Rheumatoid Arthritis: Martínez-Cordero E

Araiza MT, Aguilar León DE, Retana VN, Martínez-Cordero E. · National Institute of Respiratory Diseases (INER), Mexico City, Mexico. · J Clin Lab Anal. · Pubmed #17847114 No free full text.

Abstract: The association of rheumatoid factor (RF) and lung disease in several immunologically mediated conditions has suggested that it may be physiopathologically relevant. Since previous reports in hypersensitivity pneumonitis (HP) have dealt mainly with the immunoglobulin M (IgM) RF measurement, we studied such antibody activity in other immunoglobulins, to determine the IgG and IgA RF levels in pigeon-HP, and in asymptomatic breeders (AB) and rheumatoid arthritis (RA) as controls. RFs were measured in 35 HP patients, 41 AB, 31 RA controls, and 55 healthy donors by enzyme-linked immunosorbent assay (ELISA) using human or rabbit immunoglobulin G (IgG), anti-IgM, F(ab')2 of IgG, and IgA F(ab')2 conjugates. An affinity chromatography, fragment crystallizable (Fc) preparations of IgG, pepsin digestion, and Western blots were used to confirm RF specificity. We also evaluated anti-avian antibodies (AA) and cross-reacting antibodies. The HP group revealed positive IgM (51.4%), IgG (31.4%), and immunoglobulin A (IgA) (34.2%) RF tests, and these antibody values exceeded the AB reference levels (P<0.02). HP and RA showed a similar frequency and distribution of RFs. Possible immunoassay interferences were excluded. As in other immunologically mediated diseases, IgG and IgA RFs may play a pathogenic role in HP, amplifying the inflammatory reaction, immune-complex formation, and complement activation. IgM-RF producing cells that have been implicated in the presentation of self and foreign antigens, and T-cell activation might induce the isotype switching of RFs.

Aguilar León DE, Novelo Retana V, Martínez-Cordero E. · School of Sciences, National University of Mexico, National Institute of Respiratory Diseases (INER), Mexico City, Mexico. · Clin Exp Allergy. · Pubmed #12580916 No free full text.

Abstract: BACKGROUND: Although several immunological abnormalities may be present in pigeon hypersensitivity pneumonitis (HP), few specific hallmarks have been described. OBJECTIVE: To determine whether the presence of rheumatoid factor (RF) could be useful to discriminate pigeon HP from asymptomatic breeders (AB) and other interstitial lung diseases. METHODS: Fifty-three patients with pigeon HP, 47 AB, 31 idiopathic pulmonary fibrosis (IPF) patients and a rheumatoid arthritis (RA) group were studied. IgM RF was determined through enzyme-linked immunosorbent assay (ELISA) and western blot using human IgG and IgG Fc fragment as antigens. IgG and IgA anti-avian antibodies (AA) against pigeon serum antigen were also measured. The use of F(ab')2 fraction of peroxidase-labelled anti-human immunoglobulins prevented endogenous interferences. Possible cross-binding of RF with avian antigens and the reactivity against human IgG by AA were studied. RESULTS: RF tests were frequently positive in HP (52.8%) in comparison to AB (4.2%) and IPF (12.9%; P = 2.6 x 10-10 and 4.1 x 10-5). Therefore, the presence of RF in pigeon HP showed a sensitivity of 52% and was highly specific considering the results of AB and IPF (95 and 87%, respectively). The RA group revealed positive RF but negative AA tests. RF activity was confirmed through western blot using purified IgG Fc fragment. Overlapping levels of IgG and IgA AA were found in HP and AB. The frequency of AA was low in IPF. The cross-reaction of RF with avian antigens was excluded, and no reactivity against human IgG by AA was detected. Other endogenous interferences were ruled out. CONCLUSION: No single immunological test may definitively distinguish pigeon HP from AB and other interstitial lung disorders; however, positive RF, together with high AA levels, seems to be useful in differentiating the diagnosis.

León AD, Téllez Araiza M, Arellano García J, Martínez-Cordero E. · Faculty of Sciences, National University of Mexico, Mexico City. · Clin Exp Med. · Pubmed #12141528 No free full text.

Abstract: The assessment of antiavian antibodies is relevant for the study of pigeon breeder's disease; nevertheless, different factors may hamper their accurate detection. The objective of this study was to determine whether an endogenous interfering effect in pigeon breeder's disease might explain the simultaneous presence of IgM, IgG, and IgA antiavian antibodies in high titers as assessed by ELISA. Fifty-nine patients with pigeon breeder's disease, 80 healthy controls, and 47 asymptomatic breeders were studied. To assess possible interfering effects by endogenous immunoglobulins, serum IgG was separated through protein A-Sepharose CL-4B chromatography. Antiavian antibodies were measured in whole and separated samples by ELISA. Since a decline of IgM antiavian antibodies following IgG removal was consistent with a false-positive effect, the causes were studied. High values of IgM, IgG, and IgA antiavian antibodies were found in 47.4% [corrected] of patients with pigeon breeder's disease. An IgM rheumatoid factor activity against IgG was found through ELISA in sera with false-positive IgM antiavian antibodies. Rheumatoid factor binding was confirmed by Western blot. Experimental addition of purified rheumatoid factor to sera with IgG antiavian antibodies replicated the interfering effect. A control group of rheumatoid arthritis with high rheumatoid factor values did not show positive antiavian antibodies tests. No IgG with anti-IgM or anti-IgA activity was found, and the detection of IgA against IgM and IgG was negative. In conclusion, the study of antiavian antibodies might be affected by different immunoassay conditions. An endogenous rheumatoid factor activity produced false-positive IgM results. Other similar interferences warrant a careful evaluation during the serological assessment of pigeon breeder's disease.

Martínez-Cordero E, León DE, Ortega LA. · National Institute of Respiratory Disease, México, DF, Mexico. · Rheumatol Int. · Pubmed #11354559 No free full text.

Abstract: The association of polymyositis (PM) and rheumatoid arthritis (RA) is described in a 40-year-old female Mexican patient who was studied for a long period of time. The characteristic changes of PM that preceded the onset of RA for 7 years included proximal symmetrical muscle weakness, increased creatine kinase activity, and distinctive electromyography and muscle biopsy results. The occurrence of RA during the final 4 years of the 11-year period was characterized by long-lasting deforming and symmetric polyarthritis, high positive rheumatoid factor, subcutaneous nodules, and erosive joint changes. Through observation, myopathic changes other than those from PM were excluded. Joint changes other than from RA were also ruled out. A review of the literature revealed few specific reports of the coexistence of both diseases.