Infection of XMRV in human lymphoid tissue

Cecilia Cabrera PhD (IrsiCaixa Foundation, Badalona, Spain):

Infection of XMRV in human lymphoid tissue.
Dr. Cabrera summarized the results of a recent study on XMRV in human ton-sil tissue presented at the 15th International Conference on Human Retrovi-rology: HTLV and Related Retroviruses (Leuven/Gembloux, 2011, June 5-8).

The two key questions of this study were:
 Does XMRV replicate in human lymphoid tissue?
 Are AZT and/or Raltegravir capable of suppressing the XMRV infection?
The most relevant findings of this study, in which human tonsils were obtained from healthy donors, dissected and infected with a 22Rv1 cell culture supernatant in the presence or the absence of AZT or Raltegravir:
 Cells migrating out the tissue and tissue cells were positive for XMRV gag.
 The number of gag copies increased exponentially in time.
 Both AZT and Raltegravir blocked the detection of viral DNA.
 XMRV infection did not modify the percentage of CD3 (T cells), CD4 (T helper cells), CD8 (cytotoxic T cells), or CD19 cells (B cells),
neither the (number of naive cells/number of memory cells) ratio,
nor the immune activation markers HLA-DR and CD38.
 CXCL8 and CLCX10 could be potential candidates as markers of infection.
XMRV is able to enter, to integrate and to replicate in human lymphoid cells. The presence of XMRV didn’t result in changes of T or B cells nor in immune activation, suggesting lymphoid tissue could support latent XMRV infection.
The Irsicaixa XMRV research group has plans to study of XMRV infections in other tissues in the near future.