Some believe one thing, some believe another. The most important thing is the science is allowed to play out. Many people think that the NIH multi lab study aka the Lipkin study needs to sample lymphoid tissue.
Research using Rhesus macaques has highlighted the need to look for HGRVs in lymphoid tissues. The antibody response will dissapear with time. It becomes undetectable in Blood by PCR unless the person suffers an infection or is stressed. Without reactivation antigens will be impossible to find.
Infection, viral dissemination and antibody responses of Rhesus macaques exposed to the human gammaretrovirus XMRV (Onamoon, 2011)
"XMRV established a persistent, chronic disseminated infection, with low transient viremia and provirus in blood lymphocytes during acute infection. Although undetectable in blood after about a month, XMRV viremia was reactivated at 9 months, confirming the chronicity of the infection. Furthermore, XMRV Gag was detected in tissues throughout, with wide dissemination throughout the period of monitoring. Surprisingly, XMRV infection showed organ-specific cell tropism, infecting CD4 T cells in lymphoid organs including the gastrointestinal lamina propria, alveolar macrophages in lung, and epithelial/interstitial cells in other organs, including the reproductive tract. Of note, in spite of the intravenous inoculation, extensive XMRV replication was noted in prostate during acute but not chronic infection even though infected cells were still detectable by fluorescence in situ hybridization (FISH) in prostate at 5 and 9 months postinfection. Marked lymphocyte activation occurred immediately postinfection, but antigen-specific cellular responses were undetectable. Our findings establish a nonhuman primate model to study XMRV replication/dissemination, transmission, pathogenesis, immune responses, and potential future therapies."
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3126245/