Laurence Weiss

CD14+CD16++ cells derived in vitro from peripheral blood monocytes exhibit phenotypic and functional dendritic cell‐like characteristics

We previously reported an increased percentage of CD14+CD16++ monocytes in the peripheral blood of HIV‐infected patients but the physiopathological role of this monocyte subset remains unclear. Cells with a CD14+CD16++ phenotype may be obtained in vitro by culturing human peripheral blood monocytes in the presence of GM‐CSF, IL‐4 and IL‐10. In the present study, we compared the phenotypic and functional characteristics of monocytes‐derived CD14+CD16++ cells with those of macrophages and dendritic cells. We show that the CD14+CD16++ cells express dendritic cell markers: CD40, CD80, CD86, HLA‐DR, CD11b, CD11c, CD18, CD1a, and CD83. Using RNase protection assay, we demonstrate that CD14+CD16++ cell subset expresses a low ratio of IL‐1β / IL‐1ra mRNA and expresses IL‐6, MIP‐1α, MIP‐1β, MCP‐1, IL‐8, RANTES and I‐309 transcripts, similar to dendritic cells. CD14+CD16++ cells produce IL‐12, MCP‐1 and IL‐8, as assessed by flow cytometry. Moreover, CD14+CD16++ cells pulsed with different recall antigens induce a potent autologous T cell proliferation. Altogether, these results provide evidence that CD14+CD16++ cells differentiated in vitro from peripheral blood monocytes exhibit dendritic cell characteristics.

Prevalence of monoclonal gammopathy in patients presenting with acquired angioedema type 2

PURPOSE Acquired angioedema type 1 is characterized by a C1 inhibitor deficiency in patients with lymphoproliferative disorders, whereas acquired angioedema type 2 is characterized by anti-C1 inhibitor antibodies, and has not been thought to be associated with lymphoproliferative disease. We studied the clinical features, complement profiles, and associated diseases in 19 new patients with diagnosed acquired angioedema type 2. SUBJECTS AND METHODS Plasma concentrations and functional activity of complement components were measured by conventional techniques. Functional C1 inhibitor activity was assessed by a chromogenic assay. Autoantibodies to C1 inhibitor were detected using an enzyme-linked immunosorbent assay. RESULTS The 11 men and 8 women (median age, 60 years) presented with recurrent attacks of angioedema. All patients had detectable anti-C1 inhibitor antibodies in serum. A monoclonal gammopathy was detected in 12 patients (63%) at the time of diagnosis, 11 of whom had an immunoglobulin peak of the same heavy- and light-chain isotypes as the acquired anti-C1 inhibitor antibody. Three of these 12 patients developed a malignant lymphoproliferative disease. CONCLUSION As with type 1 disease, a large proportion of patients with acquired angioedema type 2 have a lymphoproliferative disorder.

Restoration of Normal Interleukin-2 Production by CD4+ T Cells of Human Immunodeficiency Virus-Infected Patients after 9 Months of Highly Active Antiretroviral Therapy

The present study investigated immune restoration in patients at intermediate stages of human immunodeficiency virus (HIV) disease after initiation of highly active antiretroviral therapy (HAART). A progressive increase in both memory and naive CD4+ T cells was observed from the first weeks of therapy, concomitant with a decrease in the expression of activation markers on CD8+ T cells. The early-activation marker CD69 remained, however, overexpressed on T cells after suboptimal stimulation in vitro, indicative of persistent immune activation. The percentage of interleukin (IL)-2-producing CD4+ T cells significantly increased from 9 months of HAART. In most patients, CD4+ T cells recovered an ability to produce IL-2 on stimulation, similar to that of HIV-seronegative controls. Reversal of T-cell anergy may be a key event in immune restoration for achieving long-term clinical benefit with HAART.

Molecular Basis of a Selective C1s Deficiency Associated with Early Onset Multiple Autoimmune Diseases

We have investigated the molecular basis of selective and complete C1s deficiency in 2-year-old girl with complex autoimmune diseases including lupus-like syndrome, Hashimoto’s thyroiditis, and autoimmune hepatitis. This patient’s complement profile was characterized by the absence of CH50 activity, C1 functional activity <10%, and undetectable levels of C1s Ag associated with normal levels of C1r and C1q Ags. Exon-specific amplification of genomic DNA by PCR followed by direct sequence analysis revealed a homozygous nonsense mutation in the C1s gene exon XII at codon 534, caused by a nucleotide substitution from C (CGA for arginine) to T (TGA for stop codon). Both parents were heterozygous for this mutation. We used the new restriction site for endonuclease Fok-1 created by the mutation to detect this mutation in the genomic DNA of seven healthy family members. Four additional heterozygotes for the mutation were identified in two generations. Our data characterize for the first time the genetic defect of a selective and complete C1s deficiency in a Caucasian patient.

Toxic Effects of Nucleoside Reverse Transcriptase Inhibitors on the Liver Value of Electron Microscopy Analysis for the Diagnosis of Mitochondrial Cytopathy

Nucleoside reverse transcriptase inhibitors (NRTIs) induce mitochondrial toxic effects resulting in multiple organ disorders. Liver involvement has been associated mainly with severe lactic acidosis and massive steatosis. However, patients with HIV infection who are receiving antiretroviral treatment frequently have mildly abnormal liver test results that, to date, have not been linked unambiguously to the toxic effects of NRTIs. Thirteen patients with HIV infection treated with NRTI-based regimens had low-grade abnormal liver test results associated with digestive and nonspecific general symptoms. Histologic examination of liver samples showed diffuse steatosis in only 6 cases and mild steatosis in the remaining cases, associated with megamitochondria, mild lobular inflammation and necrosis, Mallory bodies, and perisinusoidal fibrosis. In all cases, ultrastructural study disclosed mitochondrial abnormalities. Our work demonstrates that NRTI-induced toxic effects in the liver may occur as indolent nonspecific disease with variable histologic features and emphasizes the diagnostic value of electron microscopy, particularly when diffuse steatosis is absent.

Comparison of liver fibrosis blood tests developed for HCV with new specific tests in HIV/HCV co-infection

BACKGROUND & AIMS We compared 5 non-specific and 2 specific blood tests for liver fibrosis in HCV/HIV co-infection. METHODS Four hundred and sixty-seven patients were included into derivation (n=183) or validation (n=284) populations. Within these populations, the diagnostic target, significant fibrosis (Metavir F > or = 2), was found in 66% and 72% of the patients, respectively. Two new fibrosis tests, FibroMeter HICV and HICV test, were constructed in the derivation population. RESULTS Unadjusted AUROCs in the derivation population were: APRI: 0.716, Fib-4: 0.722, Fibrotest: 0.778, Hepascore: 0.779, FibroMeter: 0.783, HICV test: 0.822, FibroMeter HICV: 0.828. AUROCs adjusted on classification and distribution of fibrosis stages in a reference population showed similar values in both populations. FibroMeter, FibroMeter HICV and HICV test had the highest correct classification rates in F0/1 and F3/4 (which account for high predictive values): 77-79% vs. 70-72% in the other tests (p=0.002). Reliable individual diagnosis based on predictive values > or = 90% distinguished three test categories: poorly reliable: Fib-4 (2.4% of patients), APRI (8.9%); moderately reliable: Fibrotest (25.4%), FibroMeter (26.6%), Hepascore (30.2%); acceptably reliable: HICV test (40.2%), FibroMeter HICV (45.6%) (p<10(-3) between tests). FibroMeter HICV classified all patients into four reliable diagnosis intervals (< or =F1, F1+/-1, > or =F1, > or =F2) with an overall accuracy of 93% vs. 79% (p<10(-3)) for a binary diagnosis of significant fibrosis. CONCLUSIONS Tests designed for HCV infections are less effective in HIV/HCV infections. A specific test, like FibroMeter HICV, was the most interesting test for diagnostic accuracy, correct classification profile, and a reliable diagnosis. With reliable diagnosis intervals, liver biopsy can therefore be avoided in all patients.

Human CD90 Identifies Th17/Tc17 T Cell Subsets That Are Depleted in HIV-Infected Patients

By revisiting CD90, a GPI-anchored glycoprotein, we show that CD90 is expressed by a subset of CD4+ and CD8+ human T cells. CD4+CD90+ cells share similarities with Th17 cells because they express the Th17-specific transcription factor RORC2 and produce IL-17A. CD4+CD90+ cells are activated memory T cells that express the gut mucosal markers CCR6, CD161, and the α4 and β7 integrins. Compared with CD90-depleted CCR6+ memory Th17 cells, CD4+CD90+ cells express higher levels of IL-22 and proinflammatory cytokines (IL-6, TNF-α and GM-CSF), but they produce lower levels of IL-21 and no IL-9. Analyses of CD8+CD90+ cells reveal that they express RORC2 and are able to produce higher levels of IL-17A, IL-22, and CCL20 compared with CD90-depleted CD8+ cells. These data show that CD90 identifies Th17 and Tc17 cells with a peculiar cytokine profile. Studies of circulating CD90+ cells in HIV patients show that CD90+ cells are decreased with an imbalance of the CD4+CD90+/regulatory T cell ratio in nontreated patients compared with treated patients and healthy donors. Overall, human CD90 identifies a subset of Th17 and Tc17 cells within CD4+ and CD8+ T cells, respectively, which are depleted during HIV infection.

Anti-cardiolipin antibodies are associated with anti-endothelial cell antibodies but not with anti-β2 glycoprotein I antibodies in HIV infection

HIV infection is associated with polyclonal increase in serum immunoglobulins and with elevated titers of serum antibodies to a variety of self antigens, including anti-phospholipid antibodies. In the present study, we found a high prevalence of 46.8% of serum IgG anticardiolipin antibodies (ACA) in a group of 111 unselected HIV-seropositive individuals. The presence of ACA was correlated with that of IgG antibodies to endothelial cells (AECA) but not with that of anti-beta 2 glycoprotein I antibodies, that were only found in 7.4% of the patients. The presence of IgG ACA was not associated with detectable lupus anticoagulant activity, nor with a history of thrombosis. Serum titers of ACA were not correlated with absolute numbers of circulating CD4+ cells. We found no relationship between the presence and titers of ACA, hypergammaglobulinemia, and serum titers of natural IgG autoantibodies to a panel of self antigens. Our results suggest that increased titers of ACA in HIV infection result from a biased expansion of B cell clones producing natural autoantibodies.

A population analysis of weight-related differences in lopinavir pharmacokinetics and possible consequences for protease inhibitor-naive and -experienced patients.

BACKGROUND Lopinavir is a potent protease inhibitor (PI) used for the treatment of HIV infection. Different lopinavir target trough concentrations (C(troughs)) were previously determined according to patient treatment histories: 1 mg/l for PI-naive patients, and 4 and 5.7 mg/l for PI-experienced patients. However, the probability to achieve these target C(troughs) with the current 400 mg twice-daily or 800 mg once-daily doses of the new tablet form, and the influence of body weight on this probability are unknown. METHODS A population pharmacokinetic model for lopinavir was developed using data from 424 HIV type-1-infected patients, and the final model was used to estimate the probability to achieve target C(troughs) via Monte Carlo simulations. RESULTS A one-compartment model adequately described the data. Mean population estimates (percentage interindividual variability) were 4.61 l/h (36%) for apparent clearance (CL/F) and 63.2 l (70%) for apparent distribution volume. Body weight was found to explain the interindividual variability of lopinavir CL/F. Probability to achieve the 1 mg/l target C(trough) was >96% for the twice-daily dose and comprised between 80% and 90% for the once-daily dose. The probability to achieve the 4 and 5.7 mg/l target C(troughs) with the twice-daily dose significantly decreased when body weight increased (from 76% to 61% and from 56% to 37% respectively, for body weights increasing from 50 to 90 kg). CONCLUSIONS These results support lopinavir therapeutic drug monitoring and the use of higher lopinavir doses for PI-pretreated patients.

Immediate T-Helper 17 Polarization Upon Triggering CD11b/c on HIV-Exposed Dendritic Cells

Early on in human immunodeficiency virus (HIV) type 1 infection, gut T-helper (Th) 17 cells are massively depleted leading eventually to compromised intestinal barrier function and excessive immune activation. In contrast, the functional Th17 cell compartment of the gut is well-maintained in nonpathogenic simian immunodeficiency virus infection as well as HIV-1 long-term nonprogressors. Here, we show that dendritic cells (DCs) loaded with HIV-1 bearing high surface complement levels after incubation in plasma from HIV-infected individuals secreted significantly higher concentrations of Th17-polarizing cytokines than DCs exposed to nonopsonized HIV-1. The enhanced Th17-polarizing capacity of in vitro-generated and BDCA-1(+) DCs directly isolated from blood was linked to activation of ERK. In addition, C3a produced from DCs exposed to complement-opsonized HIV was associated with the higher Th17 polarization. Our in vitro and ex vivo data, therefore, indicate that complement opsonization of HIV-1 strengthens DC-mediated antiviral immune functions by simultaneously triggering Th17 expansion and intrinsic C3 formation via DC activation.