Figure 4

Number of anticitrullinated peptide autoantibodies positive by HLA-SE presence in pre–rheumatoid arthritis cases less than 5 years before diagnosis. Number of anticitrullinated peptide antibodies (ACPAs) positive in human leukocyte antigen shared epitope (HLA-SE)-negative (n = 23) and HLA-SE-positive (n = 40) cases diagnosed within 5 years of blood draw in the Nurses’ Health Study and Nurses’ Health Study II. P = 0.01 by χ² test for trend.