SummaryThe aim of this study is to evaluate the humoral autoimmune response in the experimental model of systemic sclerosis (SSc) induced by human type V collagen (huCol V). New Zealand rabbits were immunized with huCol V in Freund's complete adjuvant (FCA) and boosted twice with 15 days intervals with huCol V in Freund's incomplete adjuvant. Control groups included animals injected only with FCA or bovine serum albumin. Bleeding was done at days 0, 30, 75 and 120. Tissue specimens were obtained for histopathological investigation. Serological analysis included detection of antibodies against huCol V and anti-topoisomerase I (AntiScl70) by enzyme-linked immunosorbent assay, antinuclear antibodies (ANA) by indirect immunofluorescence, and rheumatoid factor (RF) by a latex agglutination test. Target antigens were characterized by immunoblot. Histological analysis revealed extracellular matrix remodeling with fibrosis and vasculitis. Anti-Scl70 and ANA were detected as early as 30 days in all huCol V animals. The universal ANA staining pattern was Golgi-like. This serum reactivity was not abolished by previous absorption with huCol V. Characterization of the target antigen by immunoblot revealed two major protein fractions of 175 000 and 220 000 MW. Similarly to ANA, there was a gradual increase of reactivity throughout the immunization and also it was not abolished by preincubation of serum samples with huCol V. RF testing was negative in hyperimmune sera. Conclusion: The production of autoantibodies, including anti-Scl70, a serological marker for SSc associated with histopathological alterations, validates huCol V induced-experimental model and brings out its potential for understanding the pathophysiology of SSc.

Definições para a padronização da pesquisa de auto-anticorpos contra constituintes do núcleo (FAN HEp-2), nucléolo, citoplasma e aparelho mitótico e suas associações clínicas II Brazilian Consensus on Antinuclear Antibodies in HEp-2 Cells Definitions for standardization of autoantibody testing against the nucleus (ANA HEp-2), nucleolus, cytoplasm and mitotic apparatus, as wel as its clinical associations

Introduction:The diagnosis of dengue and the differentiation between primary and secondary infections are important for monitoring the spread of the epidemic and identifying the risk of severe forms of the disease. The detection of immunoglobulin (Ig)M and IgG antibodies is the main technique for the laboratory diagnosis of dengue. The present study assessed the application of a rapid test for dengue concerning detection of new cases, reinfection recognition, and estimation of the epidemic attack rate. Methods: This was a retrospective, cross-sectional, descriptive study on dengue using the Fortaleza Health Municipal Department database. The results from 1,530 tested samples, from [2005][2006], were compared with data from epidemiological studies of dengue outbreaks in 1996, 2003, and 2010. Results: The rapid test confirmed 52% recent infections in the tested patients with clinical suspicion of dengue: 40% detected using IgM and 12% of new cases using IgG in the non-reactive IgM results. The positive IgM plus negative IgG (IgM+ plus IgG-) results showed that 38% of those patients had a recent primary dengue infection, while the positive IgG plus either positive or negative IgM (IgG+ plus IgM+/-) results indicated that 62% had dengue for at least a second time (recent secondary infections). This proportion of reinfections permitted us to estimate the attack rate as ≥62% of the population sample. Conclusions: The rapid test for dengue has enhanced our ability to detect new infections and to characterize them into primary and secondary infections, permitting the estimation of the minimal attack rate for a population during an outbreak.

It is recommended to evaluate the presence of latent tuberculosis infection (LTBI) prior to the use of antitumor necrosis factor α. The aim of this study is to assess the presence of LTBI in patients with rheumatic diseases undergoing treatment with infliximab in an endemic area for tuberculosis (TB). LTBI was searched through the contact history, chest X-ray and tuberculin skin test with purified protein derivative (PPD) ≥5 mm. We studied 157 patients in the period from May 2005 to October 2008, 99 (63.1%) were women with average age of 49 years and 58 (36.9%) were men with average age of 41 years. The group comprising 90 patients (57.3%) with rheumatoid arthritis (RA), 54 (34.4%) with ankylosing spondylitis (AS) and 13 (8.3%) with psoriatic arthritis (PsA) had PPD reactor 13.4% (21/157), being prevented by isoniazid (INH) in these patients. There are dissimilar responsiveness to the PPD between the three pathologies, and the reactivity was lower in RA (RA × AS: χ(2) = 12; P = 0.0004; and RA × PsA: χ(2) with Yates' correction = 3.6; P = 0.05). No significant difference between the reactivity of the PPD and the use of immunosuppressive drugs (P = 0.81) is observed. The immunoprophylaxis with INH showed an efficacy of 95% (20/21); three (1.9%) patients developed active TB (spondylodiscitis, meningitis and lymphadenopathy) after the use of infliximab, reaffirming extrapulmonary involvement. These results suggest that PPD has a low sensitivity for detection of LTBI in RA and that the previous use of immunosuppressive drugs does not affect the response to PPD.

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