Claudio M. Mastroianni

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.

Cross-presentation of caspase-cleaved apoptotic self antigens in HIV infection

We found that the proteome of apoptotic T cells includes prominent fragments of cellular proteins generated by caspases and that a high proportion of distinct T cell epitopes in these fragments is recognized by CD8+ T cells during HIV infection. The frequencies of effector CD8+ T cells that are specific for apoptosis-dependent epitopes correlate with the frequency of circulating apoptotic CD4+ T cells in HIV-1–infected individuals. We propose that these self-reactive effector CD8+ T cells may contribute to the systemic immune activation during chronic HIV infection. The caspase-dependent cleavage of proteins associated with apoptotic cells has a key role in the induction of self-reactive CD8+ T cell responses, as the caspase-cleaved fragments are efficiently targeted to the processing machinery and are cross-presented by dendritic cells. These findings demonstrate a previously undescribed role for caspases in immunopathology.

Increased activity of matrix metalloproteinases in the cerebrospinal fluid of patients with HIV-associated neurological diseases

Matrix metalloproteinases (MMPs) have been identified as mediators of brain injury in HIV-associated neurological diseases. The activity of the 72 kDa gelatinase A (MMP-2) and 92 kDa gelatinase B (MMP-9) was detected by zymography in the cerebrospinal fluid (CSF) of 138 HIV-infected patients (40 with AIDS dementia, 83 with brain opportunistic infections and 15 neurologically asymptomatic), 26 HIV-seronegative individuals with inflammatory neurological diseases (IND) and 12 HIV-seronegative subjects with noninflammatory neurological diseases (NIND). MMP-2 was present in all CSF samples from HIV-seropositive and HIV-seronegative individuals, including those of subjects with NIND. On the contrary, MMP-9 was absent in the CSF of NIND controls, whereas the activity of this MMP was found in the 77 - 100% of CSF samples from HIV-infected patients, including those with HIV dementia, central nervous system (CNS) opportunistic infections or neurologically asymptomatic subjects. The highest levels of MMP-9 were found in the CSF of patients with cryptococcosis, cytomegalovirus encephalitis and tuberculous meningitis and were comparable with those found in the CSF of HIV-negative patients with multiple sclerosis or meningitis. A significant correlation between CSF MMP-9 activity and CSF cell count was found only in patients with HIV dementia. The increased CSF activity of MMPs capable to degrade components of the extracellular matrix of blood-brain barrier may contribute to the transendothelial migration of virus-infected cells into the CNS and development of HIV-associated neurologic damage.

Hepatitis E Virus Genotype 4 Outbreak, Italy, 2011

During 2011, 5 persons in the area of Lazio, Italy were infected with a monophyletic strain of hepatitis E virus that showed high sequence homology with isolates from swine in China. Detection of this genotype in Italy parallels findings in other countries in Europe, signaling the possible spread of strains new to Western countries.

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.

HIV Persistence in the Gut Mucosa of HIV-Infected Subjects Undergoing Antiretroviral Therapy Correlates with Immune Activation and Increased Levels of LPS

We investigated the relationship between viral persistence in the gut, microbial translocation, and T cell activation during chronic HIV infection. Plasma levels of LPS, fraction of circulating CD8+CD38+ T cells, and levels of HIV-DNA in rectosigmoid biopsies and peripheral blood mononuclear cells were determined in 22 HIV-infected individuals and 10 healthy controls. We found that in untreated HIV-infected individuals, HIV-DNA load was higher in the gut mucosa than in the blood. Also, ART-treated patients exhibited lower levels of LPS and CD8+CD38+ T cells than untreated patients, but higher levels than controls. In ART-treated individuals, the level of HIV-DNA in the gut correlated with levels of LPS and fraction of CD8+CD38+ T cells. We concluded that in ART-treated individuals, higher levels of gut-associated HIV-DNA are associated with persistent immune activation and microbial translocation.

In Vivo and In Vitro Effects of Antituberculosis Treatment on Mycobacterial Interferon-γ T Cell Response

Background In recent years, the impact of antituberculous treatment on interferon (IFN)-γ response to Mycobacterium tuberculosis antigens has been widely investigated, but the results have been controversial. The objective of the present study was: i) to evaluate longitudinal changes of IFN-γ response to M. tuberculosis-specific antigens in TB patients during antituberculous treatment by using the QuantiFERON-TB Gold (QFT-G) assay; ii) to compare the differences in T-cell response after a short or prolonged period of stimulation with mycobacterial antigens; iii) to assess the CD4+ and CD8+ T cells with effector/memory and central/memory phenotype; iv) to investigate the direct in vitro effects of antituberculous drugs on the secretion of IFN-γ. Principal Findings 38 TB patients was evaluated at baseline and at month 2 and 4 of treatment and at month 6 (treatment completion). 27 (71%) patients had a QFT-G reversion (positive to negative) at the end of therapy, while 11 (29%) TB patients remained QFT-G positive at the end of therapy. Among the 11 patients with persistent positive QFT-G results, six had a complete response to the treatment, while the remaining 5 patients did not have a resolution of the disease. All 27 patients who became QFT-G negative had a complete clinical and microbiological recovery of the TB disease. In these patients the release of IFN-γ is absent even after a prolonged 6-day incubation with both ESAT-6 and CFP-10 antigens and the percentage of effector/memory T-cells phenotype was markedly lower than subjects with persistent positive QFT-G results. The in vitro study showed that antituberculous drugs did not exert any inhibitory effect on IFN-γ production within the range of therapeutically achievable concentrations. Conclusions The present study suggests that the decrease in the M. tuberculosis-specific T cells responses following successful anti-TB therapy may have a clinical value as a supplemental tool for the monitoring of the efficacy of pharmacologic intervention for active TB. In addition, the antituberculous drugs do not have any direct down-regulatory effect on the specific IFN-γ response.

Chemokine profiles in the cerebrospinal fluid (CSF) during the course of pyogenic and tuberculous meningitis

The concentrations of the chemokines IL‐8, monocyte chemotactic protein‐1 (MCP‐1) and macrophage inflammatory protein‐1α (MIP‐1α) were measured in 120 CSF samples from 23 patients with pyogenic meningitis and from 11 patients with tuberculous meningitis (TBM) and in 10 CSF from subjects with non‐infectious neurological diseases. The chemokine concentrations in patients with meningitis were significantly higher than in control subjects (P < 0.0001). The highest CSF levels were found for IL‐8 (median 2917 pg/ml) and MCP‐1 (median 2557 pg/ml), whereas those of MIP‐1α were less significantly elevated (median 24 pg/ml) (P < 0.0001). Patients with pyogenic meningitis had higher levels of IL‐8 and MCP‐1 than those with TBM (P < 0.0001). In serial samples from patients with pyogenic meningitis IL‐8 levels declined before MCP‐1 and MIP‐α. In the case of TBM, IL‐8, MCP‐1 and MIP‐1α decreased more gradually during treatment and were detectable in the CSF for several weeks, without any characteristic time course of elimination. These data indicate that patients with pyogenic meningitis and TBM show different chemokine profiles in CSF. The distinct chemokine pattern could be responsible for a differential attraction and activation of leucocytes in the CSF which is reflected in differences in the inflammatory response and clinical course of pyogenic meningitis and TBM.

In vitro effect of anti-human immunodeficiency virus CCR5 antagonist maraviroc on chemotactic activity of monocytes, macrophages and dendritic cells

Compounds targeting the chemokine receptor CCR5 have recently been approved for treatment of human immunodeficiency virus (HIV) infection. Given the central role of CCR5 in inflammation and recruitment of antigen‐presenting cells (APC), it is important to investigate the immunological consequences of pharmacological inhibition of CCR5. We evaluated the in vitro effect of different concentrations of CCR5 antagonist maraviroc (MVC) on cell migration of monocytes, macrophages (MO) and monocyte‐derived dendritic cells (MDC) towards peptide formyl‐methionyl‐leucyl‐phenylalanine (fMLP) and chemokines regulated upon activation normal T cell expressed and secreted (RANTES) and CCL4/macrophage inflammatory protein‐1 (MIP‐1β) and CCL2/monocyte chemotactic protein‐1 (MCP‐1). Results of flow cytometric analysis showed that monocytes treated in vitro with MVC exhibited a significant dose‐dependent reduction of chemotaxis towards MIP‐1β and MCP‐1. fMLP‐induced chemotactic activity decreased only at higher concentration (1 µM and 10 µM of MVC). In addition, all concentrations of MVC (0·1, 1 and 10 µM) induced in vitro a significant inhibition of chemotaxis of MO and MDC in response to all tested chemoattractants. No change in phenotype (CD1a and CD14) and CCR1, CCR4, CCR5 and formyl peptide receptor (FPR) expression was seen after in vitro treatment with MVC. These findings suggest that CCR5 antagonist MVC may have the in vitro ability of inhibiting the migration of innate immune cells by mechanism which could be independent from the pure anti‐HIV effect. The drug might have a potential role in the down‐regulation of HIV‐associated chronic inflammation by blocking the recirculation and trafficking of MO and MDC.

Current trends in management of hepatitis B virus reactivation in the biologic therapy era

Hepatitis B virus (HBV) reactivation represents an emerging cause of liver disease in patients undergoing treatment with biologic agents. In particular, the risk of HBV reactivation is heightened by the use monoclonal antibodies, such as rituximab (anti-CD20) and alemtuzumab (anti-CD52) that cause profound and long-lasting immunosuppression. Emerging data indicate that HBV reactivation could also develop following the use of other biologic agents, such as tumor necrosis factor (TNF)-α inhibitors. When HBV reactivation is diagnosed, it is mandatory to suspend biologic treatment and start antiviral agents immediately. However, pre-emptive antiviral therapy prior to monoclonal antibody administration is crucial in preventing HBV reactivation and its clinical consequences. Several lines of evidence have shown that risk of HBV reactivation is greatly reduced by the identification of high-risk patients and the use of prophylactic antiviral therapy. In this article, we discuss current trends in the management of HBV reactivation in immunosuppressed patients receiving biologic therapy, such as rituximab, alemtuzumab and TNF-α antagonists.