Isabela Goeldner

Anti-cyclic citrullinated peptide antibodies and rheumatoid factor in rheumatoid arthritis patients and relatives from Brazil

OBJECTIVES To evaluate the prevalence of anti-cyclic citrullinated peptide (anti-CCP) antibodies and RF in RA patients and their relatives from Southern Brazil. METHODS Anti-CCP2 and IgM-RF were evaluated in 156 RA patients and 200 relatives. Sera from 100 healthy unrelated individuals were used as control. The anti-CCP2 was detected by ELISA and the IgM-RF using the latex agglutination test. RESULTS We identified 117 anti-CCP2 (75%)-positive and 106 RF (67.9%)-positive patients. Anti-CCP2 was increased in relatives (5.5%; 11/200) when compared with unrelated individuals (1%; P = 0.050). Titre of anti-CCP2 in RA patients did not differ from relatives [140.4 (75.7) vs 115.6 (84.2) U, respectively; P = 0.30]. Positive relatives were younger than patients for anti-CCP2 (P = 0.0081), RF (P < 0.001) and both concomitantly (P = 0.012), and although there was no difference for anti-CCP2 positivity according to gender, increased RF positivity and concomitant anti-CCP2/RF were observed in the female relatives (P = 0.067 and 0.082, respectively). No difference regarding the relative degree of tobacco use in relatives was detected. Among the 11 anti-CCP2-positive relatives, 2 females had RA diagnosis established and 6 individuals presented with joint symptoms suggestive of RA. CONCLUSION The results demonstrate a significant positivity of anti-CCP2 in relatives of RA patients from Brazil and reinforce the importance of serological tools to identify undiagnosed RA.

MBL-associated serine proteases (MASPs) and infectious diseases.

Abstract The lectin pathway of the complement system has a pivotal role in the defense against infectious organisms. After binding of mannan-binding lectin (MBL), ficolins or collectin 11 to carbohydrates or acetylated residues on pathogen surfaces, dimers of MBL-associated serine proteases 1 and 2 (MASP-1 and MASP-2) activate a proteolytic cascade, which culminates in the formation of the membrane attack complex and pathogen lysis. Alternative splicing of the pre-mRNA encoding MASP-1 results in two other products, MASP-3 and MAp44, which regulate activation of the cascade. A similar mechanism allows the gene encoding MASP-2 to produce the truncated MAp19 protein. Polymorphisms in MASP1 and MASP2 genes are associated with protein serum levels and functional activity. Since the first report of a MASP deficiency in 2003, deficiencies in lectin pathway proteins have been associated with recurrent infections and several polymorphisms were associated with the susceptibility or protection to infectious diseases. In this review, we summarize the findings on the role of MASP polymorphisms and serum levels in bacterial, viral and protozoan infectious diseases.

The Lectin Pathway of Complement and Rheumatic Heart Disease

The innate immune system is the first line of host defense against infection and is comprised of humoral and cellular mechanisms that recognize potential pathogens within minutes or hours of entry. The effector components of innate immunity include epithelial barriers, phagocytes, and natural killer cells, as well as cytokines and the complement system. Complement plays an important role in the immediate response against microorganisms, including Streptococcus sp. The lectin pathway is one of three pathways by which the complement system can be activated. This pathway is initiated by the binding of mannose-binding lectin (MBL), collectin 11 (CL-K1), and ficolins (Ficolin-1, Ficolin-2, and Ficolin-3) to microbial surface oligosaccharides and acetylated residues, respectively. Upon binding to target molecules, MBL, CL-K1, and ficolins form complexes with MBL-associated serine proteases 1 and 2 (MASP-1 and MASP-2), which cleave C4 and C2 forming the C3 convertase (C4b2a). Subsequent activation of complement cascade leads to opsonization, phagocytosis, and lysis of target microorganisms through the formation of the membrane-attack complex. In addition, activation of complement may induce several inflammatory effects, such as expression of adhesion molecules, chemotaxis and activation of leukocytes, release of reactive oxygen species, and secretion of cytokines and chemokines. In this chapter, we review the general aspects of the structure, function, and genetic polymorphism of lectin-pathway components and discuss most recent understanding on the role of the lectin pathway in the predisposition and clinical progression of Rheumatic Fever.

Association of anticyclic citrullinated peptide antibodies with extra-articular manifestations, gender, and tabagism in rheumatoid arthritis patients from southern Brazil

Gender and environmental factors are known to influence the clinical heterogeneity and outcome of rheumatoid arthritis (RA). Some variables have been suggested to be associated with the severity of the disease, which can be of great value in the correct management of RA patients. The purpose of this study was to investigate the associations among anticyclic citrullinated antibody (anti-CCP2) positivity, extra-articular manifestations (EAM), gender, and tobacco exposure in a Brazilian RA population. We performed a transversal study comprising 156 RA patients which were investigated for EAM, functional class, presence of anti-CCP2, and IgM rheumatoid factor (IgM-RF). The determination of anti-CCP2 was performed using enzyme immunoassay (ELISA) kits and IgM-RF by latex agglutination test. Clinical and demographical data were obtained through review of charts. Anti-CCP positivity intensity was directly correlated with tobacco smoking, sex, and the development of rheumatoid nodules. Intense anti-CCP2 reaction was 19.8-fold higher in females vs. males, 2.7-fold higher in tobacco vs. non-tobacco users, 7.7-fold higher in female vs. male tobacco users, and 5.15-fold higher in patients with rheumatoid nodules. Tobacco smoking, gender, and rheumatoid nodules are significantly correlated with anti-CCP2 positivity in Brazilian RA patients.

Leprosy association with low MASP-2 levels generated by MASP2 haplotypes and polymorphisms flanking MAp19 exon 5.

Background The gene MASP2 (mannan-binding lectin (MBL)-associated serine protease 2) encodes two proteins, MASP-2 and MAp19 (MBL-associated protein of 19 kDa), bound in plasma to MBL and ficolins. The binding of MBL/MASP-2 and ficolin/MASP-2 complexes to microorganisms activates the lectin pathway of complement and may increase the ingestion of intracellular pathogens such as Mycobacterium leprae. Methods We haplotyped 11 MASP2 polymorphisms with multiplex sequence-specific PCR in 219 Brazilian leprosy patients (131 lepromatous, 29 borderline, 21 tuberculoid, 14 undetermined, 24 unspecified), 405 healthy Brazilians and 291 Danish blood donors with previously determined MASP-2 and MAp19 levels. We also evaluated MASP-2 levels in further 46 leprosy patients and 69 Brazilian controls. Results Two polymorphisms flanking exon 5 of MASP2 were associated with a dominant effect on high MASP-2 levels and an additive effect on low MAp19 levels. Patients presented lower MASP-2 levels (P = 0.0012) than controls. The frequency of the p.126L variant, associated with low MASP-2 levels (below 200 ng/mL), was higher in the patients (P = 0.0002, OR = 4.92), as was the frequency of genotypes with p.126L (P = 0.00006, OR = 5.96). The *1C2-l [AG] haplotype, which harbors p.126L and the deficiency-causing p.439H variant, has a dominant effect on the susceptibility to the disease (P = 0.007, OR = 4.15). Genotypes composed of the *2B1-i and/or *2B2A-i haplotypes, both associated with intermediate MASP-2 levels (200–600 ng/mL), were found to be protective against the disease (P = 0.0014, OR = 0.6). Low MASP-2 levels (P = 0.022), as well as corresponding genotypes with *1C2-l and/or *2A2-l but without *1B1-h or *1B2-h, were more frequent in the lepromatous than in other patients (P = 0.008, OR = 8.8). Conclusions In contrast with MBL, low MASP-2 levels increase the susceptibility to leprosy in general and to lepromatous leprosy in particular. MASP2 genotypes and MASP-2 levels might thus be of prognostic value for leprosy progression.

Association of MASP-2 Levels and MASP2 Gene Polymorphisms with Rheumatoid Arthritis in Patients and Their Relatives

Background Mannan-binding lectin-associated serine protease 2 (MASP-2) is a key protein of the lectin pathway of complement. MASP-2 levels have been associated with different polymorphisms within MASP2 gene as well as with the risk for inflammatory disorders and infections. Despite its clinical importance, MASP-2 remains poorly investigated in rheumatoid arthritis (RA). Methods In this case-control study, we measured MASP-2 serum levels in 156 RA patients, 44 patient relatives, and 100 controls from Southern Brazil, associating the results with nine MASP2 polymorphisms in all patients, 111 relatives, and 230 controls genotyped with multiplex SSP-PCR. Results MASP-2 levels were lower in patients than in controls and relatives (medians 181 vs. 340 or 285 ng/ml, respectively, P<0.0001). Conversely, high MASP-2 levels were associated with lower susceptibility to RA and to articular symptoms independently of age, gender, ethnicity, smoking habit, anti-CCP and rheumatoid factor positivity (OR = 0.05 [95%CI = 0.019–0.13], P<0.0001 between patients and controls; OR = 0.12, [95%CI = 0.03–0.45], P = 0.002 between patients and relatives; OR = 0.06, [95%CI = 0.004–0.73], P = 0.03 between relatives with and without articular symptoms). MASP2 haplotypes *2A1 and *2B1-i were associated with increased susceptibility to RA (OR = 3.32 [95%CI = 1.48–7.45], P = 0.004). Deficiency-causing p.120G and p.439H substitutions were associated with five times increased susceptibility to articular symptoms in relatives (OR = 5.13 [95%CI = 1.36–20.84], P = 0.02). There was no association of MASP-2 levels or MASP2 polymorphisms with autoantibodies, Sjögrens syndrome, nodules and functional class. Conclusions In this study, we found the first evidence that MASP-2 deficiency might play an important role in the development of RA and articular symptoms among relatives of RA patients.

Artrite reumatoide: uma visão atual

INTRODUCAO: A artrite reumatoide (AR) e uma doenca autoimune inflamatoria e cronica que afeta aproximadamente 1% da populacao adulta mundial. A doenca caracteriza-se pela inflamacao do tecido sinovial de multiplas articulacoes, levando a destruicao tecidual, dor, deformidades e reducao na qualidade de vida do paciente. Sua etiologia e complexa e em grande parte desconhecida, porem estudos demonstram a influencia de fatores geneticos e ambientais em sua patogenese. Devido a forte influencia genetica, familiares de pacientes com AR formam um grupo de risco para o desenvolvimento da doenca, principalmente em sua forma mais grave. Apesar de seu elevado potencial incapacitante, o curso da AR pode ser modificado por meio do diagnostico precoce e do manejo adequado do paciente. No entanto, o diagnostico precoce da AR e ainda bastante dificil diante da heterogeneidade das manifestacoes clinicas da doenca, o que acaba retardando a implantacao terapeutica. O tratamento da AR baseia-se no uso de anti-inflamatorios nao esteroidais (AINEs), corticosteroides, drogas antirreumaticas modificadoras do curso da doenca (DMARD) e agentes imunobiologicos. Alem da terapia medicamentosa, tambem sao adotadas medidas como educacao do paciente e terapias psico-ocupacionais. Atualmente, estudos tem se voltado a identificacao de fatores preditores de doenca mais grave, como autoanticorpos como fator reumatoide (FR) e anticorpo antipeptidio ciclico citrulinado (anti-CCP), que constituem importantes marcadores imunologicos de diagnostico e prognostico da AR. DISCUSSAO E CONCLUSAO: Apesar dos significativos avancos tanto no entendimento como no diagnostico e no tratamento da AR, ainda persistem inumeros desafios a serem superados.

Mannose-binding lectin polymorphisms and rheumatoid arthritis: A short review and meta-analysis.

Mannose-binding lectin (MBL) is a pattern recognition receptor of the lectin pathway of complement system. MBL binds to carbohydrates on microorganisms surfaces leading to complement activation, opsonization and phagocytosis. Polymorphisms in the MBL gene (MBL2) are associated with variations on MBL serum levels and with the susceptibility to various infectious and autoimmune diseases. The involvement of the lectin pathway in rheumatoid arthritis (RA) has been demonstrated by several studies and although MBL has been considered to have a dual role in the pathogenesis of the disease, the association between MBL and RA remains inconclusive. In an attempt to clarify this relationship, we developed this short review summarizing accumulated evidences in regard to MBL and RA and a meta-analysis to evaluate the influence of MBL2 polymorphisms on the susceptibility to RA. Among a total of 217 articles that were identified following a predefined search strategy on PubMed, Scopus, Scielo, EMBASE and Cochrane databases, only 13 met all inclusion criteria and were included in the meta-analysis. Data assessment was conducted by three independent investigators and presented in odds ratio (OR) and 95% confidence intervals (CIs) using forest plot charts. Both heterogeneity and publication bias were analyzed. The results of the meta-analysis evidenced that MBL2 low producing OO and XX genotypes do not confer higher risk to RA, even when data were analyzed according to cohorts ethnicity. Further studies are needed in order to clarify the importance of other genes of the lectin pathway in the pathogenesis of RA.

Autoantibodies for gastrointestinal organ-specific autoimmune diseases in rheumatoid arthritis patients and their relatives

BackgroundClustering of autoimmune diseases is common and may be due to genetic background and exposition to environmental triggers.ObjectiveThe aim is to carry out a laboratory and clinical study of the prevalence of gastrointestinal organ-specific autoantibodies in rheumatoid arthritis (RA) patients and their relatives.MethodsSerum samples of 156 RA patients, 200 relatives, and 100 healthy controls were studied for anti-smooth muscle antibody (ASMA), anti-mitochondrial (AMA), anti-parietal cell (APCA), anti-liver–kidney microsome (LKM), and anti-endomysium antibodies (IgA-EmA) by indirect immunofluorescence.ResultsA total of eight out of the 156 (5.1%) RA patients were positive for the autoantibodies (ASMA = 1; AMA = 2, APCA = 5). In the relative group, 12/200 (6%) had at least one positive autoantibody (ASMA = 1; AMA = 2, APCA = 7, IgA-EmA = 2). In the control group, two out of the100 (2%) healthy controls were positive (ASMA = 1, APCA = 1). No statistical difference was found between RA patients, their relatives, and controls in relation to the frequency of autoantibodies evaluated.ConclusionAlthough RA patients and their relatives have positivity of AMA, ASMA, and APCA without statistical difference in relation to healthy individuals, the findings may be of value for adequate clinical approach of these subjects.

Serum pentraxin 3 levels are negatively associated with carotid intima media thickness in non-obese rheumatoid arthritis patients

BACKGROUND Pentraxin-3 (PTX3) is a long pentraxin that is supposed to participate in the inflammatory process and in atherosclerosis. AIM To study PTX3 serum levels in rheumatoid arthritis (RA) patients to know if its serum levels may reflect disease activity and/or subclinical atherosclerosis. METHODS PTX3 and carotid intima media thickness (IMT) were studied in 85 RA patients (83.5% females, median age of 59years old, median disease duration of 13years) along with its demographic, clinical, serological and lipid profile. For comparison PTX3 was measured in 85 healthy volunteers. RESULTS PTX3 levels in RA patients were similar to controls (p=0.21) and did not correlate with inflammatory activity measured by ESR (p=0.39) CRP (p=0.18) and DAS28 (p=0.67). Serum PTX3 levels were higher in nonobese RA patients than in obese (BMI vs PTX3 with rho=-0.27; 95%IC=-0.46 to -0.06; p=0.009). In non-obese patients, PTX3 correlated negatively with carotid IMT (rho=-0.40; 95%IC=-0.66 to -0.06; p=0.01) but not in the obese ones (p=0.26). In the obese RA patients there was a negative correlation between PTX3 levels and LDL/HDL ratio (Rho=-0.29; 95%IC=-0.53-0.01; p=0.03). CONCLUSIONS PTX3 levels do not reflect inflammatory process in RA. However, it exerts a protective role in the process of atherogenesis in non-obese RA patients.