These studies did not investigate other EBV antibody isotypes, whereas one of the studies reported that certain cytokines were upregulated within the 5 year pre-diagnostic time window and that the presence of IgG-ACPA and IgM- and IgA-rheumatoid factors may precede RA by at least two decades indicating a long induction period (29). This evidence concerns the gene PRTN3 and rheumatoid arthritis.