Antinuclear Antibody (ANA) and ANA Profile Tests in Children with Autoimmune Disorders: A Retrospective Study

The study objective was to determine the clinical value of positive antinuclear antibody (ANA) and ANA profile tests in children with autoimmune disorders. A retrospective chart review was carried out of all patients under 18 years of age with a positive ANA test (HEp-2 cell substrate, titre ≥1:40) and ANA profile (ELISA) referred to the paediatric rheumatology service at the authors” institution between 1992 and 1996. Of 245 children with a positive ANA test, 134 (55%) had an autoimmune disease, including juvenile rheumatoid arthritis (n = 49), systemic lupus erythematosus (SLE) (n = 40) and others (n = 45). The remaining 111 patients did not have identifiable autoimmune diseases. Patients with autoimmune disorders had significantly higher ANA titres of ≥1:160 (χ²= 16, P<0.0001). In addition, of the 245 patients with a positive ANA test, 86 had an ANA profile performed; this was positive in 32 and negative in 54. All 32 patients with a positive ANA profile (100%) had an autoimmune disorder, compared to 22 ( 41%) of 54 with a negative ANA profile who had autoimmune disorders. Of 22 SLE patients with a positive ANA profile, 16 (73%) had positive anti-dsDNA and 15 (68%) had positive anti-Sm and positive anti-RNP. A positive ANA profile correlated strongly with an ANA titre ≥1:640 (χ²= 5.7 , P<0.02). The study demonstrated that only 55% of children with a positive ANA test had a definitive diagnosis of autoimmune disorder. These children tend to have higher ANA titres of ≥1:160. However, a positive ANA profile was strongly correlated with an ANA titre ≥1:640 and highly indicative of an autoimmune disorder (100%). We suggest that in order to reduce cost, an ANA profile should not be performed on all patients with positive ANA, but reserved for those with an ANA titre of ≥1:640 and/or those with a high clinical index of suspicion for autoimmune disorder, especially SLE. Received: 14 September 1999 / Accepted: 23 December 1999     

Use of ELISA to measure antinuclear antibodies in children with juvenile rheumatoid arthritis.

OBJECTIVE: To compare a series of commercial ELISA tests with an indirect immunofluorescent antibody (IFA) test for the detection of antinuclear antibodies (ANA) in children with juvenile rheumatoid arthritis (JRA). METHODS: Sera from 178 patients with JRA (88 pauciarticular, 68 polyarticular, 22 systemic) were compared with 26 healthy pediatric subjects. Twenty-one samples from patients with systemic lupus erythematosus (SLE) were also tested. All samples were analyzed by IFA and by 3 commercial ELISA methods. Concordance of ELISA results with IFA results (selected standard) were used as a measure of performance. Sensitivity and specificity were calculated for each test and likelihood ratios (LR) were established for IFA and ELISA in pauciarticular and polyarticular JRA sera. The increment in pretest probability was then obtained for each test as an additional measure of test performance. RESULTS: IFA rendered positive results on 18-77% of the JRA sera depending upon the subset, 100% of SLE sera, and 15% of normal patient sera. Using IFA as the standard, correspondence with positive results among patients with JRA ranged from 0 to 74% for the 3 ELISA tests, while it ranged from 5 to 73% in IFA negative sera. IFA tests showed intermediate range likelihood ratios (0.3, 0.5, 3.5, and 5) and increments in pretest probability ranging from 25 to 45%. While one of the ELISA tests attained 50% of increment in pretest probability for the positive test, it showed 0% increment as a negative test. The other 2 ELISA tests incremented the pretest probability from 0 to 25%. CONCLUSION: Our findings indicate that in JRA, the lack of correspondence with the historic standard IFA precludes the use of ELISA tests for detection of ANA. In addition, IFA out-performs ELISA by a substantial degree when "clinical utility" analysis of test performance is utilized. Detection of ANA in children with JRA should either continue to rely on IFA or be based on a different set of antigens if an ELISA format is chosen.     

Adenosine Deaminase Activity and its Isoenzyme Pattern in Patients with Juvenile Rheumatoid Arthritis and Systemic Lupus Erythematosus

Adenosine deaminase (ADA) is involved in purine metabolism and plays a significant role in the mechanisms of the immune system. The aim of this study was to investigate the activity of total ADA (tADA) and its isoenzymes ADA1 and ADA2 in serum and peripheral blood lymphocytes (PBLs) of children with juvenile rheumatoid arthritis (JRA) and systemic lupus erythematosus (SLE) in different phases of the diseases. The study comprised 34 patients with rheumatic disease, 24 with JRA and 10 with SLE, and 64 healthy controls. The tADA activity and its isoenzymes were measured in serum and PBLs of all patients by the method of Giusti and by the presence or absence of EHNA (erythro-9-(2-hydroxy-3-nonyl)adenine) during the active phase of the disease (before treatment), as well as during remission and relapse. Our data show that increased tADA activity in the serum and PBLs of patients with JRA and SLE is correlated mainly to increased levels of ADA2 activity in serum and ADA1 activity in PBLs. It also closely correlates with clinical disease activity and relapse. The cause of this increased tADA/ADA2 activity in serum and tADA/ADA1 activity in PBLs in JRA and SLE remains to be elucidated. Nevertheless, it may be noted that the measurement of tADA activity, together with ADA2 activity in serum and tADA with ADA1 activity in PBLs, could offer a biochemical approach to the assessment of the pathophysiology of JRA and SLE. Also, tADA and its isoenzymes could be used as alternative parameters representing disease activity. Received: 31 July 2000 / Accepted: 5 June 2001     

Renal Involvement in Juvenile Rheumatoid Arthritis: Report of Two Cases

Renal involvement is a rare occurrence in juvenile rheumatoid arthritis (JRA). We report on two JRA patients with kidney disease. The first was a 14-year-old African-American female with a 12-month history of polyarthritis. On presentation she was found to have an ESR of 127 mm/h and a positive ANA, rheumatoid factor (RF), perinuclear antineutrophil cytoplasmic antibodies (pANCA), haematuria, proteinuria with normal BUN and creatinine. Renal biopsy showed focal segmental glomerulosclerosis. Her renal function deteriorated to end-stage renal failure requiring dialysis within a few months, despite aggressive treatment with steorids and monthly i.v. pulses of cyclophosphamide. The second patient presented with a 6-week history of polyarthritis and intermittent fever, and had a salmon-coloured evanescent rash. On presentation his laboratory evaluation was significant for elevated ESR and negative ANA, RF and ANCA tests. Within 8 months the patient had developed a persistent microscopic haematuria. Renal biopsy showed mild mesangial glomerulonephritis. On low-dose methotrexate therapy his JRA went into remission and his renal function remained normal. The haematuria persisted for 1 year and then resolved spontaneously. This is the first time that focal segmental glomerulosclerosis and mesangial glomerulonephritis have been described in JRA. Although the association may be just coincidental, further studies are needed to define the role of JRA in these renal conditions. In patients with JRA, urinalysis and renal function should be routinely monitored. Received: 6 April 2000 / Accepted: 20 October 2000     

Anti-telomere antibodies in systemic lupus erythematosus (SLE): a comparison with five antinuclear antibody assays in 430 patients with SLE and other rheumatic diseases

Objective: To investigate the prevalence and diagnostic significance of antibodies against telomeric DNA in systemic lupus erythematosus (SLE) and other autoimmune rheumatic diseases, and to make comparisons with five conventional anti-DNA or anti-nuclear antibody (ANA) assays. Methods: Antibodies to telomeres, which are highly repetitive sequences of DNA (TTAGGG/CCCTAA) at the end of eukaryotic chromosomes, were measured by an enzyme linked immunosorbent assay (ELISA) in 305 patients with SLE and 125 patients with other autoimmune rheumatic diseases (78 rheumatoid arthritis, 32 primary Sjögren''s syndrome, eight mixed connective tissue disease, seven miscellaneous rheumatic diseases). Other assays used were two commercial ELISA assays for anti-dsDNA using calf thymus as antigen, Crithidialuciliae immunofluorescence, and radioimmunoassay (RIA) for anti-dsDNA and immunofluorescence using Hep-2 cells for ANA. Results: The prevalence of anti-telomere in SLE was 60%, v 5% in rheumatoid arthritis and 18% in other autoimmune rheumatic diseases. Specificity of anti-telomere for SLE was 91%; positive and negative predictive values were 95% and 46%, respectively. For anti-dsDNA by two ELISA assays using calf thymus as antigen, sensitivities were 69% and 29% and specificities 66% and 96%, respectively. Other anti-dsDNA assays had low sensitivities (RIA 43%, Crithidia immunofluorescence 13%). The association of anti-telomere with a history of nephritis in patients with SLE was stronger (p = 0.005) than by any other assay (p = 0.006–0.999). The correlations between the different assays were good (p<0.001 for all comparisons). Conclusions: The new ELISA for anti-telomere antibodies using standardised human dsDNA as antigen is a sensitive and highly specific test for SLE.     

Familial occurrence of autoimmune diseases and autoantibodies in a Caucasian population of patients with systemic lupus erythematosus

To determine the prevalence of autoimmune diseases and autoantibodies in relatives of Caucasian patients with systemic lupus erythematosus (SLE) we questioned 118 patients for the prevalence of autoimmune diseases in their relatives. Multicase SLE families were selected for further investigation: assessment of the presence of antinuclear antibodies (ANA), thyroid antibodies and IgM rheumatoid factor (IgM-RF). Thirty-three patients reported the presence of 50 autoimmune diseases in 43 relatives. Twenty-two diagnoses could be either confirmed (n=14) or refuted (n=8). SLE clustered significantly within families of SLE patients. Multiple sclerosis and rheumatoid arthritis also seemed to cluster within families of lupus patients. The prevalence of ANA (24%) and thyroid antibodies (44%) in 29 relatives of multicase SLE families was raised (P<0.05). In conclusion, the prevalence of autoimmune diseases is raised in relatives of Caucasian SLE patients. Also, the prevalence of autoantibodies is raised in relatives of multicase SLE families, both suggesting genetic influences in the pathogenesis of the disease. These findings support the genome-wide screening of SLE patients to unravel factors responsible for genetic susceptibility to SLE. Received: 1 March 2001 / Accepted: 20 September 2001     

Antinuclear antibody screening by ELISA and IF techniques: discrepant results in juvenile idiopathic arthritis but consistency in childhood systemic lupus erythematous

Lately, many hospital laboratories are using for antinuclear antibody (ANA) screening the solid-phase immunoassays (ELISA-ANA) instead of the traditional immunofluorescence ANA test (IF-ANA). Results of previous studies that compare the two technologies show poor correlation between them in both juvenile idiopathic arthritis (JIA) and childhood lupus erythematous (SLE) patients. In this study, we investigated whether ELISA-ANA and traditional IF-ANA results are comparable in pediatric patients with different rheumatic diseases. A total of 156 consecutive patients were included in the study—90 children with JIA, 33 with reactive arthritis, 19 with SLE, 4 with idiopathic chronic uveitis, and 10 with other systemic rheumatic diseases. ANA determination was performed using both assays. The higher rate of discrepancies between the two methods of ANA screening appeared in the JIA population (19/90, p?<?0.001). All JIA patients with false-negative results by ELISA had significant or high IF-ANA titres. The prevalence of JIA-associated uveitis was higher in the group of false-negative ELISA-ANA children than in the ELISA-positive patients but without statistical significance (p?=?0.62). On the contrary, in SLE group, the consistency rate of the two assays was 100 %, and the reactivity levels of ELISA-ANA were significantly higher than in ELISA-positive JIA patients (p?<?0.001). ELISA seems to be a reliable method for screening ANA in childhood SLE, but not in JIA. Limited by the few SLE patients, our findings need further consideration.     

Anti-nucleosome antibodies in the diagnosis of systemic lupus erythematosus

OBJECTIVE: To study the prevalence and diagnostic significance of antibodies against nucleosomes in patients with systemic lupus erythematosus (SLE) as compared to five anti-nuclear antibody (ANA) assays. METHODS: The study included 305 patients with SLE, 125 patients with other autoimmune rheumatic diseases, and 415 healthy controls. Anti-nucleosome antibodies were measured by an enzyme-linked immunosorbent assay (ELISA) and ANA by immunofluorescence (IF) using Hep-2 cells. Anti-double-stranded DNA (anti-dsDNA) antibodies were measured by three commercial ELISAs and by IF using Crithidia luciliae as antigen. RESULTS: Compared to three ELISAs for anti-dsDNA, the anti-nucleosome assay was less sensitive (30% vs. 29-69%) but equally specific (90% vs. 77-95%) for SLE. The most sensitive test was ANA (76%), and the least sensitive was Crithidia (13%). The correlations between the different assays were good (p < 0.001 for all comparisons). CONCLUSION: The anti-nucleosome antibody assay does not offer additional information compared to conventionally used anti-dsDNA tests in the differential diagnosis of SLE.     

Attained adult height in juvenile rheumatoid arthritis with or without corticosteroid treatment

Growth impairment has been described in patients with juvenile rheumatoid arthritis (JRA). Both the direct action of underlying disease and prolonged corticosteroid usage for disease management may contribute to growth impairment. The purpose of this retrospective study was to evaluate the effect of systemic corticosteroid treatment on attained adult height in patients with JRA. We reviewed patients who first visited our hospital from 1973 to 1995 with a diagnosis of JRA. Adult height (AH) and the reported parental heights of these patients were recorded. Target height (TH) is estimated according to midparental height. Patients who never had or had only transient (less than 1 week) systemic corticosteroid therapy were classified as group 1. Group 2 included patients who had corticosteroid therapy for more than 1 week but never continuously for more than 12 months, and group 3 included patients on long-term steroid treatment (continuously for more than 1 year). Height data were analysed using adult height and the difference between adult height and target height (AH minus TH). Thirty-three patients fulfilling the diagnostic criteria for JRA were reviewed. Fourteen belonged to group 1, 13 to group 2 and six to group 3. The difference between adult height and target height in group 1 was 2.96 ± 4.54 cm, in group 2 0.71 ± 6.08 cm (group 1 vs. group 2, P = 0.28), and in group 3 −11.65 ± 10.71 cm (group 1 vs. group 3, P<0.05). In 15 patients who never received corticosteroid therapy continuously for more than 1 year, AH–TH was statistically correlated neither with the cumulative corticosteroid exposure dose nor with cumulative corticosteroid exposure period by linear regression (P= 0.408, P= 0.278, respectively). We concluded that continuous systemic corticosteroid usage for less than 1 year does not affect attained adult height in JRA patients; however, prolonged corticosteroid treatment for more than 1 year can lead to irreversible growth impairment. Received: 23 May 2001 / Accepted: 11 February 2002     

Leukocyte count in the synovial fluid of children with culture-proven brucellar arthritis

Brucellosis is an important cause of paediatric septic arthritis in endemic areas. Because the Gram stain is frequently negative and culture results are unavailable at the time of the patient’s admission, the diagnosis of brucellar arthritis is usually entertained on the bases of epidemiological considerations and cytological examination of the synovial fluid aspirate. The aim of this study was to assess the sensitivity of a synovial fluid leukocyte count >50 000 WBC/mm³ for detecting culture-proven brucellar arthritis in children. The medical records of all children with brucellar arthritis diagnosed since 1994 in a hospital serving an endemic area for brucellosis in southern Israel were reviewed. Nine patients (six males and three females), aged 3–14 years, were identified. A single joint was affected in all patients. The median leukocyte count in the synovial fluid was 9500 WBC/mm³ (range 300–61 500 WBC/mm³), and in eight of the nine patients it was less than 50 000 WBC/mm³. Brucella melitensis was recovered from the synovial fluid culture in all patients. The diagnosis of brucellar septic arthritis cannot be excluded on the basis of a low leukocyte count in the joint aspirate. A high index of suspicion and use of modern culture techniques are recommended to improve the diagnosis of brucellar arthritis. Received: 24 March 2001 / Accepted: 29 October 2001     

Association between Serum Inflammatory Cytokines and Disease Activity in Juvenile Idiopathic Arthritis

Circulating interleukin-1β (IL-1β), IL-6, tumour necrosis factor-α (TNF-α), osteocalcin, and conventional parameters of inflammation were examined serially in 14 children with juvenile idiopathic arthritis (JIA) to determine any correlation with the disease activity. Serum IL-1β was undetectable in all JIA patients. Serum IL-6, white blood cell counts, platelet counts, erythrocyte sedimentation rate and C-reactive protein levels were significantly elevated in the active phase of JIA, whereas hemoglobin levels were significantly lower. Osteocalcin levels were decreased and TNF-α increased in active JIA status, but these differences showed no statistical significance. We concluded that inflammatory cytokines play an important role in JIA. Monitoring IL-6 in children with JIA is useful in determining disease activity and response to therapy. These findings confirm earlier reports. Received: 21 June 2000 / Accepted: 10 September 2001     

Autoantibodies to chromatin components in juvenile rheumatoid arthritis

Objective. To characterize autoantibodies to chromatin components in patients with juvenile rheumatoid arthritis (JRA). Methods. The sera of 50 children with JRA were analyzed for antinuclear antibodies (ANA) by immunofluorescence and enzyme-linked immunosorbent assay (ELISA) techniques. Results. By immunofluorescence, ANA and antibodies to high-mobility group proteins or to DNA-free histones were common in patients with pauciarticular JRA and rheumatoid factor–positive polyarticular JRA. However, reactivity with histone–DNA complexes was rare. Conclusion. Because antihistone antibodies detected by ELISA failed to bind chromatin or other histone–DNA complexes, they are not likely to represent the immunofluorescent ANA activity in serum.     

A Complex Case of Hepatitis in a Patient with Systemic Lupus Erythematosus

Liver involvement in patients with systemic lupus erythematosus (SLE) is considered rare. Previous treatment with potentially hepatotoxic drugs or viral hepatitis have usually been implicated as the main causes of liver disease in SLE patients. On the other hand, even after careful exclusion of these aetiologies, the problem remains whether to classify the patient as having a primary liver disease with associated autoimmune clinical and laboratory features resembling SLE, such as autoimmune hepatitis, or as having liver disease as a manifestation of SLE.  We report the case of an elderly woman who presented with acute hepatitis, who had been diagnosed with SLE 14 years ago and who also had Sjo¨gren’s syndrome and anti-phospholipid’s syndrome for several years. The histology depicted chronic active hepatitis and, after drug-induced hepatitis and viral hepatitis were excluded, the serological and clinical features were shown to be typical of liver damage caused by SLE. The patient was treated with azathioprine 100mg/d and prednisone 30 mg/d. The clinical symptoms resolved in 10 days and the laboratory values were normal at the end of the first month of therapy. Prednisone was progressively reduced, during a period of 4 months, to 10 mg/d but azathioprine was kept to the same dose. One year after the diagnoses the patient is still in remission.  Although uncommon, hepatic involvement is well recognised in SLE. The interest of this case lies in the differential diagnosis and recognition of this condition, which deserves an agressive treatment. Received: 8 March 1999 / Accepted: 8 March 1999     

Antibody to ribonucleoprotein in pauciarticular juvenile rheumatoid arthritis

Sera from 8 children with pauciarticular juvenile rheumatoid arthritis (JRA) were studied to determine the nuclear antigen to which antinuclear antibody (ANA) is directed. No patient had antibody to native DNA, nuclear histones, or saline soluble nuclear antigens. Trypsin treatment of the nuclear substrate abrogated ANA staining for all sera tested, while RNase treatment abrogated ANA activity for 6 of 8 sera. These results indicate that ANA in most patients with pauciarticular JRA is directed to a ribonucleoprotein that requires both RNA and protein moieties for antigenic integrity.     

Elevated plasma levels of beta-thromboglobulin and platelet factor 4 in patients with rheumatic disorders and cutaneous vasculitis

The efficacy of plasma levels of β-thromboglubulin (β-TG) and platelet factor 4 (PF4) as markers of the presence and activity of vasculiditic processes in rheumatic diseases were evaluated, first by serial measurement of their levels in a patient with rheumatoid arthritis and a chronic leg ulcer in the course of treatment, and second in 11 patients with rheumatoid arthritis without cutaneous vasculitis, and in nine patients with a variety of rheumatic diseases with cutaneous vasculitis. In the former, plasma levels of β-TG and PF4 were elevated and slowly reduced in parallel with healing, raised again after relapse, and normalized after disappearance of the leg ulcer. In the latter, both plasma levels were elevated in all of the nine patients with cutaneous vascular lesions and in one of the 11 patients rheumatoid arthritis without skin lesions. Levels of β-TG and PF4 may be useful to estimate the presence of vascular lesions in rheumatic disorders. Received: 5 November 2001 / Accepted: 18 June 2002 Correspondence and offprint requests to: Dr Toshihide Yamamoto, Kishiwada Tokushukai Hospital, 4-22-38 Isonokami-cho, Kishiwada, Osaka 596-0001, Japan. Tel: 81-724-38-8781; Fax: 81-724-37-7395; E-mail: ikyoku@kishiwada.tokushukai.or.jp     

Detection of anti-nuclear antibody by immunofluorescence assay and enzyme immunoassay in childhood systemic lupus erythematosus: experience from Bangladesh

Background: Systemic lupus erythematosus (SLE) is a multisystem, chronic but often episodic, autoimmune disease that is characterized by the presence of antinuclear antibodies (ANA). The criteria set by American College of Rheumatology are widely used for diagnosis of SLE. Elevation of ANA titer is the most sensitive of the ACR criteria. There are different methods for detection of ANA. Indirect immunofluorescence (ANA‐IFA) and enzyme immunoassay (ANA‐EIA) are commonly used methods. The sensitivity of ANA‐IFA using HEp‐2 cell substrate is 90–100% in systemic rheumatic diseases. In Bangladesh most of the laboratories use ANA‐EIA for detection of ANA. As the sensitivity of ANA‐EIA is lower than ANA‐IFA it might be that we are missing many cases of ANA positivity in childhood SLE cases. Objectives: To detect ANA by immunofluorescence assay using HEp‐2 cell substrate and enzyme immunoassay in childhood SLE and to compare the diagnostic performance of these methods. Material and methods: This is a cross‐sectional analytical study. A total of 40 patients were enrolled. Among them 20 were childhood SLE cases. Another 20 patients of childhood rheumatic diseases other than SLE were taken as the disease control group. Result: In childhood SLE cases, 100% were ANA‐positive by IFA and 55% were ANA positive by EIA. The sensitivity of ANA‐IFA was 100%. In contrast, sensitivity of ANA‐EIA was 55%. Conclusion: ANA‐IFA is superior to ANA‐EIA for detection of ANA in childhood SLE patients. ANA‐IFA should be the primary screening test for children with clinical features suggestive of SLE.     

Seronegative oligoarthritis: a 23-year follow-up study

The aim of the study was to investigate the long-term outcome of non-specific seronegative oligoarthritis in adults. The study included 64 adult patients with recent (<6 months) seronegative oligoarthritis (rheumatoid factor negative, number of swollen joints 1–4 during the first 6 months). Follow-up examinations were carried out at onset and at 1, 3 and 8 years from entry. A total of 47 patients attended the 23-year follow-up. The endpoint outcome was good. Seven had mild erosions in the hands or feet. Only one patient with HLA-B27 developed bilateral sacroiliitis. Three patients had retired from work because of joint disease. The functional outcome of the patients analysed by HAQ was very good after 23 years: 0 in 33 and 0.1–0.9 in 12 of the 47 patients. Reclassification revealed a certain heterogeneity: one case each of rheumatoid arthritis, SLE and ankylosing spondylitis, two cases of post-traumatic arthritis, four of osteoarthrosis, and six of possible reactive arthritis. Out of the remaining 49 patients 15 were HLA-B27 positive and 16 had at least one of the psoriasis-related HLA antigens (HLA-B13, 17, w16). In conclusion, our 23-year prospective follow-up study of patients with seronegative oligoarthritis confirms their favourable outcome. The reason is that the endpoint diagnoses seemed to be similar to those of mild spondylarthropathies. Received: 23 August 2001 / Accepted: 6 March 2002     

Evaluation of Cerebrospinal Fluid for the Presence of Anticardiolipin Antibodies (aCL) in NP-SLE Patients

Many neurological or psychiatric manifestations of SLE (NP-SLE) are related to the presence of anticardiolipin antibodies (aCL) in the patient’s sera. The aim of this study was to evaluate the presence of aCL in cerebrospinal fluid (CSF) in SLE patients with NP features. Fifteen SLE patients were studied, all with NP features. CSF was evaluated for intrathecal IgG synthesis, oligoclonal IgG, and blood–brain barrier impairment. Sera and CSF were tested by ELISA for the presence of aCL-IgG and aCL-IgM with and without β₂ glycoprotein (β₂ GPI) cofactor. CSF and sera of 50 low back pain patients served as controls. Six patients were aCL(+) and nine aCL(–). In all patients the general CSF examination was normal. In all patients the value of indices of intrathecal IgG synthesis were normal but oligoclonal protein was present in the CSF of three patients. In none of the patients was the blood–brain barrier impaired. Neither aCL-IgG nor aCL-IgM was detected in the CSF of any NP-SLE patient. Mean levels of aCL in patients without cofactor β₂ GPI and with cofactor were as follows: for IgG class 0.005 and 0.057 OD (negative); for IgM class 0.004 and 0.024 OD (negative). We could not detect aCL in the CSF of patients with NP-SLE, even if sera were positive for aCL. Received: 6 July 1999 / Accepted: 18 January 2000     

Antibodies against A peptide sequence located in the linker region of the HMG-1/2 box domains in sera from patients with juvenile rheumatoid arthritis

Objective. To extend our work on the mapping of B cell epitopes on nucleosomal high mobility group (HMG) proteins in the sera of patients with juvenile rheumatoid arthritis (JRA). Methods. Seventy-seven pauciarticular-onset JRA serum samples from antinuclear antibody (ANA)- positive patients and 42 polyarticular-onset JRA patient sera found to react with HMG-2 by immunoblotting were used in this study. To identify B cell epitopes on HMG-2, recombinant HMG-2 protein fragments were used in enzyme-linked immunosorbent assay (ELISA) and in competition ELISA experiments with a set of overlapping synthetic peptides. Fine epitope mapping was achieved by oligopeptide synthesis, followed by immunoblotting. Results. Pauciarticular, but not polyarticular, JRA patient sera were found to recognize a lysine-rich major epitope (KKGKKKDP), which is located in the linker region of the HMG box domains of the HMG-2 nonhistone chromosomal protein. No significant immunoreactions were observed in sera from ANA-negative JRA patients and in sera from children with nonrheumatic diseases, indicating that this epitope seems to be specific for pauciarticular-onset JRA. Conclusion. In addition to our previous finding that JRA sera will react with a defined epitope on HMG-17, pauciarticular JRA patient sera were also found to recognize a defined epitope on the HMG-2 protein, thus suggesting the importance of this epitope in the etiology of JRA.     

Autoantibodies to chromatin: prevalence and clinical significance in juvenile rheumatoid arthritis

OBJECTIVE: To determine the prevalence of anti-chromatin antibodies (Abs) in juvenile rheumatoid arthritis (JRA) and to assess any association between the presence of anti-chromatin Abs and clinical subsets of the disease. METHODS: IgG anti-chromatin Abs and anti-extractable nuclear antigens (ENA) Abs were detected by an enzyme-linked immunosorbent assay (ELISA), and antinuclear Abs (ANA) by indirect immunofluorescence in sera of 89 children with JRA. Ten children with systemic, 32 with polyarticular and 47 with pauciarticular disease onset (uveitis occurred in 17/47 children) were studied. As a control group, 12 sera of patients suffering from idiopathic uveitis and 31 age- and-sex-matched healthy children (HC) were examined. RESULTS: Abs to chromatin were detected in 14/47 (29.8%) of children suffering from pauciarticular onset JRA and in this group the higher prevalence of anti-chromatin Abs has been found in children with chronic uveitis (p = 0.002). Anti-chromatin positivity was observed in 2/10 (20%) of systemic and in 3/32 (9.3%) of polyarticular onset JRA. Furthermore, none of the patients with idiopathic uveitis and HC had Abs to chromatin. anti-chromatin Abs titers remained relatively stable over a 6-month control period. CONCLUSION: Our results confirm previous data about the presence of circulating anti-chromatin Abs in juvenile arthritis. Interestingly, anti-chromatin Abs were significantly higher in the group of patients with pauciarticular onset with past or present history of uveitis, than in patients without ocular involvement. A long-term follow-up study could be useful to demonstrate the potential utility of these autoantibodies in diagnosing, classifying and treating children affected.