpha) antibody, was tried in two patients suffering from severe refractory juvenile ankylosing spondylarthritis with disease duration of more than 10 years. To assess the response, validated clinical activity parameters were monitored prospectively. In both patients, treatment with infliximab at a dosage of 5 mg/kg body weight already led to considerable improvement with loss of joint pain the day after it was given. Bath Ankylosing Spondylitis Functional Index scores decreased from 5.8 to 0 and 7.2 to 1.0 and the Bath Ankylosing Spondylitis Disease Activity Index from 2.6 to 1.4 and 9.0 to 1.0. In one patient, the response to a single infusion continued for more than 8 months. Because of a recurrence of symptoms in intervals of 2 months, the fourth infusion has now been given to the second patient, resulting in immediate clinical response. No side effects have been noted. Infliximab seems to be a promising agent for treatment of active and refractory juvenile ankylosing spondylitis. Controlled studies and long-term observations are warranted.

Discovery: HLA and disease

This article is a personal account of the author's involvement in the discovery of HLA associations with ankylosing spondylitis; Reiter disease; acute anterior uveitis; and the arthropathies associated with psoriasis, chronic inflammatory bowel disease, and sarcoidosis.

Extraintestinal manifestations of inflammatory bowel disease

Numerous extraintestinal diseases have been associated with IBD. The role of the gastrointestinal tract in host response to the foreign antigens present in the gut makes the enteric immune system highly susceptible to any external perturbation to the system. Dysregulation of the enteric immune response results in pathology in various organs outside of the gut. The site-specific manifestations of this immune response are not understood fully. Better understanding of the pathogenesis of IBD and the complex interactions between the gut immune system and the extraintestinal systems would provide insights into the development of many of these extraintestinal manifestations. Much is unknown about the presence of cardiac, pulmonary, and hematologic diseases in patients with IBD. True association or coincidental presence of the diseases in these organ systems with IBD requires better delineation. An important consideration in all patients with IBD presenting with extraintestinal manifestations should be a careful search for medication-related complications.

Is disease severity in ankylosing spondylitis genetically determined?

OBJECTIVE

To assess the role of genes and the environment in determining the severity of ankylosing spondylitis.

METHODS

One hundred seventy-three families with >1 case of ankylosing spondylitis were recruited (120 affected sibling pairs, 26 affected parent-child pairs, 20 families with both first- and second-degree relatives affected, and 7 families with only second-degree relatives affected), comprising a total of 384 affected individuals. Disease severity was assessed by the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and functional impairment was determined using the Bath Ankylosing Spondylitis Functional Index (BASFI). Disease duration and age at onset were also studied. Variance-components modeling was used to determine the genetic and environmental components contributing to familiality of the traits examined, and complex segregation analysis was performed to assess different disease models.

RESULTS

Both the disease activity and functional capacity as assessed by the BASDAI and the BASFI, respectively, were found to be highly familial (BASDAI familiality 0.51 [P = 10(-4)], BASFI familiality 0.68 [P = 3 x 10(-7)]). No significant shared environmental component was demonstrated to be associated with either the BASDAI or the BASFI. Including age at disease onset and duration of disease as covariates made no difference in the heritability assessments. A strong correlation was noted between the BASDAI and the BASFI (genetic correlation 0.9), suggesting the presence of shared determinants of these 2 measures. However, there was significant residual heritability for each measure independent of the other (BASFI residual heritability 0.48, BASDAI 0.36), perhaps indicating that not all genes influencing disease activity influence chronicity. No significant heritability of age at disease onset was found (heritability 0.18; P = 0.2). Segregation studies suggested the presence of a single major gene influencing the BASDAI and the BASFI.

CONCLUSION

This study demonstrates a major genetic contribution to disease severity in ankylosing spondylitis. As with susceptibility to ankylosing spondylitis, shared environmental factors play little role in determining the disease severity.

Clinical and family studies in Hungarian patients with gout

In this study we examined 22 Hungarian male probands with gout and 105 of their first degree relatives. This was the first family study in Hungary in which the characteristics of distribution of gout and hyperuricaemia among patients with gout and their first degree relatives, as well as the possible correlation between the prevalence of the disease and MHC class I antigens was investigated. Our gout patients showed the following characteristics: (1) There was a typical onset after age 40, benign oligoarticular form of arthritis, underexcretion of uric acid, moderate hypertension without evidence of reduced renal function, and a relatively high frequency of hyperostosis. (2) The prevalence of hyperuricaemia and gout exceeded the general population level in the first degree relatives of our gout patients. (3) The distribution of MHC class I antigens among the first degree relatives of our patients with gout showed no characteristic patterns. (4) There was no correlation between HLA B27 antigens and prevalence of gout or hyperostosis in family sibling studies. (5) The high frequency of gout and hyperuricaemia, as well as the lack of characteristic HLA patterns among the first degree relatives of gout patients in our family studies, point to the possible cumulative effect of several genes and environmental factors in the etiopathogenesis of this disease.

Chlamydia trachomatis in reactive arthritis

Evidence of deposition of chlamydial antigen in the joint was sought in 10 patients (9 of them male) with classic sexually acquired reactive arthritis, 15 women with unclassified seronegative oligoarthritis involving the knee and 15 individuals with established rheumatic disorders not associated with genital-tract or other infections. Using a fluorosceinated monoclonal antibody to the major outer membrane protein of Chlamydia trachomatis (MicroTrak, Syva) in a direct immunofluorescence test, particulate antigen with physical characteristics of chlamydial elementary bodies was seen in synovial fluid cell smears or synovial biopsies, or both, from 6, 5, and 0 patients, respectively. No typical chlamydial intracellular inclusions were seen. Corroborative evidence of recent chlamydial infection was provided by the finding of high titres of serum chlamydial antibody in all antigen-positive patients with sexually acquired reactive arthritis, including 3 from whom a genital-tract isolate was obtained, and 3 of the 5 women with unclassified arthritis. It is postulated that Chlamydia trachomatis organisms reach the joint during acute genital-tract infection, and the processing and presentation by class I major histocompatibility determinants of chlamydial antigens is a critical step in the initiation of reactive arthritis in some patients.

Soft tissue mineralization: roentgen analysis

Numerous, incompletely understood, and undetermined physiologic factors may exert further but unappreciated influences on the development of ectopic calcification and ossification. In the former instance, in addition to serum calcium and phosphorous ion concentrations, tissue pH, blood supply, hormones, i.e., vitamin D, vitamin A, and various enzymes (e.g., alkaline phosphatase and pyrophosphatase) may all play significant, ancillary, time-dependent, but as yet undetermined roles. Ossification, like calcification, may occur in association with many types of disorders and under a variety of circumstances, some of which, such as trauma, have been reduplicated in the laboratory. However, experimental conditions that produce ectopic bone, as well as the species that are predilected do not always coincide with clinical observations in man. Not only are there differences between species in regard to susceptibility to ectopic bone production under particular circumstances, i.e., rabbits are the most susceptible and mice the least to mechanical injury, but there are differences between individuals. Individual variability in susceptibility to soft tissue ossification suggests either a personal or familial predilection. If such liability is inherited, this would be an example of an ecogenetic condition, in which someone is susceptible to an environmental agent by virtue of genetic constitution. Histocompatibility (HLS) antigens have provided substantiation of this concept. In the case of soft tissue ossification, causative environmental agents could include trauma, burns, hip replacement, and immobility secondary to neurological insults. In the case of soft tissue calcification, trauma, infections, or repeated injections could constitute the triggering environmental event. Not only do individuals at risk develop bone, but those that do tend to do so in characteristic places. Therefore, there is an additional differential susceptibility at various sites in the same individual. In cases with neurological conditions, thigh muscles are more susceptible than paraspinal muscles. The underlying condition is a further moderator, i.e., in paraplegics, thigh muscles are most apt to be involved. Elbows are most commonly affected after burns regardless of the site of the burn. Ectopic ossification also has a further predilection for distribution. Not only are muscle groups unequal in risk in terms of site, but the type of muscle affected is relevant, since skeletal muscles are involved in these same conditions to the exclusion of smooth muscles.(ABSTRACT TRUNCATED AT 400 WORDS)

Calcification of entheses associated with X-linked hypophosphatemic osteomalacia

We undertook a retrospective analysis of 26 patients with X-linked hypophosphatemic osteomalacia (or rickets), whose ages ranged from 1 to 62 years and who were from 11 different kindreds, to determine the prevalence and clinical characteristics of a unique disorder of the entheses (tendons, ligaments, and joint capsules). We found a generalized involvement of the entheses, with exuberant calcification of tendon and ligament insertions and of joint capsules, in 69 per cent of the subjects. The prevalence and extent of disease increased with age but were not correlated with sex. Commonly affected sites included the hand and sacroiliac joints. Histologic evaluation in a selected patient revealed intratendinous lamellar bone but no inflammatory cells. Our observations indicate that this disorder is an integral part of X-linked hypophosphatemic osteomalacia and exhibits clinical, radiographic, and histologic characteristics that differentiate it from degenerative disorders of these tissues and seronegative spondyloarthropathies.

Clinical study of Thai patients with ankylosing spondylitis

Sixty-one Thai patients with ankylosing spondylitis (AS), diagnosed in accordance with Rome and New York criteria for AS, were studied. The cases includes idiopathic AS (46 cases), Reiter's syndrome AS (8 cases) and psoriatic spondylitis (7 cases). The vast majority of patients were male (Male:Female = 11.2:1), and in over three-fourths the age of onset was between 10 and 39. Low back pain and peripheral arthritis as the initial manifestations were observed in 78.68 and 55.73% of patients respectively. Peripheral arthritis was evident during the course of illness in 72.13% of cases, oligoarticular arthritis being predominant (68.97%). Heel pain, tendonitis and plantar pain were noted in 19.67, 4.92 and 3.28% respectively. Most patients had lumbosacral and thoracic spine involvements, and only 49.18% showed involvement of the cervical spine. Bilateral sacroiliitis was noted in 98.36%. Uveitis was evident in 11.47% while evidence of aortic insufficiency was noted in 3.28%. An association with HLA-B27 was encountered in 91.07% of all cases. In general, the clinical features of AS in Thai patients are similar to those reported elsewhere, but an association with inflammatory bowel disease and Behcet's disease are notably absent.

HLA-B27 in possible ankylosing spondylitis with peripheral arthritis

Among 86 patients selected as possibly having ankylosing spondylitis because of clinical symptoms and radiologically normal sacroiliac joints. HLA-B27 was positive in 41%. Four years later a representative sample of 38 individuals were re-examined and radiographed. HLA-B27 positive patients developed sacroiliitis as defined by radiological criteria twice as often (P less than 0.05). They also showed increased uptake of technetium 99 m upon quantitative scintigraphy with a region of interest method and more often probable or definite ankylosing spondylitis as defined by the New York criteria. Further differences between the HLA-B27 positive and negative follow-up groups concerned the frequency of clinical symptoms and peripheral arthritis. It is suggested that HLA-B27 typing may be helpful both in diagnosis and in judging the prognosis of possible or abortive ankylosing spondylitis.

HLA antigens in acute anterior uveitis in South African blacks

Fifty-three black patients with acute nongranulomatous anterior uveitis (AAU) were tissue typed and the results compared to those from a panel of 200 healthy unrelated black volunteers. No statistically significant deviation from the norm with regard to the frequencies of 38 HLA antigens could be observed.

The role of HLA-B27 in the diagnosis of low back pain

The HLA-B27 antigen was determined in 652 patients with low back pain which had lasted for more than 3 months. A clinical and roentgenological examination of the sacroiliac joints and the thoraco-lumbar spine was performed in all the patients. The control group consisted of 302 unrelated persons who did not show signs of low back pain. Antigen HLA-B27 was found in 276 of these 652 patients attending the ward for rheumatic diseases (42.4 per cent) and in 37 of the 302 unrelated persons in the control group (12.2 per cent). The difference is statistically highly significant (P less than 0.001). Ankylosing spondylitis was found in 128 out of the 276 patients with low back pain and antigen HLA-B27. This demonstrates the importance of this antigen in the differential diagnosis of low back pain.

Ankylosing spondylitis and inflammatory bowel disease. III. Clinical characteristics and results of histocompatibility typing (HLA B27) in 50 patients with both ankylosing spondylitis and inflammatory bowel disease

A study was made, in co-operation with several gastroenterology and rheumatology centres, of the clinical and genetic characteristics (HLA B27) of 50 patients suffering from both inflammatory bowel disease (38 Crohn's disease (CD), 12 ulcerated colitis (UC)) and ankylosing spondylitis (AS), the latter diagnosis being established according to the New York criteria. 20 CD (52.6%) and 8 UC (66.7%) patients were HLA B27 positive. The presence of HLA B27 was studied in relation to clinical parameters, such as first occurrence of symptoms of AS or inflammatory bowel disease (IBD), a history of peripheral arthritis, iridocyclitis, and a positive history of AS or IBD. Our patients were found to have heterogeneous clinical features: on one side of the spectrum a group of cases was distingiushed with the typical characteristics of idiopathic AS, often being HLA B27 positive. On the other side a smaller group of HLA B27 negative patients was observed, with severe intestinal inflammatory pathology, lacking most of the typical clinical features of idiopathic AS ('secondary' form of AS). Finally, between these two extremes a group of patients was found with less pronounced clinical or genetic characteristics. These different clinical and histocompatibility patterns suggest a mixed aetiopathogenesis of AS in IBD patients. Such a 'syndrome' of AS might harbour both idiopathic AS and forms of AS 'secondary' to the intestinal inflammatory pathology.

Lymphocyte abnormalities in ankylosing spondylitis

Peripheral blood T (SRBC rosette) and B (AgG- and C-receptor) lymphocyte subpopulations and responsiveness to phytohaemagglutinin (PHA) were assayed in 40 patients with ankylosing spondylitis and in 55 normal subjects. There was no significant difference in the lymphocyte concentrations or responsiveness to PHA between the two groups. However, the percentages of T lymphocytes were significantly lower in the patients irrespective of their HLA typing. This was probably due to an increase in the 'null' population since the percentages of both the AgG- and C-receptor cells were normal.

HLA antigens and uveitis

We have studied the antigen frequencies in a group of adult patients with acute and chronic iridocyclitis and chronic, cyclitis. In patients with iridocyclitis a statistically significant increased incidence of HLA-B27 was noted, even in those patients without joint or systemic disease. Patients with chronic iridocyclitis also were noted to have an increased incidence of B27; however, those patients with chronic cyclitis did not. On the basis of HLA-B27 studies there appears to be a fundamental difference between adult and juvenile iridocyclitis.

HL-A antigens in clinical medicine

Many autoimmune diseases show a significant association with one or two second segregant series histocompatibility antigens. These associations are of great scientific interest, since they support the concept of HL-A-linked immune-response genes governing specific disease susceptibility. However, with one major exception, the association of HL-A antigens with diseases is not striking enough to provide a worthwhile diagnostic test. The exception is the extraordinarily high incidence of HLA B27 in patients with seronegative spondyloarthropathy best typified by ankylosing spondylitis (AS) and Reiter's disease (RD). In patients with these rheumatic syndromes, the antigen is present in more than 90% of cases compared to an incidence of approximately 6% in normal Caucasians and 4% in black Afro-Americans. The vast majority of rheumatic diseases are readily diagnosable on the basis of a history, physical examination and careful radiographic survey. This applies to most patients with a seronegative spondyloarthropathy, especially when the disease presents as a typical and fully formed clinical syndrome characterized as AS or RD. Sometimes the initial clinical nature may be atypical and only long-term follow-up of the patient will reveal an evolution toward the typical syndrome. In these situations, the correct diagnosis is reinforced by detecting the presence of HLA B27 on the patient's cells. Examination of the patient's family often reveals a high incidence of similar clinical syndromes, nearly always associated with the presence of the antigen. Since tissue typing at the moment is an expensive and relatively unavailable laboratory technic, its widespread and indiscriminatory use as a diagnostic test cannot be encouraged. However, in the clinical settings outlined above, tissue typing provides an invaluable diagnostic test. Presently, the combination of a negative test for rheumatoid factor and a positive test for HLA B27 is one of the strongest diagnostic laboratory profiles available to the physician when faced with a patient with early or atypical rheumatic disease. Aside from the purely clinical setting, the most exciting aspect of the association between these diseases and a specific cell surface antigen lies in the hope that we have a clue to the pathogenesis of a group of common rheumatic disorders. If the cause or causes of spondyloarthropathy can one day be found, the detection of HLA B27 may provide a useful public health measure facilitating preventive medicine. Even now, the detection of susceptible subjects within a family or a population will open the way for early diagnosis and treatment.

The histocompatibility system and human disease

The histocompatibility system and its associations with human diseases have been described. Although these associations remain unexplained, they represent an important step forward in the search for basic causes and mechanisms of diseases. Further studies may lead to better classifications of diseases and to an increased understanding of basic biologic processes, of etiologies of many important diseases, and of relationships between genetic and environmental susceptibility to disease. However, at the present time histocompatibility studied have little value as diagnostic or prognostic tests in clinical medicine, aside from their obvious usefulness in matching tissue donors to recipients.