Ioannis Theodorou

Liver fibrosis in overweight patients

BACKGROUND & AIMS A common clinical issue is whether overweight patients with abnormal liver function test results should undergo liver biopsy. Although serious liver injury can occur, its prevalence and risk factors are not well known. METHODS Ninety-three consecutive patients with abnormal liver function tests (but without overt liver disease), body mass index (BMI) > 25 kg/m(2), and no alcoholic, viral, autoimmune, drug-induced, or genetic liver disease were retrospectively studied. Clinical, biological, and histological variables were tested for association with septal fibrosis or cirrhosis. RESULTS Septal fibrosis was present in 28 patients (30%) including cirrhosis in 10 (11%). Age >/= 50 years (odds ratio [OR], 14.1), BMI >/= 28 kg/m(2) (OR, 5.7), triglycerides >/= 1.7 mmol/L (OR, 5), and alanine aminotransferase (ALT) >/= 2N (OR, 4.6) were independently associated with septal fibrosis. Among histological features, septal fibrosis was strongly associated with necroinflammatory activity (OR, 44). A score combining age, BMI, triglycerides, and ALT had 100% negative predictive value for septal fibrosis when scoring 0 or 1 (100% sensitivity for a specificity of 47%). CONCLUSIONS Septal fibrosis occurs frequently in overweight patients with abnormal liver function tests. A clinicobiological score combining BMI, age, ALT, and triglycerides could improve selection of patients for liver biopsy.

Infections in 252 Patients with Common Variable Immunodeficiency

BACKGROUND Common variable immunodeficiency is characterized by recurrent infections and defective immunoglobulin production. METHODS The DEFI French national study prospectively enrolled adult patients with primary hypogammaglobulinemia. Clinical events before inclusion were retrospectively analyzed at that time. RESULTS From April 2004 through April 2007, 341 patients were enrolled, 252 of whom had received a diagnosis of common variable immunodeficiency; of those, 110 were male, 142 were female, and 228 were white. The median age at first symptoms was 19 years. The median age at common variable immunodeficiency diagnosis was 33.9 years. The median delay for diagnosis was 15.6 years for the 138 patients with initial symptoms before 1990 and 2.9 years for the 114 patients with initial symptoms from 1990 to the time of the study. The most frequent initial symptoms were upper respiratory tract infections: bronchitis (in 38% of patients), sinusitis (36%), pneumonia (31%), and/or bronchiectasis (14%). Overall, 240 patients had respiratory symptoms. Pneumonia was reported in 147 patients; Streptococcus pneumoniae and Haemophilus influenzae were documented in 46 and 17 cases, respectively. Recurrent or chronic diarrhea was reported in 118 patients. Giardia (35 cases), Salmonella (19), and Campylobacter (19) infections were more frequent in patients with undetectable serum immunoglobulin A (P<.001). Sixteen patients developed opportunistic infections. Persistent infections and requirement for antibiotics despite immunoglobulin substitution correlated with severe defect of memory switched B cells (P=.003) but not with immunoglobulin G trough levels (P=.55). CONCLUSION Although reduced within the past decade, the delay of diagnosis of common variable immunodeficiency remains unacceptable. Recurrence of upper respiratory tract infection or pneumonia should lead to systematic evaluation of serum immunoglobulin.

Cutting Edge: Increased NK Cell Activity in HIV-1-Exposed but Uninfected Vietnamese Intravascular Drug Users

We addressed the role of innate immunity in the protection against HIV-1 infection by studying NK cell function in 37 Vietnamese intravascular drug users (IDUs), who appeared to remain HIV-1 uninfected despite many years of high-risk exposure (exposed uninfected, EU), 10 IDUs who underwent seroconversion and 28 unexposed blood donors. Main results were: NK cell lytic activities against both the NK-susceptible K562 cell line and the NK-resistant Daudi cell line were significantly augmented in EU IDUs compared with either controls or seroconverters before or after seroconversion; NK cells producing the cytokines IFN-γ and TNF-α and the β chemokines CCL3, CCL4, and CCL5 were also increased in the EU IDUs, either after in vitro activation or without stimulation. The finding of an enhanced NK cell function in EU IDUs, especially compared with IDUs who became HIV-1 infected, supports the hypothesis that NK cells contribute to the protection against HIV-1 infection.

Genome-wide association study identifies new HLA class II haplotypes strongly protective against narcolepsy

Narcolepsy is a rare sleep disorder with the strongest human leukocyte antigen (HLA) association ever reported. Since the associated HLA-DRB1*1501-DQB1*0602 haplotype is common in the general population (15–25%), it has been suggested that it is almost necessary but not sufficient for developing narcolepsy. To further define the genetic basis of narcolepsy risk, we performed a genome-wide association study (GWAS) in 562 European individuals with narcolepsy (cases) and 702 ethnically matched controls, with independent replication in 370 cases and 495 controls, all heterozygous for DRB1*1501-DQB1*0602. We found association with a protective variant near HLA-DQA2 (rs2858884; P < 3 × 10−8). Further analysis revealed that rs2858884 is strongly linked to DRB1*03-DQB1*02 (P < 4 × 10−43) and DRB1*1301-DQB1*0603 (P < 3 × 10−7). Cases almost never carried a trans DRB1*1301-DQB1*0603 haplotype (odds ratio = 0.02; P < 6 × 10−14). This unexpected protective HLA haplotype suggests a virtually causal involvement of the HLA region in narcolepsy susceptibility.

IL28B alleles associated with poor hepatitis C virus (HCV) clearance protect against inflammation and fibrosis in patients infected with non-1 HCV genotypes.

Genetic polymorphisms near IL28B are associated with spontaneous and treatment‐induced clearance of hepatitis C virus (HCV), two processes that require the appropriate activation of the host immune responses. Intrahepatic inflammation is believed to mirror such activation, but its relationship with IL28B polymorphisms has yet to be fully appreciated. We analyzed the association of IL28B polymorphisms with histological and follow‐up features in 2335 chronically HCV‐infected Caucasian patients. Assessable phenotypes before any antiviral treatment included necroinflammatory activity (n = 1,098), fibrosis (n = 1,527), fibrosis progression rate (n = 1,312), and hepatocellular carcinoma development (n = 1,915). Associations of alleles with the phenotypes were evaluated by univariate analysis and multivariate logistic regression, accounting for all relevant covariates. The rare G allele at IL28B marker rs8099917—previously shown to be at risk of treatment failure—was associated with lower activity (P = 0.04), lower fibrosis (P = 0.02) with a trend toward lower fibrosis progression rate (P = 0.06). When stratified according to HCV genotype, most significant associations were observed in patients infected with non‐1 genotypes (P = 0.003 for activity, P = 0.001 for fibrosis, and P = 0.02 for fibrosis progression rate), where the odds ratio of having necroinflammation or rapid fibrosis progression for patients with IL28B genotypes TG or GG versus TT were 0.48 (95% confidence intervals 0.30‐0.78) and 0.56 (0.35‐0.92), respectively. IL28B polymorphisms were not predictive of the development of hepatocellular carcinoma. Conclusion: In chronic hepatitis C, IL28B variants associated with poor response to interferon therapy may predict slower fibrosis progression, especially in patients infected with non‐1 HCV genotypes. (HEPATOLOGY 2012)

VJ REARRANGEMENTS OF THE TCRγ LOCUS IN PERIPHERAL T-CELL LYMPHOMAS: ANALYSIS BY POLYMERASE CHAIN REACTION AND DENATURING GRADIENT GEL ELECTROPHORESIS

Using Southern blotting for the diagnosis of clonality in peripheral T‐cell lymphomas (PTCLs), analysis of the T‐cell receptor (TCR) γ gene rearrangement was shown to be more informative than that of the TCR β gene rearrangement. In order to amplify every VJγ rearrangement, a polymerase chain reaction (PCR) procedure using newly designed GC‐clamp primers has been developed. All primers can be mixed in a single multiplex PCR. PCR products are analysed by denaturing gradient gel electrophoresis (DGGE), providing tumour‐specific imprints inasmuch as the procedure characterizes N sequence polymorphism at the VJ junctions. In a series of 30 PTCL cases, the PCR procedure demonstrated 27 cases to be clonally rearranged and failed in three cases. PCR was more accurate than Southern blotting, showing 47 rearranged γ alleles, four of which were undetectable on the Southern blot. When lymphomas were studied at different sites and at relapse, the DGGE pattern remained unchanged. In PTCL, the proposed PCR is helpful for the diagnosis and staging of the disease and should improve the follow‐up monitoring. The undetectability of clonal rearrangements in a few cases is discussed in the light of concepts of lymphomagenesis and T‐cell differentiation.

Combination of HIV-1-Specific CD4 Th1 Cell Responses and IgG2 Antibodies Is the Best Predictor for Persistence of Long-Term Nonprogression

BACKGROUND Strong T cell and antibody responses to human immunodeficiency virus (HIV), low virus production, and some genetic traits have been individually associated with nonprogression of HIV infection, but the best correlate with protection against disease progression remains unknown. METHODS We prospectively followed 66 untreated long-term nonprogressors and analyzed relationships between HIV-1-specific CD4 T helper (Th) 1 and CD8 T cell responses and HIV-1-specific antibodies, HIV-1 RNA and proviral DNA loads, host genes, and CD4 Th1 cell counts at entry into the study and 4 years later. RESULTS HIV-1 p24-specific CD4 Th1 cell proliferation, interferon (IFN)- gamma production, and IFN- gamma -producing cell frequencies at entry significantly and negatively correlated with HIV-1 RNA and proviral DNA loads and were independent of CD4 Th1 cell counts and host genes. HIV-1 Gag-specific IFN- gamma -producing CD8 T cell frequencies correlated with HIV-1 proviral DNA loads but not with RNA loads. Only high frequencies of HIV-1 p24-specific CD4 Th1 cells combined with HIV-1 gp41-specific IgG2 antibodies significantly predicted persistence of high CD4 Th1 cell counts. CONCLUSION HIV-1-specific CD4 Th1 responses combined with IgG2 antibodies and IFN- gamma -producing CD4 Th1 cells are better predictors of long-term nonprogression than are virus parameters, host genes, or HIV-1-specific CD4 Th1 or CD8 T cell proliferation.

Genome-Wide Association Study Identifies Variants Associated with Progression of Liver Fibrosis from HCV Infection

BACKGROUND & AIMS Polymorphisms in IL28B were shown to affect clearance of hepatitis C virus (HCV) infection in genome-wide association (GWA) studies. Only a fraction of patients with chronic HCV infection develop liver fibrosis, a process that might also be affected by genetic factors. We performed a 2-stage GWA study of liver fibrosis progression related to HCV infection. METHODS We studied well-characterized HCV-infected patients of European descent who underwent liver biopsies before treatment. We defined various liver fibrosis phenotypes on the basis of METAVIR scores, with and without taking the duration of HCV infection into account. Our GWA analyses were conducted on a filtered primary cohort of 1161 patients using 780,650 single nucleotide polymorphisms (SNPs). We genotyped 96 SNPs with P values <5 × 10(-5) from an independent replication cohort of 962 patients. We then assessed the most interesting replicated SNPs using DNA samples collected from 219 patients who participated in separate GWA studies of HCV clearance. RESULTS In the combined cohort of 2342 HCV-infected patients, the SNPs rs16851720 (in the total sample) and rs4374383 (in patients who received blood transfusions) were associated with fibrosis progression (P(combined) = 8.9 × 10(-9) and 1.1 × 10(-9), respectively). The SNP rs16851720 is located within RNF7, which encodes an antioxidant that protects against apoptosis. The SNP rs4374383, together with another replicated SNP, rs9380516 (P(combined) = 5.4 × 10(-7)), were linked to the functionally related genes MERTK and TULP1, which encode factors involved in phagocytosis of apoptotic cells by macrophages. CONCLUSIONS Our GWA study identified several susceptibility loci for HCV-induced liver fibrosis; these were linked to genes that regulate apoptosis. Apoptotic control might therefore be involved in liver fibrosis.

Association Study of Common Genetic Variants and HIV-1 Acquisition in 6,300 Infected Cases and 7,200 Controls

Multiple genome-wide association studies (GWAS) have been performed in HIV-1 infected individuals, identifying common genetic influences on viral control and disease course. Similarly, common genetic correlates of acquisition of HIV-1 after exposure have been interrogated using GWAS, although in generally small samples. Under the auspices of the International Collaboration for the Genomics of HIV, we have combined the genome-wide single nucleotide polymorphism (SNP) data collected by 25 cohorts, studies, or institutions on HIV-1 infected individuals and compared them to carefully matched population-level data sets (a list of all collaborators appears in Note S1 in Text S1). After imputation using the 1,000 Genomes Project reference panel, we tested approximately 8 million common DNA variants (SNPs and indels) for association with HIV-1 acquisition in 6,334 infected patients and 7,247 population samples of European ancestry. Initial association testing identified the SNP rs4418214, the C allele of which is known to tag the HLA-B*57:01 and B*27:05 alleles, as genome-wide significant (p = 3.6×10−11). However, restricting analysis to individuals with a known date of seroconversion suggested that this association was due to the frailty bias in studies of lethal diseases. Further analyses including testing recessive genetic models, testing for bulk effects of non-genome-wide significant variants, stratifying by sexual or parenteral transmission risk and testing previously reported associations showed no evidence for genetic influence on HIV-1 acquisition (with the exception of CCR5Δ32 homozygosity). Thus, these data suggest that genetic influences on HIV acquisition are either rare or have smaller effects than can be detected by this sample size.

HIV Controller CD4+ T Cells Respond to Minimal Amounts of Gag Antigen Due to High TCR Avidity

HIV controllers are rare individuals who spontaneously control HIV replication in the absence of antiretroviral treatment. Emerging evidence indicates that HIV control is mediated through very active cellular immune responses, though how such responses can persist over time without immune exhaustion is not yet understood. To investigate the nature of memory CD4+ T cells responsible for long-term anti-HIV responses, we characterized the growth kinetics, Vβ repertoire, and avidity for antigen of patient-derived primary CD4+ T cell lines. Specific cell lines were obtained at a high rate for both HIV controllers (16/17) and efficiently treated patients (19/20) in response to the immunodominant Gag293 peptide. However, lines from controllers showed faster growth kinetics than those of treated patients. After normalizing for growth rates, IFN-γ responses directed against the immunodominant Gag293 peptide showed higher functional avidity in HIV controllers, indicating differentiation into highly efficient effector cells. In contrast, responses to Gag161, Gag263, or CMV peptides did not differ between groups. Gag293-specific CD4+ T cells were characterized by a diverse Vβ repertoire, suggesting that multiple clones contributed to the high avidity CD4+ T cell population in controllers. The high functional avidity of the Gag293-specific response could be explained by a high avidity interaction between the TCR and the peptide-MHC complex, as demonstrated by MHC class II tetramer binding. Thus, HIV controllers harbor a pool of memory CD4+ T cells with the intrinsic ability to recognize minimal amounts of Gag antigen, which may explain how they maintain an active antiviral response in the face of very low viremia.