WPI remains convinced -retrovirus linked to CFS

[Guest guest]

http://www.wpinstitute.org/news/docs/WPIresponse_050911.pdf

WHITTEMORE PETERSON

INSTITUTE FOR NEURO IMMUNE DISEASE

May 9, 2011

While WPI researchers continue to review the data

presented by Dr. Singh, we believe that it is

important to correct and clarify information regarding

this study.

Several individuals were consented to

participate in this study as positive controls to

enable Dr. Singh to develop assays to detect

multiple variants of XMRV.

Of these, only three were from the original Lombardi

et al. cohort, two of whom were among those

positive for a XMRV.

A XMRV was isolated from one of those patient's

PBMCs, cloned and fully sequenced (GenBank®

accession number GQ 497343 as identified in the NIH

genetic sequence database).

Sequence data demonstrates that this virus is clearly

distinct from XMRV (vp62) and 22Rv1.

A budding virus particle from that sample was

pictured in an electron micrograph in Lombardi et

al.

Virus from that patient sample was also transmitted

both from the PBMCs and plasma to an uninfected

indicator cell line, LNCaP.

Finally, these results were supported by a separate

lab using serological methods as reported by

Lombardi et al.

Twelve additional samples from individuals not

included in the Lombardi et al. study were

independently collected by a third party and sent

directly to Dr. Singh's lab.

Some of these subjects were positive for highly

related sequences, including the polytropic and

modified polytropic sequences identified by Lo et al.,

as determined by the WPI prior to the publication of

the Singh study.

Many of those subjects were also positive for ENV

antibodies to a XMRV (vp62 and other XMRV family

members), indicating that these patients had an

immune response to a XMRV.

In addition, WPI investigators and others have

provided evidence of sequence diversity between a

XMRV (vp62), other similar XMRVs detected by WPI

(designated internally with a number corresponding

to a clinical isolate), a XMRV (p variant), and other

related human gamma retroviruses.

Therefore, we believe that it is vitally important that

investigators interested in furthering the

understanding of blood borne XMRV as a human

pathogen use a proven positive clinical isolate as the

control when developing tests to detect this newly

discovered human retrovirus.

WPI and the U.S. clinical laboratory performing XMRV

tests pursuant to a license agreement with WPI

have extensive controls in place to prevent and

detect contamination.

Approximately three thousand tests have been

performed on patient samples to date using clinically

validated tests; about one third have been found to

be positive.

Multiple sequences from these three thousand

samples have been submitted to GenBank® and are

awaiting publication.

It is critical, in light of these findings, that all

treatment decisions are left to physicians and their

patients, including the use of antiretrovirals.

While WPI researchers acknowledge that there is

still much to be learned about the lifecycle and in

vivo reservoirs of this family of human gamma

retroviruses, we remain confident in the results

reported in Science by Lombardi et al.

Most importantly, we are committed to human

gamma retroviral research in neuro-immune disease

and will continue to offer our help to the medical and

scientific community when requested.