Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Effective gene therapy for haemophilia A necessitates a vector system that is not subject to a pre-existing immune response, has adequate coding capacity, gives long-term expression and preferably can target non-dividing cells. Vector systems based on lentiviruses such as equine infectious anaemia virus (EIAV) fulfil these criteria for the delivery of factor VIII (FVIII). We have found that B domain-deleted (BDD) FVIII protein inhibits functional viral particle production when co-expressed with the EIAV vector system. Although particle numbers (as measured by reverse transcriptase activity) are near normal, RNA genome levels are reduced and measurement of integrated copies revealed the virus is severely defective in its ability to transduce target cells. This is due to the absence of sufficient vesicular stomatitis virus glycoprotein (VSV-G) envelope on viral particles derived from cells expressing FVIII. By using an internal tissue-specific promoter, that has low activity in the producer cells, to drive expression of FVIII we have overcome this inhibitory effect allowing us to generate titres approaching those obtained with vector genomes encoding reporter genes. Furthermore, we report that codon optimization of the full-length FVIII gene increased vector titres approximately 10-fold in addition to substantially improving expression per integrated vector copy.
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PMID:Analysis of factor VIII mediated suppression of lentiviral vector titres. 1804 28

When treating HIV-infected patients with hemophilia, adverse drug reactions and interactions and the effect of treatment on bleeding disorders must be considered. Raltegravir is the first HIV integrase inhibitor, but its use in patients with hemophilia is rarely reported. Nine HIV-positive patients with hemophilia were retrospectively studied with a focus on the virological response, changes in the CD4 count, the tendency to bleed, and the response to replacement therapy before and after raltegravir-based antiretroviral therapy (ART). The nine patients were highly treatment-experienced patients and they received raltegravir-based ART for at least nine months. The patients had their own reasons for changing to raltegravir-based ART. During treatment, the CD4 count increased progressively in four patients, with a median absolute increase of 233 cells/mm(3), while the count stabilized in the remaining five patients. Two previous recipients of lopinavir/ritonavir (LPV/r) who failed to respond to lamivudine (3TC) + zidovudine (ZDV) + efavirenz (EFV) had a viral rebound. Genotyping indicated multidrug resistance to nucleoside reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs). A pattern of resistance to raltegravir was evident, including the primary mutation N155H and the secondary mutation T97A. In the two patients, the tendency to bleed decreased markedly and monthly usage of clotting factor VIII decreased significantly decreased. In the remaining seven patients, the viral load remained < 40 copies/mL, there was no evidence of an increased tendency to bleed, and no evidence of changes in the response to replacement therapy. All of the patients had a stable condition with no signs of disease progression and no serious adverse reactions. Results indicated that Raltegravir-based therapy offered a safe and well-tolerated option for HIV-positive patients with hemophilia.
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PMID:Efficacy and safety of antiretroviral regimens including raltegravir to treat HIV-infected patients with hemophilia. 2691 41


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