Gabriele Forcina

Improvement in neutrophil and monocyte function during highly active antiretroviral treatment of HIV-1-infected patients

OBJECTIVE To investigate the effect of highly active antiretroviral treatment (HAART) on neutrophil and monocyte function in patients with moderately advanced HIV-1 infection. DESIGN Eighteen HIV-1-infected patients with CD4 T cell counts below 350/microl, no concomitant active infection, and no previous use of protease inhibitors were treated with indinavir or ritonavir and two reverse-transcriptase inhibitors and were followed up for 9 months. Ten age- and sex-matched healthy subjects were included as controls. METHODS The functional activity of neutrophils and monocytes was measured by assessing chemotaxis towards a bacterial peptide, killing activity against Candida albicans, and oxidative burst as measured by chemiluminescence production. RESULTS Neutrophils and monocytes from the treatment group exhibited a significantly diminished baseline chemotactic and fungicidal activity compared with healthy controls (P < 0.001). After starting HAART, there was a significant improvement in chemotaxis and fungicidal activity of phagocytic cells (P < 0.001). Values of chemotaxis reached normal ranges in 13 out of 18 patients (72%) for neutrophils and eight out of 18 (44%) for monocytes, whereas phagocyte killing was rarely restored to normal values (3/18 cases for monocytes and 0/18 for neutrophils). The administration of HAART was also associated with significantly increased phagocyte chemiluminescence production in response to phorbol-12-myristate 13-acetate or opsonized C. albicans (P < 0.01). CONCLUSION The functional improvement of two critical components of innate antimicrobial immunity, such as neutrophils and monocytes, may contribute to the improved cell-mediated immune responses against opportunistic infections in HAART-treated patients.

Interleukin-15 in HIV infection: immunological and virological interactions in antiretroviral-naive and -treated patients.

Objective To investigate the immunological and virological interactions between interleukin (IL)-15 and HIV in antiretroviral-naive and highly active antiretroviral therapy (HAART)-treated patients. Design Three groups of HIV-infected patients were studied: 20 untreated patients with advanced disease; eight patients with viral suppression and immunological response to HAART; and 10 patients with virological and immunological treatment failure. Eleven healthy blood donors were included as controls. Methods The following parameters were evaluated: the production of IL-15 by peripheral blood mononuclear cells (PBMC) stimulated with lipopolysaccharide, Candida albicans and Mycobacterium avium complex; the ability of IL-15 to induce the secretion of IL-8 and monocyte chemotactic protein-1 (MCP-1) from HIV-positive monocytes; and the virological effect of IL-15 and IL-2 on HIV replication in mononuclear cells. Results IL-15 production by PBMC was significantly decreased in antiretroviral-naive patients and in those with treatment failure. On the contrary, in patients with response to HAART IL-15 production was comparable to that of healthy donors. IL-15 was able to stimulate HIV-positive monocytes to produce chemokines, such as IL-8 and MCP-1, that specifically attract neutrophils and monocytes to the site of inflammation thus possibly improving immune response to pathogens during HIV infection. Finally, IL-15 had no major effect on HIV replication in vitro, while only simultaneous administration with IL-2 may induce high levels of HIV production. Conclusions This in vitro study provides new insights in the area of IL-15–HIV interactions and suggests that IL-15 may represent a potential candidate for cytokine treatment in combination with HAART during HIV infection.

Circulating levels of interleukin-7 in antiretroviral-naïve and highly active antiretroviral therapy-treated HIV-infected patients

Abstract Interleukin (IL)-7 is a critical cytokine regulating T-lymphocyte development, regeneration, and function. Purpose: This study analyzes the endogenous IL-7 production in HIV-infected patients receiving highly active antiretroviral treatment (HAART). Method: Plasma levels of IL-7 were measured by enzyme-linked immunosorbent assay (ELISA) in 11 patients with untreated advanced HIV disease, in 8 patients who successfully responded to HAART, and in 9 individuals with virological and immunological treatment failure. Results: We found that in the patients with advanced HIV disease and no treatment IL-7 concentrations were elevated and were inversely related to both CD4 + and CD8 + T-cell counts. When IL-7 was assessed in treated patients, this cytokine was below the detection limit of the assay in all participants who responded to HAART. On the contrary, patients with evidence of HAART failure had increased concentrations of IL-7 that were comparable to those found in the untreated group with progressive disease. Conclusion: These data suggest that IL-7 may play a role in the immune reconstitution of T-cells during HIV infection, especially in the context of potent antiretroviral treatments.

Ex vivo and in vitro effect of human immunodeficiency virus protease inhibitors on neutrophil apoptosis

Polymorphonuclear leukocytes (PMNL) from human immunodeficiency virus (HIV)-infected patients exhibit accelerated apoptosis and impaired functional activity. HIV protease inhibitor-based therapy produces improvements in both acquired and innate immune responses. Ex vivo and in vitro effects of HIV protease inhibitors on apoptosis and chemotaxis of PMNL were evaluated. After therapy, there was a rapid and significant decrease of PMNL apoptosis, which correlated with increased chemotactic function. These findings were found both in patients with immunological and virological response and in control subjects who showed an increase in CD4(+) T cell counts but no concomitant decline in HIV load. After in vitro treatment with ritonavir or indinavir, apoptosis of both HIV-infected and -uninfected PMNL markedly decreased and correlated with significant enhancement of chemotaxis. These results suggest that HIV protease inhibitors may improve the PMNL function by reducing the apoptosis rate and that this effect may, at least in part, be independent of their antiviral activity.

Discordant response to antiretroviral therapy: HIV isolation, genotypic mutations, T-cell proliferation and cytokine production

Objective: To study virologic and immunologic factors associated with discordant treatment response in HIV-infected patients receiving highly active antiretroviral therapy (HAART). Design: Study participants included a total of 27 patients: (a) 10 discordant patients (mean CD4+ cell count, 396.1 × 106 cells/l; mean HIV-RNA, 5.4 log10 copies/ml); (b) seven responder patients (mean CD4+ cell count, 997.5 × 106 cells/l); and (c) 10 failing patients (mean CD4+ cell count 66.5 × 106 cells/l; mean HIV-RNA, 5.4 log10 copies/ml). Methods: The HIV-1 isolation rate and biological phenotype, drug resistance genotypic mutations of HIV-1 strains, recall and HIV-1-specific antigen lymphocyte proliferation (LP), and interleukin (IL)-15 production were studied. Results: Virus isolation was obtained in 30% of discordant patients, and in 100% of failing patients. A higher replication constant was reported in discordant patients. No difference in the number of drug resistance mutations and biological phenotypes of HIV-1 was found in discordant patients with respect to failing patients. Discordant patients developed positive LP responses to Candida albicans and HIV-1 p24. LP in response to C. albicans, HIV-1 p24 and gp160 was positive in responder patients. No significant LP was found in failing patients. Increased levels of IL-15 after stimulation with lipopolysaccaride (LPS) and C. albicans were found in both discordant patients and responder patients. Conversely, a strong reduction of IL-15 levels was observed in failing patients. Conclusion: The present results suggest that decreased virus isolation rate, restoration of both lymphocyte proliferation and IL-15 production are factors involved in the discordant antiretroviral therapy response of HIV-infected patients.

Interleukin-15 production by monocyte-derived dendritic cells and T cell proliferation in HIV-infected patients with discordant response to highly active antiretroviral therapy

A discordant response to highly active antiretroviral therapy (HAART) occurs when CD4 T cell counts are stable or increased over time despite persistently detectable HIV‐RNA levels. In order to identify immunological factors affecting discordant treatment responses, a total of 27 HIV‐infected patients were studied: (a) 10 naive patients (mean CD4+ = 101·5 cells/µl; mean HIV‐RNA = 4·8 log10 copies/ml); (b) seven responder patients (mean CD4+ = 908·9 cells/µl); and (c) 10 discordant patients (mean CD4+ = 396·1 cells/µl; mean HIV‐RNA = 5·4 log10 copies/ml). Five healthy blood donors were included as HIV‐seronegative controls. The following parameters were evaluated: interleukin (IL)‐15 production by monocyte‐derived dendritic cells (MDDC) after stimulation with lypopolysaccaride (LPS) and Candida albicans; recall and HIV‐1‐specific antigen lymphocyte proliferation (LP). Increased levels of IL‐15 production by MDDC after stimulation with LPS and C. albicans were found both in discordant patients and responder patients. Conversely, a strong reduction of IL‐15 levels was observed in naive patients. Discordant patients developed positive LP responses to C. albicans and HIV‐1 p24. LP in response to C. albicans and HIV‐1 p24 was also positive in responder patients. Decreased LP response was found in naive patients. In conclusion, HIV‐infected patients with discordant viro‐immunological responses to HAART present increased levels of IL‐15 production by MDDC and enhanced recall and HIV‐1‐specific antigen LP responses, suggesting an improvement in indices of immune function.

Adherence and Genotypic Drug Resistance Mutations in HIV-1-Infected Patients Failing Current Antiretroviral Therapy

Abstract The aim of this study was to assess the correlation between the estimated adherence of HIV-1 infected patients with antiretroviral (ARV) therapy failure and drug-resistant mutations. We studied 40 patients with virological and immunological ARV-therapy failure. in order to assess the adherence of patients we used the SERAD questionnaire. Genomic sequencing of the HIV-1 pol gene was performed. 100% adherence was reported by 27 patients (67.5%) (adherent patients). multivariate analysis showed that only baseline and nadir CD4+ counts maintained a significant correlation with the adherence. for PR and NNRTI mutations, we did not find any difference between the two groups of patients. baseline NRTI mutations were higher in adherent patients than in non-adherent patients (p<0.05). No differences were found between plasma mutations and PBMC mutations. The authors conclude that genotypic resistance mutations were found in the majority of patients with ARV-therapy failure despite a good self-reported adherence to therapy. Adequate adherence to therapy is not the only key factor in viral suppression.