Achilles tendon elastic properties remain decreased in long term after rupture.

PURPOSE: Rupture of the Achilles tendon results in inferior scar tissue formation. Elastography allows a feasible in vivo investigation of biomechanical properties of the Achilles tendon. The purpose of this study is to investigate the biomechanical properties of healed Achilles tendons in the long term. MATERIALS AND METHODS: Patients who suffered from Achilles tendon rupture were recruited for an elastographic evaluation. Unilateral Achilles tendon ruptures were included and scanned in the mid-substance and calcaneal insertion at least 2 years after rupture using shear wave elastography. Results were compared to patients' contralateral non-injured Achilles tendons and additionally to a healthy population. Descriptive statistics, reliability analysis, and correlation analysis with clinical scores were performed. RESULTS: Forty-one patients were included in the study with a mean follow-up-time of 74 ± 30; [26-138] months after rupture. Significant differences were identified in shear wave elastography in the mid-substance of healed tendons (shear wave velocity 1.2 ±1.5 m/s) compared to both control groups [2.5 ±1.5 m/s (p < 0.01) and 2.8 ±1.6 m/s (p < 0.0001) contralateral and healthy population, respectively]. There was no correlation between the measurements and the clinical outcome. CONCLUSIONS: This study shows that the healed Achilles tendon after rupture has inferior elastic properties even after a long-term healing phase. Differences in elastic properties after rupture mainly originate from the mid-substance of the Achilles tendon, in which most of the ruptures occur. Elastographic results do not correspond with subjective perception. Clinically, sonoelastographical measurements of biomechanical properties can be useful to provide objective insights in tendon recovery.

Fc gamma receptor IIIb polymorphism and systemic lupus erythematosus: association with disease susceptibility and identification of a novel FCGR3B*01 variant.

OBJECTIVE: The objective of this study was to evaluate the association between Fc gamma receptor IIIb polymorphism and susceptibility to systemic lupus erythematosus and clinical traits of the disease. METHODS: Genomic DNA was obtained from 303 consecutive systemic lupus erythematosus patients and 300 healthy blood donors from the southeastern region of Brazil. The polymorphic region of the FCGR3B gene was sequenced and the alleles FCGR3B*01, FCGR3B*02 and FCGR3B*03 were analyzed. RESULTS: The FCGR3B*01 allele was more frequent in systemic lupus erythematosus patients (43.1%) while the FCGR3B*02 allele prevailed among controls (63.7%) (P = 0.001). The FCGR3B*03 allele was found equally in both groups. The FCGR3B*01/*01 (20.7%) and FCGR3B*01/*02 (41.1%) genotypes were more frequent among systemic lupus erythematosus patients (P = 0.028 and P = 0.012, respectively) while the FCGR3B*02/*02 genotype was more frequent in controls (45.5%) (P < 0.001). One variant of the FCGR3B*01 allele previously described in Germany was found in only one control. A new variant of the FCGR3B*01 allele with two substitutions (A227G/G277A) was found in one control. Three variants of the FCGR3B*02 allele previously described in African-Americans, Brazilians, Chinese and Japanese were found in ten 10 patients and two controls. In addition, several single nucleotide polymorphisms at non-polymorphic positions were identified in both patients and controls. CONCLUSION: Susceptibility to systemic lupus erythematosus was associated with the FCGR3B*01 allele, as well as with the FCGR3B*01/*01 and FCGR3B*01/*02 genotypes. No association was found between FCGR3B genotypes and clinical manifestations, disease severity or the presence of autoantibodies.

Long-term persistence of anti-ß2 glycoprotein I in treated leprosy patients.

ß2 glycoprotein I (ß2GPI) is a phospholipid binding protein that plays an important role in endothelial stability, blood coagulation, clearance of apoptotic debris and other physiologic processes. Anti-ß2GPI antibodies occur in normal individuals and transiently during the course of infections, but are also associated with thrombotic events in autoimmune disease: the antiphospholipid syndrome (APS). A total of 31 out of 37 treated leprosy patients previously found to present high titers of IgM anti-ß2GPI and/or anticardiolipin antibodies (aCL) remained positive for IgM antiphospholipid antibodies (aPL), and exhibited high titers of anti-ß2GPI. The 37 patients were part of the 77 aPL-positive patients from a previous study that evaluated 158 leprosy patients. The median time elapsed between the first and second sample was 66 months. None of the 37 patients had any thrombotic event and 24 had a reactional state and were still requiring the use of prednisone, thalidomide or both. None of them fulfilled World Health Organization criteria for leprosy recurrence.

The effect of acute physical exercise on cytokine levels in patients with systemic lupus erythematosus.

BACKGROUND: Acute exercise increases IL-6, IL-10 and TNF-α levels in healthy subjects. There is no study evaluating the effect of exercise on cytokines level in systemic lupus erythematosus (SLE) patients. OBJECTIVE: Our aim was to assess IL-10, IL-6 and TNF-α levels at baseline and after acute physical exercise in patients with SLE. METHODS: In total, 27 female SLE patients and 30 healthy controls were evaluated. Serum levels of IL-10, IL-6 and TNF-α at baseline and soon after the ergospirometric test were measured by ELISA test. Student's t-tests and Mann-Whitney test were used for intra- and inter-group comparisons; p values <0.05 were considered significant. RESULTS: Patients with SLE presented worse ergospirometric parameters compared with controls: VO2max (25.78 ± 5.51 vs. 32.74 ± 5.85 ml/kg/min, p < 0.001); maximum heart rate (174.18 ± 12.36 vs. 185.15 ± 2.07 bpm, p = 0.001); maximum ventilation (65.51 ± 15.68 vs. 80.48 ± 18.98 l/min, p = 0.001) and maximum speed (7.70 ± 1.24 vs. 9.40 ± 1.22 km/h, p < 0.001). At baseline, SLE patients presented higher levels of IL-6 (2.38 ± 1.70 vs. 1.71 ± 0.29 pg/ml, p = 0.035) and IL-10 (1.09 ± 1.55 vs. 0.30 ± 0.11 pg/ml, p = 0.037) than controls. Acute exercise in controls increased IL-6 level (1.71 ± 0.29 vs. 2.01 ± 0.27 pg/ml, p = 0.003) without change in IL-10 and TNF-α levels. However, no significant change in cytokine levels was observed in SLE patients after acute exercise. CONCLUSION: This is the first study evaluating the effect of acute exercise on cytokine levels in patients with SLE. In contrast to healthy controls, acute physical exercise did not increase the levels of IL-6 in patients with SLE, and seems to be safe in those patients with inactive or mild active disease.

Increased neutrophil oxidative burst metabolism in systemic lupus erythematosus.

INTRODUCTION: There is increased frequency of discoid lesions (2.7%) and SLE (0.5%) in patients with chronic granulomatosus disease, but the literature is still controversial about phagocyte oxidative burst in SLE patients. MATERIALS AND METHODS: 300 SLE patients and 301 blood donors were evaluated for quantitation of the oxidative burst in phagocytes by flow cytometry based on the oxidation of 2,7-dichlorofluorescein-diacetate after stimuli with Staphylococcus aureus and Pseudomonas aeruginosa. RESULTS: Neutrophils from SLE patients displayed higher basal reactive oxygen species (ROS) production than healthy controls [Mean of fluorescence intensity (MFI) = 53.77 ± 11.38 vs 15.08 ± 2.63, p < 0.001] and after stimulation with S. aureus (MFI = 355.46 ± 58.55 vs 151.92 ± 28.25, p < 0.001) or P. aeruginosa (MFI = 82.53 ± 10.1 vs 48.99 ± 6.74, p < 0.001). There was stronger neutrophil response after bacterial stimuli (ΔMFI) in SLE patients than in healthy controls (S. aureus = 301.69 ± 54.42 vs 118.38 ± 26.03, p < 0.001; P. aeruginosa = 28.76 ± 12.3 vs 15.45 ± 5.15, p < 0.001), but no difference with respect to the oxidative burst profile according to disease activity (SLEDAI ≥ 6) or severity (SLICC-DI ≥2). Patients with kidney involvement presented higher basal and stimulated ROS production in neutrophils. DISCUSSION: The present findings corroborate the important role of innate immunity in SLE and implicate neutrophils in the pathophysiology of the disease.

Follicular helper T cell in immunity and autoimmunity.

The traditional concept that effector T helper (Th) responses are mediated by Th1/Th2 cell subtypes has been broadened by the recent demonstration of two new effector T helper cells, the IL-17 producing cells (Th17) and the follicular helper T cells (Tfh). These new subsets have many features in common, such as the ability to produce IL-21 and to express the IL-23 receptor (IL23R), the inducible co-stimulatory molecule ICOS, and the transcription factor c-Maf, all of them essential for expansion and establishment of the final pool of both subsets. Tfh cells differ from Th17 by their ability to home to B cell areas in secondary lymphoid tissue through interactions mediated by the chemokine receptor CXCR5 and its ligand CXCL13. These CXCR5+ CD4+ T cells are considered an effector T cell type specialized in B cell help, with a transcriptional profile distinct from Th1 and Th2 cells. The role of Tfh cells and its primary product, IL-21, on B-cell activation and differentiation is essential for humoral immunity against infectious agents. However, when deregulated, Tfh cells could represent an important mechanism contributing to exacerbated humoral response and autoantibody production in autoimmune diseases. This review highlights the importance of Tfh cells by focusing on their biology and differentiation processes in the context of normal immune response to infectious microorganisms and their role in the pathogenesis of autoimmune diseases.

Clinical implications of autoantibodies in HIV infection.

OBJECTIVE: To study the frequency and specificity of autoantibodies in HIV-infected subjects and their association with rheumatic manifestations, immunodeficiency, and prognosis. DESIGN: Prospective study of sequentially selected HIV-infected patients. Indirect immunofluorescence reading was performed by two independent observers blinded for the patient diagnosis. Enzyme-linked immunosorbent assay (ELISA) was performed using coded serum samples. SETTING: The study was performed at the Infectious Disease and Rheumatology Divisions of a tertiary care university hospital. PATIENTS: One hundred sequentially selected HIV-infected patients formed group A. Controls included 80 non-HIV-infected high-risk individuals (group B), 20 herpesvirus-infected patients (group C), and 30 healthy blood donors (group D). MAIN OUTCOME MEASURES: Patients were followed for 2 years and evaluated for the presence of immunodeficiency, rheumatic manifestations, circulating autoantibodies and total CD4+ cell count. Indirect immunofluorescence was used to investigate antinuclear antibodies, antibodies to native DNA, smooth muscle, parietal cell, glomeruli, thyroid, and neutrophil cytoplasm. Agglutination was used to detect antibodies to erythrocytes and rheumatoid factor. ELISA was used to determine antibodies to cardiolipin and denatured DNA. CD4+ lymphocytes were counted by flow cytometry. Immunoglobulin (Ig) G, IgM and IgA serum levels were determined by radial immunodiffusion. RESULTS: HIV-infected patients presented higher overall frequency of autoantibodies than the other groups. No difference was observed between immunodeficient and asymptomatic HIV-infected patients. The most frequent specificities were antibodies to cardiolipin and to denatured DNA. Ig serum levels did not correlate with the occurrence of autoantibodies. The presence of autoantibodies was associated with lower CD4+ cell counts and with higher mortality within 2 years. Rheumatic manifestations were observed in 35 HIV-infected patients and were not associated with the occurrence of autoantibodies or the presence of immunodeficiency. CONCLUSIONS: HIV infection is associated with an increased incidence of autoantibodies. Although not related to the occurrence of rheumatic manifestations, the presence of autoantibodies was significantly associated with lower CD4+ lymphocyte counts and increased mortality, which implies prognostic significance to this phenomenon in the context of HIV infection.

PIP: A study was conducted at the Infectious Disease and Rheumatology Divisions of a tertiary care university hospital in Sao Paulo to assess the frequency and specificity of autoantibodies in HIV-infected subjects and their association with rheumatic manifestations, immunodeficiency, and prognosis. 100 sequentially selected HIV-infected patients formed group A, 80 non-HIV-infected high-risk subjects served as controls in group B, 20 herpesvirus-infected patients formed group C, and 30 healthy blood donors formed group D. The patients were followed for 2 years and evaluated for the presence of immunodeficiency, rheumatic manifestations, circulating autoantibodies, and total CD4+ cell counts. HIV-infected patients presented with a higher overall frequency of autoantibodies than did the other groups. No difference was observed between immunodeficient and asymptomatic HIV-infected patients. The most frequent specificities were antibodies to cardiolipin and to denatured DNA, while Ig serum levels did not correlate with the occurrence of autoantibodies. The presence of autoantibodies was associated with lower CD4+ cell counts and with higher mortality within 2 years. Rheumatic manifestations were observed in 35 HIV-infected patients and were not associated with the occurrence of autoantibodies or the presence of immunodeficiency.

Clinical significance of anticardiolipin antibodies in juvenile idiopathic arthritis.

OBJECTIVE: Anticardiolipin antibodies (aCL) have been demonstrated in a large spectrum of autoimmune diseases. However, its occurrence in childhood, in particular in juvenile idiopathic arthritis (JIA), is not well established. The present study addressed the frequency and clinical significance of aCL in a group of JIA patients. METHODS: aCL (IgG and IgM isotypes), antinuclear antibodies (ANA), and rheumatoid factor (RF) were determined in 86 children with JIA (33 systemic, 31 polyarticular and 22 oligoarticular onset type). Thirty-two juvenile systemic erythematosus lupus patients (JSLE) and 52 healthy children formed the control groups. The disease activity and functional status of the JIA patients were scored to study their possible associations with the presence of aCL. RESULTS: Serum aCL levels above the normal range were detected in 28/86 JIA patients (32.5%), 12/32 JSLE patients (37.5%), and 3/52 healthy children (6%). Positive aCL levels were slightly or moderately elevated (usually below 30 GPL and 20 MPL). The presence of aCL was not associated with the presence of ANA or RF. Associations between aCL and clinical parameters, such as disease onset, duration, activity or severity could not be established. No JIA patient had vascular thrombosis, thrombocytopenia or "livedo reticularis". CONCLUSION: aCL occurred in low titers in JIA children, in a similar frequency to that observed in JSLE. No association with JIA clinical parameters or the clinical features classically linked to the antiphospholipid antibody syndrome were observed.

Wa idiotype in seropositive rheumatoid arthritis.

Antibodies against cross-reactive idiotypes (CRIs) may prove useful as phenotypic tracers of immunoglobulin variable region genes (VH or VL). CRIs of human rheumatoid factors (RFs) seem to be useful in the elucidation of the incidence and structural characteristics of the latter. Anti-Wa CRI antibodies were produced and an enzyme immunoassay was developed to test polyclonal RFs isolated from sera of 20 rheumatoid arthritis (RA) patients, 7 males and 13 females, aged 17 to 74 years. Seventeen patients had clinically active disease and three were in remission. Disease duration ranged from 1 to 25 years and RF titers ranged from 1:160 to 1:640. The immunoassay could detect as little as 8 ng of a monoclonal purified WaRF and positive results were found in 30% of patient sera. Therefore, we may conclude that at least part of the RFs seen in RA patients derives from germ line genes.

Colocalization of coilin and nucleolar proteins in Cajal body-like structures of micronucleated PtK2 cells.

Cajal bodies (CB) are ubiquitous nuclear structures involved in the biogenesis of small nuclear ribonucleoproteins and show narrow association with the nucleolus. To identify possible relationships between CB and the nucleolus, the localization of coilin, a marker of CB, and of a set of nucleolar proteins was investigated in cultured PtK2 cells undergoing micronucleation. Nocodazol-induced micronucleated cells were examined by double indirect immunofluorescence with antibodies against coilin, fibrillarin, NOR-90/hUBF, RNA polymerase I, PM/Scl, and To/Th. Cells were imaged on a BioRad 1024-UV confocal system attached to a Zeiss Axiovert 100 microscope. Since PtK2 cells possess only one nucleolus organizer region, micronucleated cells presented only one or two micronuclei containing nucleolus. By confocal microscopy we showed that in most micronuclei lacking a typical nucleolus a variable number of round structures were stained by antibodies against fibrillarin, NOR-90/hUBF protein, and coilin. These bodies were regarded as CB-like structures and were not stained by anti-PM/Scl and anti-To/Th antibodies. Anti-RNA polymerase I antibodies also reacted with CB-like structures in some micronuclei lacking nucleolus. The demonstration that a set of proteins involved in RNA/RNP biogenesis, namely coilin, fibrillarin, NOR-90/hUBF, and RNA polymerase I gather in CB-like structures present in nucleoli-devoid micronuclei may contribute to shed some light into the understanding of CB function.

Exposição crônica ao cloridrato de metformina e à glibenclamida causa alterações comportamentais, glicêmicas e de mortalidade em Hemigrammus caudovittatus e Danio rerio / Chronic exposure to metformin chloridrate and glibenclamide causes behavioral, blood glucose and mortality changes of Hemigrammus caudovittatus and Danio rerio

Hemigrammus caudovittatus e Danio rerio foram expostos aos hipoglicemiantes orais (HOs) cloridrato de metformina a 40µg/L e 120µg/L e glibenclamida a 0,13µg/L e 0,39µg/L durante 100 dias. Foram avaliados os efeitos tóxicos dos fármacos em relação ao peso, ao comportamento animal, à glicemia e à mortalidade. H. caudovittatus expostos à menor concentração dos fármacos apresentaram aumento significativo (P<0,05) no evento Respiração Aérea. Ainda, foi observado aumento no comportamento Descansar quando os animais foram expostos à glibenclamida a 0,39µg/L. Em D. rerio expostos ao cloridrato de metformina a 120µg/L, foi observado aumento (P<0,05) no comportamento Descansar. A glibenclamida provocou redução (P<0,05) na glicemia de H. caudovittatus. Ambos os fármacos causaram efeito letal na espécie D. rerio, contudo a glibenclamida foi mais tóxica, causando 100% de mortalidade em 30 dias de exposição. Os animais que vieram a óbito apresentaram congestão nos arcos branquiais e hemorragia. Os HOs foram desenvolvidos para apresentarem efeitos fisiológicos em mamíferos, entretanto efeitos tóxicos foram encontrados nas duas espécies de peixe estudadas. Isso levanta a preocupação sobre possíveis efeitos tóxicos de HOs e sobre quais métodos serão utilizados para a sua degradação no ambiente aquático.(AU)

Hemigrammus caudovittatus and Danio rerio were exposed to oral hypoglycemic drugs (HOs) metformin hydrochloride at 40µg/L and 120µg/L and to glibenclamide at 0.13µg/L and 0.39µg/L during 100 days. Toxic effects of the drugs were evaluated based on weight, animal behavior, blood glucose and mortality. H. caudovittatus exposed to lowest concentration of the drugs showed significant increase (P< 0.05) in the Air breathing event. Furthermore, increase in Rest event was observed when animals were exposed to glibenclamide at 0.39µg/L. An increase (P< 0.05) in the frequency of Rest behavior in the D. rerio exposed to metformin hydrochloride at 120µg/L was observed. Glibenclamide caused decrease (P< 0.05) in the blood glucose of H. caudovittatus. Both drugs caused lethal effect against D. rerio. Nevertheless, glibenclamide was more toxic causing 100% of mortality after 30 days of exposure. The animals that died showed congestion on the branchial arches and hemorrhage. The HOs were developed to have physiological effects in mammals. However, toxic effects were found in both species of fish studied. This raises concerns about possible toxic effects of HOs and what methods will be used for their degradation in the aquatic environment.(AU)

Efeitos tóxicos de compostos de vanádio sobre os parâmetros biológicos de embriões e adultos de zebrafish (Danio rerio) / Toxic effects of vanadium compounds on biological parameters of embryos and adults of zebrafish (Danio rerio)

Foram avaliados os efeitos tóxicos do metavanadato de sódio (MV), pentóxido de vanádio (PV) e sulfato de oxovanádio (SV), potenciais fármacos antidiabéticos, em embriões e adultos de zebrafish (Danio rerio). Os embriões foram expostos a concentrações de 10-1000µg/mL para avaliação da CL50 96h e seus efeitos teratogênicos. Os adultos foram expostos a 10 e 20µg/mL dos mesmos compostos para se avaliarem alterações comportamentais relacionadas à exposição química e à mortalidade. A CL50 96h foi de 22,48, 53,62 e 74,14µg/mL para MV, SV e PV, respectivamente. Houve 100% de mortalidade nas concentrações de 400-1000µg/mL dos três compostos. Os efeitos teratogênicos mais observados (P<0,05) nos embriões foram edemas de pericárdio e saco vitelínico. Foram constatados, nos animais adultos expostos aos compostos de vanádio, maior batimento opercular e congestão nos arcos branquiais. A exibição dos comportamentos Flutuar e Descansar nos adultos expostos foi significativa (P<0,05), como também a exibição do comportamento Respiração Aérea. Pode-se concluir que a exposição química aos compostos de vanádio causou efeitos tóxicos em embriões e adultos de zebrafish com alta mortalidade. Diante disso, o seu uso como potencial fármaco antidiabético deve ser mais bem estudado em razão do efeito tóxico dessas substâncias.(AU)

The toxic effects of sodium metavanadate (MV), vanadium pentoxide (PV) and oxovanadium sulfate (SV), potential antidiabetic drug, on embryos and adults of zebrafish (Danio rerio) were evaluated. Embryos were exposed to concentrations of 10-1000µg/mL for evaluation of 96-h LC50 and their teratogenic effects. Adults were exposed to 10 and 20µg/mL of the same compounds to evaluate behavioral changes related to chemical exposure and mortality. The 96-h LC50 were 22.48, 53.62, and 74.14µg/mL for MV, SV, and PV, respectively. Mortality of 100% was observed at the concentrations of 400-1000µg/mL of the three compounds. The teratogenic effects most observed (P<0.05) were pericardial and yolk sac edemas. Adult animals exposed to the vanadium compounds had higher opercular beats and congestion in the gill arches. The exhibition of behaviors Floating and Resting in the exposed adults was significant (P<0.05), as well as the Air breathing behavior. Chemical exposure to vanadium compounds caused toxic effects in embryos and adults of zebrafish with high mortality. In conclusion, its use as a potential antidiabetic drug should be better studied due to the toxic effect.(AU)

Anti-ß2-glycoprotein I antibodies are highly prevalent in a large number of Brazilian leprosy patients.

OBJECTIVES: To determine the prevalence of anticardiolipin (aCL) and anti-ß2-glycoprotein I (anti-ß2GPI) antibodies in leprosy patients, during and after specific multidrug therapy (MDT), and to evaluate a possible association between these antibodies and some clinical characteristics of leprosy, including clinical forms, reactional episodes and treatment. METHODS: The study included 158 leprosy patients, 129 gender-and-age matched healthy individuals, and 38 women with primary antiphospholipid syndrome (APS). Clinical and demographic characteristic of leprosy patients were collected, and serum samples, obtained from all participants, were kept frozen at - 20°C. Antibodies were measured either by an in house-developed ELISA (aCL) or by a commercial ELISA (anti-ß2GPI). RESULTS AND CONCLUSIONS: Increased levels of aCL and anti-ß2GPI antibodies were found in leprosy patients and in the APS group, however, in contrast to APS, the predominant isotype in leprosy was IgM. The frequency of aCL and anti-ß2GPI antibodies was significantly higher in leprosy patients than in healthy individuals (15.8% vs. 3.1%; p>0.01; 46.2% vs. 9.4%, p>0.01), respectively. The lepromatous form predominated among aCL positive leprosy patients (p>0.01). There was no difference in aCL and anti-ß2GPI positivity between leprosy patients taking MDT and those completed MDT as cured. Furthermore the duration of discharged period (period between discharge from MDT and the realization of the study) had no effect on anti-ß2GPI positivity, and a slight increase in aCL positivity was observed in patients with longer follow up periods (p=0.04), suggesting that the presence of antiphospholipid antibodies (aPL) was not a transient phenomenon. Although aPL in leprosy were frequent and ß2GPI-dependent as those found in APS, IgM was the predominant isotype, and there was no association with thrombosis or other APS manifestations.

Follicular helper T cell in immunity and autoimmunity

The traditional concept that effector T helper (Th) responses are mediated by Th1/Th2 cell subtypes has been broadened by the recent demonstration of two new effector T helper cells, the IL-17 producing cells (Th17) and the follicular helper T cells (Tfh). These new subsets have many features in common, such as the ability to produce IL-21 and to express the IL-23 receptor (IL23R), the inducible co-stimulatory molecule ICOS, and the transcription factor c-Maf, all of them essential for expansion and establishment of the final pool of both subsets. Tfh cells differ from Th17 by their ability to home to B cell areas in secondary lymphoid tissue through interactions mediated by the chemokine receptor CXCR5 and its ligand CXCL13. These CXCR5+ CD4+ T cells are considered an effector T cell type specialized in B cell help, with a transcriptional profile distinct from Th1 and Th2 cells. The role of Tfh cells and its primary product, IL-21, on B-cell activation and differentiation is essential for humoral immunity against infectious agents. However, when deregulated, Tfh cells could represent an important mechanism contributing to exacerbated humoral response and autoantibody production in autoimmune diseases. This review highlights the importance of Tfh cells by focusing on their biology and differentiation processes in the context of normal immune response to infectious microorganisms and their role in the pathogenesis of autoimmune diseases.

Anti-cyclic citrullinated peptide antibodies and rheumatoid factor in leprosy patients with articular involvement.

The objective of the present research was to evaluate the usefulness of anti-cyclic citrullinated peptide (anti-CCP) antibodies and the IgM rheumatoid factor (IgM RF) test for the differential diagnosis of leprosy with articular involvement and rheumatoid arthritis (RA). Anti-CCP antibodies and IgM RF were measured in the sera of 158 leprosy patients (76 with and 82 without articular involvement), 69 RA patients and 89 healthy controls. Leprosy diagnosis was performed according to Ridley and Jopling classification criteria and clinical and demographic characteristics of leprosy patients were collected by a standard questionnaire. Leprosy patients with any concomitant rheumatic disease were excluded. Serum samples were obtained from all participants and frozen at -20 degrees C. Measurement of anti-CCP antibodies and IgM RF were performed by ELISA, using a commercial second-generation kit, and the latex agglutination test, respectively. Anti-CCP antibodies and IgM RF were detected in low frequencies (2.6 and 1.3%, respectively) in leprosy patients and were not associated with articular involvement. Among healthy individuals both anti-CCP antibodies and IgM RF were each detected in 3.4% of the subjects. In contrast, in the RA group, anti-CCP antibodies were present in 81.2% and IgM RF in 62.3%. In the present study, both anti-CCP antibodies and IgM RF showed good positive predictive value for RA, helping to discriminate between RA and leprosy patients with articular involvement. However, anti-CCP antibodies were more specific for RA diagnosis in the population under study.

Serum cartilage oligomeric matrix protein (COMP) levels in knee osteoarthritis in a Brazilian population: clinical and radiological correlation.

OBJECTIVES: In this study we present data on serum cartilage oligomeric matrix protein (COMP) levels in a Brazilian population with isolated knee osteoarthritis (OA) compared to healthy controls. Clinical and radiological correlations with COMP levels were also evaluated. METHODS: Two hundred and seventy-two patients seen at the Rheumatology Division of the Federal University of São Paulo (UNIFESP) with a symptom of 'pain in the knees' for at least 3 months were invited to participate in this study. History and clinical examination were performed in all patients. Eighty-six patients with clinical isolated knee OA according to the American College of Rheumatology (ACR) criteria and without other causes of pain in the knee were included. Fifty-eight healthy individuals were selected, matched for age and sex, and used as controls. OA evaluation included Lequesne and Western Ontario and MacMaster Universities osteoarthritis index (WOMAC) questionnaires, visual analogue scale (VAS) for pain and standard knee X-rays. Blood samples were taken from all participants and serum COMP levels were measured by enzyme-linked immunosorbent assay (ELISA). OA radiological analysis was performed using the Kellgren and Lawrence (K/L) grading scale. RESULTS: Patients with symptomatic knee OA presented significantly higher serum COMP levels compared to healthy controls and to those with non-symptomatic narrowing of the articular space (p<0.001). Patients with clinical evidence of knee OA and without radiological abnormalities (K/L grade 0 or 1) had intermediate serum COMP levels, significantly higher than those observed in healthy controls (p<0.03). CONCLUSIONS: We observed increased serum COMP levels in patients with symptomatic radiological knee OA. High serum COMP levels may also indicate cartilage damage in selected symptomatic patients without significant radiological abnormalities.

Impact of hypertension and hyperhomocysteinemia on arterial thrombosis in primary antiphospholipid syndrome.

The aim of this study was to evaluate traditional risk factors for coronary artery disease (CAD), homocysteine, anti-oxidized low-density lipoprotein (anti-oxLDL), anti-lipoprotein lipase (anti-LPL) and endothelin-1 (ET-1) in patients with primary anti-phospholipid syndrome (APS), furthermore verify possible association among these variables and arterial thrombosis. Thirty-eight women with primary APS and 30 age-and-sex-matched controls were evaluated. Patients presented higher-LDL and triglycerides levels and lower-HDL levels than controls. Anti-LPL antibodies were not detected in both groups. The mean number of risk factors was higher in patients than in controls (P = 0.030). Anti-oxLDL antibodies, homocysteine and ET-1 mean levels were similar between groups, but abnormal homocysteine levels were found only among primary APS patients (P = 0.031). Hypertension and the presence of at least one risk factor for CAD were more prevalent in patients with arterial involvement than those without. Homocysteine levels and mean number of risk factors for CAD were significantly higher in patients with arterial thrombosis than controls. In a multivariate analysis hypertension was the only independently associated with arterial thrombosis (OR 14.8, 95% CI = 2.1-100.0, P = 0.006). This study showed that in primary APS patients other risk factors besides anti-phospholipid antibodies contribute for the occurrence of arterial events and the most important factor was hypertension.

Role of distinct immune components in the radiation-induced abrogation of systemic lupus erythematosus development in mice.

The New Zealand Black x New Zealand White F1 [(NZB/NZW) F1] mouse develops an autoimmune condition resembling aspects of human systemic lupus erythematosus (SLE). We investigated the effects of a novel prophylactic thoraco-abdominal gamma irradiation protocol on the onset and evolution of lupus in these animals. Survival of irradiated mice was higher when compared with nonirradiated mice. Kidney lesions were milder and autoantibody levels were lower in irradiated mice. To identify possible mechanisms involved in the radiation-induced improvement of disease, distinct components of humoral and cellular immune responses were evaluated. Because B-1 cells are known to be involved in various autoimmune diseases, we investigated the participation of these cells in SLE progression. Unexpectedly, B-1 cells were not depleted in (NZB/NZW) F1, even after several rounds of irradiation. No alterations were found in viability and physiology of B-1 cells in SLE animals with the exception of constitutive overexpression of the anti-apoptotic molecule Bcl-2, which may account for the observed radioresistance. Thus, a role for B-1 cells in murine SLE cannot be excluded, since the irradiation protocol did not effectively eliminate these cells. Additionally, we demonstrate a marked delay in the ability of splenocytes to repopulate the spleen after irradiation in (NZB/NZW) F1, in contrast to leucocytes in other cellular compartments. The implications of these findings for the fate of SLE in this model are discussed.

Human autoantibodies to diacyl-phosphatidylethanolamine recognize a specific set of discrete cytoplasmic domains.

The aim of this study was to characterize a novel human autoantibody-autoantigen system represented as cytoplasmic discrete speckles (CDS) in indirect immunofluorescence (IIF). A distinct CDS IIF pattern represented by 3-20 discrete speckles dispersed throughout the cytoplasm was identified among other cytoplasmic speckled IIF patterns. The cytoplasmic domains labelled by human anti-CDS-1 antibodies did not co-localize with endosome/lysosome markers EEA1 and LAMP-2, but showed partial co-localization with glycine-tryptophan bodies (GWB). CDS-1 sera did not react with several cellular extracts in immunoblotting and did not immunoprecipitate recombinant GW182 or EEA1 proteins. The typical CDS-1 IIF labelling pattern was abolished after delipidation of HEp-2 cells. Moreover, CDS-1 sera reacted strongly with a lipid component co-migrating with phosphatidylethanolamine (PE) in high performance thin-layer chromatography (HPTLC)-immunostaining of HEp-2 cell total lipid extracts. The CDS-1 major molecular targets were established by electrospray ionization-mass spectrometry (ESI-MS), HPTLC-immunostaining and chemiluminescent enzyme-linked immunosorbent assay as diacyl-PE species, containing preferentially a cis-C18 : 1 fatty acid chain at C-2 of the glycerol moiety, namely 1,2-cis-C18 : 1-PE and 1-C16 : 0-2-cis-C18 : 1-PE. The clinical association of CDS-1 sera included a variety of systemic and organ-specific autoimmune diseases but they were also observed in patients with no evidence of autoimmune disease.