Novel human immunodeficiency virus type 1 protease mutations potentially involved in resistance to protease inhibitors

Plasma-derived sequences of human immunodeficiency virus type 1 (HIV-1) protease from 1,162 patients (457 drug-naive patients and 705 patients receiving protease inhibitor [PI]-containing antiretroviral regimens) led to the identification and characterization of 17 novel protease mutations potentially associated with resistance to PIs. Fourteen mutations were positively associated with PIs and significantly correlated in pairs and/or clusters with known PI resistance mutations, suggesting their contribution to PI resistance. In particular, E34Q, K43T, and K55R, which were associated with lopinavir treatment, correlated with mutations associated with lopinavir resistance (E34Q with either L33F or F53L, or K43T with I54A) or clustered with multi-PI resistance mutations (K43T with V82A and I54V or V82A, V32I, and I47V, or K55R with V82A, I54V, and M46I). On the other hand, C95F, which was associated with treatment with saquinavir and indinavir, was highly expressed in clusters with either L90M and I93L or V82A and G48V. K45R and K20T, which were associated with nelfinavir treatment, were specifically associated with D30N and N88D and with L90M, respectively. Structural analysis showed that several correlated positions were within 8 A of each other, confirming the role of the local environment for interactions among mutations. We also identified three protease mutations (T12A, L63Q, and H69N) whose frequencies significantly decreased in PI-treated patients compared with that in drug-naive patients. They never showed positive correlations with PI resistance mutations; if anything, H69N showed a negative correlation with the compensatory mutations M36I and L10I. These mutations may prevent the appearance of PI resistance mutations, thus increasing the genetic barrier to PI resistance. Overall, our study contributes to a better definition of protease mutational patterns that regulate PI resistance and strongly suggests that other (novel) mutations beyond those currently known to confer resistance should be taken into account to better predict resistance to antiretroviral drugs

Occupational HIV infection in a research laboratory with unknown mode of transmission : a case report

A lab-worker was infected with HIV-1 in a biosafety level-2 of containment, without any apparent breach. Through full-genome sequencing and phylogenetic analyses, we could identify the source of infection in a replication-competent clone, unknowingly contaminating a safe experiment. Mode of transmission remains unclear. Caution is warranted when handling HIV-derived constructs

Macrophages and HIV infection: Therapeutical approaches toward this strategic virus reservoir

Cells of macrophage lineage represent a key target of human immunodeficiency virus (HIV) in addition to CD4-lymphocytes. The absolute number of infected macrophages in the body is relatively low compared to CD4-lymphocytes. Nevertheless, the peculiar dynamics of HIV replication in macrophages, their long-term survival after HIV infection, and their ability to spread virus particles to bystander CD4-lymphocytes, make evident their substantial contribution to the pathogenesis of HIV infection. In addition, infected macrophages are able to recruit and activate CD4-lymphocytes through the production of both chemokines and virus proteins (such as nef). In addition, the activation of the oxidative pathway in HIV-infected macrophages may lead to apoptotic death of bystander, not-infected cells. Finally, macrophages are the most important target of HIV in the central nervous system. The alteration of neuronal metabolism induced by infected macrophages plays a crucial role in the pathogenesis of HIV-related encephalopathy. Taken together, these results strongly support the clinical relevance of therapeutic strategies able to interfere with HIV replication in macrophages. In vitro data show the potent efficacy of all nucleoside analogues inhibitors of HIV-reverse transcriptase in macrophages. Nevertheless, the limited penetration of some of these compounds in sequestered districts, coupled with the scarce phosphorylation ability of macrophages, suggests that nucleoside analogues carrying preformed phosphate groups may have a potential role against HIV replication in macrophages. This hypothesis is supported by the great anti-HIV activity of tenofovir and other acyclic nucleoside phosphonates in macrophages that may provide a rationale for the remarkable efficacy of tenofovir in HIV-infected patients. Non-nucleoside reverse transcriptase inhibitors (NNRTI) do not affect HIV-DNA chain termination, and for this reason their antiviral activity in macrophages is similar to that found in CD4-lymphocytes. Interestingly, protease inhibitors (PIs), acting at post-integrational stages of virus replication, are the only drugs able to interfere with virus production and release from macrophages with established and persistent HIV infection (chronically-infected cells). Since this effect is achieved at concentrations and doses higher than those effective in de-novo infected CD4-lymphocytes, it is possible that lack of adherence to therapy, and/or suboptimal dosage leading to insufficient concentrations of PIs may cause a resumption of virus replication from chronically-infected macrophages, ultimately resulting in therapeutic failure. For all these reasons, therapeutic strategies aimed to achieve the greatest and longest control of HIV replication should inhibit HIV not only in CD4-lymphocytes, but also in macrophages. Testing new and promising antiviral compounds in such cells may provide crucial hints about their efficacy in patients infected by HIV. © 2002 Elsevier Science B.V. All rights reserved

Diagnostic yield of endoscopic ultrasound-guided tissue acquisition of solid pancreatic lesions after inconclusive percutaneous ultrasound-guided tissue acquisition

Introduction: After a failed percutaneous ultrasound (US)-guided sampling, it is recommended that endoscopic ultrasound (EUS)-guided tissue acquisition (TA) be performed for non-resectable solid pancreatic lesions according to the European Federation of Societies for Ultrasound in Medicine and Biology. However, the diagnostic performance of EUS-guided TA in this setting is unknown. Methods: We retrospectively analyzed the performance and safety of EUS-guided TA in patients with a previous failed percutaneous biopsy. We also evaluated the diagnostic delays between the percutaneous approach and EUS diagnosis. Results: Over a period of 2 years, 49 patients were identified (29 males, mean age 65 years). The reasons for failure of percutaneous sampling were inadequate samples in 25 (52.1%) cases and lesions that were not visible or targetable in 24 (47.9%) cases. In one case, EUS-guided TA was not performed because of the interposition of a metallic biliary stent. No adverse events were recorded for both the percutaneous and EUS approaches. The median diagnostic delay was 12 days. Overall, the sensitivity and accuracy of EUS-guided TA were 92.7 and 93.7%, respectively. A subgroup analysis examined cases with inadequate samples obtained with the percutaneous approach, and the sensitivity and accuracy of EUS-guided TA were 85.7 and 88%, respectively. Conclusion: EUS-guided TA is safe and accurate for the diagnosis of pancreatic lesions after a previous inconclusive percutaneous approach