Measurement of serum level of IgA-alpha[1]-AT complex in patients with rheumatoid arthritis

ABSTRACT

Rheumatoid arthritis [RA] is a severe chronic inflammatory disease that can not be easily rapidly treated. It can cause joint destruction and disability. Generally some laboratory tests, such as Rheumatoid Factor [RF], Erythrocyte Sedimentation Rate [ESR] or C-Reactive Protein [CRP] can be used for diagnosis and monitoring of the rheumatoid arthritis. However, they are not always ideal. In inflammatory diseases such as rheumatoid arthritis, the level of IgA will increase in serum; the surplus IgA can then react with some of the serum proteins such as Alpha-1-antirypsin [alpha[1] AT] to form a non-immune complex. The complex IgA - alpha[1]AT is formed by disulfide bonding between an active thiol group available on the both proteins. Some reports suggested that this complex is a good marker for RA disease without false results, while RF test has some false negative results. In this study the level of IgA-alpha[1]AT complex in thirty seven RA patients and in forty four normal subjects by ELISA methods using anti- alpha[1] antirypsin monoclonal and anti-IgA polyclonal HRP conjugated antibodies was evaluated. Routine laboratory tests of RF, CRP and ESR in patients and controls were also investigated. Our results showed that IgA-alpha [1] AT complex level in patients [43.7 +/- 15.4] is significantly higher than controls [21.5 +/- 8.3] [p<0.05]. There were significant differences between the sera complex levels in patients and controls. The RF results revealed eleven false negatives [30%] while the level of complex had only one false result [3%]. Instead of RF, a rapid and sensitive ELISA test for IgA-alpha[1]AT complex level in RA patients is strongly recommended