CCR2 and rheumatoid arthritis: Persistent infection in the latent phase (latent infection) was determined for HHV-6 in one RA patient only; for B19V, in three RA and four OA patients; for HHV-7, in eight RA and nine OA patients; and did not correlate with the clinical characteristics or levels of cytokines and chemokine receptors (CCR1 and CCR2).