Rheumatoid Arthritis: Abreu I

Ligeiro D, Fonseca JE, Abade O, Abreu I, Cruz M, Nero P, Cavaleiro J, Teles J, Trindade H, Caetano JM, Branco J. · Centro de Histocompatibilidade do Sul, Lisboa, Portugal. · Ann Rheum Dis. · Pubmed #16793843 No free full text.

Abstract: OBJECTIVE: To clarify the influence of the HLA-DRB1 locus on the susceptibility to rheumatoid arthritis and the production of anti-cyclic citrullinated peptide antibodies (anti-CCP) in a Portuguese population. METHODS: 141 patients with rheumatoid arthritis fulfilling the American College of Rheumatology 1987 revised criteria for rheumatoid arthritis were compared with 150 healthy controls. Human leucocyte antigen (HLA)-DRB1 locus genotyping was assessed by polymerase chain reaction reverse probing assays and sequence-specific primers. Anti-CCP antibodies were quantified by ELISA in patients with rheumatoid arthritis. Frequencies between groups were compared by the two-sided Fisher's exact test and considered significant if p<0.05. RESULTS: The HLA-DRB1*04 and HLA-DRB1*10 groups were highly associated with rheumatoid arthritis (p<0.001 and p = 0.031, respectively). High titres of anti-CCP antibodies were largely associated with the presence of HLA-DRB1*04/10. CONCLUSION: The well-recognised susceptibility alleles to rheumatoid arthritis, HLA-DRB1*04, were associated with rheumatoid arthritis in Portuguese patients. The relatively rare DRB1*10 was also associated with rheumatoid arthritis, as was described previously in other southern European countries. Both groups were associated with high anti-CCP titres, reinforcing its relevance to disease onset.

Abreu I, Laroche P, Bastos A, Issert V, Cruz M, Nero P, Fonseca JE, Branco J, Machado Caetano JA. · Faculty of Medical Sciences, Department of Immunology, New University of Lisbon, Lisbon, Portugal. · Ann N Y Acad Sci. · Pubmed #16014552 No free full text.

Abstract: Our objective was to (i) compare FIDIS Rheuma, a new multiplexed immunoassay designed for simultaneous detection of IgM class rheumatoid factors (RF) directed against Fc determinants of IgG from humans and animals, with agglutination and ELISA (conventional methods) and (ii) evaluate the clinical sensitivity and specificity of biological markers for rheumatoid arthritis (RA). To do this, FIDIS technology was employed using the Luminex system. It consists of distinct color-coded microsphere sets, a flow cytometer, and digital signal processing hardware and software. Agglutination and ELISA tests were performed with commercial kits. The study included 134 samples from RA patients and 105 from healthy blood donors. For human specificity, we compared FIDIS with latex agglutination and ELISA. Relative sensitivities were 98.9% and 88.5% and specificities were 90.2% and 94.6%, respectively. For animal specificity, we compared FIDIS with Waaler-Rose and ELISA. The results were 84.9% and 71.9% for the sensitivities and 97.5% and 98.4% for the specificities, respectively. Detection of IgG anti-CCP by ELISA and IgG antikeratin by immunofluorescence was also determined in order to compare their clinical sensitivity and specificity with IgM-RF, according to the method used. The results were: IgG anti-CCP 72.3%, 97.2%; IgG antikeratin 36.6%, 100%; latex agglutination 66.4%, 97.2%; Waaler-Rose 55.9%, 96.3%; FIDIS human 73.9%, 92.1%; FIDIS animal 49.2%, 97.2%; ELISA human 93.2%, 95.5%; and ELISA animal 74.6%, 91.3%. The results showed the efficiency of FIDIS with analytical performance equivalent to the conventional methods, but having the advantage of giving quantitative results (IU/mL).

Fonseca JE, Carvalho T, Cruz M, Nero P, Sobral M, Mourão AF, Cavaleiro J, Ligeiro D, Abreu I, Carmo-Fonseca M, Branco JC. · No affiliation provided · Ann Rheum Dis. · Pubmed #15834068 links to  free full text

This publication has no abstract.