Evaluation of a machine learning tool for the early identification of patients with undiagnosed psoriatic arthritis - A retrospective population-based study

Background

Psoriatic arthritis (PsA), an immune-mediated chronic inflammatory skin and joint disease, affects approximately 0.27% of the adult population, and 20% of patients with psoriasis. Up to 10% of psoriasis patients are estimated for having undiagnosed PsA. Early diagnosis and treatment can prevent irreversible joint damage, disability and deformity. Questionnaires for screening to identify undiagnosed PsA patients require patient and physician involvement.

Objective

To evaluate a proprietary machine learning tool (PredictAI™) developed for identification of undiagnosed PsA patients 1-4 years prior to the first time that they were suspected of having PsA (reference event).

Methods

This retrospective study analyzed data of the adult population from Maccabi Healthcare Service between 2008 and 2020. We created 2 cohorts: The general adult population ("GP Cohort") including patients with and without psoriasis and the Psoriasis cohort ("PsO Cohort") including psoriasis patients only. Each cohort was divided into two non-overlapping train and test sets. The PredictAI™ model was trained and evaluated with 3 years of data predating the reference event by at least one year. Receiver operating characteristic (ROC) analysis was used to investigate the performance of the model, built using gradient boosted trees, at different specificity levels.

Results

Overall, 2096 patients met the criteria for PsA. Undiagnosed PsA patients in the PsO cohort were identified with a specificity of 90% one and four years before the reference event, with a sensitivity of 51% and 38%, and a PPV of 36.1% and 29.6%, respectively. In the GP cohort and with a specificity of 99% and for the same time windows, the model achieved a sensitivity of 43% and 32% and a PPV of 10.6% and 8.1%, respectively.

Conclusions

The presented machine learning tool may aid in the early identification of undiagnosed PsA patients, and thereby promote earlier intervention and improve patient outcomes.

IVIG ameliorate inflammation in collagen-induced arthritis: projection for IVIG therapy in rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic inflammatory autoimmune disease that leads to joint destruction and disability. Despite a significant progress in administration of biological agents for RA patients, there is still a need for improved therapy. Intravenous immunoglobulins (IVIG), a pooled polyspecific immunoglobulin (Ig)G extracted from 5000 to 20 000 healthy subjects, showed beneficial therapeutic effect in patients with immune deficiency, sepsis and autoimmune diseases. The current study aimed to investigate the beneficial effect of treatment with IVIG in established collagen-induced arthritis in DBA/1j mice. Murine arthritis was induced in DBA/1j mice. Treatment with IVIG began when the disease was established. The clinical score was followed twice a week until day 48. The mice were bled for plasma and the paws were hematoxylin and eosin (H&E)-stained. Cytokine profile in the plasma was analyzed by Luminex technology and titers of circulating anti-collagen antibodies in the plasma was tested by enzyme-linked immunosorbent assay. Our results show that treatment with IVIG in murine significantly reduced the clinical arthritis score (P < 0·001). Moreover, mode of action showed that IVIG significantly reduced circulating levels of inflammatory cytokines [interferon (IFN)-γ, interleukin (IL)-1β, IL-17, IL-6, tumor necrosis factor (TNF)-α, P < 0·001], inhibiting anti-collagen antibodies (P < 0·001) in the plasma of collagen-induced arthritis mice. Importantly, histopathological examination revealed that IVIG treatment prevented the migration of inflammatory immune cells into the cartilage and synovium, reduced the extent of joint damage and preserved joint architecture. Our results proved for the first time the valuable anti-inflammatory treatment of IVIG in experimental RA. We propose IVIG therapy for a subgroup of patients with rheumatologically related diseases.

Tuftsin-phosphorylcholine (TPC) equally effective to methylprednisolone in ameliorating lupus nephritis in a mice model

The role of helminth treatment in autoimmune diseases is growing constantly. Systemic lupus erythematosus (SLE) is a multi-system autoimmune disease with challenging treatment options. Tuftsin-phosphorylcholine (TPC) is a novel helminth-based compound that modulates the host immune network. This study was conducted to evaluate the potential value of TPC in ameliorating lupus nephritis in a murine model and specifically to compare the efficacy of TPC to the existing first-line therapy for SLE: corticosteroids (methylprednisolone). Lupus-prone NZBxW/F₁ mice were treated with TPC (5 µg/mouse), methylprednisolone (MP; 5 mg/body weight) or phosphate-buffered saline (PBS) (control) three times per week once glomerulonephritis, defined as proteinuria of grade > 100 mg/dl, was established. Levels of anti-dsDNA autoantibodies were evaluated by enzyme-linked immunosorbent assay (ELISA), splenic cytokines were measured in vitro and the kidney microscopy was analysed following staining. TPC and MP treatments improved lupus nephritis significantly and prolonged survival in NZBxW/F₁ mice. TPC-treated mice showed a significantly decreased level of proteinuria (P < 0·001) and anti-dsDNA antibodies (P < 0·001) compared to PBS-treated mice. Moreover, TPC and MP inhibited the production of the proinflammatory cytokines interferon IFN-γ, interleukin IL-1β and IL-6 (P < 0·001) and enhanced expression of the anti-inflammatory cytokine IL-10 (P < 0·001). Finally, microscopy analysis of the kidneys demonstrated that TPC-treated mice maintained normal structure equally to MP-treated mice. These data indicate that the small molecule named TPC hinders lupus development in genetically lupus-prone mice equally to methylprednisolone in most of the cases. Hence, TCP may be employed as a therapeutic potential for lupus nephritis.

Improved accuracy in DFS pattern interpretation using a novel HEp-2 ELITE system

INTRODUCTION/OBJECTIVES

Accurate interpretation of DFS70 (dense fine speckled 70) and mixed antinuclear antibodies (ANAs) patterns can be challenging using conventional HEp-2 immunofluorescence (IIF) method. We evaluated a novel HEp-2 IIF substrate (HEp-2 ELITE/DFS70-KO) composed of a mixture of engineered HEp-2 devoid of the DFS70 autoantigen and conventional HEp-2 cells. The study assessed the utility of the new substrate in ANA screening and its advantages.

METHOD

One thousand and five consecutive routine samples sent for ANA screening were tested on both standard HEp-2 and the HEp-2 ELITE DFS70 KO substrates (ImmuGlo ANA HEp-2 and HEp-2 ELITE/DFS70-KO, Trinity Biotech, Buffalo, NY). Anti-DFS70 antibody specificity was additionally determined by immunoblot (IB). Clinical and serological data were included in the analysis of the overall impact of the novel HEp-2 substrate on DFS pattern interpretation.

RESULTS

Of the 22 cases suspected as positive for DFS pattern alone or in combination with homogeneous or speckled patterns on conventional HEp-2 cells, 17 were interpreted with a higher accuracy using the new HEp-2 ELITE method as positive for DFS70 (monospecific DFS70 (10), mixed DFS70 (7)), speckled (3), and DFS (2) patterns.

CONCLUSIONS

The new substrate was not only useful in deciphering unclear mixed ANA patterns but also highly sensitive in detecting DFS70 pattern in comparison to the DFS70 positivity obtained using IB.

Novel therapeutic compound tuftsin-phosphorylcholine attenuates collagen-induced arthritis

Treatment with helminthes and helminthes ova improved the clinical symptoms of several autoimmune diseases in patients and in animal models. Phosphorylcholine (PC) proved to be the immunomodulatory molecule. We aimed to decipher the tolerogenic potential of tuftsin-PC (TPC), a novel helminth-based compound in collagen-induced arthritis (CIA) a mouse model of rheumatoid arthritis (RA). CIA DBA/1 mice were treated with TPC subcutaneously (5 µg/0.1 ml) or orally (250 µg/0.1 ml), starting prior to disease induction. The control groups were treated with PBS. Collagen antibodies were tested by enzyme-linked immunosorbent assay (ELISA), cytokine protein levels by ELISA kits and regulatory T (Treg ) and regulatory B (Breg ) cell phenotypes by fluorescence-activated cell sorter (FACS). TPC-treated mice had a significantly lower arthritis score of 1.5 in comparison with control mice 11.8 (P < 0.0001) in both subcutaneous and orally treated groups at day 31. Moreover, histology analysis demonstrated highly inflamed joints in control mice, whereas TPC-treated mice maintained normal joint structure. Furthermore, TPC decreased the titres of circulating collagen II antibodies in mice sera (P < 0.0001), enhanced expression of IL-10 (P < 0.0001) and inhibited production of tumour necrosis factor (TNF)-α, interleukin (IL)-17 and IL-1β (P < 0.0001). TPC significantly expanded the CD4(+) CD25(+) forkhead box protein 3 (FoxP3(+) ) Treg cells and CD19(+) IL-10(+) CD5(high) CD1d(high) T cell immunoglobulin mucin-1 (TIM-1(+) ) Breg cell phenotypes (P < 0.0001) in treated mice. Our data indicate that treatment with TPC attenuates CIA in mice demonstrated by low arthritic score and normal joints histology. TPC treatment reduced proinflammatory cytokines and increased anti-inflammatory cytokine expression, as well as expansion of Treg and Breg cells. Our results may lead to a new approach for a natural therapy for early rheumatoid arthritis onset.

Aortic aneurysm association with SLE - a case-control study

OBJECTIVES

Aortic aneurysm is a life threatening cardiovascular complication in patients with systemic lupus erythematosus (SLE).The purpose of this study was to investigate the association between SLE and occurrence of aortic aneurysms.

METHODS

Patients with SLE were compared with age- and sex-matched controls regarding the proportion of aortic aneurysm in a case-control study. Chi-square and t-tests were used for univariate analysis and a logistic regression model was used for multivariate analysis. The study was performed utilizing the medical database of Clalit Health Services.

RESULTS

The study included 5018 patients with SLE and 25,090 age- and sex-matched controls. The proportion of aortic aneurysm in patients with SLE was increased compared with the proportion in controls (0.6% and 0.1%, respectively, p < 0.001). In a multivariate analysis SLE was associated with the coexistence of aortic aneurysms (odds ratio 2.06, 95% confidence interval 1.21-3.51).

CONCLUSIONS

Patients with SLE have a higher proportion of aortic aneurysms as compared with matched controls. Therefore, physicians treating patients with SLE should be aware of this life threatening association.

Tocilizumab-induced neutropenia in rheumatoid arthritis patients with previous history of neutropenia: case series and review of literature

One of the adverse events of tocilizumab (TCZ) is a transient, dose-dependent neutropenia. The recommendations of the Summary of Product Characteristics state that this neutropenia should be managed according to the absolute neutrophil count (ANC). However, the approach to a patient who had a history of neutropenia induced by previous DMARDs and developed TCZ-induced neutropenia remains unclear. We would like to report a series of four patients with rheumatoid arthritis who developed Grade 2 neutropenia (ANC 1-1.5 × 10(9)/L) following intravenous TCZ treatment at a dose of 8 mg/kg. All of them had a previous history of neutropenia (Grade 2 or Grade 3) due to Etanercept (three patients) and Sulfasalazine (one patient). Therefore, we decided to decrease the TCZ dosage by 10-20% approximately. Reducing of the dosage did not have any influence on the efficacy of TCZ, and all of our patients remained in clinical remission. The mechanisms underlying neutropenia induced by Tocilizumab, Etanercept and Sulfasalazine are also discussed in this article.

Anti-citrullinated-protein-antibody-specific intravenous immunoglobulin attenuates collagen-induced arthritis in mice

Administration of intravenous immunoglobulin (IVIg) is a recognized safe and efficient immunomodulation therapy for many autoimmune diseases. Anti-idiotypic antibody binding to pathogenic autoantibodies was proposed as one of the mechanisms attributed to the protective activity of IVIg in autoimmunity. The aim of this study was to fractionate the anti-anti-citrullinated protein anti-idiotypic-antibodies (anti-ACPA) from an IVIg preparation and to test it as a treatment for collagen-induced arthritis in mice. IVIg was loaded onto an ACPA column. The eluted fraction was defined as ACPA-specific-IVIg (ACPA-sIVIg). Collagen-induced-arthritis (CIA) was induced in mice. Mice were treated weekly with ACPA-sIVIg, low-dose-IVIg, high-dose-IVIg and phosphate-buffered saline (PBS). Sera-ACPA titres, anti-collagen anitbodies and cytokine levels were analysed by enzyme-linked immunosorbent assay (ELISA); antibody-forming-cell activity by enzyme-linked imunospot (ELISPOT) assay; and expansion of regulatory T cell (Treg ) population by fluorescence activated cell sorter (FACS). ACPA-sIVIg inhibited ACPA binding to citrullinated-peptides (CCP) in vitro 100 times more efficiently than the IVIg compound. ACPA-sIVIg was significantly more effective than the IVIg-preparation in attenuating the development of collagen-induced arthritis. Splenocytes from CIA mice treated with ACPA-sIVIg reduced the ACPA and anti-collagen-antibody titres, including the number of anti-collagen and ACPA antibody-forming cells. In parallel, splenocytes from ACPA-sIVIg treated mice secreted higher levels of anti-inflammatory cytokines and lower proinflammatory cytokines. The ACPA-sIVIg inhibitory potential was accompanied with expansion of the Treg population. Low-dose IVIg did not affect the humoral and cellular response in the CIA mice in comparison to the PBS-treated mice. Based on our results, IVIg may be considered as a safe compound for treating patients with rheumatoid arthritis by neutralizing pathogenic autoantibodies, reducing proinflammatory cytokines and expanding the Treg population.

Coincidence of granulomatosis and polyangiitis with atypical clinical manifestation and antiphospholipid syndrome

Granulomatosis and angiitis (GPA) is a multisystemic disease characterized by a granulomatous inflammation, tissue necrosis, and vasculitis of small and medium-sized blood vessels. Although the disease has a predilection for the upper respiratory tract, lungs, and kidneys, any organ system may be affected. Here, we present a case of generalized GPA manifested initially by necrotizing isolated parotitis and later by pulmonary-renal syndrome. Simultaneously with pulmonary hemorrhage, our patient developed an antiphospholipid syndrome (APS) presenting with deep vein thrombosis and strongly positive lupus anticoagulant. To the best of our knowledge the coincidence of parotitis and pulmonary-renal syndrome due to GPA and APS has never been reported previously. Concomitant venous thromboembolism may be life-threatening in a patient with GPA. Early diagnosis and institution of the proper therapy are critical in order to prevent organ damage.

QuantiFERON-TB Gold in the identification of latent tuberculosis infection in rheumatoid arthritis: a pilot study

OBJECTIVE

To compare the performance of QuantiFERON-TB Gold (QFT-G) with that of the tuberculin skin test (TST) in detecting latent tuberculosis (LTBI) among patients with rheumatoid arthritis (RA).

PATIENTS AND METHODS

A total of 35 RA patients and 15 healthy controls underwent TST, QFT-G assays and chest X-ray and filled out a questionnaire on predisposing conditions for TB disease. Serum interferon gamma (IFN-gamma) levels were tested by an enzyme-linked immunosorbent assay.

RESULTS

Forty-five per cent of RA patients had a TST > 5 mm vs. 26% in healthy controls. In the RA patients, QFT-G was positive in 11.4%, negative in 60% and indeterminate in 28.6%. The overall agreement between TST and QFT-G was significantly lower in the RA population than in controls (56% vs. 84%). No correlation was found between the use of prednisone, methotrexate and QFT-G results or agreement between TST and QFT-G. A low IFN-gamma level (<4 pg/ml) was found in 51.5% of the RA patients. No correlation was found between serum IFN-gamma levels and QFT-G results.

CONCLUSION

The clinical significance of negative QFT-G in TST-positive patients with low TB risk remains to be assessed. The high rate of indeterminate results questions the clinical utility of QFT-G in the diagnosis of LTBI in RA patients.

Increased prevalence of anti-third generation cyclic citrullinated peptide antibodies in patients with rheumatoid arthritis and CREST syndrome

To investigate the prevalence of anti-third generation cyclic citrullinated peptide antibodies (anti-CCP3) in patients with systemic connective tissue diseases, we assembled a training set consisting of 115 patients with rheumatoid arthritis (RA), 52 with Calcinosis, Raynaud's phenomenon, oesophageal dysmotility, sclerodactyly, telangiectasia (CREST) syndrome, 21 with scleroderma, 20 with ankylosing spondylitis, 18 with reactive arthritis, 25 with juvenile rheumatoid arthritis (RA), 51 with osteoarthritis, 26 with mixed connective tissue disease, 23 with primary Sjogren's syndrome, 74 with systemic lupus erythematosus, 49 with Polymyalgia rheumatica, and 39 with polymyositis/dermatomyositis. The commercial enzyme-linked immunosorbent assay (ELISA) was used to detect anti-CCP antibodies, including anti-CCP2 (regular, second generation of CCP antigen) and anti-CCP3 (third generation of CCP antigen) in disease-related specimens and normal controls. These serum samples were also evaluated for anti-centomere antibodies by anti-centromere ELISA kit. The higher frequencies of anti-CCP3 and anti-CCP2 were detected in 75.6 and 70.4% patients with RA, respectively. At the same time, anti-CCP3 (not anti-CCP2) was significantly increased in samples isolated from patients with CREST syndrome. The clinical sensitivity of IgG anti-CCP3 for the patients with CREST syndrome was 29% (15 of 52) and the specificity was 96% (384 of 397), with the exception of the RA group. The anti-centromere antibodies were significantly higher in patients with CREST only. The results of our study suggest that compared to anti-CCP2 assay, the new anti-CCP3 assay can enhance the clinical sensitivity for diagnosis of RA and, as an associate marker combined with anticentromere, can distinguish CREST syndrome from other systemic connective tissue diseases, especially RA. The clinical specificity of anti-CCP3 was lower than anti-CCP2 assay in diagnosis of RA because of the crossreaction to the patients with CREST syndrome.

Restricted specificity of anti-ribosomal P antibodies to SLE patients in Israel

OBJECTIVE

Anti-ribosomal P antibodies (aRib-P Ab) are highly specific for systemic lupus erythematosus (SLE), but their correlatation with disease activity and manifestations including renal, hepatic and central nervous system (CNS) involvement is still controversial. The aim of our study was to evaluate the prevalence of aRib-P Ab and their correlation with clinical manifestations and anti-dsDNA antibodies in SLE patients from Israel.

METHODS

Elevated titers of aRib-P Ab utilizing the ELISA method were analyzed in 141 sera samples from 44 SLE patients, 20 Familial Mediterranean Fever (FMF) patients, 22 primary antiphospholipid syndrome (PAPS) patients, 12 patients with infections, and 43 healthy individuals. The SLEDAI score was utilized for assessing SLE disease activity.

RESULTS

Elevated titers of aRib-P Ab were present in 11% of SLE patients (n = 6). The mean SLEDAI was 7 (range: 3-10). No statistically significant association was observed between the presence of aRib-P Ab and disease manifestations present in the SLEDAI. The 6 SLE patients had renal disease (n = 1), leucopenia (n = 1), rash (n = 3), and CNS involvement manifested as psychosis (n = 1) or depression (n = 1). Elevated titers of anti-dsDNA antibodies were found in 50% of patients with elevated titers of aRib- P Ab. Patients with PAPS, FMF, infections or healthy controls did not harbor elevated titers of aRib-P Ab.

CONCLUSION

Elevated titers of aRib-P Ab were restricted to SLE patients. We confirm previously reported associations of aRib-P Ab reactivity with disease activity and elevated anti-dsDNA Ab titers. No significant correlation with a specific manifestation described on the SLEDAI score was established in this small cohort of patients.

The diagnostic utility of anti-cyclic citrullinated peptide antibodies, matrix metalloproteinase-3, rheumatoid factor, erythrocyte sedimentation rate, and C-reactive protein in patients with erosive and non-erosive rheumatoid arthritis

Objective: To compare the diagnostic utility of laboratory variables, including matrix metalloproteinase-3 (MMP-3), anti-cyclic citrullinated peptide (CCP) antibodies, rheumatoid factor (RF), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) in patients with erosive and non-erosive rheumatoid arthritis (RA).

Methods: We assembled a training set, consisting of 60 patients with RA, all fulfilling the revised criteria of the American College of Rheumatology. A commercial enzyme linked immunosorbent assay (ELISA) was used both to test for anti-CCP antibodies (second generation ELISA kit) and MMP; RF were detected by latex-enhanced immunonephelometric assay. CRP was measured by latex turbidimetric immunoassay.

Results: The levels of anti-CCP antibody titers and ESR were significantly higher in patients with erosive disease than those in non-erosive RA patients (p < 0.001 and 0.0341) respectively. Moreover, a higher frequency of elevated titers of anti-CCP antibodies was found in RA patients with erosions compared to patients with non-erosive RA (78.3% vs. 43.2% respectively). The ROC curves of anti-CCP passed closer to the upper left corner than those other markers and area under the curve (AUC) of anti-CCP was significantly larger than AUC of other markers (0.755 for anti-CCP, 0.660 for ESR, 0.611 for CRP, 0.577 for RF, and 0.484 for MMP-3 female).

A positive predictive value was higher for anti-CCP antibodies in comparison to other markers. We did not find significant statistical correlation between anti-CCP antibody titers and inflammatory markers such as ESR or CRP. However, we confirmed the correlation of elevated titers of anti-CCP antibodies and RF in both groups of patients whereas the degree of correlation was more significant in non-erosive patients.

Conclusion: The results of our study suggest that the presence of elevated anti-CCP antibody titers have better diagnostic performance than MMP-3, RF, CRP and ESR in patients with erosive RA.

Evaluation of the BioPlex 2200 ANA screen: analysis of 510 healthy subjects: incidence of natural/predictive autoantibodies

The BioPlex 2200 ANA Screen is a fully automated system that determines levels for 13 different autoimmune antibodies of established clinical significance. The objective of this study was to determine the specificity of the BioPlex 2200 ANA Screen assay and to analyze the antibody profile samples collected from healthy subjects against comparative ELISA and IIF screening methods. A total of 510 specimens were randomly selected from a cohort of apparently healthy blood bank donors. Samples were distributed to five age brackets. All samples were tested using Bio-Rad's ANA Screen kit. Specificity was compared to IIF and ELISA results. Most of the samples were found negative in all ANA screening systems (84.5% by IIF, 92.5% by BioPlex 2200 ANA Screen kit, and 94.5% by ELISA). The frequency of positive results was highest (15.5%) using IIF, in comparison to almost similar results (5.5% vs. 7.5%) achieved by ANA ELISA and BioPlex 2200 ANA Screen kits. The positive rate of autoantibodies was significantly reduced when analyzed by different combinations of ANA screen assays (from 2.35% using IIF + BioPlex ANA Screen tests to 0.98% by using all three tests). Using the BioPlex 2200 ANA Screen system, we were able to identify samples with high levels of individual antibodies: anti-dsDNA at 20-63 IU/mL, antichromatin at 4-8 AI, anti-SmRNP at 2-6 AI, and anti-RNPA at 2-4.5 AI. Importantly, from 7 IIF and ELISA positive sera, 5 of these were also BioPlex 2200 positive, suggesting that the BioPlex is seeing the samples that are of the greatest interest, using the established techniques. The specificity of the BioPlex 2200 ANA Screen analysis of 13 different analytes (dsDNA, centromere B, chromatin, Jo1, ribosomal P, RNP 68, RNP A, Scl-70, Sm, SmPNP, SS-A52, SS-A60, SS-B) is comparable (P < 0.252) to the ELISA ANA screening test. Like the ELISA, the BioPlex 2200 has a lower (P < 0.001) positive rate than IIF for the autoantibody screening.

Anti-serum amyloid component P antibodies in patients with systemic lupus erythematosus correlate with disease activity

OBJECTIVE

To determine the presence of raised titres of anti-serum amyloid P component (SAP) antibodies in patients with systemic lupus erythematosus (SLE) and to evaluate their correlation with clinical disease by the SLEDAI and clinical manifestations.

METHODS

452 samples were screened for raised anti-SAP antibody titres by an ELISA. Clinical measures and SLEDAI scores were independently reviewed from medical records. 21 serial samples from 7 patients with SLE were assessed for a change in anti-SAP antibody titres after treatment.

RESULTS

Raised anti-SAP antibody titres were detected in 145/328 (44%) SLE samples. In 112 randomly selected samples, 69/112 (62%) patients had raised anti-SAP antibodies and anti-dsDNA antibody titres, whereas only 32/112 (28%) had raised anti-dsDNA antibody titres without raised anti-SAP antibody titres. The mean titre of anti-SAP antibodies in patients with active disease was higher than in patients with inactive disease and controls. SLEDAI scores, assessed in 54 patients, were raised in 26/31 (84%) patients with raised anti-SAP antibody titres. A SLEDAI score >or=8 was found in 16/31 (52%) patients with raised anti-SAP antibody titres but in only 5/23 (22%) patients without raised titres. No specific pattern of disease was detected in patients with or without raised titres of anti-SAP antibodies. Serial sampling from patients with active SLE and raised anti-SAP antibody titres showed that anti-SAP antibody titres decreased after treatment and correlated with clinical improvement.

CONCLUSION

Raised anti-SAP antibody titres detected in patients with SLE correlate with disease activity and decrease with improvement of clinical disease, and thus may serve as an additional prognostic marker.

Multiplexed AtheNA multi-lyte immunoassay for ANA screening in autoimmune diseases

BACKGROUND

Multiplexed assays using fluorescence microspheres is an exciting technology with multiple applications including the detection of antinuclear autoantibodies (ANA) and autoantibody profiles. It is a rapid, sensitive and automatic method for simultaneous quantitative detection of several autoantibodies. The aim of our study was to determinate ANA and other autoantibodies to the nine extractable nuclear antigens by the AtheNA Multi-Lyte ANA system and compare the results achieved by this method to the routinely used enzyme immunoassay.

METHODS

Four hundred eighteen serum samples were tested utililizing the multiplexed method: 96 healthy donors, 86 requested ANA specimens obtained from routine lab, and 236 samples from patients with known autoimmune diseases (43-scleroderma, 113-systemic lupus erythematosus, 38-Sjogren's syndrome, and 42 rheumatoid arthritis). The ANA and antibodies to nine different analytes (SS/A, SS/B, Sm, RNP, Jo-1, Scl-70, dsDNA, Centromere B and Histone) were tested.

RESULTS

ANA screening by AtheNA system revealed high concordance of 99 and 97.7% with the enzyme immunoassay test in samples obtained from healthy donors and ANA requested samples, respectively. Evaluation of autoimmune disease-related samples for ANA by AtheNA technology also confirmed a high rate of concordance of 92-97.7% and correlated with the enzyme immunoassay. Positive discrepant results were found for Scl-70 specificity in 12.7% of SLE specimens by AtheNA technology, while all tested sera were negative for this antibody by enzyme immunoassay. Negative discrepant results were observed by the AtheNA system for anti-dsDNA. The sera (15 randomly obtained samples from SLE patients) were positive for anti-dsDNA in 50% of samples in Farr assay and 55% in enzyme immunoassay, respectively.

CONCLUSION

We suggest that the AtheNA technology may be a useful diagnostic tool for ANA screening. Additional investigations are required to compare an analytic performance between AtheNA and routine methods in determination of the individual autoantibody profile.

Antineutrophil cytoplasmic autoantibodies penetrate into human polymorphonuclear leukocytes and modify their apoptosis

OBJECTIVE

The interaction of extracellular anti-neutrophil cytoplasmic autoantibodies (ANCA) with neutrophilic granules may play an important role in the pathogenesis of ANCA-related disorders. It has been confirmed that apoptosis is an essential trigger associated with translocation of the cytoplasmic granules to the cell surface, and with the expression of ANCA antigens. Since cell penetration by autoantibodies and apoptosis may be associated processes, we tested the hypothesis that penetration of ANCA-autoantibodies into polymorphonuclear leukocytes (PMNs) has an effect on apoptosis and thereby can influence surface antigen expression.

METHODS

PMNs were isolated from the blood of healthy volunteers and incubated in the presence of anti-proteinase3 (PR3) enriched IgG or normal human IgG. For each period of incubation (40 minutes or 12 hours) we evaluated: 1) PMN morphology by light microscopy (LM) and transmission electron microscopy (TEM) for general estimation of the apoptotic process, and 2) ANCA binding to the target antigen by immunogold electron microscopy (IgEM).

RESULTS

Both normal and anti-PR3 IgG penetrate PMNs. The labeled PR3-ANCA were localized on PR3 granules, regardless of the granules' location within the cell, and in the sites where the PMN destruction processes were most expressed. The destructive processes showed extensive apoptotic characteristics, in contrast to PMNs penetrated by normal IgG.

CONCLUSION

PR3 ANCA penetrate PMNs and, via the interaction between PR3-ANCA and PR3-containing granule components, initiate a modification of the apoptotic process.

Induction of anti-RA33 hnRNP autoantibodies and transient spread to U1-A snRNP complex of spliceosome by idiotypic manipulation with anti-RA33 antibody preparation in mice

OBJECTIVE

Anti-RA33 antibodies occur in patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and mixed connective tissue disease (MCTD) and target the A2/B1 protein of the heterogeneous nuclear ribonucleoprotein (hnRNP) complex 4 which forms part of the spliceosome. The aim of the present study was to evaluate the immune response and pathological features induced in mice immunized with anti-RA33 antibodies or patient-derived recombinant single-chain variable fragments (scFv) of anti-RA33 antibodies.

METHODS

In the first set of the experiment, two strains of mice (C57BL/6J and BALB/c) were immunized with IgG preparations obtained from two patients with RA and one normal donor. One of the patients had high titer anti-RA33 antibodies; the other one showed weak borderline reactivity. In the second set of the experiment three groups of C57BL/6J mice were immunized, respectively, with affinity-purified (AP) anti-RA33 antibodies, scFv of anti-RA33 antibodies and normal human IgG. The immunological response induced in immunized mice was studied by immunoblotting and line immunoassay (LIA). The presence of arthritis, serositis or myositis was assessed six-months following initial immunization.

RESULTS

While anti-RA33 antibodies developed in only two of the mice immunized with different human IgG fractions, anti-RA33 antibodies were clearly detected in 7 sera of 13 mice immunized with AP anti-RA33 antibodies three months after the boost immunization and, moreover, also in 2 sera of 13 mice immunized with scFv of anti-RA33 antibodies. In contrast, mice immunized with normal human IgG did not develop anti-RA33 antibodies. Interestingly, transient autoantibody production against another nuclear autoantigen, U1 snRNP, was observed in 3 C57BL/6J mice immunized with scFv and in 1 mouse immunized with AP autoantibodies. However, these immunological responses were not associated with pathological findings.

CONCLUSIONS

Active immunization of naive mice with AP anti-RA33 antibodies and scFv of anti-RA33 antibodies resulted on the one hand in the production of murine anti-RA33 antibodies and led, on the other hand, to transient "autoantibody spread" to snRNP component of the spliceosome and other nuclear autoantigens. This "autoantibody spread" probably reflected disregulation of the idiotypic anti-idiotypic cascade.

[Primary subclavian vein thrombosis after intensive physical exertion]

Subclavian vein thrombosis accounts for approximately 1-2% of recorded deep venous thromboses. It may be primary or secondary, and insertion of a central venous catheter is the most common cause of secondary subclavian vein thrombosis. Traumas, anatomic abnormalities and carcinoma are important additional risk factors for secondary thrombosis. Primary thrombosis of the subclavian veins is known as Paget-Schroetter syndrome. New criteria for its diagnosis include a history of increased upper extremity use prior to onset of symptoms, the presence of a venographically demonstrated thrombus and absence of any definable causes. We describe a 42-year-old woman with a history of intensive physical exertion admitted with swelling, pain and difficulty moving her arm. The diagnosis of primary subclavian vein thrombosis was established from the history of physical effort, results of Doppler ultrasound, and exclusion of other causes of subclavian vein thrombosis. This case suggests that primary subclavian vein thrombosis should be considered in young patients with subclavian vein thrombosis after exclusion of secondary disease.

[Q fever endocarditis and bicuspid aortic valve]

Q fever is caused by the rickettsia Coxiella burnetti, an obligate intracellular bacterium acquired by inhalation of infected dust from subclinically infected animals. Q fever may be acute or chronic; the chronic form mostly presents as endocarditis. Immunocompromised states and underlying heart disease are the most important risk factors. Usually the symptoms of Q fever endocarditis are nonspecific and diagnosis is often established very late. New criteria for diagnosis include a single blood culture positive for Coxiella burnetti, positive Q fever serology and characteristic echocardiographic studies. We describe a 49-year-old man with bicuspid aortic valve admitted with fever, weight loss and a new heart murmur. The diagnosis of Q fever endocarditis was established by positive Q fever serology, and an echocardiogram showing vegetations and valvular dysfunction. This case suggests that Q fever endocarditis should be considered in patients with "sterile" endocarditis.

[Ischemic hepatitis in congestive heart failure after an episode of hypotension]

Ischemic hepatitis can occur as an acute episode in advanced congestive heart failure (CHF). The mechanism is massive necrosis of the central lobules resulting from acute hypoxia when low cardiac output further reduces oxygen supply, aggravating underlying congestion due to poor venous outflow. We describe a 70-year-old woman with congestive heart failure for 7 years who was admitted with jaundice, vomiting, abdominal pain and oliguria after an episode of hypotension. The diagnosis of ischemic hepatitis was established by a documented episode of severe hypotension, followed by elevation of serum transaminases, a rise in serum bilirubin and LDH levels, prolonged prothrombin time and acute renal failure. Other causes of acute hepatitis, such as a virus or drugs were excluded, and improved liver and renal function followed hemodynamic stabilization. We conclude that ischemic hepatitis should be considered whenever acute hepatitis follows a recent episode of systemic hypotension, especially in the context of concomitant CHF.