Association analysis of anti-Epstein-Barr nuclear antigen-1 antibodies, anti-cyclic citrullinated peptide antibodies, the shared epitope and smoking status in Brazilian patients with rheumatoid arthritis

INTRODUCTION: Epstein-Barr virus exposure appears to be an environmental trigger for rheumatoid arthritis that interacts with other risk factors. Relationships among anti-cyclic citrullinated peptide antibodies, the shared epitope, and smoking status have been observed in patients with rheumatoid arthritis from different populations. OBJECTIVE: To perform an association analysis of anti-Epstein-Barr nuclear antigen-1 antibodies, anti-cyclic citrullinated peptide antibodies, the shared epitope, and smoking status in Brazilian patients with rheumatoid arthritis. METHODS: In a case-control study, 140 rheumatoid arthritis patients and 143 healthy volunteers who were matched for age, sex, and ethnicity were recruited. Anti-Epstein-Barr nuclear antigen-1 antibodies and anti-cyclic citrullinated peptide antibodies were examined using an enzyme-linked immunosorbent assay, and shared epitope alleles were identified by genotyping. Smoking information was collected from all subjects. A comparative analysis of anti-Epstein-Barr nuclear antigen-1 antibodies, anti-cyclic citrullinated peptide antibodies, the shared epitope, and smoking status was performed in the patient group. Logistic regression analysis models were used to analyze the risk of rheumatoid arthritis. RESULTS: Anti-Epstein-Barr nuclear antigen-1 antibodies were not associated with anti-cyclic citrullinated peptide antibodies, shared epitope alleles, or smoking status. Anti-cyclic citrullinated peptide antibody positivity was significantly higher in smoking patients with shared epitope alleles (OR = 3.82). In a multivariate logistic regression analysis using stepwise selection, only anti-cyclic citrullinated peptide antibodies were found to be independently associated with rheumatoid arthritis (OR = 247.9). CONCLUSION: Anti-Epstein-Barr nuclear antigen-1 antibodies did not increase the risk of rheumatoid arthritis and were not associated with the rheumatoid arthritis risk factors studied. Smoking and shared epitope alleles were correlated with anti-cyclic citrullinated peptide-antibody-positive rheumatoid arthritis. Of the risk factors, only anticyclic citrullinated peptides antibodies were independently associated with rheumatoid arthritis susceptibility.

Identificación de epitopes Tipo Grupo Sanguíneo ABO en larvas de Ascaris lumbricoides mantenidas in vitro / Identification of ABO Blood Group like epitopes in vitro maintained Ascaris lumbricoides larvae

En investigaciones previas se identificaron los mismos epitopes del Sistema ABO en extractos de A. lumbricoides y en sus respectivos hospederos. Los objetivos de este trabajo fueron estudiar la absorción de determinantes antigénicas ABO por cultivo in vitro de estadios larvales de este helminto e investigar la presencia de sustancias Tipo Grupo Sanguíneo ABO en los productos de secreción/excreción de las larvas. Se trabajó con larvas obtenidas de la eclosión de huevos de A. lumbricoides y recolectadas por el método de Baermann en cinco tubos con medio RPMI 1640. En tres de los tubos se adicionaron eritrocitos (A, B y O). Los dos tubos restantes se usaron como control negativo de absorción y para investigar los productos de excreción- /secreción de las larvas. Se aplicaron técnicas de Inhibición de la Aglutinación Semicuantitativa usando anticuerpos monoclonales. Los resultados mostraron que las larvas absorben epitopes A, B y H de los eritrocitos agregados al medio de cultivo. Se identificaron sustancias Tipo A y B en los productos de excreción/secreción de las larvas. La experiencia puede contribuir a la comprensión de los mecanismos de evasión de la respuesta inmune del hospedero utilizados por A. lumbricoides.

Previous experiences have demonstrated the same ABO System epitopes in A. lumbricoides extracts and in their hosts. The aims of this work were to study ABO antigenic determiner absorption by in vitro culture of the helminth's larvae and to investigate ABO-Blood-Group-like substances in larvae's excretion/ secretion products. Larvae were obtained by hatching of A. lumbricoides eggs. The larvae were collected in 5 tubes with RPMI 1640 medium by the Baermann method. A, B and O erythrocytes were added in 3 of the tubes. The two remaining tubes were used as absorption Negative Control and to investigate larvae's excretion/secretion products. The Semiquantitative Inhibition Agglutination Test was applied by using monoclonal antibodies. The results showed that the larvae may adsorb A, B and H epitopes from the erythrocytes that were added to the culture medium. A and B-Blood-Group-like substances were identified in the excretion/secretion products. The experience can contribute to understand the host's escape mechanism used by A. lumbricoides.

Burkholderia pseudomallei-specific recombinant protein and its potential in the diagnosis of melioidosis.

Melioidosis is an important public health problem in Southeast Asia and Northern Australia. This disease is caused by the gram-negative bacilli, Burkholderia pseudomallei. Wide spectra of clinical manifestations are observed in melioidosis ranging from asymptomatic to septicemic infection. Although serodiagnostic methods of melioidosis have been improved significantly in recent years, a highly specific diagnostic test that can differentiate asymptomatic seropositive individuals and melioidosis patients remains to be the subject of current investigations. In this study, a B. pseudomallei-specific gene, pBps-1, expressing a novel 18.7 kDa recombinant protein was selected from genomic libraries of two B. pseudomallei virulent isolates by using pooled sera from septicemic melioidosis patients. Nucleotide sequence analysis demonstrated that this gene is unique and does not show substantial similarity with any known genes in the Genbank database. The Bps-1 recombinant protein was evaluated for its potential in serodiagnosis of melioidosis by Western blot analysis. A high degree of specificity was demonstrated using sera from healthy individuals in the endemic (98.5%) and non-endemic areas (100%), with moderate sensitivity (69.7%) in melioidosis patients. The study demonstrated that this approach can be used to obtain highly specific recombinant antigens such as that described in the present report. A combination of such antigens should provide materials for successful serodiagnosis of melioidosis in the endemic areas.