Genetic polymorphisms in vitamin D receptor, vitamin D-binding protein, Toll-like receptor 2, nitric oxide synthase 2, and interferon-gamma genes and its association with susceptibility to tuberculosis

Association of Vitamin D Receptor Polymorphism (rs2228570, rs1544410, rs7975232, and rs731236) and Macrophage Migration Inhibitory Factor -173 G/C (rs755622) with the Susceptibility of Active Pulmonary Tuberculosis in Makassar, Indonesia

BACKGROUND: The study of Vitamin D Receptor (VDR) and Macrophage Migration Inhibitory Factor (MIF) polymorphisms, associated with active pulmonary tuberculosis (ATB) presents varying results. AIMS: This study aimed to investigate the association between VDR rs2228570, rs1544410, rs7975232, rs731236 and MIF -173 G/C (rs755622) single nucleotide polymorphism (SNP), with susceptibility of developing ATB, and positivity of Interferon Gamma Release Assay (IGRA) results (in household contact). METHODS AND MATERIAL: This study involved 83 ATB and 73 household contacts in Makassar. We checked IGRA based on ELISA in household contacts by using QuantiFERON TB Gold Plus test, and we found that 61.64% (n = 45) of household contacts had positive IGRA. Polymorphism examination was carried out by Sanger sequencing. RESULTS: VDR rs2228570 T/T and T/C-T/T were significantly associated with higher risk of active tuberculosis. VDR rs7975232 G/G genotype was associated with an increased risk of developing active TB compared to T/T-T/G. Haplotype analysis of VDR rs2228570, rs1544410, rs7975232, rs731236 and combination with MIF rs755622 demonstrated that TGGTG was observed to have a higher risk of tuberculosis. CONCLUSIONS: The combination of VDR and MIF variants may contribute to the susceptibility of active tuberculosis disease.

Vitamin D Status among First-Generation Immigrants from Different Ethnic Groups and Origins: An Observational Study Using the Canadian Health Measures Survey

One in five Canadians are first-generation immigrants. Evidence suggests the baseline risk for vitamin D (vitD) deficiency is increased among immigrants who move from equatorial to northern countries. We investigated the prevalence and determinants of vitD deficiency/insufficiency among first-generation immigrants compared with native-born Canadians and identified explanatory covariables. We used a cross-sectional design with data from the national Canadian Health Measures Survey (Cycles 3 and 4) (11,579 participants aged 3-79 years). We assessed serum 25-hydroxyvitamin D (S-25(OH)D) levels, sociodemographic and environmental factors, immigration status, length of time in Canada, vitD-rich food intake, ethnicity, and place of birth. Immigrants had lower mean S-25(OH)D than non-immigrants (51.23 vs. 62.72 nmol/L, p < 0.001). Those with younger age at the time of immigration (<18 years) had a high risk for low vitD, and S-25(OH)D levels increased with the length of time they had lived in Canada. The highest deficiency levels were in immigrants born in Morocco, India, and Lebanon compared with native-born Canadians. Ethnicity was the factor most strongly associated with S-25(OH)D. Compared with the white ethnic grouping, the Japanese had the highest level of vitD deficiency, followed by Arabs and Southeast Asians. Ethnic variations, dietary intake, and lifestyle factors are the main predictors of/explanatory factors for vitD status among Canadian immigrants.

Genetic polymorphism in association with susceptibility to tuberculosis: a study in a Pakistani population

Tuberculosis is becoming a global issue with raising occurrences; particularly in developing countries, the situation is alarming. Besides environmental factors, host genetic factors are vital in disease development. A demographical and genotypic analysis in relation to tuberculosis commencement is conducted in a Pakistani population, and genotypic frequency of EBI3 (rs4740) was analyzed. Allelic frequencies of EBI3 (rs4740) were significantly associated with disease susceptibility in the reviewed population. Analysis for EBI3 (rs4740) genotyping showed a significant association of "GG" with reduced risk for disease. Moreover, females and older age found to be more perilous to develop TB while smoking and a family history of TB are additional risk factors for disease development. Further work with a larger population is necessary to identify the true causative variants of tuberculosis.

Association of Lung Function with Serum 25-Hydroxyvitamin D Level according to the Presence of Past Pulmonary Tuberculosis in Korean Adults

Background

Vitamin D deficiency is associated with an increased risk of pulmonary tuberculosis (PTB) infection and the treatment outcome. The aim of this study was to examine the relationship between the serum 25-hydroxyvitamin D (25[OH]D) level and lung function in Korean adults according to whether or not there is a history of PTB.

Methods

The data for subjects aged 19 years or older from the Korea National Health and Nutrition Examination Survey 2008–2012 who underwent spirometry, chest radiography, and serum 25(OH)D level measurement were analyzed.

Results

Evidence of past PTB infection was found in 1,482 (9.6%) of 15,516 subjects. The serum 25(OH)D level was lower in the group with past PTB than in the non-PTB group (P=0.013). Respiratory dysfunction was more common in the past PTB group than in the non-PTB group (restrictive pattern, 14.0% vs. 9.6%; obstructive pattern, 29.6% vs. 8.2%; both P<0.001). After adjusting for age, sex, height, and season, the mean difference in forced expiratory volume in 1 second (FEV₁) between the highest and lowest quartiles of 25(OH)D was 100.2 mL (standard error=49.3 mL, P for trend=0.049) in the past PTB group and 34.7 mL (standard error=13.6 mL, P=0.009) in the non-PTB group.

Conclusion

FEV₁ tended to increase as the vitamin D quartile increased in both study groups. This relationship was more pronounced in subjects with a history of PTB. A higher serum 25(OH)D level might be beneficial in preserving lung function after PTB infection.

VDR polymorphism, gene expression and vitamin D levels in leprosy patients from North Indian population

Background

Leprosy is a chronic infectious disease caused by Mycobacterium leprae and mainly affects skin, peripheral nerves. Vitamin D receptor (VDR) gene polymorphism has been found to be associated with leprosy. Vitamin D has been shown to control several host immunomodulating properties through VDR gene. Vitamin D deficiency was also found to be linked to an increased risk for several infections and metabolic diseases.

Objective

In the present study, we investigated the association of VDR gene polymorphism, mRNA gene expression of VDR and the vitamin D levels with leprosy and its reactional states.

Methodology

A total of 305 leprosy patients consisting of tuberculoid (TT), borderline tuberculoid (BT), borderline lepromatous (BL), lepromatous leprosy (LL), as well as 200 healthy controls were enrolled in the study. We identified single nucleotide polymorphisms (SNPs) of VDR Taq1, Fok1 and Apa1, as well as the expression of VDR mRNA gene using PCR-based restriction fragment length polymorphism (RFLP) analysis and real-time PCR respectively. We also performed ELISA to measure vitamin D levels.

Result

We observed that SNP of VDR gene (Fok1 and Taq1) are associated with the leprosy disease. The allelic frequency distribution of T and t allele (p = 0.0037), F and f allele (p = 0.0024) was significantly higher in leprosy patients and healthy controls. ff genotype of Fok1 was found to be associated with leprosy patients [p = 0.0004; OR (95% CI) 3.148 (1.662–5.965)]. The recessive model of Fok1 genotype was also found to be significantly associated in leprosy patients in comparison to healthy controls [p = 0.00004; OR (95% CI) 2.85 (1.56–5.22)]. Leprosy patients are significantly associated with t-F-a haplotype. Further, VDR gene expression was found to be lower in non-reaction group compared to that of reaction group of leprosy and healthy controls. Paradoxically, we noted no difference in the levels of vitamin D between leprosy patients and healthy controls.

Conclusion

Blood levels of vitamin D do not play any role in clinical manifestations of any forms of leprosy. ff genotype of Fok1 and tt genotype of Taq1 was found to be associated with leprosy per se. Association of t-F-a haplotype with leprosy was found to be significant and could be used as a genetic marker to identify individuals at high risk for developing leprosy. VDR gene expression was lower in TT/BT and BL/LL groups of leprosy in comparison to that of healthy controls.

Present study was carried out to find out the association of vitamin D receptor (VDR) gene polymorphism, mRNA gene expression of VDR gene and level of vitamin D with leprosy reactions and leprosy patients. Surprisingly, level of vitamin D in leprosy patients was not found to be associated with the disease and its manifestations. VDR genotypes (Fok1 and Taq1) were found to be associated with leprosy patients. t-F-a haplotype was significantly associated with leprosy patients. Gene expression of vitamin D receptor was lower in leprosy patients in comparison to healthy controls.

Vitamin D receptor gene (FokI, TaqI, BsmI, and ApaI) polymorphisms in children with urinary tract infection

BACKGROUND

Little is known about the genetic background of urinary tract infection (UTI) in children.

METHODS

In this study, vitamin D receptor (VDR) gene polymorphisms were compared between 60 children with UTI (case group) and 60 healthy children (control group). DNA extraction, polymerase chain reaction, and the restriction fragment length polymorphism methods were used to perform the genetic analysis.

RESULTS

There was a significant difference between the case and control groups for VDR gene, ApaI and Bsml, polymorphisms (P < 0.05). The frequency of VDR Bb, bb, Aa, and aa genotypes, and the b and a alleles in the case group was significantly higher than that in the control group (P < 0.05). A significant difference was also found between lower UTI and acute pyelonephritis groups for the VDR Apal and Bsml genotypes (P < 0.05). There was no significant difference between children with first UTI and those with more than one UTI for VDR gene polymorphisms (P > 0.05).

CONCLUSION

This study showed that there is a significant relationship between VDR gene, Apal and Bsml, polymorphisms and UTI in children. The results indicate that these polymorphisms may play a role in pathogenesis of UTI.

Association of high serum vitamin D concentrations with active pulmonary TB in an HIV co-endemic setting, Harare, Zimbabwe

Background

There is paucity data on the association of vitamin D deficiency (VDD) and active tuberculosis (TB) in southern Africa where the human immunodeficiency virus (HIV) is co-endemic. We examined the association of serum vitamin D concentrations with active pulmonary tuberculosis (PTB) in HIV-infected (n = 284) and uninfected (n = 267) Black Zimbabweans, in Harare, Zimbabwe.

Methods

We conducted a cross-sectional study of 551 participants comprising 145 HIV⁺/PTB ⁺, 139 HIV⁺/PTB⁻, 134 HIV⁻/PTB⁺ and 133 HIV⁻/PTB⁻. PTB status was confirmed using sputum by culture, or smear microscopy, or GeneXpert MTB/RIF. Serum 25-hydroxyvitamin D (25(OH)D) concentrations were measured using a competitive chemiluminescent immunoassay prior to commencement of anti-TB treatment.

Results

In all four groups, the median vitamin D concentrations were above the 20 ng/ml cut off for VDD. However, the median vitamin D concentrations in all the four groups were below the cut off for vitamin D sufficiency ≥30 ng/ml. The median vitamin D concentrations were significantly higher in PTB⁺ cases; 24.2 ng/ml (IQR: 18.8–32.0) compared to PTB⁻ controls 20.9 ng/ml (IQR: 17.1–26.9), p < 0.0001 regardless of HIV status. The HIV⁺/PTB⁺ group had the highest median vitamin D concentration (25.3 (IQR: 18.0–33.7 ng/ml) whilst the HIV⁺/PTB⁻ group had the lowest; 20.4 ng/ml (IQR: 14.6–26.9), p = 0.0003. Vitamin D concentration <30 ng/ml was associated with 43% lower odds of being PTB⁺ OR 0.57 (95% CI 0.35–0.89).

Conclusions

Our results are not in agreement with the generally accepted hypothesis that VDD is associated with active PTB. To the contrary our results showed an association of higher vitamin D concentrations with active TB irrespective of HIV status. Although findings from the available pool of case control studies remain inconsistent, the results from the current study provide further rationale for larger-scale, prospectively designed studies to evaluate whether sufficient vitamin D concentrations do indeed precede the development of active PTB in our setting.

Are low sun exposure and/or vitamin D risk factors for type 1 diabetes?

Ultraviolet radiation and vitamin D, with their known immunosuppressive effects, have the potential to delay or inhibit type 1 diabetes.

Genetic polymorphisms of IL-17A, IL-17F, TLR4 and miR-146a in association with the risk of pulmonary tuberculosis

Genetic factors affect host susceptibility to pathogens. In this population-based case control study, we explored the genetic polymorphisms of IL-17, TLR4 and miR-146a in association with pulmonary tuberculosis in a Chinese Han population. We recruited 1601 pulmonary tuberculosis patients matched with 1526 healthy controls and genotyped twelve functional single nucleotide polymorphisms (SNPs). After the correction for multiple comparisons, two SNPs (rs10759932 and rs2737190) in the TLR4 gene remained significant. Individuals carrying the rs2737190-AG genotype (vs. AA) had a significantly increased risk of either clinical tuberculosis (OR: 1.31, 95% CI: 1.11–1.53) or sputum smear-positive tuberculosis (OR: 1.35, 95% CI: 1.13–1.61). Stratification analysis revealed that the effects of genetic variations on tuberculosis were more evident among non-smokers. People with haplotype TLR4 rs10983755G–rs10759932C had a significantly increased risk of tuberculosis (OR: 3.43, 95% CI: 2.34–5.05). Moreover, we found that SNPs of rs3819024 in IL-17A and rs763780 in IL-17F were weakly related to a prognosis of tuberculosis. Our results suggest that genetic polymorphisms of IL-17 and TLR4 may play a role in host susceptibility to tuberculosis in the Chinese Han population. More work is necessary to identify specific causative variants of tuberculosis underlying the observed associations.

Polymorphisms of IFN-γ (+874A/T) and IL-12 (+1188A/C) in tuberculosis patients and their household contacts in Hyderabad, India

Several cytokine gene variants have shown to be associated with host susceptibility to infectious diseases including tuberculosis (TB). High rates of transmission were identified within household members of TB patients. In this study, we examined whether single nucleotide polymorphisms of IFN-γ +874A/T and IL-12 +1188A/C affect susceptibility to TB. Genomic DNA from patients with active disease, their household contacts HHC and healthy controls HC was genotyped for IFN-γ +874A/T and IL-12 +1188A/C SNPs by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR). IFN-γ +874 AA and AT genotypes were significantly with different frequencies in patients and total HHC as compared to HC (p<0.0001). In patients IL-12 +1188 AC and CC genotypes were associated with TB (p<0.003, p<0.008). In total HHC AC, CC genotypes and both alleles (A&C) were significantly different as compared to HC (p<0.004, p<0.001, p<0.034) and the same result was obtained when HHC were stratified into related (p<0.02, p<0.001) and unrelated (p<0.009, p<0.017) individuals. Allelic frequencies, however, were significant only in related contacts (p<0.021). Generalized multifactor dimensionality reduction method (GMDR) testing revealed high risk combinations of several genotypes in IFN-γ & IL-12 genes. Our findings suggest an important role of genetic variations of IFN-γ and IL-12 for susceptibility to TB.

The NRAMP1, VDR, TNF-α, ICAM1, TLR2 and TLR4 gene polymorphisms in Iranian patients with pulmonary tuberculosis: A case-control study

The innate immune response drives early events in Mycobacterium tuberculosis infection. Since human genetic variation is an important determinant in the outcome of infection with M. tuberculosis, we typed polymorphisms in the innate immune molecules, such as natural-resistance-associated macrophage protein 1 (NRAMP1), Vitamin D receptor (VDR), Tumor necrosis factor alpha (TNF-α), intercellular adhesion molecule1 (ICAM-1), Toll-like receptor 2 (TLR2) and Toll-like receptor 4 (TLR4) in a case-control study of pulmonary tuberculosis in Iranian population. We conducted an association study and included 96 patients and 122 matched healthy individuals. We used single ARMS-PCR technique to simultaneously genotype fourteen polymorphisms in this survey. Among all fourteen polymorphisms that were examined, three polymorphisms were significantly different between case and control groups. The TNF -308A polymorphism showed significant increase in allele and genotype frequencies among patients compared to control individuals [-308A allele: 19.3 vs. 9.4%, GA genotype: 28.1 vs. 17.2%, AA genotype: 5.2 vs. 0.8%; Corrected P (Pc)<0.05], and the TLR4 variant allele and genotypes prevalence (D299G and T399I) were significantly higher among patients compared to controls [DG genotype: 14.6 vs. 5.7%, Pc<0.05 and I399 allele: 4.2 vs. 0.8%, TI genotype: 8.3 vs. 1.6%; Pc<0.05], respectively. In conclusion, our data suggest that TLR4 (D299G and T399I) and TNF (-308G/A) genetic polymorphisms may influence the risk of developing tuberculosis after exposure to Mycobacterium.

Urban and rural comparison of vitamin D status in Pakistani pregnant women and neonates

We undertook a cross-sectional study in rural Jehlum and urban Karachi to evaluate the prevalence of vitamin D deficiency in Pakistani pregnant women and neonates and to assess any association of serum 25(OH) vitamin D [25(OH)D] concentration with vitamin D binding protein (Gc) genotypes. Altogether, 390 women and 266 neonates were recruited from urban and rural sites, respectively. Serum 25(OH)D was measured by an immunoassay, while Gc genotypes were identified using polymerase chain reaction followed by restriction fragment length polymorphism or PCR-RFLP. One-way analysis of variance or ANOVA and linear regression were used for statistical analysis. In urban Karachi, 99.5% of women and 97.3% of neonates were vitamin D deficient (< 50 nmol/L), while 89% of women and 82% of neonates were deficient in rural Jehlum. Gc genotypes were not associated with serum 25(OH)D concentrations in both women and their neonates. We conclude that vitamin D deficiency is highly prevalent in Pakistani women and their neonates, and Gc genotypes are not associated with serum 25(OH)D concentrations.

"Let there be light": the role of vitamin D in the immune response to vaccines

Vitamin D's non-skeletal actions, including immunomodulatory role, have been increasingly recognized. Of significance, many immune cells are able to synthesize a biologically active form of vitamin D from circulating 25-hydroxyvitamin D with subsequent intracrine actions, and the vitamin D receptor is broadly distributed. In this review, we discuss vitamin D's potent role in innate and adaptive immune responses and published studies evaluating the impact of serum vitamin D, vitamin D gene pathway polymorphisms or empiric vitamin D supplementation on vaccine immunogenicity. We highlight existing knowledge gaps and propose the steps needed to advance the science and answer the question of whether vitamin D may prove valuable as a vaccine adjuvant for certain vaccines against infectious diseases.

Vitamin d receptor gene polymorphism and vitamin d plasma concentration: correlation with susceptibility to tuberculosis

PURPOSE

It is estimated that one third of the world's population were infected with M. tuberculosis, but only 10% of them have developed in to disease form. This subject refers to differences in host immune system activity against the tuberculosis. Vitamin D and its receptor (VDR) are important factors in the host innate immune system against the tuberculosis. In the present study VDR gene polymorphisms and its relationship with plasma vitamin D levels in susceptibility to tuberculosis have been investigated.

METHODS

The subjects were 84 patients with tuberculosis and 90 healthy controls. Vitamin D levels were measured in all study participants. DNA was isolated from the blood leukocytes of all groups and amplified by polymerase chain reaction (PCR). Then restriction fragment length polymorphism (RFLP) was performed on each PCR products to study the VDR gene polymorphisms. The statistical analyses were conducted using SPSS.

RESULTS

There was no statistically significant relationship between polymorphisms of FokI, BsmI, ApaI and TaqI in VDR gene and susceptibility to tuberculosis. Vitamin D deficiency and susceptibility to tuberculosis were closely related (95% CI -0.08 - 4.7, P = 0.059). Also the relationship between plasma vitamin D levels and frequency of FokI-ff gene polymorphism was significant in all study participants (P = 0.045).

CONCLUSION

When the genotype frequencies of VDR gene polymorphisms were analyzed with respect to plasma vitamin D levels, a significant association was seen. As an enhancement in plasma vitamin D levels in individuals (with FokI-ff genotype and low levels of vitamin D) may protect them against active tuberculosis.

Genetic polymorphisms of IFNG and IFNGR1 in association with the risk of pulmonary tuberculosis

OBJECTIVE

Genetic host factors play an important role in controlling individual's susceptibility to the pathogen. This study aims to explore the single and joint effect of genetic polymorphisms of interferon-gamma (IFNG) and its receptor (IFNGR1) in association with the pulmonary tuberculosis in a Chinese Han population.

METHODS

This population-based case control study consisted of 1434 pulmonary tuberculosis patients and 1412 healthy controls. Six tag SNPs in IFNG/IFNGR1 were genotyped using TaqMan allelic discrimination technology. The logistic regression model was carried out to analyze the associations between the genotypes and haplotypes and the risk of tuberculosis by calculating the odds ratio (OR) and 95% confidence interval (CI).

RESULTS

After the Bonferroni correction for multiple comparisons, three SNPs (rs2234711, rs1327475 and rs7749390) in IFNGR1 gene were observed to be significantly associated with the altered risks of tuberculosis. For the SNP rs2234711, individuals carrying C allele (vs. T) showed a decreased risk, with the adjusted OR(95% CI) of 0.82(0.76-0.91). The additive model revealed that each additional allele contributed about 14% decreased risk (OR: 0.86, 95% CI: 0.77-0.95). Moreover, we observed a strong linkage disequilibrium between rs2234711 and rs3799488. Compared with the common rs2234711C-rs3799488C haplotype, the haplotype rs2234711T-rs3799488C contributed to a significant increase in the risk of tuberculosis (adjusted OR: 1.24, 95% CI: 1.09-1.41).

CONCLUSIONS

Our results suggest that genetic polymorphisms in IFNGR1 gene are involved in the risk of tuberculosis in the Chinese population. Future studies should include a comprehensive sequencing analysis to identify the specific causative sequence variants underlying the observed associations.

Navigating through the maze of TLR2 mediated signaling network for better mycobacterium infection control

Toll-like receptor 2 (TLR2), a member of pattern recognition receptors (PRRs) abundant on macrophages, dendritic cells (DCs) and respiratory epithelial cells lining the lung, plays critical role in host immune response against Mycobacterium tuberculosis (MTB) infection. TLR2-mediated elimination of MTB involves multiple pathways such as promoting DCs maturation, generating biased Th1, Th2, Th17 type response, regulating the macrophage activation and cytokine secretion. MTB can also hijack the TLR2 signaling to subvert the host immunity by dampening the macrophages response to IFN-γ, suppressing the processing and presentation of antigens. This review summarizes the intricate network of TLR2-mediated signaling and Mycobacteria effectors involved in MTB-host interaction with an aim to find better target for improved tuberculosis control, especially the host-derived therapy targets. TLR2 agonists with potential to be included in novel tuberculosis vaccines are also discussed.

Host genome polymorphisms and tuberculosis infection: What we have to say?

Several epidemiology studies suggest that host genetic factors play important roles in susceptibility, protection and progression of tuberculosis infection. Here we have reviewed the implications of some genetic polymorphisms in pathways related to tuberculosis susceptibility, severity and development. Large case-control studies examining single-nucleotide polymorphisms (SNPs) in genes have been performed in tuberculosis patients in some countries. Polymorphisms in natural resistance-associated macrophage protein 1 (NRAMP1), toll-like receptor 2 (TLR2), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), interleukin-1 receptor antagonist (IL-1RA), IL-10, vitamin D receptor (VDR), dendritic cell-specific ICAM-3-grabbing non-integrin (DC-SIGN), monocyte chemoattractant protein-1 (MCP-1), nucleotide oligomerization binding domain 2 (NOD2), interferon-gamma (IFN-γ), inducible nitric oxide synthase (iNOS), mannose-binding lectin (MBL) and surfactant proteins A (SP-A) have been reviewed. These genes have been variably associated with tuberculosis infection and there is strong evidence indicating that host genetic factors play critical roles in tuberculosis susceptibility, severity and development.

An association study of functional polymorphic genes IRF-1, IFNGR-1, and IFN-γ with disease progression, aspartate aminotransferase, alanine aminotransferase, and viral load in chronic hepatitis B and C

BACKGROUND

Investigational approaches based on genome-wide association studies have proven useful in identifying genetic predictors for many diseases, including susceptibility to chronic hepatitis B and C. In these studies, the majority of genetic variants that have shown a positive association have been identified in genes involved in the immune response. In this study IFN-γ, IFNGR-1, and IRF-1 genes were analyzed for their role in susceptibility to the development of chronic hepatitis B and chronic hepatitis C in a Turkish population.

METHODS

Polymorphic genes IRF-1 (-410, -388), IFNGR-1 (-56, -611), and IFN-γ (+874) were analyzed in a total of 400 individuals: 100 chronic hepatitis B patients, 100 hepatitis B carriers, 100 chronic hepatitis C patients, and 100 healthy controls. A single base primer extension assay was used. Correlations between genes and gender, viral load, and aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were also investigated.

RESULTS

The IRF-1 gene at positions -388 and -410 were observed to be candidate gene markers for susceptibility to the development of chronic hepatitis B and C (p<0.05). IFN-γ +874 and IFNGR-1 (-56 and -611) correlated with chronic hepatitis B but not chronic hepatitis C. Correlation of functional genotype with viral load and AST and ALT levels revealed an association of IFN-γ +874 and IFNGR-1 -611 with chronic hepatitis C and IFN-γ +874 with viral load and chronic hepatitis B (p<0.05).

CONCLUSIONS

Findings suggest that IFN-γ (+874), IRF-1 (-410, -388), and IFNGR-1 (-56, -611) are candidate gene markers for determining patient susceptibility to the development of chronic hepatitis B and C.

Vitamin D receptor gene polymorphism in children with urinary tract infection

It is known that small alterations leading to different vitamin D receptor (VDR) alleles affect resistance or susceptibility to infections. In this study, we examined VDR gene polymorphisms in urinary tract infections (UTI), which are common and an important cause of morbidity in children and subsequently of renal scar formation. We evaluated 92 patients diagnosed with UTI and 105 children without prior history of UTI as a control group. The VDR gene polymorphisms BsmI, FokI, ApaI, and TaqI were evaluated in patients and controls. BsmI polymorphism genotype distribution was similar between groups. There was a significant difference between groups for FokI (p =0 < 001); for the ff genotype, the risk of UTI was significantly increased (p < 0.01) ,at 3.94 times higher (odds ratio = 3.94; 95% confidence interval 1.71-9.09). ApaI polymorphism was significantly increased in the control group (p < 0.01) and evaluated as a protective factor. Comparing the TaqI genotype between groups, there was no statistically significant difference, but in both Tt and tt genotypes, there was minimal increased risk of UTI. The results of this study suggest that VDR gene polymorphisms can be important for susceptibility to UTI and renal scar formation. Association between VDR polymorphisms and UTI is in accordance with the understanding of how vitamin D modulates the immune response against infections.

Genetic risk factors for human susceptibility to infections of relevance in dermatology

BACKGROUND

In the pre-microbiological era, it was widely accepted that diseases, today known to be infectious, were hereditary. With the discovery of microorganisms and their role in the pathogenesis of several diseases, it was suggested that exposure to the pathogen was enough to explain infection. Nowadays, it is clear that infection is the result of a complex interplay between pathogen and host, therefore dependant on the genetic make-up of the two organisms. Dermatology offers several examples of infectious diseases in different stages of understanding of their molecular basis. In this review, we summarize the main advances towards dissecting the genetic component controlling human susceptibility to infectious diseases of interest in dermatology. Widely investigated diseases such as leprosy and leishmaniasis are discussed from the genetic perspective of both host and pathogen. Others, such as rare mycobacterioses, fungal infections and syphilis, are presented as good opportunities for research in the field of genetics of infection.

Vitamin D status and expression of vitamin D receptor and LL-37 in patients with spontaneous bacterial peritonitis

BACKGROUND

Vitamin D, which exerts its effect through vitamin D receptor (VDR), and LL-37, a vitamin D-dependent antimicrobial peptide, are involved in many infectious diseases.

AIM

The objective of this study was to evaluate whether vitamin D status and expressions of VDR and LL-37 are involved in the pathogenesis of spontaneous bacterial peritonitis (SBP).

METHODS

Serum and ascitic fluid 25-dihydroxyvitamin D [25(OH)D] concentrations and levels of VDR and LL-37 in peritoneal leukocytes were measured by ELISA and real-time PCR methods in cirrhotic patients with SBP (n = 19) and cirrhotic patients with simple ascites (n = 28). The correlations between these levels and clinical variables were evaluated.

RESULTS

Cirrhotic patients with ascites showed low vitamin D concentrations in both serum and ascitic fluid. Lower serum vitamin D concentrations were observed in cirrhotic patients with Child-Pugh C class. 25(OH)D concentrations in ascitic fluid were positive correlated with that in serum (r = 0.74, P < 0.001). The SBP group showed significantly higher levels of both VDR and LL-37 mRNA expressions in peritoneal leukocytes than the simple ascites group (P = 0.005 and P = 0.003, respectively). In the SBP group, VDR and LL-37 expressions in peritoneal leukocytes were positively correlated (r = 0.70, P = 0.001).

CONCLUSIONS

Vitamin D insufficiency was universal among cirrhotic patients with ascites, and the situation was more severe with more serious cirrhosis. Expressions of peritoneal leukocytes VDR and LL-37 genes were simultaneously up-regulated in cirrhotic patients with SBP when compared with cirrhotic patients with simple ascites. It is indicated that the vitamin D-VDR system and its downstream gene, LL-37, are involved in the pathogenesis and antibacterial immune response to SBP.

Differential combination of cytokine and interferon- γ +874 T/A polymorphisms determines disease severity in pulmonary tuberculosis

BACKGROUND

Mycobacterium tuberculosis infects nearly 1/3 of the world population and this reservoir forms the largest pool from which new cases arise. Among the cytokines, IFN-γ is a key determinant in protection against tuberculosis. Single nucleotide polymorphisms (SNPs) in IFN-γ gene (+874 T/A) which determine TT high ((hi)), AA low ((lo)) and TA intermediate ((int)) responder phenotypes have shown variable associations with tuberculosis disease outcome in different ethnic populations. The objective of the current study was to analyze IFN-γ gene combinations with other IFN-γ regulating cytokine genes (IL-10, TNF -α, IL-6) to see the effect of gene- combinations on disease severity outcome in pulmonary tuberculosis.

METHODS AND FINDINGS

Study groups comprised of pulmonary TB patients stratified according to lung tissue involvement into mild (Pmd = 74) or advance (Pad = 23) lung disease and compared with healthy controls (TBNA = 166). Genotype analysis was carried out using amplification refractory mutation system-PCR (ARMS-PCR). IFN-γ gene (+874 T/A) functional SNP combinations in TNFα (-308 G/A), IL-10 (-1082 A/G) and IL-6 (-174 G/C) were analyzed. Single gene analysis (Pearson χ²) showed a dominant association of IFN-γ TT (hi) genotype (p = 0.001) and T allele (p = 0.001) with mild disease. IFN-γ(lo) -IL-10(lo) genotype combination was associated with advanced disease (p = 0.002). IFN-γ(hi) -IL-6(hi) combination was associated with mild disease (p = 0.0005) while IFN-γ(lo) -IL-6(int) was associated with protection against both forms of pulmonary disease (p = 0.002).

CONCLUSION

Our results show that a limited number of IFN-γ gene combinations with other cytokine functional SNPs determine the outcome of disease severity in tuberculosis.

Vitamin D receptor gene polymorphism in children with urinary tract infection

It is known that small alterations leading to different vitamin D receptor (VDR) alleles affect resistance or susceptibility to infections. In this study, we examined VDR gene polymorphisms in urinary tract infections (UTI), which are common and an important cause of morbidity in children and subsequently of renal scar formation. We evaluated 92 patients diagnosed with UTI and 105 children without prior history of UTI as a control group. The VDR gene polymorphisms BsmI, FokI, ApaI, and TaqI were evaluated in patients and controls. BsmI polymorphism genotype distribution was similar between groups. There was a significant difference between groups for FokI (p =0 < 001); for the ff genotype, the risk of UTI was significantly increased (p < 0.01) ,at 3.94 times higher (odds ratio = 3.94; 95% confidence interval 1.71-9.09). ApaI polymorphism was significantly increased in the control group (p < 0.01) and evaluated as a protective factor. Comparing the TaqI genotype between groups, there was no statistically significant difference, but in both Tt and tt genotypes, there was minimal increased risk of UTI. The results of this study suggest that VDR gene polymorphisms can be important for susceptibility to UTI and renal scar formation. Association between VDR polymorphisms and UTI is in accordance with the understanding of how vitamin D modulates the immune response against infections.

Endogenously activated interleukin-4 differentiates disease progressors and non-progressors in tuberculosis susceptible families: a 2-year biomarkers follow-up study

OBJECTIVE

Dynamic cytokine profiles from endogenously activated T cells in transit from lymph node to the infected sites via the blood compartment after recent exposure to Mycobacterium tuberculosis may differentiate disease progressors from non-disease progressors in a BCG-vaccinated population.

METHODS

Household contacts (N = 107) from families with (six families) or without (14 families) secondary cases were assessed for Types 1 and 2 cytokines serially in plasma of whole blood cultures without exogenous stimulation. "ARMS" PCR was carried out for detection of single nucleotide polymorphism T/A in IFN-γ +874.

RESULTS

In the absence of IFN-γ expansion, raised IL-4 at 6 months was associated with disease progression in TB-susceptible families. Resistant families on the other hand showed overrepresentation of IFN-γ +874 A allele and expansion of IFN-γ secreting cells at 6 months followed by contraction at 12 months.

CONCLUSION

Six months may be an important checkpoint for biomarker assessment in high-risk individuals post-exposure.

TNF-308 gene polymorphism and tuberculosis susceptibility: a meta-analysis involving 18 studies

A number of studies have investigated the association between TNF-308 (rs1800629 G/A) polymorphisms and the susceptibility towards tuberculosis (TB) in different populations. However, many of these studies provided inconsistent results. In this study, a systematic review and meta-analysis of the published studies was performed to gain a clearer understanding of this association. The PubMed, Embase, Web of Science and CNKI databases were searched for case-control studies published up to Jan 2011, we used no lower date limit. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. A total of 18 publications from 2001 to 2010, involving 2584 TB cases and 3817 controls were included. Overall, for the A allele carriers (G/A + A/A) vs. homozygote GG, the pooled OR was 1.03 (95% CI = 0.89-1.19; P = 0.912 for heterogeneity). For the allele A vs. allele G, the pooled OR was 1.07 (95% CI = 0.93-1.22; P = 0.013 for heterogeneity). In the stratified analysis by ethnicity, among Asians significant risk was found for allele A vs. allele G (OR = 1.22, 95% CI = 1.02-1.47; P = 0.152 for heterogeneity), no significant risks were found among Caucasians. This meta-analysis indicated that the TNF-308 polymorphism was not associated with the risk of TB in the total population, however the significant risk for TNF-308 A allele was found among Asians not Caucasians.

The role of vitamin D in pulmonary disease: COPD, asthma, infection, and cancer

The role of vitamin D (VitD) in calcium and bone homeostasis is well described. In the last years, it has been recognized that in addition to this classical function, VitD modulates a variety of processes and regulatory systems including host defense, inflammation, immunity, and repair. VitD deficiency appears to be frequent in industrialized countries. Especially patients with lung diseases have often low VitD serum levels. Epidemiological data indicate that low levels of serum VitD is associated with impaired pulmonary function, increased incidence of inflammatory, infectious or neoplastic diseases. Several lung diseases, all inflammatory in nature, may be related to activities of VitD including asthma, COPD and cancer. The exact mechanisms underlying these data are unknown, however, VitD appears to impact on the function of inflammatory and structural cells, including dendritic cells, lymphocytes, monocytes, and epithelial cells. This review summarizes the knowledge on the classical and newly discovered functions of VitD, the molecular and cellular mechanism of action and the available data on the relationship between lung disease and VitD status.

Major histocompatibility complex class III (C2, C4, factor B) and C3 gene variants in patients with pulmonary tuberculosis

The complement system is an integral part of the host immune system and plays an immunoregulatory role at the interface of innate and acquired immune responses. Limited data are available on the influence of variations in complement genes in infectious diseases such as pulmonary tuberculosis (PTB). The aim of this study was to investigate the role of genetic variations in complement system components C2, C4, BF, and C3 in PTB (n = 125) compared with healthy controls (n = 125) in the Indian population. The study showed, for the first time, an increased occurrence of null alleles at the C4A, i.e., C4AQ0; an increased frequency of BF*FA and C3*F in patients with PTB compared with healthy individuals, and contributed a risk with odds ratios of 18.16 (95% confidence interval [CI] = 3.0-108.6, p = 0.0004), 2.9 (95% CI = 1.9-4.37, p(c) = 3.15E-06), and 2.26 (95% CI = 1.5-3.3, p(c) = 6.7E-05), respectively. A combinatorial analysis of complement gene variants as risk determinants and their phenotypic effects in various populations may provide unique insights into the genetic basis of susceptibility to PTB.

Healthcare costs of Staphylococcus aureus and Clostridium difficile infections in veterans: role of vitamin D deficiency

Clostridium difficile and staphylococcal infections are associated with increased morbidity, mortality and healthcare costs. Vitamin D deficiency may also contribute to increased healthcare costs. There is increasing evidence that vitamin D may have an antimicrobial role. We examined the relationship of serum 25(OH)D levels to staphylococcal and C. difficile infections to determine if vitamin D deficiency was associated with adverse outcomes. In the outpatient setting, vitamin D deficiency in patients with C. difficile and staphylococcal infections were associated with significantly increased total outpatients costs and fee-based consultation. Laboratory expenses had a trend towards higher costs in the vitamin D-deficient group but did not reach statistical significance. The differences were most clearly seen in the in-patient group with enhanced laboratory, pharmacy and radiology costs. These differences resulted in vitamin D-deficient patients with C. difficile or staphylococcal infections having costs more than five times higher than the non-deficient patients. The total length of hospital stay was four times greater in the vitamin D-deficient group. In addition, the total number of hospitalizations was also significantly greater in the vitamin D-deficient group. Surgery costs demonstrated a tendency to be higher in the vitamin D-deficient group but failed to reach statistical significance. Vitamin D deficiency is intimately linked to adverse health outcomes and costs in Veterans with staphylococcal and C. difficile infections in North East Tennessee. We recommend that vitamin D status be checked in patients with these infections and appropriate therapy be instituted to restore vitamin D level to normal in an expeditious manner.