Iara José de Messias-Reason

Efficacy of granulocyte-macrophage colony-stimulating factor (GM-CSF) as a vaccine adjuvant for hepatitis B virus in patients with HIV infection.

Recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) is a cytokine with a potential vaccine adjuvant activity. It is also known that human immunodeficiency virus (HIV) infected patients often show poor immunologic responses to immunization. We examined whether the use of GM-CSF could augment the immunologic response to recombinant vaccine against the hepatitis B virus (HBV) in 80 HIV infected patients (18-35 years old). They received a double dose (40 microg) of recombinant HBV vaccine IM at 0, 1 and 6 months and were randomized to receive either concurrent 20 microg of GM-CSF (n=40) or placebo IM (n=40) with the first vaccine dose. A significant increase in the seroconversion rate was observed after the second vaccine dose in the GM-CSF group (62% GM-CSF versus 30% control group P<0.0074). The average anti-HBs titers measured on days 28, 60 and 210 were 40.3; 366.5 and 644.8 milli-international units per milliliter (mIU/ml), respectively, in the GM-CSF group, and 62.4; 166.4 and 375.0 mIU/ml, respectively, in the control group, with significant differences at 60 and 210 days (P<0.01). There were no significant differences between CD4/CD8 cells, viral load, risk factors, age, sex and the serological responses to the HBV vaccine. This study suggests that GM-CSF increases the immunogenicity of recombinant HBV vaccine in HIV infected individuals.

Mannan-binding lectin MBL2 gene polymorphism in chronic hepatitis C: association with the severity of liver fibrosis and response to interferon therapy

Hepatitis C virus (HCV) is a major cause of hepatic disease and of liver transplantation worldwide. Mannan‐binding lectin (MBL), encoded by the MBL2 gene, can have an important role as an opsonin and complement activating molecule in HCV persistence and liver injury. We assessed the MBL2 polymorphism in 102 Euro–Brazilian patients with moderate and severe chronic hepatitis C, paired for gender and age with 102 HCV seronegative healthy individuals. Six common single nucleotide polymorphisms in the MBL2 gene, three in the promoter (H/L, X/Y and P/Q) and three in exon 1 (A, the wild‐type, and B, C or D also known as O) were evaluated using real‐time polymerase chain reaction with fluorescent hybridization probes. The concentration of MBL in plasma was measured by enzyme‐linked immunosorbent assay. The frequency of the YA/YO genotype was significantly higher in the HCV patients compared with the controls (P = 0·022). On the other hand, the genotypes associated with low levels of MBL (XA/XA, XA/YO and YO/YO) were decreased significantly in the patients with severe fibrosis (stage F4), when compared with the patients with moderate fibrosis (stage F2) (P = 0·04) and to the control group (P = 0·011). Furthermore, MBL2 genotypes containing X or O mutations were found to be associated with non‐responsiveness to pginterferon and ribavirin treatment (P = 0·023). MBL2 polymorphisms may therefore be associated not only with the development of chronic hepatitis C, but also with its clinical evolution and response to treatment.

High-producing MBL2 genotypes increase the risk of acute and chronic carditis in patients with history of rheumatic fever

Rheumatic fever (RF) and its most severe sequela, chronic rheumatic heart disease (CRHD), are mediated by an abnormal immunological host response following a Streptococcus pyogenes oropharyngeal infection. Mannan-binding lectin (MBL), a collectin that activates complement, binds to N-acetylglucosamine, a molecule present on the streptococcus cell wall and on human heart valves. As high levels of MBL and MBL2 associated genotypes have previously been seen to be associated with CRHD, we investigated the association between MBL2 polymorphisms and the presence of acute carditis and arthritis in patients with a history of RF. Polymorphisms in exon 1 and in the X/Y promoter region of the MBL2 gene were determined by PCR-SSP in 149 patients with a history of RF and 147 controls. Genotypes associated with the high production of MBL (YA/YA and YA/XA) were more frequent in the patients with acute (26/35, 74%) and chronic carditis (79/107, 74%) when compared to the controls (79/147, 54%; OR 2.48, 95% CI 1.09-5.67, p=0.035 and OR 2.42, 95% CI 1.41-4.16, p=0.001, respectively). Logistic regression analysis showed that MBL levels >2,800 ng/ml increased the risk of CRHD (OR 2.91, 95% CI 1.41-6.03, p=0.003). Among the RF patients without cardiac sequela, YA/YA and YA/XA genotypes were significantly associated with acute carditis when compared to the patients without this clinical manifestation (26/28, 93% vs. 9/14, 64%, OR 7.22, 95% CI 1.18-43.98, p=0.031); on the other hand, arthritis was more frequently observed in those patients presenting MBL2 genotypes related to the low production of MBL (10/14, 71% vs. 10/28, 36%; p=0.048, OR 0.22, 95% CI 0.05-0.89). We concluded that MBL2 genotypes associated with the high production of MBL seem to be involved in the pathogenesis of rheumatic carditis and its progression to CRHD.

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.

Mechanisms of complement lectin pathway activation and resistance by trypanosomatid parasites

Studies in the past decade have demonstrated a crucial role for the complement lectin pathway in host defence against protozoan microbes. Recognition of pathogen surface molecules by mannan-binding lectin and ficolins revealed new mechanisms of innate immune defence and a diversity of parasite strategies of immune evasion. In the present review, we will discuss the current knowledge of: (1) the molecular mechanism of lectin pathway activation by trypanosomes; (2) the mechanisms of complement evasion by trypanosomes; and (3) host genetic deficiencies of complement lectin pathway factors that contribute to infection susceptibility and disease progression. This review will focus on trypanosomatids, the parasites that cause Chagas disease, leishmaniasis and sleeping sickness (African trypanosomiasis).

MASP2 gene polymorphism is associated with susceptibility to hepatitis C virus infection

Abstract Hepatitis C virus (HCV) has become a major public health issue and is prevalent in most countries. We examined several MASP2 functional polymorphisms in 104 Brazilian patients with moderate and severe chronic hepatitis C using the primers set to amplify the region encoding the first domain (CUB1), a critical region for the formation of functional mannan-binding lectin (MBL)/MBL-associated serine proteases (MASP)–2 complexes, and the fifth domain (CCP2), which is essential for C4 cleavage of the MASP2 gene. We identified five single nucleotide polymorphisms in patients and controls: p. R99Q, p. D120G, p.P126L, p.D371Y, and p.V377A. Our results show that the p.D371Y variant (c.1111 G > T) is associated with susceptibility to HCV infection (p = 0.003, odds ratio = 6.33, 95% confidence interval = 1.85–21.70). Considered as a dominant function for the T allele, this variant is associated with high plasma levels of the MASP-2 in hepatitis C patients (p < 0.001). However, further functional investigations are necessary to understand the degree of involvement between MASP2 and the HCV susceptibility.

Prevalence of autoantibodies in patients with endemic pemphigus foliaceus (fogo selvagem)

ObjectiveThe aim of the present study was to investigate a broad spectrum of autoantibodies in patients with endemic pemphigus foliaceus (EPF)—fogo selvagem—and to determine the possible association between EPF and other autoimmune diseases.Materials and methodsIndirect immunofluorescence was used to test 120 patients with EPF and 200 healthy controls for the presence of the following autoantibodies: anti-desmoglein-1 (APF), anti-neutrophil cytoplasmic (ANCA), anti-smooth muscle (SMA), anti-mitochondrial (AMA), anti-nuclear (ANA), anti-liver kidney microsomal (LKM), anti-gastric parietal cells (GPCA) and anti-thyroid microsome (TMA).ResultsAPF antibodies were detected in 62.5% of the patients (75/120), ANA and SMA in 0.8% (1/120), and TMA in 1.6% (2/120). None of the patients was positive for ANCA, AMA, LKM or GPCA. In the control group, a positivity of 2% was observed for SMA (4/200), 1.5% for TMA (3/200), and 0.5% (1/200) for ANA and GPCA. None of the controls was positive for APF, LKM, AMA or ANCA.ConclusionsThe prevalence of the autoantibodies ANA, SMA, AMA, GPCA, LKM and ANCA in patients with EPF was similar to that observed in the control group. No association with clinical or laboratory manifestations of other concomitant autoimmune diseases was observed in EPF patients. These results confirm the concept that EPF is an organ-specific autoimmune disease.

Functional MASP2 gene polymorphism in patients with history of rheumatic fever

In this study we investigated whether partial or total MASP-2 deficiencies resulting from Asp105Gly mutation are associated with rheumatic fever (RF) and chronic rheumatic heart disease (RHD). The Asp105Gly MASP2 mutation (D105G) was detected by polymerase chain reaction-restriction fragment length polymorphism in 148 patients (43 men and 105 women; mean age 39.1 +/- 14.4 years) with a history of RF, including 106 (73%) with RHD and 42 (27%) without cardiac sequelae, and 129 control subjects (52 men and 77 women, mean age 38.4 +/- 12.2 years). The D105G mutation was detected in four patients with RHD (3.77%) and in five control subjects (3.88%), all in the heterozygous state. None of the patients without cardiac sequelae had the mutation. No significant difference was found in the frequency of the mutant allele between the groups (p < 0.6). These results suggest that the D105G mutation in the MASP2 gene does not play a major role in the pathogenesis of RF. Whether D105G plays a role in the development of RHD should be ascertained in future studies.

Soroepidemiologia da hepatite B e C em índios Kaingang do Sul do Brasil

OBJETIVO: Investigar a prevalencia de infeccao pelo virus da hepatite B e C na populacao indigena Kaingang da reserva de Mangueirinha, no Estado do Parana, Brasil. METODO: A presenca dos marcadores sorologicos anti-HBc, anti-HBs, AgHBs e anti-VHC foi investigada em amostras de sangue de 214 voluntarios (81 do sexo masculino e 133 do sexo feminino) usando tecnicas imunoenzimaticas. Os participantes responderam a um questionario sobre os aspectos sociodemograficos, as condicoes de vida, os habitos e o historico de doencas e de vacinacao. RESULTADOS: A media de idade foi de 29,85 anos (1 a 90 anos). Foi observada uma positividade de 71,02% para o marcador anti-HBs e de 15,42% para o anti-HBc. Nenhum caso foi positivo para o marcador AgHBs. Somente um participante, uma mulher de 30 anos, apresentou positividade para anti-VHC. CONCLUSAO: Os resultados mostram baixa prevalencia de infeccao pelo VHB e pelo VHC na populacao Kaingang estudada. A alta prevalencia de anti-HBs nas faixas etarias mais baixas indica uma boa abrangencia da imunizacao ativa artificial. Na populacao adulta, e provavel que a imunidade contra o VHB tenha sido adquirida principalmente de forma natural, pelo contato com o virus.

Association of MASP2 polymorphisms and protein levels with rheumatic fever and rheumatic heart disease.

MASP-2 is a key protein of the lectin pathway of complement system. Several MASP2 polymorphisms were associated with MASP-2 serum levels or functional activity. Here we investigated a possible association between MASP2 polymorphisms and MASP-2 serum levels with the susceptibility to rheumatic fever (RF) and rheumatic heart disease (RHD). We haplotyped 11 MASP2 polymorphisms with multiplex sequence-specific PCR in 145 patients with history of RF from south Brazil (103 with RHD and 42 without cardiac lesion [RFo]) and 342 healthy controls. MASP-2 levels were determined by ELISA. The low MASP-2 producing p.377A and p.439H variants were negatively associated with RF (P=0.02, OR=0.36) and RHD (P=0.01, OR=0.25). In contrast, haplotypes that share the intron 9 - exon 12 g.1961795C, p.371D, p.377V and p.439R polymorphisms increased the susceptibility to RHD (P=0.02, OR=4.9). MASP-2 levels were associated with MASP2 haplotypes and were lower in patients (P<0.0001), which may reflect protein consumption due to complement activation. MASP2 gene polymorphisms and protein levels seem to play an important role in the development of RF and establishment of RHD.