HLA-DRB1 and rheumatoid arthritis: Saal et al. used RT-PCR and PCR to show that EBV DNA and EBER-1 were detected at a high rate in RA lesions of patients with the HLA-DRB1 * 0401, 0404, 0405, or 0408 allele, and that the frequency of EBV positivity in RA lesions was 41 times higher than that in the normal controls [60].