HIV Coreceptor Use in Heavily Treatment-Experienced Patients: Does It Take Two to Tangle?

A SERS based clinical study on HIV-1 viral load quantification and determination of disease prognosis

In resource limited settings, a cost-effective point-of-care diagnostic testing possessing the characteristics of detecting the minimum viral load of a malady like human immunodeficiency virus (HIV) acquired immune deficiency syndrome (AIDS) is a pressing priority. The present work describes a novel, rapid and field-deployable method using surface enhanced Raman spectroscopy (SERS) for detection and prognosis of HIV positive clinical samples, in seven different viral load ranges varying between 200 and 1 million copies/ml. A relationship between the increasing and decreasing intensity peaks of HIV-1 was also established for quantitation efficacy of the handheld tool. Three different types of SERS substrates: single arm Ag nanorods, double arm Ag nanorods and Au sputtered single arm Ag nanorods were used and the obtained data was compared for the three substrates. It was demonstrated that maximum enhancement was obtained for Au sputtered Ag nanorods. Rigorous coupled wave analysis (RCWA) simulations were performed to study the 'hotspots' in three different SERS substrates. Further, to explore the utility of our platform and to differentiate between the clade specific X4 and R5 tropism, their corresponding SERS spectra were studied using HIV-1 strains belonging to four different HIV-1 subtypes (A, B, C and D) which showed a clear distinction, implying the usefulness of the platform in understanding the disease prognosis. Statistical analysis of the obtained SERS spectra using principal component analysis (PCA) showed good agreement with the experimental results, confirming the ability of SERS platform to quantitate HIV-1 viral load and distinguish HIV-1 strains on the basis of their SERS spectra.

[CCR5-antagonists: contribution of a new antiretroviral class to the management of HIV infection]

Maraviroc, the first approved CCR5-antagonist, is indicated for treatment-experienced adult patients infected with mainly detectable CCR5-tropic HIV-1, which predominates throughout infection. The antiretroviral effectiveness of maraviroc in combination with an optimized ARV therapy has been reported in clinical trials including previously treated patients. The significantly greater increase in CD4 cell counts in patients treated with maraviroc could result from a specific action as well as a better capacity to diffuse in deep compartments. According to available reports, a tropic switch from R5 to X4 induced by maraviroc treatment is not expected. These observations, combined with the predominance of R5-virus throughout the disease, support the early use of maraviroc as soon as patients fail their therapy. Provided genotypic tests assessing R5 tropism are available when the plasma viral load is not detectable, the good safety profile of maraviroc, which includes lipid parameters, could justify its use in patients with successful regimen in order to reduce the subsequent risk of major adverse events.

Persistence of CCR5 usage among primary human immunodeficiency virus isolates of individuals receiving intermittent interleukin-2

OBJECTIVE

To investigate the impact of intermittent interleukin-2 (IL-2) plus combination antiretroviral therapy (cART) on HIV-1 entry co-receptor use.

METHODS

Primary HIV-1 isolates were obtained from 54 HIV-1-positive individuals at baseline and after 12 months using co-cultivation of peripheral blood mononuclear cells (PBMC) with activated PBMC of HIV-negative healthy donors. HIV-1 co-receptor use was determined on U87-CD4 cells.

RESULTS

Fourteen out of the 21 (67%) IL-2-treated individuals harbouring a primary CCR5-dependent (R5) HIV-1 isolate at baseline confirmed an R5 virus isolation after 12 months in contrast to 3 out of 7 (43%) of those receiving cART only. After 12 months, only 1 R5X4 HIV-1 isolate was obtained from 21 cART+IL-2-treated individuals infected with an R5 virus at entry (5%) vs. 2/7 (29%) patients receiving cART alone, as confirmed by a 5-year follow-up on some individuals.

CONCLUSIONS

Intermittent IL-2 administration plus cART may prevent evolution towards CXCR4 usage in individuals infected with R5 HIV-1.

Access denied? The status of co-receptor inhibition to counter HIV entry

As resistance and long-term metabolic abnormalities hamper the efficacy of previous drugs against HIV-1, targeting of HIV co-receptors represents an exciting new frontier for antiretroviral therapeutics. CCR5 inhibitors are most likely to be the new available drugs within the class of entry inhibitors. This paper reviews the most recent clinical data available on the small-molecule compounds vicriviroc and maraviroc and on the antibodies PRO 140 and CCR5mAb004, as well as some novel genetic approaches. A thorough overview of the many challenges, past, present and future, that CCR5 inhibitors encounter during their development pathway is then presented. Possible immunologic consequences are also discussed. It could be foreseen that the benefit for HIV-infected individuals derived by the use of these potential novel drugs will outweigh the costs/risks intrinsically present in every new therapeutic approach.