Autoantibody profile in juvenile chronic arthritis

Combined occipitoatlantoaxial rotatory fixation

Occipitoatlantoaxial rotatory fixation (OAARF) is a rare condition involving fixed rotational subluxation of the atlas in relation to both the occiput and axis. Atlantoaxial rotatory fixation (AARF) appears to precede OAARF in most cases, as untreated AARF may cause compensatory counter-rotation and occipitoaxial fixation at an apparently neutral head position. We report a case of OAARF in an 8-year-old girl with juvenile idiopathic arthritis. Cervical imaging demonstrated slight rightward rotation of the occiput at 7.63° in relation to C-2 and significant rightward rotation of C-1 at 65.90° in relation to the occiput and at 73.53° in relation to C-2. An attempt at closed reduction with halo traction was unsuccessful. Definitive treatment included open reduction, C-1 laminectomy, and occipitocervical internal fixation and fusion.

Recent advances in uveitis of juvenile idiopathic arthritis

Chronic scarring-type uveitis is a frequent extra-articular manifestation of juvenile idiopathic arthritis. It occurs in about 20% of children with this disease, commencing typically within a few years from its onset. The risk of uveitis is greatest in antinuclear antibody-positive girls with early onset oligoarthritis. The classic clinical picture is chronic bilateral anterior uveitis, usually asymptomatic until substantial damage to intraocular structures occurs. In view of the asymptomatic nature of the condition, routine screening of juvenile idiopathic arthritis patients 2-4 times a year is crucial to prevent complications. The treatment consists of topical corticosteroids and mydriatics, in severe cases with immunosuppressive agents, and surgical management of complications. Although the prognosis of uveitis is improving, there are cases refractory to standard regimens. Patients in whom uveitis commences prior to the onset of arthritis present a special problem.

Juvenile chronic arthritis profile in Greek children

BACKGROUND

Juvenile chronic arthritis (JCA) is the commonest autoimmune rheumatic disease in childhood and presents different clinical subtypes. Juvenile chronic arthritis is considered to be of a polygenic nature and its genetic background is still under investigation. The clinical profile of JCA in the Greek population has not been studied completely. This study retrospectively analyzed the clinical and immunological features of JCA in Greek children presented between 1989 and 1994. Human leukocyte antigen (HLA)-positive or -negative associations in the different clinical subtypes were also detected. The findings of this study were correlated with those reported from other populations.

METHODS AND RESULTS

Antinuclear antibodies (ANA) anti-ds DNA and anti-extractable nuclear antigen antibodies were estimated by immunofluorescent and ELISA assays. Human leukocyte antigen typing was performed by microlymphocytotoxicity, using immunobeads. The peak ages of JCA onset were between 2 and 5 years and also between 9 and 12 years. There was a high female predominance in pauciarticular and polyarticular groups. The most common disease was pauciarticular (58.7%) followed by systemic (25%) arthritis. The incidence of eye involvement was 12.5% and presented only in the pauciarticular group. Overall, ANA positivity was 53.7%, increasing to 90% in pauciarticular cases associated with chronic uveitis. In the early onset (EOPA) pauciarticular subtype, positive-HLA associations with alleles DR11 and DR8 were shown. In the late onset pauciarticular (LOPA) group only B27 allele was increased.

CONCLUSIONS

The results of this retrospective study did not reveal major differences between JCA in Greek children compared with other Caucasian series.

Juvenile rheumatoid arthritis: The Saudi Experience

We retrospectively studied the charts of 115 Arab children with juvenile rheumatoid arthritis (JRA), all of whom satisfied the American College of Rheumatology (ACR) criteria for JRA. They were followed between 1978 and 1993 at King Faisal Specialist Hospital and Research Centre and King Khalid University Hospital in Riyadh, Saudi Arabia. All patients were followed up for at least 18 months. The female to male ratio was 1.2:1, and the mean age of onset of the disease was six years. Ninety of the patients were Saudis and the remainder were Middle Eastern Arabs. The mode of onset was systemic in 44%, polyarticular in 30%, and periarticular in 26%. Chronic uveitis was found in only two of the children (1.7%). Antinuclear antibody (ANA) was determined in 96 patients and was positive in 29 (30%). Amyloidosis was not detected in this study population. The clinical and laboratory manifestations of this disease are presented. This review shows that the spectrum of clinical presentation differs in Arab children from those in the West. Systemic and polyarticular onset subtypes were more common, and the incidence of uveitis and amyloidosis was lower. Whether this reflects a genuine difference in the pattern of the disease, or is due to bias in referral pattern, remains to be detected. The answer is currently being sought through an ongoing prospective study.

Expression of a human fetal anti-DNA antibody idiotype BEG-2 beta in the families of patients with rheumatoid arthritis

BEG-2 is a monoclonal antibody produced by the human-human hybridoma technique from a 12 weeks old human fetus. A polyclonal antiserum was raised in an (NZW x Half-lop hybrid) rabbit against BEG-2 and the anti-BEG-2 anti-idiotype was purified and characterised. Using this rabbit reagent the expression of the BEG-2 beta idiotype was analysed in 12 patients with active rheumatoid arthritis and their close family members (n = 54). Twenty five sera from healthy controls were analysed to establish a normal range. Ten of 12 patients (83%) with rheumatoid arthritis expressed the BEG-2 idiotype as well as 11 of 54 healthy unaffected relatives (20%).

Immunological aspects of juvenile rheumatoid arthritis

This article reviews the evidence from recent studies on immunological abnormalities associated with pathophysiologic mechanisms operating in three clinical subtypes of juvenile rheumatoid arthritis (JRA) (polyarticular, pauciarticular and systemic). The main discussion is focused on three hallmarks of immunopathological studies. First, abnormalities in phenotype and function of lymphocytes from peripheral blood and inflamed synovium are discussed. The aberrations of lymphocytes are elucidated by T and B cells expressing phenotypic cell-markers such as CD20, CD21, CD4, CD8 and DR in association with different subtypes and disease activity. The functional imbalance and impairment of T and B cells are mainly observed by abnormal proliferation and/or in vitro Ig production in response to mitogens and alloantigens. Second, because the appearance of rheumatoid factors (RF) in serum indicates that the pathogenesis of JRA may be based on the autoimmune mechanism, the prevalence of RF including IgM, IgA and IgG isotype, hidden IgM RF and cross-reactive idiotype RF, and their characteristic properties are discussed. Moreover, specific auto-antibodies (antinuclear antibodies and others) for JRA are illustrated in this paper. Third, the production of various pro-inflammatory cytokines resulting in the release of tissue-damaging chemical mediators is also discussed. This may play a central role in the generation of systemic inflammation and joint involvement in JRA.

Aetiological role of bacteria associated with reactive arthritis in pauciarticular juvenile chronic arthritis

BACKGROUND

The cause of juvenile chronic arthritis (JCA) is unknown. Pauciarticular JCA is the most common subtype and can be subdivided into early (type I) and late onset (type II) forms, the latter clinically resembling reactive arthritis.

METHODS

The cellular immune responses to bacteria associated with reactive arthritis in blood and synovial fluid from 39 children with pauciarticular JCA, three children with classical reactive arthritis, and two children with psoriatic arthritis were examined. Specific titres of antibodies to bacteria in serum samples were measured in all patients.

RESULTS

A bacteria specific synovial cellular immune response was found in two of three (67%) patients with reactive arthritis and 14 of 28 (50%) patients with pauciarticular JCA type II but only in one of 11 (9%) patients with pauciarticular JCA type I and none in patients with psoriatic arthritis. Six patients responded specifically to Chlamydia trachomatis and 11 to Yersinia enterocolitica. Antigen specific lymphocyte proliferation correlated poorly with the specific antibody response.

CONCLUSIONS

These findings suggest that bacteria with associated reactive arthritis may have a causative role in pauciarticular JCA type II but not in JCA type I.

Prevalence of anticardiolipin antibodies in juvenile chronic arthritis

The prevalence of anticardiolipin antibodies was evaluated in 70 children with juvenile chronic arthritis (JCA), in 25 adult patients with rheumatoid arthritis, in 42 healthy children and in 40 adult controls. Thirty seven (53%) patients with JCA were positive for IgG or IgM anticardiolipin antibodies, or both, and 30 (43%) for IgG anticardiolipin antibodies. In contrast, only seven (28%) adult patients with rheumatoid arthritis presented anticardiolipin antibodies, which were of IgG class in four (16%) cases. IgG anticardiolipin antibodies were negative in all control subjects while IgM anticardiolipin antibodies were detected in two (5%) children and in four (10%) adult controls. No correlations were found in patients with JCA between the presence or titres of anticardiolipin antibodies and various clinical or laboratory variables. No patient with anticardiolipin antibodies showed any feature of the anticardiolipin syndrome.

Autoantibodies in patients with juvenile chronic arthritis and their immediate family relatives

Antibodies to nuclear antigens were assessed in 23 children with juvenile chronic arthritis (JCA) and 66 of their first degree relatives. Serum samples from 16 patients with JCA (70%) and nine relatives (14%) had antinuclear antibodies by indirect immunofluorescence. Antibodies against nuclear antigens in rabbit thymus extract or an erythroblastoid cell line (K562) were detected by countercurrent immunoelectrophoresis and immunoblotting in 16 patients (70%) and 39 family relatives (59%). Immunoblotting did not show any banding patterns common to all patients with JCA, though bands in the 43-45 kD range were detected in 5/23 patients. Anticardiolipin antibodies were found in 7/23 patients. In total, 18/20 families (90%) had members other than the probands with detectable autoantibodies. In five families immunoblotting showed common banding patterns between the probands and other members. This suggests that there might be an inherited trend towards autoimmune responses in some families of patients with JCA.

Antibodies to histones H1 and H5 in sera of patients with juvenile rheumatoid arthritis

The specificity of juvenile rheumatoid arthritis (JRA) sera for histone subclasses was examined by immunoblotting. Antibodies to H1 alone were found in 4 of 21 pauciarticular-onset JRA sera, 4 of 19 polyarticular-onset JRA sera, and 2 of 11 systemic-onset JRA sera. Antibodies to H5 alone were found in 1 of 21 pauciarticular JRA sera, 1 of 19 polyarticular JRA sera, and 3 of 11 systemic JRA sera. Antibodies to both H1 and H5 were found in 4 of 21 pauciarticular JRA sera, 4 of 19 polyarticular JRA sera, and 1 of 11 systemic JRA sera. Antibodies to the core histones (H2A and H2B) were found in 1 of 21 pauciarticular JRA sera, 1 of 19 polyarticular JRA sera, and no systemic JRA sera. No reactivity to histones was observed in 30 sera from age-matched children with nonrheumatic diseases. The presence of H1 and H5 antibodies did not correlate with antinuclear antibody titers or with a homogeneous pattern of immunofluorescence. The predominance of H1 and H5 antibodies and relative absence of antibodies binding to core histones in JRA contrast with findings in adult systemic lupus erythematosus. Further, the presence of antibodies to H5 alone in some of the JRA patients indicates that the immune response in these patients is directed to determinants that are not shared by sequences of mammalian proteins.

Identification of antihistone antibodies in subsets of juvenile chronic arthritis

Antihistone antibodies (AHAs) as measured by an enzyme linked immunosorbent assay (ELISA) were detected in the sera of 58 (48%) of 121 unselected patients with juvenile chronic arthritis (JCA). AHAs were found in 28 (93%) of 30 patients with JCA with uveitis but in only 30 (33%) of 91 patients with JCA without uveitis. AHA positivity was unrelated to the type of joint involvement, disease activity, and drug regimen. When the AHA positive group was divided into 28 patients with JCA with uveitis and 30 patients with JCA without uveitis a distinct response pattern of AHA was detected in each group. Anti-H3 dominated in the JCA/uveitis group, whereas a more heterogeneous AHA pattern was shown in the group without uveitis. The results indicate that subtyping for AHA reactivity may define patients who are highly susceptible for the development of anterior uveitis.