A genetic variant in the interleukin 28B gene as a major predictor for sustained virologic response in chronic hepatitis C virus infection

Geographic variations in test reactivity for the serological diagnosis of Trypanosoma cruzi infection

Chagas disease is a neglected disease caused by Trypanosoma cruzi parasites. Most diagnosis is based on serological tests, but the lack of a gold standard test complicates the measurement of test performance. To overcome this limitation, we used samples from a cohort of well-characterized T. cruzi-infected women to evaluate the reactivity of two rapid diagnostic tests and one enzyme-linked immunosorbent assay (ELISA). Our cohort was derived from a previous study on congenital transmission of T. cruzi and consisted of 481 blood/plasma samples from Argentina (n = 149), Honduras (n = 228), and Mexico (n = 104), with at least one positive T. cruzi PCR. Reactivity of the three tests ranged from 70.5% for the Wiener ELISA to 81.0% for the T-Detect and 90.4% for the Stat-Pak rapid tests. Test reactivity varied significantly among countries and was highest in Argentina and lowest in Mexico. When considering at least two reactive serological tests to confirm seropositivity, over 12% of T. cruzi infection cases from Argentina were missed by serological tests, over 21% in Honduras, and an alarming 72% in Mexico. Differences in test performance among countries were not due to differences in parasitemia, but differences in antibody levels against ELISA antigens were observed. Geographic differences in T. cruzi parasite strains as well as genetic differences among human populations both may contribute to the discrepancies in serological testing. Improvements in serological diagnostics for T. cruzi infections are critically needed to ensure an optimum identification of cases.

The presence of IFL3/4 rs12979860 C allele influences the in vitro IP-10 production by mononuclear cells from patients with systemic lupus erythematosus

OBJECTIVE

To explore whether the IFNL3/4 rs12979860 genotype may influence serum levels or production of interferon-inducible protein-10 (IP-10) by peripheral blood mononuclear cells from patients with systemic lupus erythematosus (SLE).

METHODS

Sixty-six patients with SLE and 22 healthy blood donors (controls) were included. The IFNL3/4 rs12979860 polymorphism was genotyped by real-time polymerase chain reaction. IP-10 levels in sera supernatants of IFNα stimulated peripheral blood mononuclear cells were measured by enzime-linked immunosorbent assay.

RESULTS

Allelic frequencies were CC (29%), CT (52%) and TT (20%) in SLE, and CC (32%), CT (41%) and TT (27%) in healthy controls. Median serum IP-10 levels were higher in SLE patients than in controls (190.8 versus 118.1 pg/ml; p < 0.001), particularly in those with high disease activity (278.5 versus 177.2 pg/ml; p = 0.037). However, serum IP-10 levels were not influenced by IFNL3/4 genotypes. Higher IP-10 production by peripheral blood mononuclear cells was found in both SLE patients (median 519.3 versus 207.6 pg/ml; p = 0.012) and controls (median 454.0 versus 201.7 pg/ml; p = 0.034) carrying the IFNL3/4 C allele compared with carriers of the T allele.

CONCLUSIONS

Although IFNL3/4 rs12979860 allele C does not appear to influence serum IP-10 levels in SLE, it plays an important role in the production of IP-10 by peripheral blood mononuclear cells after IFNα stimulation.

Type III Interferons (Lambda Interferons) in Rheumatic Autoimmune Diseases

The last 2 decades have witnessed the discovery and characterization of a new family of cytokines with immunological characteristics similar to those described for type I interferons, type III or lambda interferons. Unraveling the molecular mechanisms underlying each type of interferon has allowed us to understand how some autoimmune diseases can be considered as interferonopathies. Under normal conditions, type III interferons play a key role in the defense against viruses by modulating the functioning of several types of innate and adaptive immune cells. These effects include upregulation of major histocompatibility complex molecules by myeloid dendritic cells, increased functioning of pattern recognition receptors by plasmacytoid dendritic cells, decreased activity of regulatory T cells, enhanced production of antibodies by plasmatic cells and increased expression of chemokines and adhesion molecules by leukocytes and endothelial cells. Notably, all these mechanisms have been described to boost autoimmunity, and type III interferons pathway activation has been related to the pathogenesis of autoimmune conditions such as systemic lupus erythematosus, systemic sclerosis and Sjögren's syndrome. This review provides an overview of the current evidence on the contribution of type III interferons in the pathogenesis of rheumatic autoimmune diseases in humans.

Hepatitis C virus pharmacogenomics in Latin American populations: implications in the era of direct-acting antivirals

In recent years, great progress has been made in the field of new therapeutic options for hepatitis C virus (HCV) infection. The new direct-acting antiviral agents (DAAs) represent a great hope for millions of chronically infected individuals because their use may lead to excellent cure rates with fewer side effects. In Latin America, the high prevalence of HCV genotype 1 infection and the significant association of Native American ancestry with risk predictive single-nucleotide polymorphisms (SNPs) in IFNL4 and ITPA genes highlight the need to implement new treatment regimens in these populations. However, the universal accessibility to DAAs is still not a reality in the region as their high cost is one of the major, although not the only, limiting factors for their broad implementation. Therefore, under these circumstances, could the assessment of host genetic markers be a useful tool to prioritize DAA treatment until global access to these new drugs can be achieved? This review will summarize the scientific evidences and the potential implications of HCV pharmacogenomics in this rapidly evolving era of anti-HCV drug development.

IL28B rs12980275 and HLA rs4273729 genotypes as a powerful predictor factor for rapid, early, and sustained virologic response in patients with chronic hepatitis C

Single-nucleotide polymorphisms (SNPs) in the Interleukin-28B (IL28B) gene and rs4273729 in the human leukocyte antigen (HLA) gene in chronic hepatitis C (CHC) virus infection are important for predicting treatment outcome. In this study, the distribution of IL28B SNPs (rs12979860 and rs12980275) and HLA rs4273729 in rapid virologic response (RVR), complete early virologic response (cEVR) and sustained virologic response (SVR) in HCV Iranian patients with CHC virus infection was assessed. IL28B genotyping and rs4273729 were performed using the amplification refractory mutation system (ARMS)-PCR and direct sequencing in 190 CHC virus infections, respectively. RVR, cEVR, and SVR were 53.2 %, 78.9 %, and 65.8 %, respectively. Multivariate regression analysis demonstrated that the responses significantly predicted SVR in patients with age <40 years (p = 0.008), HCV genotypes (p = 0.032), IL28B rs12979860 CC genotype (p < 0.001), rs12980275 AA genotype (p < 0.001), rs4273729 GG genotype (p < 0.001), RVR (p < 0.001) and cEVR (p = 0.024). Three critical predictor factors based on RVR response were rs12979860 CC genotype (p = 0.033), rs12980275 AA genotype (p < 0.001) and rs4273729 GG genotype (p < 0.001), while rs12980275 AA (p = 0.003) and rs4273729 GG genotypes (p < 0.001) predicted cEVR. For the first time in Iran, these results revealed that the rs12980275 and HLA rs4273729 are important for the treatment of CHC infection. These findings may help predict responses to CHC infection treatment and reduce the cost and side effects of therapy.

Association with Spontaneous Hepatitis C Viral Clearance and Genetic Differentiation of IL28B/IFNL4 Haplotypes in Populations from Mexico

AIM

To analyze the genetic heterogeneity of the Amerindian and admixed population (Mestizos) based on the IL28B (rs12979860, rs8099917) and IFNL4 (rs368234815) haplotypes, and their association with spontaneous clearance (SC) and liver damage in patients with hepatitis C infection from West Mexico.

METHODS

A total of 711 subjects from West Mexico (181 Amerindians and 530 Mestizos) were studied for the prevalence of IL28B (rs12979860C/T, rs8099917G/T) and IFNL4 (rs368234815∆G/TT) genotypes. A case-control study was performed in 234 treatment-naïve HCV Mestizos (149 chronic hepatitis C and 85 with SC) for the association of haplotypes with SC and liver damage. A real-time PCR assay was used for genotyping, and transitional elastography staged liver damage.

RESULTS

Significant Fst-values indicated differentiation between the studied populations. The frequencies of the protective C, T, TT alleles were significantly lower in the Amerindians than in Mestizos (p<0.05). The r2 measure of linkage disequilibrium was significant for all variants and the T/G/ΔG risk haplotype predominated in Amerindians and secondly in Mestizos. The protective C/T/TT haplotype was associated with SC (OR = 0.46, 95% IC 0.22-0.95, p = 0.03) and less liver damage (OR = 0.32, 95% IC 0.10-0.97, p = 0.04) in chronic patients. The Structure software analysis demonstrated no significant differences in ancestry among SC and chronic patients.

CONCLUSIONS

West Mexico's population is genetically heterogeneous at the IL28B/IFNL4 polymorphisms. The T/G/ΔG high-risk haplotype predominated in Amerindians and the beneficial alternative haplotype in Mestizos. The C/T/TT haplotype was associated with SC and less liver damage in chronically infected Mestizo patients.