Fig. 1

Flow chart. Following removal of duplicates, the search produced 2482 abstracts and two articles were identified from references of review articles. Sixty-seven were considered for inclusion and full texts accessed. Forty-four articles were excluded due to a number of the following reasons: no seropositivity values (n = 9); no or inappropriate controls (n = 12); no EBV IgG or IgA data (n = 6); and non-RA data (n = 2). Full results were not available for four articles and authors were contacted for available data, however, there were insufficient data provided in each case and all were excluded. The remaining 23 studies were considered eligible for inclusion and are summarised in Additional file 2. EBV Epstein-Barr virus, Ig immunoglobulin, RA rheumatoid arthritis