Detection of anti-citrullinated albumin antibodies as a point-of-care test for assessment of rheumatoid arthritis

Project title Detection of anti-citrullinated albumin antibodies as a point-of-care test for assessment of rheumatoid arthritis.

Summary The objective of this proposal is to validate a rapid, non-invasive, point-of-care (POC) test for anti-citrullinated albumin (anti-cit Alb) antibodies in serum and gingival crevicular fluid (GCF) for diagnosis of Rheumatoid Arthritis (RA). The use of such simple-to-use, low-cost and non-invasive POC tests in serum and oral fluid would eliminate the complexity, discomfort, biohazards, and phlebotomy costs of blood tests, and to even further expand health access to rural populations. This is a prospective, single-center, observational study for citrullinated albumin (cit-Alb) specific IgG antibodies in biological fluids, in serum and collected non-invasively in oral fluid, in RA disease.   For serum and oral fluid (GCF) validation and POC test performance for anti-cit Alb serology, these test reports are compared distinctly in people with and without RA disease as confirmed by anti-cyclic-citrullinated peptide/protein antibody (ACCP/ACPA, ACPA) and / or rheumatoid factor (RA) tests measured in accredited reference laboratories. A single blood sample and another oral fluid (GCF) sample are collected from 50 test subjects with sero-negative (SN) or sero-positive (SP) RA receiving specific medications for RA, and from about 50 controls without clinical and biochemical parameters suggestive of RA. Tests for significance of a relationship between POC and laboratory test reports, and between serum and salivary anti-cit Alb antibodies measured in POC devices, are analysed via parametric and non-parametric correlation coefficients. Investigators hypothesize that there is a direct association between serum and salivary antibodies, as anti-cit Alb IgG antibodies in serum are comparably expressed in oral fluid. It is also hypothesized that there is a positive association between presence and absence of (serum and salivary) IgG antibodies against cit-Alb and, severity and duration of disease.