It was reported earlier that a few @entity1 suffering from @entity1893 had low amounts of DNA from the so-called fifth @entity1 exogenous retrovirus, HRV-5. A sensitive and rational method for large-scale screening for HRV-5 DNA was therefore developed. It is a single-tube nested quantitative PCR (stnQPCR), which uses two functionally isolated primer pairs and one probe target distinct from related endogenous retroviral sequences, yet encompassing known HRV-5 variation, allowing optimal use of sequence conservation. DNA from @entity706 , @entity1582 , and follicular dendritic cell lines was tested for HRV-5 positivity, as was DNA from whole blood of blood donors, @entity1893 and @entity1252 @entity1 , as well as DNA from lymph node biopsies of @entity309 @entity1 with @entity706 . One blood donor, one @entity1252 @entity1 , two previously known positive @entity1893 @entity1 , and one @entity309 @entity1 , came out positive. They had 24, 2, 148, 480 and 30 proviral copies per microg of DNA from PBMC or @entity706 tissue, respectively. During the completion of this work it was reported that HRV-5 is a @entity95 endogenous retrovirus (RERV-H), and that HRV-5 positivity was due to presence of @entity95 DNA. DNA from six RERV-H/HRV-5 positive samples was therefore retested. Three also contained @entity95 mitochondrial DNA. A search for HRV-5 antibodies using synthetic peptides was negative in sera from three RERV-H/HRV-5 positive individuals, as well as in 144 other sera, according with a noninfectious origin of the RERV-H/HRV-5 DNA in @entity1 samples. A search for possible sources of @entity95 DNA contamination was negative. Methods for prevention of PCR contamination were strictly adhered to. Three samples from RERV-H/HRV-5 positive individuals positive at the Uppsala laboratory were retested at one or two other laboratories, and all three were positive. Two other samples, which were positive in the Riga laboratory, were tested also in London and also found positive. One @entity1893 @entity1 was RERV-H/HRV-5 positive in four consecutive samples, showing that positivity was a property of that @entity1 . It is concluded that the stnQPCR developed to detect and quantify minute amounts of RERV-H/HRV-5 DNA is a principle which can be applied widely and HRV-5 is a RERV-H. Its presence in a few @entity1 blood samples could not be explained.

Single-tube nested quantitative PCR: a rational and sensitive technique for detection of retroviral DNA. Application to RERV-H/HRV-5 and confirmation of its XXXX origin.

@entity1 :: ('9606', 'Species') :: ['human', 'patients', 'patient'] @entity706 :: ('MESH:D008223', 'Disease') :: ['lymphoma'] @entity1252 :: ('MESH:D008180', 'Disease') :: ['systemic lupus erythematosus'] @entity95 :: ('9986', 'Species') :: ['rabbit'] @entity1582 :: ('MESH:D009101', 'Disease') :: ['myeloma'] @entity1893 :: ('MESH:D008228', 'Disease') :: ["non-Hodgkin's lymphoma"] @entity309 :: ('MESH:D001172', 'Disease') :: ['rheumatoid arthritis', 'rheumatoid arthritis lymphoma']
@entity95 :: (9986,Species) :: ['rabbit']
