IFN-gamma polymorphisms (IFN-gamma +2109 and IFN-gamma +3810) are associated with severe hepatic fibrosis in human hepatic schistosomiasis (Schistosoma mansoni)

Identification of Genomic Regions Implicated in Susceptibility to Schistosoma mansoni Infection in a Murine Backcross Genetic Model

Only a small number of infected people are highly susceptible to schistosomiasis, showing high levels of infection or severe liver fibrosis. The susceptibility to schistosome infection is influenced by genetic background. To assess the genetic basis of susceptibility and identify the chromosomal regions involved, a backcross strategy was employed to generate high variation in schistosomiasis susceptibility. This strategy involved crossing the resistant C57BL/6J mouse strain with the susceptible CBA/2J strain. The resulting F1 females (C57BL/6J × CBA/2J) were then backcrossed with CBA/2J males to generate the backcross (BX) cohort. The BX mice exhibited a range of phenotypes, with disease severity varying from mild to severe disease, lacking a fully resistant group. We observed four levels of infection intensity using cluster and principal component analyses and K-means based on parasitological, pathological, and immunological trait measurements. The mice were genotyped with 961 informative SNPs, leading to the identification of 19 new quantitative trait loci (QTL) associated with parasite burden, liver lesions, white blood cell populations, and antibody responses. Two QTLs located on chromosomes 15 and 18 were linked to the number of granulomas, liver lesions, and IgM levels. The corresponding syntenic human regions are located in chromosomes 8 and 18. None of the significant QTLs had been reported previously.

Correlation of single-nucleotide polymorphism at interferon-gamma R1 (at Position - 56) in positive purified protein derivative health workers with COVID-19 infection

Background

The aim of the present study was to investigate the susceptibility of purified protein derivative (PPD) plus health-care workers to SARS-CoV-2 (COVID-19). For this reason, single-nucleotide polymorphism (SNP) of interferon-gamma (IFN-γ) gene at position +2109 and IFN-γ receptor 1 (R1) at position -56 was assessed in PPD plus group before and after COVID-19 infection (2017-2018; 2020-2021).

Methods

The selected study cases (n = 100) that were working in tuberculosis (TB) unite (5-10 years) with PPD positivity >15 mm (16-20 mm) were included in this investigation. Sampling was done twice, once before and after the COVID-19 pandemic. Group A contains 50 samples collected from the GenBank TB laboratory that belong to TB staff before the pandemic (2017-2018). The other sample (Group B; 2021) was collected from the same unite during the COVID-19 pandemic. The SNP in the IFN-γ gene (+2109; 670 bp) and IFN-γ R 1 (-56; 366 bp) was performed using a specific primer and the polymerase chain reaction products were digested using restriction enzyme Fau I and Bts I, respectively. Statistical analyses were used to obtain the frequency of alleles among all studied cases. The confidence intervals (CIs) and t-test were calculated using the SPSS and GraphPad Prism software.

Results

In overall, the most frequent genotype in Group A was AA (41/50; 82%) and Group B was 76% (38/50) in position + 2109 (odds ratio [OR] = 0.69, 95% CI, 0.26-1.83, and P = 0.46). Although in position -56, the most frequent genotype in Group A was TT (35/50; 70%) which significantly was than Group B TT (15/50; 30%) (OR = 0.184, 95% CI, 0.78-0.43, and P = 0.00). The frequency of allele A was more in both groups at position + 2109 (OR = 0.815, 95% CI, 0.23-2.86, and P = 0.75), whereas the dominate allele at position -56 was T in Group A (OR = 1.37, 95% CI, 0.62-3.02, and P = 0.42).

Conclusion

No significant differences were observed in + 2109 in genotype among Group A and B. The main differences were seen in IFN-γ R1 at position (-56) between Group A and B. Hence, the IFN-γ R1 may play important role in COVID-19 infection. However, more study is needed to clear the IFN-γ correlation to COVID-19 infection.

Cellular Mechanisms of Liver Fibrosis

The liver is a central organ in the human body, coordinating several key metabolic roles. The structure of the liver which consists of the distinctive arrangement of hepatocytes, hepatic sinusoids, the hepatic artery, portal vein and the central vein, is critical for its function. Due to its unique position in the human body, the liver interacts with components of circulation targeted for the rest of the body and in the process, it is exposed to a vast array of external agents such as dietary metabolites and compounds absorbed through the intestine, including alcohol and drugs, as well as pathogens. Some of these agents may result in injury to the cellular components of liver leading to the activation of the natural wound healing response of the body or fibrogenesis. Long-term injury to liver cells and consistent activation of the fibrogenic response can lead to liver fibrosis such as that seen in chronic alcoholics or clinically obese individuals. Unidentified fibrosis can evolve into more severe consequences over a period of time such as cirrhosis and hepatocellular carcinoma. It is well recognized now that in addition to external agents, genetic predisposition also plays a role in the development of liver fibrosis. An improved understanding of the cellular pathways of fibrosis can illuminate our understanding of this process, and uncover potential therapeutic targets. Here we summarized recent aspects in the understanding of relevant pathways, cellular and molecular drivers of hepatic fibrosis and discuss how this knowledge impact the therapy of respective disease.

The Genetics of Human Schistosomiasis Infection Intensity and Liver Disease: A Review

Schistosomiasis remains the fourth most prevalent parasitic disease affecting over 200 million people worldwide. Control efforts have focussed on the disruption of the life cycle targeting the parasite, vector and human host. Parasite burdens are highly skewed, and the majority of eggs are shed into the environment by a minority of the infected population. Most morbidity results from hepatic fibrosis leading to portal hypertension and is not well-correlated with worm burden. Genetics as well as environmental factors may play a role in these skewed distributions and understanding the genetic risk factors for intensity of infection and morbidity may help improve control measures. In this review, we focus on how genetic factors may influence parasite load, hepatic fibrosis and portal hypertension. We found 28 studies on the genetics of human infection and 20 studies on the genetics of pathology in humans. S. mansoni and S. haematobium infection intensity have been showed to be controlled by a major quantitative trait locus SM1, on chromosome 5q31-q33 containing several genes involved in the Th2 immune response, and three other loci of smaller effect on chromosomes 1, 6, and 7. The most common pathology associated with schistosomiasis is hepatic and portal vein fibroses and the SM2 quantitative trait locus on chromosome six has been linked to intensity of fibrosis. Although there has been an emphasis on Th2 cytokines in candidate gene studies, we found that four of the five QTL regions contain Th17 pathway genes that have been included in schistosomiasis studies: IL17B and IL12B in SM1, IL17A and IL17F in 6p21-q2, IL6R in 1p21-q23 and IL22RA2 in SM2. The Th17 pathway is known to be involved in response to schistosome infection and hepatic fibrosis but variants in this pathway have not been tested for any effect on the regulation of these phenotypes. These should be priorities for future studies.

The Impact of Interferon-γ (IFN-γ) and IFN-γ-Inducible Protein 10 (IP-10) Genes' Polymorphism on Risk of Hepatitis C Virus-Related Liver Cirrhosis

Background: Today there is increasing evidence concerning the association between individual genetic polymorphisms within proinflammatory cytokines and chronic hepatitis C (CHC) severity. It has been demonstrated that polymorphisms in some genes may significantly predict HCV infected patients' susceptibility to developing liver cirrhosis or their responsiveness to the treatment.Aim: We investigated the influence of single nucleotide polymorphisms (SNPs) in Interferon (IFN-γ) and Interferon Gamma-Inducible Protein 10 (IP-10) genes on cirrhosis risk in HCV-infected patients and their association with response to various direct-acting antiviral drugs (DAAs).Methods: IFN-γ (+874T/A, +2109A/G) and IP-10 (-135G/A, -1447A/G) genotypes were determined in 175 CHC Egyptian HCV patients (69 liver cirrhotic and 106 non-cirrhotic patients) using either single-stranded polymorphism polymerase chain reaction (SSP-PCR) or Restriction fragment length-PCR (RFLP-PCR) methods.Results: IFN-γ + 874 TA, IP-10 - 135AA, and IP-10 - 1447AA and IP-10 - 1447GG genotypes are increased in patients developing liver cirrhosis compared to non-cirrhotic ones. Although, no statistical significance in their distribution was demonstrated, indicating the lack of association between these SNPs and liver cirrhosis susceptibility in HCV-infected patients. Haplotypes analysis between different loci on all selected genes showed a significant increase in AGGA and TAGA and a significant decrease in TGGA haplotypes in cirrhotic patients. Genotype frequencies at loci -135 and -1447 of IP-10 appeared to be in complete Linkage disequilibrium (LD) (D' = 0.999, r² = 0.689).Conclusion: Our data support the concept that IFN-γ and IP-10 gene polymorphisms are not predictors of disease progression among Egyptian patients with HCV infection.

Mechanism by which the combination of SjCL3 and SjGAPDH protects against Schistosoma japonicum infection

A vaccine is an important method to control schistosomiasis. Molecules related to lung-stage schistosomulum are considered potential vaccine candidates. We previously showed that glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and cathepsin L3 (CL3) displayed differential expression in the lung-stage schistosomula of Schistosoma japonicum cocultured with host cells. In the present study, we prepared the two proteins and detected the protective effects of SjGAPDH by immunizing mice with this protein alone and in combination with SjCL3 with or without Freund's adjuvant. Then, we investigated the possible mechanisms underlying S. japonicum infection. The results showed that vaccination of adjuvanted SjGAPDH decreased the worm burden (37.8%) and egg load (38.1%), and the combination of adjuvanted SjGAPDH and SjCL3 further decreased the worm burden (65.6%) and egg load (70.9%) during Schistosoma japonicum infection. However, the immunization of a combination of adjuvant-free SjGAPDH and SjCL3 displayed a lower protective effect (< 15%) than those of the adjuvanted SjCL3, the adjuvanted SjGAPDH, and a combination of adjuvanted SjGAPDH and SjCL3. Flow cytometric results showed that the frequency of regulatory T cells (Tregs) was lower (P < 0.05) in the group with adjuvanted SjGAPDH and SjCL3 (2.61%) than the remaining groups. The enzyme-linked immunosorbent assay (ELISA) results indicated that except for the uninfected and infected control groups, the remaining groups displayed a Th1-type shift in immune responses. These results showed the immunization of SjGAPDH resulted in partial protection (approximately 38%); inoculation with a combination of SjCL3 and SjGAPDH in Freund's adjuvant resulted in a high immunoprotective effect (> 65%) against Schistosoma japonicum infection in mice, which was possibly caused by the reduced percentage of Tregs and a Th1-type shift in immune responses; and SjCL3 has no adjuvant-like effect, dissimilar to SmCL3.

Genetic algorithms identify individuals with high risk of severe liver disease caused by schistosomes

Schistosomes induce severe hepatic disease, which is fatal in 2-10% of cases, mortality being higher in cases of co-infection with HBV or HCV. Hepatic disease occurs as a consequence of the chronic inflammation caused by schistosome eggs trapped in liver sinusoids. In certain individuals, the repair process leads to a massive accumulation of fibrosis in the periportal spaces. We and others have shown that genetic variants play a crucial role in disease progression from mild to severe fibrosis and explain why hepatic fibrosis progresses rapidly in certain subjects only. We will review here published findings concerning the strategies that have been used in the analysis of hepatic fibrosis in schistosome-infected individuals, the genetic variants that have associated with fibrosis, and variants in new pathways crucial for fibrosis progression. Together, these studies show that the development of fibrosis is under the tight genetic control of various common variants with moderate effects. This polygenic control has made it possible to develop models that identify schistosome-infected individual at risk of severe hepatic disease. We discuss the performances and limitations of these models.

Lack of Association between Cytokine Genetic Polymorphisms in Takayasu's Arteritis in Mexican Patients

Aim: To investigate the relation between polymorphisms in the interleukin 10 (IL)-10, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β and interferon (IFN)-γ genes and Takayasu's arteritis in the Mexican population. Methods: A case-control study was performed to investigate the associations of IL-10, TNF-α, TGF-β and IFN-γ polymorphisms in a sample of 52 Takayasu's arteritis patients, diagnosed according to the criteria of the American College of Rheumatology and EULAR PRINTO criteria when the patients were under 18 years of age; 60 clinically healthy unrelated Mexican individuals by the 5' exonuclease TaqMan polymerase chain reaction. Polymorphic haplotypes were constructed after linkage disequilibrium analysis. Results: Significant differences were not found in the distribution for genotype and allele frequencies of the polymorphisms studied between healthy controls and Takayasu´s arteritis patients. Likewise, significant associations were not detected in the haplotype analysis with the different genes studied. Conclusions: These findings suggest that the polymorphisms in IL-10, TNF-α, TGF-β and IFN-γ might not contribute to the susceptibility of Takayasu´s arteritis in the Mexican population.

Genetic Polymorphisms of IFNG and IFNGR1 with Latent Tuberculosis Infection

Previous studies indicated that single-nucleotide polymorphisms (SNPs) of interferon gamma (IFNG) and IFNG receptor 1 (IFNGR1) may be involved in the pathogenesis of pulmonary tuberculosis (PTB) in different populations. In order to further explore the results in a Chinese Han population, this study was designed to investigate potential associations between the polymorphisms in IFNG and IFNGR1 and susceptibility to latent tuberculosis infection (LTBI) and/or PTB in a Chinese Han population. A total of 209 PTB, 173 LTBI, and 183 healthy control subjects (HCS) were enrolled in our study. Genotyping was conducted using an improved multiplex ligase detection reaction (iMLDR). We performed a logistic regression including sex and age as covariates to test the effect of alleles/genotypes on LTBI and/or TB. All six markers studied in IFNG and IFNGR1 conformed to the Hardy-Weinberg equilibrium (HWE). The IFNG rs1861494 was significantly associated with LTBI in recessive model, and the CC+CT genotype decreased risk of LTBI by 50% (P = 0.046, OR = 0.50, 95%CI: 0.25-0.99). The IFNGR1 rs2234711 was significantly associated with LTBI, and allele A increased the risk of LTBI by 55% (P = 0.047, OR = 1.55, 95%CI: 1.00-2.40). In the present study, we found that IFNG and IFNGR1 polymorphisms were associated with LTBI.

Host Regulators of Liver Fibrosis During Human Schistosomiasis

Liver fibrosis is a wound-healing process purposely aimed at restoring organ integrity after severe injury caused by autoimmune reactions, mechanical stress or infections. The uncontrolled solicitation of this process is pathogenic and a pathognomonic feature of diseases like hepatosplenic schistosomiasis where exacerbated liver fibrosis is centrally positioned among the drivers of the disease morbidity and mortality. Intriguingly, however, liver fibrosis occurs and progresses dissimilarly in schistosomiasis-diseased individuals with the same egg burden and biosocial features including age, duration of residence in the endemic site and gender. This suggests that parasite-independent and currently poorly defined host intrinsic factors might play a defining role in the regulation of liver fibrosis, the hallmark of morbidity, during schistosomiasis. In this review, we therefore provide a comprehensive overview of all known host candidate regulators of liver fibrosis reported in the context of human schistosomiasis.

Population genetic evidence for positive and purifying selection acting at the human IFN-γ locus in Africa

Despite its critical role in the defense against microbial infection and tumor development, little is known about the range of nucleotide and haplotype variation at IFN-γ, or the evolutionary forces that have shaped patterns of diversity at this locus. To address this gap in knowledge, we examined sequence data from the IFN-γ gene in 1461 individuals from 15 worldwide populations. Our analyses uncovered novel patterns of variation in distinct African populations, including an excess of high frequency-derived alleles, unusually long haplotype structure surrounding the IFN-γ gene, and a "star-like" genealogy of African-specific haplotypes carrying variants previously associated with infectious disease. We also inferred a deep time to coalescence of variation at IFN-γ (~ 0.8 million years ago) and ancient ages for common polymorphisms predating the evolution of modern humans. Taken together, these results are congruent with a model of positive selection on standing variation in African populations. Furthermore, we inferred that common variants in intron 3 of IFN-γ are the likely targets of selection. In addition, we observed a paucity of non-synonymous substitutions relative to synonymous changes in the exons of IFN-γ in African and non-African populations, suggestive of strong purifying selection. Therefore, we contend that positive and purifying selection have influenced levels of diversity in different regions of IFN-γ, implying that these distinct genic regions are, or have been, functionally important. Overall, this study provides additional insights into the evolutionary events that have contributed to the frequency and distribution of alleles having a role in human health and disease.

IFN-γ-mediated hematopoietic cell destruction in murine models of immune-mediated bone marrow failure

Interferon gamma (IFN-γ) has been reported to have both negative and positive activity on hematopoietic cells, adding complexity to the interpretation of its pleiotropic functions. We examined the effects of IFN-γ on murine hematopoietic stem cells (HSCs) and progenitors in vitro and in vivo by using mouse models. IFN-γ treatment expanded bone marrow (BM) c-Kit(+)Sca1(+)Lin(-) (KSL) cell number but reduced BM KLCD150(+) and KLCD150(+)CD48(-) cells. IFN-γ-expanded KSL cells engrafted poorly when tested by competitive repopulation in vivo. KSL, KLCD150(+), and KLCD150(+)CD48(-) cells from IFN-γ-treated animals all showed significant upregulation in Fas expression. When cocultured with activated T cells in vitro, KSL and KLCD150(+) cells from IFN-γ-treated donors showed increased apoptosis relative to those from untreated animals, and infusion of activated CD8 T cells into IFN-γ-injected animals in vivo led to partial elimination of KSL cells. Exposure of BM cells or KSL cells to IFN-γ increased expression of Fas, caspases, and related proapoptotic genes and decreased expression of Ets-1 and other hematopoietic genes. In mouse models of BM failure, mice genetically deficient in IFN-γ receptor expression showed attenuation of immune-mediated marrow destruction, whereas effector lymphocytes from IFN-γ-deficient donors were much less potent in initiating BM damage. We conclude that the activity of IFN-γ on murine hematopoiesis is context dependent. IFN-γ-augmented apoptotic gene expression facilitates destruction of HSCs and progenitors in the presence of activated cytotoxic T cells, as occurs in human BM failure.

Pleiotropic Effects of Immune Responses Explain Variation in the Prevalence of Fibroproliferative Diseases

Many diseases are differentially distributed among human populations. Differential selection on genetic variants in ancestral environments that coincidentally predispose to disease can be an underlying cause of these unequal prevalence patterns. Selected genes may be pleiotropic, affecting multiple phenotypes and resulting in more than one disease or trait. Patterns of pleiotropy may be helpful in understanding the underlying causes of an array of conditions in a population. For example, several fibroproliferative diseases are more prevalent and severe in populations of sub-Saharan ancestry. We propose that this disparity is due to selection for an enhanced Th2 response that confers resistance to helminthic infections, and concurrently increases susceptibility to fibrosis due to the profibrotic action of Th2 cytokines. Many studies on selection of Th2-related genes for host resistance to helminths have been reported, but the pleiotropic impact of this selection on the distribution of fibrotic disorders has not been explicitly investigated. We discuss the disproportionate occurrence of fibroproliferative diseases in individuals of African ancestry and provide evidence that adaptation of the immune system has shaped the genetic structure of these human populations in ways that alter the distribution of multiple fibroproliferative diseases.

The Impact of IFN-γ Gene Polymorphisms on Spontaneous Clearance of HCV Infection in Fars Province, Southern of Iran

BACKGROUND

Certain polymorphisms in cytokine genes such as IFN-γ may influence the outcome of hepatitis C virus (HCV) infection. Here the frequency of the genotype, allele, and haplotype of IFN-γ gene at some loci is investigated in HCV-infected patients.

METHODS

Totally 255 patients with chronic HCV infection and 44 spontaneously cleared individuals were included. The chronic or clearance states were confirmed using enzyme-linked immunosorbent assay (ELISA) and two different qualitative reverse transcriptase polymerase chain reaction (RT-PCR) techniques. IFN-γ gene polymorphisms were performed by PCR using sequence-specific primers and PCR-RLFP on extracted genomic DNA.

RESULTS

The frequency of GG genotype (P = 0.0001, OR: 5.69 and CI: 2.21-14.62) and allele (P = 0.0003, OR: 2.73 and CI: 1.54-4.83) of IFN-γ gene at +2109 locus was significantly higher in cases that spontaneously cleared the infection. Haplotype analysis showed the association of AG haplotype (P = 0.0046, OR = 6.14 and CI = 1.56-25) with spontaneous clearance of the infection.

CONCLUSION

Our finding indicated that individuals with GG genotype at +2109 loci of IFN-γ gene and also AG haplotype (A allele at +874 loci and G allele at +2109 loci) may clear HCV infection more frequently than those with AA and AG genotype at +2109 loci and AA, TA, and TG haplotype.

Interferon gamma polymorphisms and hepatitis B virus-related liver cirrhosis risk in a Chinese population

Background

Previous studies proved that interferon gamma (IFN-γ) gene polymorphisms were associated with the risk of hepatitis B virus (HBV) infection. However, the association between IFN-γ polymorphisms and HBV-related liver cirrhosis (HBV-LC) risk is still unclear.

Methods

IFN-γ +874 T/A and +2109G/A genotypes were determined in 126 HBV-LC patients, 129 chronic hepatitis B(CHB) patients, and 173 early HBV infection controls using a sequence-specific primer-polymerase chain reaction and a polymerase chain reaction-restriction fragment length polymorphism, respectively.

Results

Significant associations were observed between +2109A/G polymorphisms and HBV-LC risk in the co-dominant model (GG vs. AA: OR = 0.321, 95% CI = 0.130-0.793, P = 0.014), the allelic model (OR = 0.565, 95% CI = 0.388-0.825, P = 0.003), the dominant model (OR = 0.551, 95% CI = 0.344-0.883, P = 0.013), and the recessive model (OR = 0.385, 95% CI = 0.159-0.930, P = 0.034). In addition, haplotype analysis indicated that the T⁺⁸⁷⁴G⁺²¹⁰⁹ haplotype significantly decreased the HBV-LC risk (OR = 0.106, 95% CI = 0.022-0.502, P = 0.000), and A⁺⁸⁷⁴A⁺²¹⁰⁹ haplotype significantly increased the LC risk (OR = 1.485, 95% CI = 1.065-2.070, P = 0.019). No significant associations were observed between IFN-γ +874 T/A polymorphisms and HBV-LC risk, as well as the two single-nucleotide polymorphisms (SNPs) and CHB risk (P > 0.05).

Conclusions

Our observations suggested a significant association of IFN-γ polymorphisms with HBV-LC risk in the Chinese population.

Clinical implications of interferon-γ genetic and epigenetic variants

Interferon-γ (IFN-γ) is an integral and critical molecule of the immune system, with multiple functions, mostly related to the T helper type 1 (Th1) response to infection. It is critical for defence against mycobacterial infection and is of increasing interest in defence against fungi. In this article, we review the genetic and epigenetic variants affecting IFN-γ expression and investigate its role in disease, with an emphasis on fungal diseases such as invasive and chronic pulmonary aspergillosis. Over 347 IFN-γ gene variants have been described, in multiple ethnic populations. Many appear to confer a susceptibility to disease, especially tuberculosis (TB) and hepatitis, but also some non-infectious conditions such as aplastic anaemia, cervical cancer and psoriasis. Several epigenetic modifications are also described, increasing IFN-γ expression in Th1 lymphocytes and reducing IFN-γ expression in Th2 lymphocytes. Recombinant IFN-γ administration is licensed for the prophylaxis of infection (bacterial and fungal) in patients with the phagocyte functional deficiency syndrome chronic granulomatous disease, although the benefits appear limited. Interferon-γ therapy is given to patients with profound defects in IFN-γ and interleukin-12 production and appears to be beneficial for patients with invasive aspergillosis and cryptococcal meningitis, but the studies are not definitive. A high proportion of patients with chronic pulmonary aspergillosis are poor producers of IFN-γ in response to multiple stimuli and could also benefit from IFN-γ administration. The investigation and management of patients with possible or demonstrated IFN-γ deficiency in adulthood is poorly studied and could be greatly enhanced with the integration of genetic data.

Prostate adenocarcinoma associated with prostatic infection due to Schistosoma haematobium. Case report and systematic review

Schistosomiasis affects more than 240 million people worldwide, an infection which may cause urogenital manifestations including, among others, squamous bladder cancer and prostate involvement. We describe the first case of a prostate adenocarcinoma associated with prostatic Schistosoma haematobium infection occurring in Angola. Prostate carcinoma was suspected because of high levels of prostate-specific antigen. This observation prompted us to review the literature on schistosomiaisis with respect to genital pathology and prostate cancer. Described genital manifestations in men include funiculitis, epididymitis, granulomata of the seminal vesicles, testicular masses, and prostate lesions which may cause haematospermia and infertility. In contrast to bladder cancer, only 12 reports including the present case on 17 cases on prostate carcinoma associated with schistosomiasis have been published worldwide. The rarity of reports on prostate carcinoma associated with schistosomiasis is partly due to diagnostic constraints, and its incidence is underestimated. However, in emerging countries, the incidence of prostate cancer appears to increase mainly as a result of urbanization and improved access to health care where schistosomiasis prevalence is decreasing.

Host genetics and parasitic infections

Parasites still impose a high death and disability burden on human populations, and are therefore likely to act as selective factors for genetic adaptations. Genetic epidemiological investigation of parasitic diseases is aimed at disentangling the mechanisms underlying immunity and pathogenesis by looking for associations or linkages between loci and susceptibility phenotypes. Until recently, most studies used a candidate gene approach and were relatively underpowered, with few attempts at replicating findings in different populations. However, in the last 5 years, genome-wide and/or multicentre studies have been conducted for severe malaria, visceral leishmaniasis, and cardiac Chagas disease, providing some novel important insights. Furthermore, studies of helminth infections have repeatedly shown the involvement of common loci in regulating susceptibility to distinct diseases such as schistosomiasis, ascariasis, trichuriasis, and onchocherciasis. As more studies are conducted, evidence is increasing that at least some of the identified susceptibility loci are shared not only among parasitic diseases but also with immunological disorders such as allergy or autoimmune disease, suggesting that parasites may have played a role in driving the evolution of the immune system.

IFNG rs1861494 polymorphism is associated with IBD disease severity and functional changes in both IFNG methylation and protein secretion

BACKGROUND

Mucosal expression of interferon (IFN)-γ plays a pivotal role in the pathogenesis of inflammatory bowel disease (IBD) and IBD risk regions flank IFNG. The conserved IFNG rs1861494 T/C introduces a new CpG methylation site, is associated with disease severity and lack of therapeutic response in other infectious and immune-mediated disorders, and is in linkage disequilibrium with a ulcerative colitis (UC) disease severity region. It seems likely that CpG-altering single nucleotide polymorphisms modify methylation and gene expression. This study evaluated the association between rs1861494 and clinical, serologic, and methylation patterns in patients with IBD.

METHODS

Peripheral T cells of UC and Crohn's disease (CD) patients were genotyped for rs1861494 and analyzed for allele-specific and IFNG promoter methylation. Serum antineutrophil cytoplasmic autoantibodies and IFN-γ secretion were measured by enzyme-linked immunosorbent assay and nucleoprotein complex formation by electrophoretic mobility shift assay.

RESULTS

IFNG rs1861494 T allele carriage in patients with IBD was associated with enhanced secretion of IFN-γ. T allele carriage was associated in UC with high levels of antineutrophil cytoplasmic autoantibodies and faster progression to colectomy. In CD, it was associated with complicated disease involving a stricturing/penetrating phenotype. Likewise, IFNG rs1861494 displayed genotype-specific modulation of DNA methylation and transcription factor complex formation.

CONCLUSIONS

This study reports the first association of IFNG rs1861494 T allele with enhanced IFN-γ secretion and known IBD clinical parameters indicative of more aggressive disease and serological markers associated with treatment resistance to anti-tumor necrosis factor therapy in patients with IBD. These data may be useful prognostically as predictors of early response to anti-tumor necrosis factor therapy to identify patients with IBD for improved personalized therapeutics.

The WHO ultrasonography protocol for assessing hepatic morbidity due to Schistosoma mansoni. Acceptance and evolution over 12 years

The aim of this study is to review the worldwide acceptance of the World Health Organization (WHO) ultrasound protocol for assessing hepatosplenic morbidity due to Schistosoma mansoni since its publication in 2000. A PubMed literature research using the keywords "schistosomiasis and ultrasound," "schistosomiasis and ultrasonography," and "S. mansoni and ultrasound" from 2001 to 2012 was performed. Case reports, reviews, reports on abnormalities due to parasites other than S. mansoni, organ involvement other than the human liver, and reports where ultrasound method was not described were excluded. Six studies were retrieved from other Brazilian sources. Sixty studies on 37,424 patients from 15 countries were analyzed. The WHO protocol was applied with increasing frequency from 43.75% in the years 2001 to 2004 to 84.61% in 2009 to 2012. Results obtained using the pictorial image pattern approach of the protocol are reported in 38/41 studies, whereas measurements of portal branch walls were applied in 19/41 and results reported in 2/41 studies only. The practical usefulness of the pictorial approach of the WHO protocol is confirmed by its wide acceptance. This approach alone proved satisfactory in terms of reproducibility, assessment of evolution of pathology, and comparability between different settings. The measurements of portal branches, also part of the protocol, may be omitted without losing relevant information since results obtained by these measurements are nonspecific. This would save resources by reducing the time required for each examination. It is also more feasible for examiners who are not specialized in medical imaging. As with all protocols, incipient liver fibrosis is difficult to distinguish from normal ultrasound findings of the liver. The ability of this protocol to predict complications in severe cases should be further evaluated in a higher number of patients.

Functional polymorphisms of interferon-gamma affect pneumonia-induced sepsis

OBJECTIVE

Sepsis is an inflammatory syndrome caused by infection, and both its incidence and mortality are high. Because interferon-gamma (IFN-γ) plays an important role in inflammation, this work assessed IFN-γ single nucleotide polymorphism (SNPs) that may be associated with sepsis.

METHODS

A total of 196 patients with pneumonia-induced sepsis and 213 age- and sex-matched healthy volunteers participated in our study from July 2012 to July 2013 in Guangzhou, China. Patient clinical information was collected. Clinical pathology was assessed in subgroups defined based on clinical criteria, APACHE II (acute physiology and chronic health evaluation) and SOFA (sepsis-related organ failure assessment) scores and discharge rate. Four functional SNPs, -1616T/C (rs2069705), -764G/C (rs2069707), +874A/T (rs2430561) and +3234C/T (rs2069718), were genotyped by Snapshot in both sepsis patients and healthy controls. Pearson's chi-square test or Fisher's exact test were used to analyze the distribution of the SNPs, and the probability values (P values), odds ratios (OR) and 95% confidence intervals (CIs) were calculated.

RESULTS

No mutations in the IFN-γ -764G/C SNP were detected among the participants in our study. The +874A/T and +3234C/T SNPs were in strong linkage disequilibrium (LD) (r(2) = 0.894). The -1616 TC+TT, +874 AT+AA genotype and the TAC haplotype were significantly associated with sepsis susceptibility, while the CTT haplotype was associated with protection against sepsis incidence. Genotype of -1616 TT wasn't only protective against severity of sepsis, but also against higher APACHE II and SOFA scores as +874 AA and +3234 CC. The TAC haplotype was was protective against progression to severe sepsis either.

CONCLUSION

Our results suggest that functional IFN-γ SNPs and their haplotypes are associated with pneumonia-induced sepsis.

The Role of Interferon Gamma Gene Polymorphism (+874A/T, +2109A/G, and -183G/T) in Response to Treatment Among Hepatitis C Infected Patients in Fars Province, Southern Iran

BACKGROUND

Hepatitis C virus (HCV) infection as a worldwide health problem is associated with cirrhosis and hepatocellular carcinoma. With current treatment regimen, pegylated interferon (PEG-IFN) plus ribavirin, sustain virological response (SVR) is achieved in only 50% of infected individuals. In HCV infection, an inappropriate ratio of cytokines may affect the benefit of antiviral therapy. Given the polymorphisms in regulatory regions of cytokines genes may influence cytokines production.

OBJECTIVES

We aimed to investigate both the frequency of genotypes and alleles of interferon gamma (IFN-γ) gene at +874A/T, +2109A/G, and -183G/T loci in HCV-infected patients and their associations with response to therapy.

PATIENTS AND METHODS

A total of 158 patients were included and treated with PEG-IFN plus ribavirin. The presence of HCV infection in patients was confirmed by reverse transcription polymerase chain reaction, and genomic DNA was extracted from peripheral leukocytes using salting out method. IFN-γ gene polymorphisms were identified by polymerase chain reaction using sequence specific primers and restriction fragment length polymorphism analysis on genomic DNA.

RESULTS

Of 158 patients, 110 (69.5%) subjects achieved SVR and 48 (30.5%) subjects did not respond to therapy. The frequency of AA genotype (P = 0.001; OR: 11.2; CI: 2.26-63.21) and A allele (P = 0.01; OR: 3.23; CI: 1.23 8.56) of IFN-γ gene at +2109 locus were significantly different between the responder and non-responder subjects infected with genotype 1. Regardless of HCV genotype, the frequency of AG genotype was also higher in responder group than those who did not respond to therapy (P = 0.041; OR: 05.05; CI: 1.05-33.25)). In case of IFN-γ gene at +874 locus, there was no difference in genotypes and alleles frequencies between the responder and non-responder subjects infected with HCV genotypes 1 and 3. Haplotype analysis showed no association between haplotypes and response to therapy. All participants had G/T genotype at -183 locus.

CONCLUSIONS

Our findings indicate that heterogeneity at +2109 locus of IFN-γ gene but not at +874 locus could interfere with successful therapy in patients infected with HCV genotype 1.

The gene-immune-behavioral pathway: Gamma-interferon (IFN-γ) simultaneously coordinates susceptibility to infectious disease and harm avoidance behaviors

Cytokine gene variants are known to influence both infectious disease susceptibility and harm-avoidant behaviors, suggesting that these risk variants may be pleiotropically linked to instinctual disease-avoidant traits. The gamma-interferon (IFNG) +874 T>A polymorphism (rs2430561) is an ideal candidate gene variant for immune-behavioral studies. It is a functional SNP, regulating IFNG mRNA expression; it is known to modulate serotonergic activity and is therefore capable of modifying behavior; and it has previously been associated with increased susceptibility to malaria, tuberculosis, leprosy and Chagas disease. We hypothesized that the infectious disease-high-risk IFNG +874 A-allele would be associated with four personality traits previously reported as behavioral defenses against infection: Harm Avoidance (HA), Extraversion (E), Exploratory Excitability (Exp E), and Openness to Experience (O). We tested this hypothesis in a sample of 168 healthy university students from Southern California genotyped for IFNG +874 T>A and evaluated by the Temperament and Character Inventory-Revised (TCI-R) and the NEO Five-Factor Inventory (NEO-FFI). We found that the infectious disease-high-risk IFNG +874 A-allele was associated with increased HA (P=0.001) and decreased E (P=0.030) and Exp E (P=0.030). These findings suggest that the IFNG +874 A gene variant is linked both to infectious disease susceptibility and to proactive behavioral defenses that reduce infection risk in healthy subjects.

Genetic analysis of human predisposition to hepatosplenic disease caused by schistosomes reveals the crucial role of connective tissue growth factor in rapid progression to severe hepatic fibrosis

Schistosome worms inhabit mammalian mesenteric veins. Their eggs cause chronic inflammation, which progresses to periportal fibrosis in 5 to 30% of cases, increasing portal blood pressure and leading to esophageal varices. Episodes of bleeding cause hepatic necrosis and may ultimately lead to hepatic failure and the death of the patient. Schistosome infections can also cause pulmonary hypertension and heart failure. The mechanisms of fibrogenesis and fibrolysis are beginning to be unraveled, but it remains unclear why disease occurs only in certain subjects, as also observed for other types of chronic liver inflammation, as in hepatitis C or B. We summarize here the results that showed that fibrosis progression is determined by a genetic locus on chromosome 6. The CCN2 gene at this locus, encodes CTGF that is a crucial regulator of fibrosis. Two groups of CCN2 polymorphisms independently modulate the progression of hepatic fibrosis. These results were obtained in an Asian population, but were extended to humans living in Africa and South America and are presently tested in liver fibrosis of other etiological origins.

Distribution of the IL-1RN, IL-6, IL-10, INF-γ, and TNF-α Gene Polymorphisms in the Mexican Population

BACKGROUND

Cytokines are a group of polypeptides with an important role in the inflammatory response. It has been suggested that certain polymorphisms located in several cytokine genes are associated with different diseases. The aim of the present study was to establish the gene frequency of 13 polymorphisms of the IL-1RN, IL-6, IL-10, INF-γ, and TNF-α genes in a Mexican population. These polymorphisms have been reported in several populations, with important variation in frequency according to the studied population.

METHODS

Thirteen polymorphisms (rs419598, rs315951, rs2234663, rs3811058, rs1800796, rs2069827, rs1800896, rs1800871, rs1800872, rs1800629, rs2069709, rs2069710, and rs361525) were analyzed by 5' exonuclease TaqMan genotyping assays in a group of 248 healthy unrelated Mexican individuals.

RESULTS

The results obtained showed that the studied Mexican population presents significant differences (p<0.05) in the distribution of the IL1RN (rs419598, rs315951, and and rs2234663), IL1F10 (rs3811058), IL6 (rs1800796, rs2069827), IL10 (rs1800896, rs1800871, and rs1800872), and TNF-α (rs1800629) polymorphisms when compared to Caucasian, Asian, and African populations.

CONCLUSIONS

In summary, the distribution of the IL-1RN, IL-6, IL-10, and TNF-α cytokine gene polymorphisms distinguishes the studied Mexican population from other groups. Since the alleles of these cytokines are associated with the development of several inflammatory diseases, knowledge of the distribution of these alleles in the studied Mexican population could be helpful to understand their true role as a genetic susceptibility marker in this population.

IFN-γ-driven IDO production from macrophages protects IL-4Rα-deficient mice against lethality during Schistosoma mansoni infection

The balance between alternatively activated macrophages (AAMs)/M2 cells and classically activated macrophages (M1 cells) is largely dependent on the effects of IL-4 and interferon (IFN)-γ, respectively. Although AAM/M2 cells can suppress inflammation and repair damaged tissue, M1 cells produce an array of pro-inflammatory molecules. Macrophage effector functions are critical for host protection against many infectious diseases, but it remains unknown whether lethal immunopathological characteristics, caused by Schistosoma mansoni infection in IL-4 receptor α-deficient mice (IL-4Rα(-/-)), results from the absence of M2 cells or increased numbers of M1 cells. In this study, we generated mice that completely lack IL-4Rα signaling in the context of a macrophage-specific loss of IFN-γ responsiveness (MIIG × IL-4Rα(-/-)). Contrary to what we expected, acute schistosomiasis resulted in greater liver injury and mortality in MIIG × IL-4Rα(-/-) mice compared with IL-4Rα(-/-) mice. Greater tissue injury in MIIG × IL-4Rα(-/-) mice was likely because of a lack of indoleamine 2,3 dioxygenase (IDO), a critical regulator of immunosuppression. Indeed, MIIG × IL-4Rα(-/-) failed to up-regulate IDO expression, and IL-4Rα(-/-) mice treated with an IDO antagonist underwent greater liver damage and mortality compared with mock-treated IL-4Rα(-/-) mice. Thus, we propose that, in the absence of AAM/M2 cells, IFN-γ-induced M1 cells suppress tissue-damaging inflammation during acute schistosomiasis through an IDO-dependent mechanism.

Polyinosinic-polycytidylic acid attenuates hepatic fibrosis in C57BL/6 mice with Schistosoma japonicum infection

The development of hepatic fibrosis is the principal cause of morbidity and mortality in human beings infected with schistosoma. In this study, we investigated the effect of polyinosinic-polycytidylic acid (poly I:C) on Schistosoma japonicum (S. japonicum) egg-induced liver fibrosis. S. japonicum cercariae infected mice were injected with poly I:C at the onset of egg granuloma formation (early phase poly I:C treatment) or after the formation of liver fibrosis (late phase poly I:C treatment). Our results showed that both early and late phase poly I:C treatment significantly reduced collagen deposition and hepatic stellate cell activation in the liver. Poly I:C is one of the most effective adjuvants for Th1 type responses, and its protective effect on liver fibrosis was accompanied by increased IFN-α, IFN-β, IFN-γ, IL-12, TNF-α, and IL-10 mRNA expression, and decreased IL-4 and IL-5 mRNA expression. Moreover, poly I:C injection also enhanced the mRNA expression of natural killer group 2 member D (NKG2D) and tumor necrosis factor related apoptosis-inducing ligand (TRAIL). Therefore, it is indicated that poly I:C can significantly attenuate S. japonicum egg-induced hepatic fibrosis, which may be partly dependent on the increased Th1 response and decreased Th2 response.

Negative regulation of Schistosoma japonicum egg-induced liver fibrosis by natural killer cells

The role of natural killer (NK) cells in infection-induced liver fibrosis remains obscure. In this study, we elucidated the effect of NK cells on Schistosoma japonicum (S. japonicum) egg-induced liver fibrosis. Liver fibrosis was induced by infecting C57BL/6 mice with 18–20 cercariae of S. japonicum. Anti-ASGM1 antibody was used to deplete NK cells. Toll-like receptor 3 ligand, polyinosinic-polycytidylic acid (poly I∶C) was used to enhance the activation of NK cells. Results showed that NK cells were accumulated and activated after S. japonicum infection, as evidenced by the elevation of CD69 expression and IFN-γ production. Depletion of NK cells markedly enhanced S. japonicum egg-induced liver fibrosis. Administration of poly I∶C further activated NK cells to produce IFN-γ and attenuated S. japonicum egg-induced liver fibrosis. The observed protective effect of poly I∶C on liver fibrosis was diminished through depletion of NK cells. Disruption of IFN-γ gene enhanced liver fibrosis and partially abolished the suppression of liver fibrosis by poly I∶C. Moreover, expression of retinoic acid early inducible 1 (RAE 1), the NKG2D ligand, was detectable at high levels on activated hepatic stellate cells derived from S. japonicum-infected mice, which made them more susceptible to hepatic NK cell killing. In conclusion, our findings suggest that the activated NK cells in the liver after S. japonicum infection negatively regulate egg-induced liver fibrosis via producing IFN-γ, and killing activated stellate cells.

Schistosomiasis continues to be a major public health problem in the developing world. Parasite egg-induced liver fibrosis is the principal cause of morbidity and mortality in human infected with schistosoma. Thus, elucidating the mechanisms that restrict tissue fibrosis may lead to more effective strategies for immunological intervention in this and a variety of chronic diseases. NK cells have been demonstrated to play an important role in suppressing carbon tetrachloride (CCl₄)-induced liver fibrosis. However, little is known about the role of NK cells in an infection-based model of fibrosis. In the current study, we determined, for the first time, the role of NK cells in S. japonicum egg-induced liver fibrosis. Our findings suggest that the activated NK cells in the liver after S. japonicum infection negatively regulate egg-induced liver fibrosis via producing IFN-γ, and killing activated stellate cells. These results further our understanding of the innate immune cells that regulate the development of S. japonicum-induced fibrosis and aid in the development of potential strategies to enhance immunity against this and other chronic inflammatory diseases of the liver where fibrosis is a common feature.

Chronic hepatosplenomegaly in African school children: a common but neglected morbidity associated with schistosomiasis and malaria

Chronic hepatosplenomegaly, which is known to have a complex aetiology, is common amongst children who reside in rural areas of sub-Saharan Africa. Two of the more common infectious agents of hepatosplenomegaly amongst these children are malarial infections and schistosomiasis. The historical view of hepatosplenomegaly associated with schistosomiasis is that it is caused by gross periportal fibrosis and resulting portal hypertension. The introduction of ultrasound examinations into epidemiology studies, used in tandem with clinical examination, showed a dissociation within endemic communities between presentation with hepatosplenomegaly and ultrasound periportal fibrosis, while immuno-epidemiological studies indicate that rather than the pro-fibrotic Th2 response that is associated with periportal fibrosis, childhood hepatosplenomegaly without ultrasound-detectable fibrosis is associated with a pro-inflammatory response. Correlative analysis has shown that the pro-inflammatory response is also associated with chronic exposure to malarial infections and there is evidence of exacerbation of hepatosplenomegaly when co-exposure to malaria and schistosomiasis occurs. The common presentation with childhood hepatosplenomegaly in rural communities means that it is an important example of a multi-factorial disease and its association with severe and subtle morbidities underlies the need for well-designed public health strategies for tackling common infectious diseases in tandem rather than in isolation.

Association of HLA and post-schistosomal hepatic disorder: a systematic review and meta-analysis

Several human genetic variants, HLA antigens and alleles are reportedly linked to post-schistosomal hepatic disorder (PSHD), but the results from these reports are highly inconclusive. In order to estimate overall associations between human genetic variants, HLA antigens, HLA alleles and PSHD, we systematically reviewed and performed a meta-analysis of relevant studies in both post-schistosomal hepatic disorder and post-schistosomal non-hepatic disorder patients. PubMed, Scopus, Google Scholar, The HuGE Published Literature database, Cochrane Library, and manual search of reference lists of articles published before July 2009 were used to retrieve relevant studies. Two reviewers independently selected articles and extracted data on study characteristics and data regarding the association between genetic variants, HLA antigens, HLA alleles and PSHD in the form of 2×2 tables. A meta-analysis using fixed-effects or random-effects models to pooled odds ratios (OR) with corresponding 95% confidence intervals were calculated only if more than one study had investigated particular variation. We found 17 articles that met our eligibility criteria. Schistosoma mansoni and Schistosoma japonicum were reported as the species causing PSHD. Since human genetic variants were only investigated in one study, these markers were not assessed by meta-analysis. Thus, only HLA-genes (a total of 66 HLA markers) were conducted in the meta-analysis. Our meta-analysis showed that human leucocyte antigens HLA-DQB1*0201 (OR=2.64, P=0.018), DQB1*0303 (OR=1.93, P=0.008), and DRB1*0901 (OR=2.14, P=0.002) alleles and HLA-A1 (OR=5.10, P=0.001), A2 (OR=2.17, P=0.005), B5 (OR=4.63, P=0.001), B8 (OR=2.99, P=0.02), and B12 (OR=5.49, P=0.005) serotypes enhanced susceptibility to PSHD, whereas HLA-DQA1*0501 (OR=0.29, P≤0.001) and DQB1*0301 (OR=0.58, P=0.007) were protective factors against the disease. We further suggested that the DRB1*0901-DQB1*0201, DRB1*0901-DQB1*0303 and A1-B8 haplotypes enhanced susceptibility to PSHD, whereas DQA1*0501-DQB1*0301 linkage decreased the risk of PSHD. The result improved our understanding of the association between the HLA loci and PSHD with regard to pathogenic or protective T-cells and provided novel evidence that HLA alleles may influence disease severity.

Genetic studies of the etiology of asthma

Asthma is a heterogeneous disease for which a strong genetic basis is firmly established. Although the generally accepted definition includes three domains of symptoms (variable airway obstruction, airway hyper-responsiveness, and airway inflammation), there is general agreement that, rather than being a single disease entity, asthma consists of related, overlapping syndromes. A considerable proportion of asthma is IgE-mediated, but the observation that not all individuals with asthma are atopic adds to the heterogeneity. Although a genetic basis for asthma is undeniable, elucidation of polymorphisms that are "causal" is greatly hampered by variability in the clinical phenotype, which is likely due to the multiple molecular mechanisms underlying the complex pathological processes involved in disease development and progression. One objective of this review is to consider progress that has been made to date in gene discovery in the field of asthma, with a focus on the evolution of molecular genetic methods that have led to the discoveries thus far, and with a particular focus on the major advances owed to the published genome-wide association studies (GWAS) on asthma to date. A second objective is to consider a Darwinian approach toward understanding the genetic underpinnings of asthma, including evidence supporting a modified Hygiene Hypothesis, which suggests that there are co-associations between asthma risk polymorphisms and polymorphisms associated with another IgE-mediated disease, schistosomiasis. The overall conclusion is that the huge research efforts and expense committed to asthma genetics have changed the perception about disease etiology in general and the functional relevance of the asthma genes identified thus far in particular.

Avaliação das citocinas IL-10 e IL-13 como mediadores na progressão da fibrose de Symmers em portadores de esquistossomose mansônica na forma hepatoesplênica

OBJETIVO: Investigar os níveis de IL-10 e IL-13 no soro de portadores da esquistossomose mansônica na forma hepatoesplênica (EHE), avaliando o papel destas citocinas no desenvolvimento da fibrose hepática. MÉTODOS: O estudo foi prospectivo e analítico, desenvolvido no Departamento de Cirurgia da Universidade Federal de Pernambuco, Laboratório de Imunologia Keizo Asami. Foram estudados três grupos: Grupo I - 25 portadores de esquistossomose mansônica na forma hepatoesplênica e não submetidos a tratamento cirúrgico; Grupo II - 30 submetidos à esplenectomia e ligadura da veia gástrica esquerda; Grupo III - 33 indivíduos sem esquistossomose mansônica na forma hepatoesplênica ou qualquer outra doença ou agravo que comprometesse a reserva funcional hepática. As concentrações séricas de IL-10 e IL-13 foram obtidas pelo método ELISA. Considerando-se a natureza não paramétrica, todas as concentrações foram analisadas pelo teste de Kruskal-Wallis. p<0,05 foi usado para rejeição da hipótese de nulidade. RESULTADOS: As médias das concentrações de IL-10, em ng/mL, no soro foram: GI 50,0 ± 59,0; GII 38,0 ± 270; GIII 38,0 ± 20,0. As concentrações de IL-13, em ng/mL, no soro dos pacientes foram respectivamente: GI 41,0 ± 93,0; GII 16,0 ± 17,0; GIII 18,0 ± 34,0. Não se observou diferença significante entre as médias das concentrações de IL-10 e IL-13 entre os grupos de estudo (p>0,05). CONCLUSÃO: As médias das concentrações séricas de IL-10 e IL-13 foram similares nos três grupos estudados, indicando que, possivelmente, estas citocinas no soro não estejam associadas aos diferentes graus de fibrose de Symmers nos pacientes.

Schistosomiasis in the People's Republic of China: the era of the Three Gorges Dam

The potential impact of the Three Gorges Dam (TGD) on schistosomiasis transmission in China has invoked considerable global concern. The TGD will result in changes in the water level and silt deposition downstream, favoring the reproduction of Oncomelania snails. Combined with blockages of the Yangtze River's tributaries, these changes will increase the schistosomiasis transmission season within the marshlands along the middle and lower reaches of the Yangtze River. The changing schistosome transmission dynamics necessitate a comprehensive strategy to control schistosomiasis. This review discusses aspects of the epidemiology and transmission of Schistosoma japonicum in China and considers the pathology, clinical outcomes, diagnosis, treatment, immunobiology, and genetics of schistosomiasis japonica together with an overview of current progress in vaccine development, all of which will have an impact on future control efforts. The use of synchronous praziquantel (PZQ) chemotherapy for humans and domestic animals is only temporarily effective, as schistosome reinfection occurs rapidly. Drug delivery requires a substantial infrastructure to regularly cover all parts of an area of endemicity. This makes chemotherapy expensive and, as compliance is often low, a less than satisfactory control option. There is increasing disquiet about the possibility that PZQ-resistant schistosomes will develop. Consequently, as mathematical modeling predicts, vaccine strategies represent an essential component in the future control of schistosomiasis in China. With the inclusion of focal mollusciciding, improvements in sanitation, and health education into the control scenario, China's target of reducing the level of schistosome infection to less than 1% by 2015 may be achievable.

Variants of CTGF are associated with hepatic fibrosis in Chinese, Sudanese, and Brazilians infected with schistosomes

Abnormal fibrosis occurs during chronic hepatic inflammations and is the principal cause of death in hepatitis C virus and schistosome infections. Hepatic fibrosis (HF) may develop either slowly or rapidly in schistosome-infected subjects. This depends, in part, on a major genetic control exerted by genes of chromosome 6q23. A gene (connective tissue growth factor [CTGF]) is located in that region that encodes a strongly fibrogenic molecule. We show that the single nucleotide polymorphism (SNP) rs9402373 that lies close to CTGF is associated with severe HF (P = 2 x 10(-6); odds ratio [OR] = 2.01; confidence interval of OR [CI] = 1.51-2.7) in two Chinese samples, in Sudanese, and in Brazilians infected with either Schistosoma japonicum or S. mansoni. Furthermore, SNP rs12526196, also located close to CTGF, is independently associated with severe fibrosis (P = 6 x 10(-4); OR = 1.94; CI = 1.32-2.82) in the Chinese and Sudanese subjects. Both variants affect nuclear factor binding and may alter gene transcription or transcript stability. The identified variants may be valuable markers for the prediction of disease progression, and identify a critical step in the development of HF that could be a target for chemotherapy.

Conquering 'snail fever': schistosomiasis and its control in China

Schistosomiasis japonica is a serious parasitic disease and a major health risk for more than 60 million people living in the tropical and subtropical zones of south China. The disease is a zoonosis and its cause, the parasitic trematode Schistosoma japonicum, has a range of mammalian reservoirs, making control efforts difficult. Current control programs are heavily based on community chemotherapy with a single dose of the highly effective drug praziquantel. However, vaccines (for use in bovines and in humans) in combination with other control strategies are needed to eliminate the disease. In this review, we provide an overview of the transmission, clinical features, pathogenesis, diagnosis, treatment, genetics and susceptibility, epidemiology, and prospects for control of schistosomiasis japonica in China. The threat posed by the Three Gorges Dam may undermine control efforts because it will change the local ecology and associated schistosomiasis transmission risks over the next decade and beyond.

Immunopathogenesis of human schistosomiasis

Schistosomiasis continues to be a significant cause of parasitic morbidity and mortality worldwide. This review considers the basic features of the pathology and clinical outcomes of hepatointestinal and genitourinary schistosomiasis, presents an overview of the numerous studies on animal models that have clarified many of the immunopathological features, and provides insight into our current understanding of the immunopathogenesis and genetic control of human schistosomiasis. In murine schistosomiasis, pathology is induced by a CD4(+) Th2 driven granulomatous response directed against schistosome eggs lodged in the host liver. The Th2 cytokines IL-4 and IL-13 drive this response, whereas IL-10, IL13Ralpha2, IFN-gamma and a subset of regulatory T-cells act to limit schistosome induced pathology. A variety of cell types including hepatic stellate cells, alternatively activated macrophages and regulatory T-cells have also been implicated in the pathogenesis of schistosomiasis. Current knowledge suggests the immunopathogenic mechanisms underlying human schistosomiasis are likely to be similar. The review also considers the future development of anti-pathology schistosome vaccines. As fibrosis is an important feature of many other diseases such as Crohn's disease and sarcoidosis, a comprehensive understanding of the cellular and molecular mechanisms involved in schistosomiasis may also ultimately contribute to the development an effective disease intervention strategy for other granulofibrotic diseases.

Single nucleotide polymorphisms of cytokine genes are associated with fibrosis of the intrahepatic bile duct wall in human clonorchiasis

This study examined the association of cytokine gene polymorphisms with intrahepatic bile duct wall fibrosis in human clonorchiasis. A total of 240 residents in Heilongjiang, China underwent ultrasonography, blood sampling, and stool examination. Single nucleotide polymorphism (SNP) sites for IFN-gamma (+874 T/A), IL-10 (-1,082 G/A, -819 C/T, -592 C/A), TNF-alpha (-308 G/A), and TGF-beta1 (codon 10 T/C, codon 25 G/C) genes were observed with the TaqMan allelic discrimination assay. No significant correlation was observed between individual cytokine gene polymorphisms and intrahepatic duct dilatation (IHDD). Among individuals with clonorchiasis of moderate intensity, the incidence of IHDD was high in those with IFN-gamma intermediate-producing genotype, +874AT (80.0%, P = 0.177), and in those with TNF-alpha low-producing genotype, -308GG (63.0%, P = 0.148). According to the combination of IFN-gamma and TNF-alpha genotypes, the risks for IHDD could be stratified into high (intermediate-producing IFN-gamma and low producing TNF-alpha), moderate, and low (low-producing IFN-gamma and high producing TNF-alpha) risk groups. The incidence of IHDD was significantly different among these groups (P = 0.022): 88.9% (odds ratio, OR = 24.0) in high, 56.5% (OR = 3.9) in moderate, and 25.0% (OR = 1) in low risk groups. SNP of IFN-gamma and TNF-alpha genes may contribute to the modulation of fibrosis in the intrahepatic bile duct wall in clonorchiasis patients.

Human study and experimental behavior of Schistosoma mansoni isolates from patients with different clinical forms of schistosomiasis

Twenty Schistosoma mansoni strains were isolated from three groups of patients (intestinal, hepatointestinal and hepatosplenic clinical forms) born and living in the town of Capitão Andrade, Minas Gerais, Brazil. Schistosomal isolate from each group was inoculated into three sets of mice with 25, 50 and 100 cercariae. The animals were killed 90 and 180 days after infection and submitted to extensive histopathological study of the liver, lung, intestine and spleen to determine qualitative and quantitative morphological characteristics, mainly of the granulomas. The histopathological changes caused the same patterns of infection in mice and were proportional to the inoculum and the time of infection, confirming the relevance of quantitative aspects in the determination of the disease. These data indicate three possibilities: (1) mouse model is not adequate to predict possible differences in the S. mansoni isolates obtained from patients; (2) field isolates are probably genetic polymorphic and undifferentiated; (3) schistosomiasis in human does not depend on parasite intrinsic factors, but on multivariable factors, such as intensity and duration of infection, time of infection, age and gender and other characteristics such as host response.

Genetic epidemiology of human schistosomiasis in Brazil

Human schistosomiasis presents the classic, complex disease phenotype, with marked variation in the intensity of infection, the immune response to infection, and the development of schistosome-related pathology. Determining the role of host genetics in schistosomiasis is complicated by the numerous parasite and environmental factors involved in transmission. However, as a result of the increased availability of sequence data, novel statistical methods, and new methods of study design, the last decade has seen significant advances in identifying the role of host genetics in schistosome infection around the world. Many of these advances have taken place in Brazil. Epidemiological studies in Brazil have shown that the intensity of infection (worm burden) is a heritable phenotype (41%). Human genome scans have identified a locus responsible for controlling Schistosoma mansoni infection intensity on chromosome 5q31-q33. There is also evidence for genetic control of pathology due to S. mansoni, with linkage reported to a region containing the gene for the interferon-gamma receptor 1 subunit. Numerous association studies have also provided evidence for major histocompatibility complex control of pathology in schistosomiasis. Recent candidate gene studies suggest a role of other immune response genes in controlling helminth infection and pathology. We chronicle the many advances made in understanding the role of host genetics in S. mansoni infection that have taken place in Brazil by phenotype studied: infection intensity, immune response, and disease development. Results from Brazilian studies are compared with studies of S. mansoni and other schistosome species elsewhere in the world.

Regulatory role of interleukin-10 and interferon-gamma in severe hepatic central and peripheral fibrosis in humans infected with Schistosoma japonicum

BACKGROUND

Schistosoma japonicum is the most pathogenic agent of hepatosplenic schistosomiasis. It causes fibrosis of the central (CentF) and peripheral (PerF) portal areas. We investigated whether CentF and PerF in Chinese fishermen infected with S. japonicum were associated with an abnormal production of cytokines and chemokines that, in experimental models, have been implicated in the regulation of fibrosis.

METHODS

Cytokines were measured by enzyme-linked immunosorbent assay in cultures of peripheral blood mononuclear cells from 127 patients, after stimulation with S. japonicum egg antigens. Data were analyzed by logistic regression that included age, sex, number of treatment episodes, alcohol use, and exposure as covariates.

RESULTS

CentF was associated with low levels of interleukin (IL)-10 (P= .0004), regulated on activation normally T cell expressed and secreted (P= .0004), and macrophage inflammatory protein-1alpha (P= .007). In a multivariate analysis, only IL-10 was associated with CentF (odds ratio [OR], 10.8; 95% confidence interval [CI], 3.2-38; P= .0004). Splenomegaly was also associated with low IL-10 production and, independently, with CentF. In multivariate analysis, PerF was associated with low production of interferon (IFN)-gamma (OR, 8.2; 95% CI, 2-33; P= .0035) but not with production of IL-10.

CONCLUSIONS

IL-10 is associated with protection against central fibrosis, because of its anti-inflammatory and antifibrosis effects. IFN-gamma is associated with protection against PerF, which depends more on egg load and egg-associated toxicity.

Genetic studies of African populations: an overview on disease susceptibility and response to vaccines and therapeutics

Africa is the ultimate source of modern humans and as such harbors more genetic variation than any other continent. For this reason, studies of the patterns of genetic variation in African populations are crucial to understanding how genes affect phenotypic variation, including disease predisposition. In addition, the patterns of extant genetic variation in Africa are important for understanding how genetic variation affects infectious diseases that are a major problem in Africa, such as malaria, tuberculosis, schistosomiasis, and HIV/AIDS. Therefore, elucidating the role that genetic susceptibility to infectious diseases plays is critical to improving the health of people in Africa. It is also of note that recent and ongoing social and cultural changes in sub-Saharan Africa have increased the prevalence of non-communicable diseases that will also require genetic analyses to improve disease prevention and treatment. In this review we give special attention to many of the past and ongoing studies, emphasizing those in Sub-Saharan Africans that address the role of genetic variation in human disease.

Transmission consequences of coinfection: cytokines writ large?

Coinfection of a host by multiple parasite species is commonly observed and recent epidemiological work indicates that coinfection can enhance parasite transmission. This article proposes an immunoepidemiological framework to understand how within-host interactions during coinfection might affect between-host transmission. Cytokines, immune signalling molecules with a fundamental role in the amplification of antiparasitic effector mechanisms, provide a useful way to simplify immunological complexity for this endeavour--focusing on cytokines offers analytical tractability without sacrificing realism. Testable predictions about the epidemiological consequences of coinfection are generated by this conceptual framework.

The 434(G>C) polymorphism within the coding sequence of Eosinophil Cationic Protein (ECP) correlates with the natural course of Schistosoma mansoni infection

Schistosomiasis is a chronic parasitic infection with over 200 million people infected worldwide. In Schistosoma mansoni infections, parasite-derived eggs get trapped in the liver, causing the formation of granulomas, which may develop into periportal fibrosis and portal hypertension, and thus severe morbidity. Eosinophil cationic protein (ECP) is a secretory protein of eosinophil granulocytes that efficiently kills the larval stage of S. mansoni, but also affects fibroblast functions. We have investigated the prevalence of the ECP gene polymorphism 434(G>C) in two African populations, from an S. mansoni endemic area in Uganda (n=297) and from a non-endemic area in Sudan (n=78), and also compared these with a Swedish population (n=209). The genotype frequencies in the Ugandan population differed significantly from both the Sudanese and Swedish populations (P<0.001). In the Ugandan population there was a significant association between genotype and prevalence of infection (P=0.03), with lower prevalence in subjects with the GG genotype compared with GC (P=0.02) and CC (P=0.03). There was also a trend towards an association with periportal fibrosis (P=0.08) in the Ugandan population. This suggested association was confirmed when the predominant tribe (n=212) was analysed separately (P=0.004). Our results suggest that ECP may be an important protein, both in the immune response against S. mansoni and in the development of periportal fibrosis. The results also suggest genetic selection towards the ECP 434CC genotype in populations living in S. mansoni endemic areas.

Association of interferon-gamma gene haplotype in the Chinese population with hepatitis B virus infection

In general, cytokines encoded by different genes of human genome might strongly influence host cell-mediated immune responses, which play an important role in the clearance of virus by the infected host. Interferon gamma (IFN-gamma) produced by T lymphocytes and natural killer cells plays an essential role in affecting cellular immune responses. A functional study demonstrated that two single nucleotide polymorphisms located in the IFN-gamma gene intron (at positions +874 and +2109) were involved in its transcriptional regulation. The aim of this study was to evaluate whether IFN-gamma gene polymorphisms or its haplotypes might be associated with predisposition to hepatitis B virus (HBV) infection in the Chinese population. The study included 181 cases with HBV infection and 272 gender, age-matched healthy controls. All genotyping were identified by polymerase chain reaction in association with the measurement of amplification refractory mutation system. A significant difference was observed between case and control groups. The frequency of +874A allele was significantly higher in patients than in controls (OR = 2.25, 95%CI = 1.69-2.99, P < 0.0001). However, no significant difference was found in the allelic frequencies of IFN-gamma +2109A/G between cases and controls (P > 0.05). By haplotype analysis, the frequency of haplotype AG (+874A and +2109G) revealed a significant difference in the cases in comparison to controls (P < 0.0001). Multiple logistic regression analysis showed that individuals possessing haplotype AG had an increased likelihood of HBV infection (OR = 8.14, 95%CI = 4.98-13.30). Our results suggest that haplotype AG containing +874A and +2109G may be a crucial risk factor of genetic susceptibility to HBV infection in the Chinese population.

Mendelian and complex genetics of susceptibility and resistance to parasitic infections

Uncovering the complex genetic basis of susceptibility and resistance to parasitic infectious diseases is an enormous challenge. It probably involves many different host genes, interacting with multiple parasite genetic and environmental factors. Several genes of interest have been identified by family and association studies in humans and by using mouse models, but more robust epidemiological studies and functional data are needed to authenticate these findings. With new technologies and statistical tools for whole-genome association analysis, the next few years are likely to see acceleration in the rate of gene discovery, which has the potential to greatly assist drug and vaccine development.

Prevention of hepatic fibrosis in nonobese diabetic mice: a critical role for interferon-gamma

BACKGROUND/AIMS

Nonobese diabetic (NOD) mice, a model of type I diabetes mellitus, harbor certain unique defects in their immune system. The aim of this study was to investigate how NOD mice show hepatic injury and subsequent fibrogenic responses.

METHODS

Hepatic fibrosis was induced by intraperitoneal injections of dimethylnitrosamine (DMN), and assessed biochemically and histologically. Expressions of cytokine messenger RNA (mRNA) in the liver were determined.

RESULTS

In a model of liver cirrhosis induced by dimethylnitrosamine (DMN), we found that NOD mice had lower levels of hepatic fibrosis and better survival than control ICR mice. The resistance to DMN-induced lethality in NOD mice was independent of apoptosis and necrosis of hepatocytes, but apparently due to the prevention of hepatic fibrosis. We also found increased inductions of interferon-gamma (IFN-gamma) mRNA in the liver of NOD mice and of intracellular IFN-gamma from intrahepatic T cells following DMN administration. Treatment with neutralizing anti-IFN-gamma-antibody cancelled the inhibition of hepatic fibrosis in NOD mice.

CONCLUSIONS

These results suggest that IFN-gamma is effective for inhibiting hepatic fibrosis and that genetic host factors may be important in determining differential responses to injury.

Genetic susceptibility to infectious diseases: big is beautiful, but will bigger be even better?

Genetic epidemiology, including twin studies, provides robust evidence that genetic variation in human populations contributes to susceptibility to infectious disease. One of the major limitations of studies that attempt to identify the genes and mechanisms that underlie this susceptibility has been lack of power caused by small sample size. With the development of novel technologies, burgeoning information on the human genome, the HapMap project, and human genetic diversity, we are at the beginning of a new era in the study of the genetics of complex diseases. This review looks afresh at the epidemiological evidence that supports a role for genetics in susceptibility to infectious disease, examines the somewhat limited achievements to date, and discusses current advances in methodology and technology that will potentially lead to translational data in the future.

Hemophilic siblings with chronic hepatitis C: Familial aggregation of spontaneous and treatment-related viral clearance

BACKGROUND & AIMS

Hemophilic siblings provide a unique population to explore the natural history of chronic hepatitis C.

METHODS

From 3993 hemophilic patients with hepatitis C, 257 sibling pairs, of which both members had evidence of hepatitis C infection, were studied to evaluate the genetic contribution to spontaneous and treatment-induced clearance of hepatitis C infection and progression of liver disease. Familial aggregation was assessed by comparing observed probabilities of concordance for these disease characteristics within sibling pairs to those expected for randomly paired hemophilic subjects. Additional measures of familial aggregation, heritability, and sibling relative risk were also calculated.

RESULTS

Among human immunodeficiency virus-negative subjects, concordance for spontaneous viral clearance was 2-fold higher in siblings compared with randomly paired subjects (8.8% vs 4.3%, respectively, P = .04). Similarly, the concordance rate for treatment-related viral clearance was over twice that among sibling pairs than among randomly paired hemophiliacs (31.3% vs 13.3%, respectively, P = ns). Heritability estimates for spontaneous and treatment-induced viral clearance were 0.24 +/- 0.14 (P = .04) and 0.43 +/- 0.42 (P = .10), respectively. The sibling relative risks for these respective characteristics were 1.6 and 1.7. Concordance for advanced liver disease was higher among siblings but did not reach statistical significance (4.0% vs 2.3%, respectively, P = ns). The heritability estimate was 0.29 +/- 0.13 (P = .02).

CONCLUSIONS

Concordance rates and heritability estimates for spontaneous and treatment-related viral clearance indicate that genetic factors have a modest influence on the outcome of hepatitis C, although shared environmental factors cannot be excluded. Investigations to map candidate disease-susceptibility genes associated with these characteristics must be approached with caution.