Fecal Microbiota Transplantation for Refractory Clostridioides Difficile Infection Is Effective and Well Tolerated Even in Very Old Subjects: A Real-Life Study

OBJECTIVES

Fecal microbiota transplantation (FMT) is an innovative therapy indicated for the treatment of recurrent Clostridioides difficile infections. Although CDI and its complications are more common in very old patients (≥80 years) due to their comorbidities, frailty and senescence of the immune system, limited data are available for this older patient population.

DESIGN

This was a single-center, real-life cohort study with retrospective outcome data registration, conducted at Toulouse, France.

SETTING AND PARTICIPANTS

Older people group was compared to the control group aged 18-79 years.

MEASUREMENTS

The primary outcome was overall survival at 52 weeks for ≥80 years patients compared to the control group after FMT. Recurrence-free survival at 52 weeks and, the occurrence of adverse events in the short and long term were the secondary endpoints.

RESULTS

A total of 58 patients were included, 19 were aged ≥80 years and 39 were aged 18-79 years. Overall survival at 52 weeks after FMT of the very old patients was not different from the control group (78.9% versus 89.7%, p= 0.29). Recurrence-free survival of CDI was not different between groups, with 94.3% in the 18-79-group versus 86.9% in the ≥80 group (p=0.44). The occurrence of short- or long-term adverse events was not statistically different between the two groups (36.8% vs 41%, p=0.45).

CONCLUSIONS

FMT is effective and well-tolerated in very old frail patients. This treatment brings a rapid benefit and limits the loss of functions. It also favors their maintenance at home or in a non-medical institution dedicated to dependent subjects and improves their quality of life.

Microelimination or Not? The Changing Epidemiology of Human Immunodeficiency Virus-Hepatitis C Virus Coinfection in France 2012–2018

Background

The arrival of highly effective, well-tolerated, direct-acting antiviral agents (DAA) led to a dramatic decrease in hepatitis C virus (HCV) prevalence. Human immunodeficiency virus (HIV)-HCV–coinfected patients are deemed a priority population for HCV elimination, while a rise in recently acquired HCV infections in men who have sex with men (MSM) has been described. We describe the variations in HIV-HCV epidemiology in the French Dat’AIDS cohort.

Methods

This was a retrospective analysis of a prospective cohort of persons living with HIV (PLWH) from 2012 to 2018. We determined HCV prevalence, HCV incidence, proportion of viremic patients, treatment uptake, and mortality rate in the full cohort and by HIV risk factors.

Results

From 2012 to 2018, 50 861 PLWH with a known HCV status were followed up. During the period, HCV prevalence decreased from 15.4% to 13.5%. HCV prevalence among new HIV cases increased from 1.9% to 3.5% in MSM but remained stable in other groups. Recently acquired HCV incidence increased from 0.36/100 person-years to 1.25/100 person-years in MSM. The proportion of viremic patients decreased from 67.0% to 8.9%. MSM became the first group of viremic patients in 2018 (37.9%). Recently acquired hepatitis represented 59.2% of viremic MSM in 2018. DAA treatment uptake increased from 11.4% to 61.5%. More treatments were initiated in MSM in 2018 (41.2%) than in intravenous drug users (35.6%). In MSM, treatment at the acute phase represented 30.0% of treatments in 2018.

Conclusions

A major shift in HCV epidemiology was observed in PLWH in France from 2012 to 2018, leading to a unique situation in which the major group of HCV transmission in 2018 was MSM.

Clinical Trials Registration. NCT02898987.

Severe adverse events during medical and surgical treatment of hip and knee prosthetic joint infections

INTRODUCTION

The management of prosthetic joint infection requires a complex treatment procedure and can be associated with complications. However, the occurrence of severe adverse events during this intervention has been poorly evaluated.

PATIENTS AND METHODS

A 5-year multicentric retrospective study including patients from 3 hospitals in the South-Western France referral center for complex bone and joint infections (Crioac GSO) and treated for hip or knee prosthetic joint infection with 1 or 2-stage implant exchanges. The objective was to describe grade≥3 adverse events, according to the CTCAE classification, occurring within 6 weeks after surgery and to identify their associated factors.

RESULTS

One hundred and eighteen patients were identified. We observed 71 severe events in 50 patients (42.3%; 95% confidence interval [CI95%]: 33.8-51.4%). Sixteen severe events were an evolution of the infection. The remaining 55 others (47 grade 3 and 8 grade 4) occurred in 41 patients (34.7%; CI95%: 26.8-43.7%). They were distributed as follows: 27 (49.1%) medical complications, 21 (38.2%) surgical complications and 7 (12.7%) antibiotic-related complications. The main identified risk factor was a two-stage prosthetic exchange with OR=3.6 (CI95% [1.11-11.94], P=0.032). Obesity was limit of significance with OR=3.3 (CI95% [0.9-12.51], P=0.071). Infection with coagulase negative Staphylococcus was a protective factor with OR=0.3 (CI95% [0.12-0.99], P=0.047).

CONCLUSION

Severe adverse events are frequent following prosthetic exchange for PJI (34.7%) and are related to the high frequency of comorbidities in this population and to the complex surgical procedures required. The risk factor significantly associated with these events was a two-stage exchange.

Clinical characteristics and outcome of hospitalized patients with SARS-CoV-2 infection at Toulouse University hospital (France). Results from the Covid-clinic-Toul cohort

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has spread worldwide from epicenter of Wuhan, China since December 2019. The aim of our study was to describe the clinical characteristics and outcome of hospitalized patients with SARS-CoV-2 pneumonia at the Toulouse university hospital, France.

Patients and methods

We selected the patients included from March 7, 2020 to April 20, 2020 in the retrolective Covid-clinic-Toul cohort that follows all hospitalized patients with SARS-CoV-2 infection at the Toulouse Hospital. Cases were confirmed by real-time reverse transcriptase polymerase chain reaction. We report demographics, clinical, biological and radiological features, as well as unfavorable outcome at Day 14 after admission (admission in an intensive care unit, mechanical ventilation, death).

Results

Among 263 hospitalized patients, the median age was 65 years and 155 (58.9%) were males. Two hundred and twenty-seven patients (86.3%) had at least one comorbidity. The median time from first symptom to hospital admission was 7.0 days (interquartile range: 4–10). On day 14 after admission, 111 patients (42.2%) had been transferred to intensive care unit (ICU), including 50 (19.0%) on Day 1; 61 (23.1%) needed mechanical ventilation and 19 patients (7.2%) had died. Patients admitted to ICU at Day 1 of admission (n = 50) were more frequently men (66.0% vs 57.3%), smokers (25.0% vs 7.1%), with obesity (42.0% vs 24.7%) and had a higher mean level of C-reactive protein (median: 110.9 mg/L vs 46.2 mg/L).

Conclusion

This cohort provides epidemiological data on SARS-CoV-2 in hospitalized patients in a University hospital in the South of France.

AB1095 DIAGNOSTIC PERFORMANCE OF THE AORTIC WALL THICKENING DETERMINED BY ROUTINE CT-SCAN FOR THE DIAGNOSIS OF AORTITIS OVER 50 YEARS OF AGE

Background:

Making the diagnosis of aortitis may be challenging in the “real life”.18F-FDG PET/CT (PET) has emerged has the gold standard to diagnose aortitis but it is expensive and not always quickly available. Injected CT-scan (CT) can also be used to diagnose aortitis, which is suspected when there is an extended circumferential, non-atherosclerotic increase of the aortic wall thickness (AWT). However, data are lacking on the diagnostic performances of AWT to diagnose aortitis.

Objectives:

To describe the diagnostic performance of AWT measured by CT to diagnose aortitis in patients over 50 years of age.

Methods:

We performed a monocentric retrospective study between 2013 and 2018 including 1) all patients over 50 years of age who had performed a PET for inflammation or fever of unknown origin or for suspicion of classical giant cell arteritis (GCA), aortitis or large vessel vasculitis (LVV); 2) with an injected CT-scan performed in the 30 days before or after PET; 3) not diagnosed to have cancer or infection 4) exposed to corticosteroids for less than 3 days at the time of CT and PET. The gold standard for aortitis was PET positivity according to the 2018 European consensus grading criteria (1). AWT was measured at different aortic segments (ascending aorta, descending thoracic aorta and suprarenal abdominal aorta) by a single radiologist unaware of the result of PET and of the previous interpretation of CT-scan.

Results:

Eighty-nine patients were included (female: 47%; mean age 68.8 (50-93) years; GCA: n=28). Twenty patients had aortitis according to the PET result (GCA: n=16).

Mean maximal aortic wall thickening was: 3.25 mm (median: 3.3; range: 2-4.6) in the aortitis group and 2.2 mm (median: 2.1; range 1-3.8) in the negative PET group (p < 0.001).

The best ROC curve AUC (85%) was obtained considering the maximal AWT on the thoracic and suprarenal abdominal aorta only. The AUC of the ROC curve at the ascendant thoracic aorta was poor (75%) (Figure).

The Youden’s index of the ROC curve was 2.6 mm with a sensitivity of 85 % and specificity of 71 % (Table) for aortitis diagnosis. An AWT ≤ 2.0 mm exclude the diagnosis of aortitis. The 3 mm threshold had a PPV of only 52% and an AWT ≥ 4 mm was fully specific.

Conclusion:

Aortitis diagnosis using a routine injected CT-scan interpreted by a single radiologist may be certain when showing an AWT ≥ 4 and excluded for an AWT≤ 2.0. The threshold of 3 mm seems not sufficiently specific to diagnose aortitis without a confirmatory PET.

References:

[1]Riemer H.J.A. Slart et al. FDG-PET/CT(A) imaging in large vessel vasculitis and polymyalgia rheumatica: joint procedural recommendation of the EANM, SNMMI, and the PET Interest Group (PIG), and endorsed by the ASNC. Eur J Nucl Med Mol Imaging. 2018 Jul;45(7):1250–69.

Table.

Performance of different threshold for maximal thickness of the aortic wall for diagnosis of aortitis using PET positivity as the gold standard*.

Thickness (mm)SensitivitySpecificityNPVPPVaccuracy≥ 1.9100 %30.4%100 %29.41 %46 %≥ 2.0100 %31.88 %100 %29.85 %47 %≥ 2.295 %53.62 %97.36 %37.25 %63 %≥ 2.685 %71.01 %94.23 %45.94 %74 %≥ 3.060 %84.05 %87.88 %52.17 %78 %≥ 3.360 %92.75 %88.89 %70.59 %85 %≥ 3.535 %95.65 %83.54 %70 %82 %≥ 3.825 %98.55 %81.92 %83.33 %82 %≥ 4.020 %100 %81.17 %100 %82 %

*Made with ROC curve in descendant thoracic and suprarenal segment of the aorta; PET:18F-FDG PET/CT; NPV: negative predictive value; PPV: positive predictive value.

Figure.

ROC curve of aortic wall thickness, in descendant thoracic and suprarenal abdominal segments for the diagnosis of aortitis.

Disclosure of Interests:

None declared

Kaposi sarcoma among people living with HIV in the French DAT'AIDS cohort between 2010 and 2015

Background

Although antiretroviral therapy (ART) has reduced the risk of Kaposi sarcoma (KS), KS cases still occur in HIV‐infected people.

Objective

To describe all KS cases observed between 2010 and 2015 in a country with high ART coverage.

Methods

Retrospective study using longitudinal data from 44 642 patients in the French Dat’AIDS multicenter cohort. Patients’ characteristics were described at KS diagnosis according to ART exposure and to HIV‐plasma viral load (HIV‐pVL) (≤50 or >50) copies/mL.

Results

Among the 209 KS cases diagnosed during the study period, 33.2% occurred in ART naïve patients, 17.3% in ART‐experienced patients and 49.5% in patients on ART, of whom 23% for more than 6 months. Among these patients, 24 (11.5%) had HIV‐pVL ≤50 cp/mL, and 16 (66%) were treated with a boosted‐PI‐based regimen. The distribution of KS localization did not differ by ART status nor by year of diagnosis.

Limitations

Data on human herpesvirus 8, treatment modalities for KS and response rate were not collected.

Conclusion

Half of KS cases observed in the study period occurred in patients not on ART, reflecting the persistence of late HIV diagnosis. Factors associated with KS in patients on ART with HIV‐pVL ≤50 cp/mL remain to be explored.

COVID-19, Virology and Geroscience: A Perspective

A new coronavirus, called SARS-CoV-2, was identified in Wuhan, China, in December 2019. The SARS-CoV-2 spread very rapidly, causing a global pandemic, Coronavirus Disease 2019 (COVID-19). Older adults have higher peak of viral load and, especially those with comorbidities, had higher COVID-19-related fatality rates than younger adults. In this Perspective paper, we summarize current knowledge about SARS-CoV-2 and aging, in order to understand why older people are more affected by COVID-19. We discuss about the possibility that the so-called "immunosenescence" and "inflammaging" processes, already present in a fraction of frail older adults, could allow the immune escape of SARS-CoV-2 leading to COVID-19 serious complications. Finally, we propose to use geroscience approaches to the field of COVID-19.

Too fast to stay on track? Shorter time to first anti-retroviral regimen is not associated with better retention in care in the French Dat'AIDS cohort

BACKGROUND

Rapid antiretroviral therapy (ART) initiation has been proven beneficial for patients and the community. We aimed to analyze recent changes in timing of ART initiation in France and consequences of early start.

METHODS

We selected from a prospective nationwide cohort, on 12/31/2017, patients with HIV-1 infection diagnosed between 01/01/2010 and 12/31/2015. We described time from (1) diagnosis to first specialized medical encounter, (2) from this encounter to ART initiation, (3) from diagnosis to first undetectable HIV viral load (VL). We analyzed the determinants of measured temporal trends. A multivariate logistic regression was performed to assess characteristics related with 1-year retention in care.

RESULTS

In the 7 245 included patients, median time (1) from HIV diagnosis to first medical encounter was 13 (IQR: 6-32) days, (2) to ART initiation was 27 (IQR: 9-91) days, decreasing from 42 (IQR: 13-272) days in 2010 to 18 (IQR: 7-42) in 2015 (p<0.0001), (3) to first undetectable VL was 257 (IQR: 151-496) days, decreasing from 378 (IQR: 201-810) days in 2010 to 169 (IQR: 97-281) in 2015. After one year, proportion of patients alive and still in care was significantly lower in those in the lower quartile of time from first encounter to ART (<9 days) than those in the higher quartile (>90 days), 79.9% and 85.2%, respectively (p<0.0001).

CONCLUSIONS

In a country with unrestricted rapid access to ART, keeping recently diagnosed HIV infected patients in care remains challenging. Starting ART rapidly did not seem to be profitable for all and every patient.

Increased CXCR3+ T Cells Impairs Recruitment of T-Helper Type 17 Cells via Interferon γ and Interleukin 18 in the Small Intestine Mucosa During Treated HIV-1 Infection

The restoration of CD4+ T cells, especially T-helper type 17 (Th17) cells, remains incomplete in the gut mucosa of most human immunodeficiency virus type 1 (HIV-1)–infected individuals despite sustained antiretroviral therapy (ART). Herein, we report an increase in the absolute number of CXCR3+ T cells in the duodenal mucosa during ART. The frequencies of Th1 and CXCR3+ CD8+ T cells were increased and negatively correlated with CCL20 and CCL25 expression in the mucosa. In ex vivo analyses, we showed that interferon γ, the main cytokine produced by Th1 and effector CD8+ T cells, downregulates the expression of CCL20 and CCL25 by small intestine enterocytes, while it increases the expression of CXCL9/10/11, the ligands of CXCR3. Interleukin 18, a pro-Th1 cytokine produced by enterocytes, also contributes to the downregulation of CCL20 expression and increases interferon γ production by Th1 cells. This could perpetuate an amplification loop for CXCR3-driven Th1 and effector CD8+ T cells recruitment to the gut, while impairing Th17 cells homing through the CCR6-CCL20 axis in treated HIV-1–infected individuals.

Antiretroviral unbound concentration during pregnancy: piece of interest in the puzzle?

Atazanavir and darunavir total concentrations (drug bound to plasma proteins plus unbound drug) progressively decrease during pregnancy. This pharmacokinetic variation leads physicians to recommend increasing doses. Conversely, the unbound concentration (Cu), i.e. the pharmacologically active form of the drug, remains unchanged. The explanation of this desynchronization lies in the fact that the clearance of the unbound form, corresponding to the intrinsic metabolic capacity of the hepatocytes, is the only factor driving Cu, and is constant during pregnancy. The attention of HIV physicians should be attracted to this aspect of pharmacokinetics, which is often incompletely understood and could lead to inadequate dose adjustment, which could then cause overexposure of the foetus for many months, with unknown consequences.

Direct-acting antiviral treatment against hepatitis C virus infection in HIV-Infected patients - "En route for eradication"?

OBJECTIVES

Direct-Acting Antivirals (DAAs) opened a new era in HCV treatment. We report the impact of HCV treatment in French HIV-HCV coinfected patients.

METHODS

All HIV-HCV patients from the Dat'AIDS cohort followed between 2012 and 2015 were included. HCV status was defined yearly as naive, spontaneous cure, sustained virological response (SVR12), failure or reinfection.

RESULTS

Among 32,945 HIV-infected patients, 15.2% were positive for anti-HCV antibodies. From 2012 to 2015, HCV incidence rate increased from 0.35%PY to 0.69%PY in MSM, while median incidence was 0.08%PY in other patients. Median reinfection rate was 2.56%PY in MSM and 0.22%PY in other patients. HCV treatment initiation rate rose from 8.2% in 2012 to 29.6% (48.0% in pre-treated patients vs 22.6% in naïve patients). SVR12 rate increased from 68.7% to 95.2%. By the end of 2015, 62.7% of the patients were cured either spontaneously or following SVR.

CONCLUSIONS

HCV treatment dramatically increased in HIV-HCV patients in France from 2012 to 2015 resulting in HCV cure in nearly two-thirds of the patients in this cohort. Combined with a declining HCV prevalence, the prevalence of active HCV infection among HIV patients will drastically decrease in the forthcoming years.

FDG-PET/CT findings during immune reconstitution in an HIV-1 patient infected with visceral leishmaniasis

Visceral leishmaniasis can rarely be unmasked by immune reconstitution in human immunodeficiency virus (HIV)-1-infected patients. We report the first case of immune reconstitution associated with leishmaniasis in an HIV patient to be imaged with [(18)F]fluorodeoxyglucose positron emission tomography (FDG/PET), at both baseline and after therapy.

A 'fragile cell' sub-population revealed during cytometric assessment of Saccharomyces cerevisiae viability in lipid-limited alcoholic fermentation

AIMS

To show that in anaerobic fermentation with limiting lipid nutrients, cell preparation impacts the viability assessment of yeast cells, and to identify the factors involved.

METHODS AND RESULTS

Saccharomyces cerevisiae viability was determined using propidium iodide staining and the flow cytometry. Analyses identified intact cells, dead cells and, under certain conditions, the presence of a third subpopulation of apparently damaged cells. This intermediate population could account for up to 40% of the entire cell population. We describe, analyse and discuss the effects of different solutions for cell resuspension on the respective proportion of these three populations, in particular that of the intermediate population. We show that this intermediate cell population forms in the absence of Ca(2+)/Mg(2+).

CONCLUSIONS

Cell preparation significantly impacts population viability assessment by FCM. The intermediate population, revealed under certain conditions, could be renamed as 'fragile cells'. For these cells, Ca(2+) and Mg(2+) reduce cell membrane permeability to PI.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study that analyses and discusses the factors influencing the formation of an intermediate population when studying viability in yeast alcoholic fermentation. With a wider application in biological research, this study provides important support to the relatively new questioning of propidium iodide staining as a universal cell death indicator.

Factors associated with a strictly undetectable viral load in HIV-1-infected patients

OBJECTIVES

The aim of the study was to identify factors associated with a strictly undetectable viral load (VL) using a routine sensitive real-time polymerase chain reaction (RT-PCR) technology.

METHODS

From a large prospective cohort, 1392 patients with a VL<50 HIV-1 RNA copies/mL while receiving a three-drug suppressive regimen for at least 1 year were included in a cross-sectional analysis. Patients were classified into three groups and compared by univariate and multivariate analysis: 479 patients with a strictly undetectable VL (group 1; 34%), 617 patients with detectable VL below the threshold of 20 copies/mL (group 2; 44%), and 296 patients with a VL of 20-50 copies/mL (group 3; 12%).

RESULTS

Comparing groups 1 and 2, VL zenith<5 log(10) copies/mL [odds ratio (OR) 1.51; 95% confidence interval (CI) 1.15-1.99; P=0.003], current CD4 T-cell count<500 cells/μL (OR 1.44; 95% CI 1.08-1.92; P=0.01), and duration of viral suppression<50 copies/mL longer than 2 years (OR 2.32; 95% CI 1.20-4.54; P=0.01) were associated with undetectable VL. Comparing groups 1 and 3, VL zenith<5 log(10) copies/mL (OR 2.48; 95% CI 1.75-3.50; P<0.001), duration of viral suppression<50 copies/mL longer than 1 year (OR 3.33; 95% CI 1.66-6.66; P=0.0006), and nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimens (OR 1.45; 95% CI 1.03-2.04; P=0.03) were associated with undetectable VL. No individual drug effect was found within NNRTI molecules.

CONCLUSIONS

Longer duration of viral suppression<50 copies/mL, lower viral load zenith and NNRTI-based regimen were independently associated with a strictly undetectable viral load. This routinely used RT-PCR assay may prove to be a valuable tool in further large-scale studies.

[Impact of malaria on HIV infection]

Malaria and HIV are two major public health issues, especially in sub-Saharan Africa. HIV infection increases the incidence of clinical malaria, inversely correlated with the degree of immunodepression. The effect of malaria on HIV infection is not as well established. Malaria, when fever and parasitemia are high, may be associated with transient increases in HIV viral load. The effect of subclinical malaria on HIV viral load is uncertain. During pregnancy, placental malaria is associated with higher plasma and placental HIV viral loads, independently of the severity of immunodeficiency. However, the clinical impact of these transient increases of HIV viral load remains unknown. Although some data suggests that malaria might enhance sexual and mother-to-child transmissions, no clinical study has confirmed this. Nevertheless pregnant women and children with malaria-induced anemia are also exposed to HIV through blood transfusions. Integrated HIV and malaria control programs in the regions where both infections overlap are necessary.

Low interleukin-10 production by monocytes of patients with a self-limiting hepatitis C virus infection

Host factors seem to be crucial for the spontaneous clearance of hepatitis C virus (HCV). Monocytes play a pivotal role in innate immunity and help regulate adaptive responses. This study assesses the characteristics of monocytes from patients with self-limiting HCV infections. We studied 35 consecutive patients [11 with a self-limiting HCV infection, 16 chronically infected with HCV and sustained virological responders (SVR) following antiviral therapy, and eight chronically infected HCV but untreated] and eight healthy donors (HD). The production of interleukin (IL)-10, tumour necrosis factor-alpha (TNF-alpha) and IL-12p40 by monocytes stimulated with lipopolysaccharides(LPS) or HCV Core protein was measured by enzyme-linked immunoassay. Monocyte surface markers were analysed by flow cytometry. LPS and Core protein triggered IL-10 and TNF-alpha production, but monocytes from self-limiting infection patients produced significantly less IL-10 and TNF-alpha than those of SVR, chronically infected or HD (P < 0.05), while IL-12p40 production was unchanged. This cytokine production profile did not appear to be due to expansion of the CD14(+) CD16(+) monocyte subset or to a classical or alternative activation monocyte profile. Monocytes from self-limiting infection patients had more CCR7 than those from SVR or chronically infected patients (P < 0.05). Monocytes of self-limiting infection patients appear to produce little IL-10 and TNF-alpha in response to viral or unspecific stimulation and to have a higher CCR7 expression. This profile seems to be independent to a particular monocyte subset or activation state. Low IL-10 production may help establish an effective immune response and spontaneous HCV clearance.

Gene expression profiling of Spodoptera frugiperda hemocytes and fat body using cDNA microarray reveals polydnavirus-associated variations in lepidopteran host genes transcript levels

Background

Genomic approaches provide unique opportunities to study interactions of insects with their pathogens. We developed a cDNA microarray to analyze the gene transcription profile of the lepidopteran pest Spodoptera frugiperda in response to injection of the polydnavirus HdIV associated with the ichneumonid wasp Hyposoter didymator. Polydnaviruses are associated with parasitic ichneumonoid wasps and are required for their development within the lepidopteran host, in which they act as potent immunosuppressive pathogens. In this study, we analyzed transcriptional variations in the two main effectors of the insect immune response, the hemocytes and the fat body, after injection of filter-purified HdIV.

Results

Results show that 24 hours post-injection, about 4% of the 1750 arrayed host genes display changes in their transcript levels with a large proportion (76%) showing a decrease. As a comparison, in S. frugiperda fat body, after injection of the pathogenic JcDNV densovirus, 8 genes display significant changes in their transcript level. They differ from the 7 affected by HdIV and, as opposed to HdIV injection, are all up-regulated. Interestingly, several of the genes that are modulated by HdIV injection have been shown to be involved in lepidopteran innate immunity. Levels of transcripts related to calreticulin, prophenoloxidase-activating enzyme, immulectin-2 and a novel lepidopteran scavenger receptor are decreased in hemocytes of HdIV-injected caterpillars. This was confirmed by quantitative RT-PCR analysis but not observed after injection of heat-inactivated HdIV. Conversely, an increased level of transcripts was found for a galactose-binding lectin and, surprisingly, for the prophenoloxidase subunits. The results obtained suggest that HdIV injection affects transcript levels of genes encoding different components of the host immune response (non-self recognition, humoral and cellular responses).

Conclusion

This analysis of the host-polydnavirus interactions by a microarray approach indicates that the presence of HdIV induces, directly or indirectly, variations in transcript levels of specific host genes, changes that could be responsible in part for the alterations observed in the parasitized host physiology. Development of such global approaches will allow a better understanding of the strategies employed by parasites to manipulate their host physiology, and will permit the identification of potential targets of the immunosuppressive polydnaviruses.

Proteasome inhibition and Tau proteolysis: an unexpected regulation

Increasing evidence suggests that an inhibition of the proteasome, as demonstrated in Parkinson's disease, might be involved in Alzheimer's disease. In this disease and other Tauopathies, Tau proteins are hyperphosphorylated and aggregated within degenerating neurons. In this state, Tau is also ubiquitinated, suggesting that the proteasome might be involved in Tau proteolysis. Thus, to investigate if proteasome inhibition leads to accumulation, hyperphosphorylation and aggregation of Tau, we used neuroblastoma cells overexpressing Tau proteins. Surprisingly, we showed that the inhibition of the proteasome led to a bidirectional degradation of Tau. Following this result, the cellular mechanisms that may degrade Tau were investigated.

Unusual form of neurocysticercosis associated with HIV infection

Concurrent infection with Taenia solium and HIV would be expected to occur more frequently because of the increasing frequency of HIV infection in endemic areas of cysticercosis. However, little is known about the influence of HIV infection on the frequency and the clinical course of cysticercosis. Giant cysts and racemose forms of neurocysticercosis seem to be more frequent in HIV-infected patients and may be secondary to an uncontrolled parasitic growth because of an impaired cell-mediated immune response. We report an unusual case of epidural spinal racemose neurocysticercosis revealed by compression of cauda equina in an HIV-infected man and discuss the potential interactions between T. solium and HIV infections.