The role of single nucleotide polymorphisms, contained in proinflammatory cytokine genes, in the development of congenital infection with human cytomegalovirus in fetuses and neonates

Single Nucleotide Polymorphisms of Interleukins and Toll-like Receptors and Neuroimaging Results in Newborns with Congenital HCMV Infection

Congenital cytomegalovirus infection (cCMV) is the most common intrauterine infection with central nervous system (CNS) involvement. There is limited data on the associations between Single Nucleotide Polymorphisms (SNPs) in genes involving the first-line defense mechanism and the risk of CNS damage during cCMV. We investigated the associations between neuroimaging findings and SNPs in genes encoding the following cytokines and cytokine receptors in 92 infants with cCMV: interleukins (IL1B rs16944, IL12B rs3212227, IL28B rs12979860), C-C motif chemokine ligand 2 (CCL2 rs1024611), dendritic cell-specific intercellular adhesion grabbing non-integrin (DC-SIGN rs735240), Toll-like receptors (TLR2 rs5743708, TLR4 rs4986791, TLR9 rs352140). The SNP of IL1B rs16944 (G/A) was associated with a reduced risk of ventriculomegaly on MRI (OR = 0.46, 95% CI, 0.22-0.95; p = 0.03) and cUS (OR = 0.38, 95% CI, 0.0-0.93; p = 0.034). Infants carrying heterozygous (T/C) genotype at IL28B rs12979860 had an increased risk of cystic lesions on cUS (OR = 3.31, 95% CI, 1.37-8.01; p = 0.0064) and MRI (OR = 4.97, 95% CI, 1.84-13.43; p = 0.001), and an increased risk of ventriculomegaly on MRI (OR = 2.46, 95% CI, 1.03-5.90; p = 0.04). No other associations between genotyped SNPs and neuroimaging results were found. This is the first study demonstrating new associations between SNPs of IL1B and IL28B and abnormal neuroimaging in infants with cCMV.

Association between single nucleotide polymorphisms and viral load in congenital cytomegalovirus infection

Background

There are limited data on factors that determine viral load (VL) in congenital cytomegalovirus (cCMV) infection. Single nucleotide polymorphisms (SNPs) might influence individual host response to infection. This study aimed to investigate the association between SNPs in genes encoding cytokines or cytokine receptors and VL in newborns with cCMV.

Material and methods

Eight polymorphisms (IL1B rs16944, IL12B rs3212227, IL28B rs12979860, CCL2 rs1024611, DC-SIGN rs735240, TLR2 rs5743708, TLR4 rs4986791 and TLR9 rs352140) were analyzed in study population of 233 newborns, including 92 cCMV-infected newborns (73 symptomatic and 19 asymptomatic) by TaqMan SNP Predesigned Genotyping Assays. The association analysis was performed using SNPStats software and STATISTICA10.

Results

The association between IL12B polymorphism and viruria was observed (p = 0.029). In multiple comparison tests, heterozygous T/G genotype of IL12B was associated with higher viruria than T/T genotype (p = 0.041) in cCMV-infected newborns. In allele analysis, T allele of IL12B was associated with higher viremia (p = 0.037) in symptomatic newborns. We observed higher VL in symptomatic newborns in comparison to asymptomatic (median viremia: 1.7 × 10⁴ copies/mL vs. 2.0 × 10³ copies/mL (p = 0.002), median viruria: 1.0 × 10⁷ copies/mL versus 6.9 × 10⁵ copies/mL (p = 0.001), respectively).

Conclusions

IL12B rs3212227 was associated with VL in cCMV. Symptomatic newborns had significantly higher viremia and viruria. The role of SNPs in pathogenesis of cCMV warrants further investigations.

Association between single nucleotide polymorphisms (SNPs) of IL1, IL12, IL28 and TLR4 and symptoms of congenital cytomegalovirus infection

Congenital cytomegalovirus (cCMV) infection is the most common intrauterine infection. A non-specific immune response is the first line of host defense mechanism against human cytomegalovirus (HCMV). There is limited data on associations between Single Nucleotide Polymorphisms (SNPs) in genes involving innate immunity and the risk and clinical manifestation of cCMV infection. The aim of the study was to investigate association between selected SNPs in genes encoding cytokines and cytokine receptors, and predisposition to cCMV infection including symptomatic course of disease and symptoms. A panel of eight SNPs: IL1B rs16944, IL12B rs3212227, IL28B rs12979860, CCL2 rs1024611, DC-SIGN rs735240, TLR2 rs5743708, TLR4 rs4986791, TLR9 rs352140 was analyzed in 233 infants (92 cCMV-infected and 141 healthy controls). Associations between genotyped SNPs and predisposition to cCMV infection and symptoms were analyzed. The association analysis was performed using SNPStats software. No statistically significant association was found between any genotyped SNPs and predisposition to cCMV infection and symptomatic course of disease. In relation to particular symptoms, polymorphism of IL12B rs3212227 was linked to decreased risk of prematurity (OR = 0.37;95%CI,0.14-0.98;p = 0.025), while polymorphism of IL1B rs16944 was linked to reduced risk of splenomegaly (OR = 0.36;95%CI,0.14-0.98; p = 0.034) in infants with cCMV infection. An increased risk of thrombocytopenia was associated with IL28B rs12979860 polymorphism (OR = 2.55;95%CI,1.03-6.32;p = 0.042), while hepatitis was associated with SNP of TLR4rs4986791 (OR = 7.80;95%CI,1.49-40,81; p = 0.024). This is the first study to demonstrate four new associations between SNPs in selected genes (IL1B, IL12B, IL28B, TLR4) and particular symptoms in cCMV disease. Further studies on the role of SNPs in the pathogenesis of cCMV infection and incorporation of selected SNPs in the clinical practice might be considered in the future.

Host Genetics of Cytomegalovirus Pathogenesis

Human cytomegalovirus (HCMV) is a ubiquitous herpes virus (human herpes virus 5) with the highest morbidity and mortality rates compared to other herpes viruses. Risk groups include very young, elderly, transplant recipient, and immunocompromised individuals. HCMV may cause retinitis, encephalitis, hepatitis, esophagitis, colitis, pneumonia, neonatal infection sequelae, inflammatory, and age-related diseases. With an arsenal of genes in its large genome dedicated to host immune evasion, HCMV can block intrinsic cellular defenses and interfere with cellular immune responses. HCMV also encodes chemokines, chemokine receptors, and cytokines. Therefore, genes involved in human viral defense mechanisms and those encoding proteins targeted by the CMV proteins are candidates for host control of CMV infection and reactivation. Although still few in number, host genetic studies are producing valuable insights into biological processes involved in HCMV pathogenesis and HCMV-related diseases. For example, genetic variants in the immunoglobulin GM light chain can influence the antibody responsiveness to CMV glycoprotein B and modify risk of HCMV-related diseases. Moreover, CMV infection following organ transplantation has been associated with variants in genes encoding toll-like receptors (TLRs), programmed death-1 (PD-1), and interleukin-12p40 (IL-12B). A KIR haplotype (2DS4+) is proposed to be protective for CMV activation among hematopoietic stem cell transplant patients. Polymorphisms in the interferon lambda 3/4 (IFNL3/4) region are shown to influence susceptibility to CMV replication among solid organ transplant patients. Interestingly, the IFNL3/4 region is also associated with AIDS-related CMV retinitis susceptibility in HIV-infected patients. Likewise, interleukin-10 receptor 1 (IL-10R1) variants are shown to influence CMV retinitis development in patients with AIDS. Results from genome-wide association studies suggest a possible role for microtubule network and retinol metabolism in anti-CMV antibody response. Nevertheless, further genetic epidemiological studies with large cohorts, functional studies on the numerous HCMV genes, and immune response to chronic and latent states of infection that contribute to HCMV persistence are clearly necessary to elucidate the genetic mechanisms of CMV infection, reactivation, and pathogenesis.

Racial and Ethnic Differences in the Prevalence of Congenital Cytomegalovirus Infection

OBJECTIVE

To evaluate the impact of race and ethnicity upon the prevalence and clinical spectrum of congenital cytomegalovirus infection (cCMV).

STUDY DESIGN

From 2007 to 2012, 100 332 infants from 7 medical centers were screened for cCMV while in the hospital. Ethnicity and race were collected and cCMV prevalence rates were calculated.

RESULTS

The overall prevalence of cCMV in the cohort was 4.5 per 1000 live births (95% CI, 4.1-4.9). Black infants had the highest cCMV prevalence (9.5 per 1000 live births; 95% CI, 8.3-11.0), followed by multiracial infants (7.8 per 1000 live births; 95% CI, 4.7-12.0). Significantly lower prevalence rates were observed in non-Hispanic white infants (2.7 per 1000 live births; 95% CI, 2.2-3.3), Hispanic white infants (3.0 per 1000 live births; 95% CI, 2.4-3.6), and Asian infants (1.0 per 1000 live births; 95% CI, 0.3-2.5). After adjusting for socioeconomic status and maternal age, black infants were significantly more likely to have cCMV compared with non-Hispanic white infants (adjusted prevalence OR, 1.9; 95% CI, 1.4-2.5). Hispanic white infants had a slightly lower risk of having cCMV compared with non-Hispanic white infants (adjusted prevalence OR, 0.7; 95% CI, 0.5-1.0). However, no significant differences in symptomatic cCMV (9.6%) and sensorineural hearing loss (7.8%) were observed between the race/ethnic groups.

CONCLUSIONS

Significant racial and ethnic differences exist in the prevalence of cCMV, even after adjusting for socioeconomic status and maternal age. Although once infected, the newborn disease and rates of hearing loss in infants are similar with respect to race and ethnicity.

Genetic modifications of cytokine genes and Toxoplasma gondii infections in pregnant women

PURPOSE

Toxoplasma gondii causes one of the most common intrauterine infections worldwide, thus being a severe threat during pregnancy. IL1, IL6, IL10, IL12, and TNF-α cytokines were reported to be involved in immune responses to infections with T. gondii. The research was aimed to reveal relationships between genetic changes within the polymorphisms of these cytokine genes and the incidence of T. gondii infection among pregnant women, as well as congenital transmission of the parasite to the foetuses of their infected mothers.

METHODS

The primary study was performed in 148 Polish pregnant women, including 74 T. gondii-infected patients and 74 age-matched uninfected individuals; and further analysis - among the additional 142 pregnant women. Genotypes within IL1A -889 C>T, IL1B +3954 C>T, IL6 -174 G>C, IL10 -1082 G>A, IL12B -1188 A>C and TNFA -308 G>A single nucleotide polymorphisms (SNPs) were determined, using self-designed nested PCR-RFLP assays. Randomly selected PCR products, representing distinct genotypes in the analyzed polymorphisms, were confirmed by sequencing, using the Sanger method. A statistical analysis was carried out of relationships between genetic alterations within studied SNPs and the occurrence of T. gondii infection, using the following tools: cross-tabulation, Pearson's Chi-square test and the logistic regression model to estimate genetic models of inheritance. A power analysis of statistically significant outcomes was performed by Cramér's V test.

RESULTS

A multiple-SNP analysis showed TC haplotype for IL1A and IL1B SNPs to be significantly associated with a decreased risk of the parasitic infection (OR 0.41, P≤0.050). The association remained important after power analysis (Cramér's V = 0.39, χ² = 7.73, P≤0.050), and the additional analysis with larger groups of patients (OR 0.47, P≤0.050). Moreover, the CCCAGA complex variants were for all the studied polymorphisms at an increased risk of T. gondii infection (OR 8.14, P≤0.050), although this strong relationship was not significant in the further analysis (Cramér's V = 0.76, χ² = 26.81, P = 0.310). Regarding the susceptibility to congenital transmission of T. gondii from mothers to their foetuses among the infected pregnant women, the presence of GA heterozygotic status within IL10 polymorphism significantly increased the risk of parasitic transmission (OR 5.73 in the codominant model and OR 5.18 in the overdominant model; P≤0.050). The correlation stayed important in the power analysis (Cramér's V = 0.29, χ² = 6.03, P≤0.050), although it was non-significant in larger groups of patients. Important relationships specific for the first study cohort remained non-significant in the second group of studied pregnant women.

CONCLUSIONS

Within the analyzed cohort of Polish pregnant women, the genetic modifications from SNPs of genes, encoding both the proinflammatory IL1α, IL1β, IL6, IL12 and TNF-α, and anti-inflammatory IL10 cytokines, may have been associated with susceptibility to T. gondii infection. It is the first study on the contribution of cytokine genes polymorphisms to the occurrence of T. gondii infection during pregnancy. Further studies for other populations of pregnant women would be justified to reveal a detailed role of the analyzed polymorphisms for the occurrence of T. gondii infections during pregnancy.

Maternal and fetal cytomegalovirus infection: diagnosis, management, and prevention

Congenital cytomegalovirus infection is a major cause of central nervous system and sensory impairments that affect cognition, motor function, hearing, language development, vestibular function, and vision. Although the importance of congenital cytomegalovirus infection is readily evident, the vast majority of maternal and fetal infections are not identified, even in developed countries. Multiple studies of prenatal cytomegalovirus infections have produced a body of knowledge that can inform the clinical approach to suspected or proven maternal and fetal infection. Reliable diagnosis of cytomegalovirus infection during pregnancy and accurate diagnosis of fetal infection are a reality. Approaches to preventing the transmission of cytomegalovirus from mother to fetus and to the treatment of fetal infection are being studied. There is evidence that public health approaches based on hygiene can dramatically reduce the rate of primary maternal cytomegalovirus infections during pregnancy. This review will consider the epidemiology of congenital cytomegalovirus infection, the diagnosis and management of primary infection during pregnancy, and approaches to preventing maternal infection.

Maternal immune correlates of protection against placental transmission of cytomegalovirus

Human cytomegalovirus (HCMV) is the most common congenitally transmitted pathogen worldwide, impacting an estimated 1 million newborns annually. In a subset of infected infants, congenital HCMV causes severe, long-lasting sequelae, including deafness, microcephaly, neurodevelopmental delay, and even death. Accordingly, a maternal vaccine to prevent congenital HCMV infection continues to be a top public health priority. Nevertheless, all vaccines tested to date have failed to meet clinical trial endpoints. Maternal immunity provides partial protection against congenital HCMV transmission, as vertical transmission from seropositive mothers is relatively rare. Therefore, an understanding of the maternal immune correlates of protection against HCMV congenital infection will be critical to inform design of an efficacious maternal vaccine. This review summarizes our understanding of the innate and adaptive immune correlates of protection against congenital transmission of HCMV, and discusses the advantages and applications of a novel nonhuman primate model of congenital CMV transmission to aid in rational vaccine design and evaluation.

Toll-like receptors genes polymorphisms and the occurrence of HCMV infection among pregnant women

Background

Human cytomegalovirus (HCMV) is the most common cause of intrauterine infections worldwide. The toll-like receptors (TLRs) have been reported as important factors in immune response against HCMV. Particularly, TLR2, TLR4 and TLR9 have been shown to be involved in antiviral immunity. Evaluation of the role of single nucleotide polymorphisms (SNPs), located within TLR2, TLR4 and TLR9 genes, in the development of human cytomegalovirus (HCMV) infection in pregnant women and their fetuses and neonates, was performed.

Methods

The study was performed for 131 pregnant women, including 66 patients infected with HCMV during pregnancy, and 65 age-matched control pregnant individuals. The patients were selected to the study, based on serological status of anti-HCMV IgG and IgM antibodies and on the presence of viral DNA in their body fluids. Genotypes in TLR2 2258 A > G, TLR4 896 G > A and 1196 C > T and TLR9 2848 G > A SNPs were determined by self-designed nested PCR-RFLP assays. Randomly selected PCR products, representative for distinct genotypes in TLR SNPs, were confirmed by sequencing. A relationship between the genotypes, alleles, haplotypes and multiple variants in the studied polymorphisms, and the occurrence of HCMV infection in pregnant women and their offsprings, was determined, using a logistic regression model.

Results

Genotypes in all the analyzed polymorphisms preserved the Hardy-Weinberg equilibrium in pregnant women, both infected and uninfected with HCMV (P > 0.050). GG homozygotic and GA heterozygotic status in TLR9 2848 G > A SNP decreased significantly the occurrence of HCMV infection (OR 0.44 95% CI 0.21–0.94 in the dominant model, P ≤ 0.050). The G allele in TLR9 SNP was significantly more frequent among the uninfected pregnant women than among the infected ones (χ² = 4.14, P ≤ 0.050). Considering other polymorphisms, similar frequencies of distinct genotypes, haplotypes and multiple-SNP variants were observed between the studied groups of patients.

Conclusions

TLR9 2848 G > A SNP may be associated with HCMV infection in pregnant women.

Electronic supplementary material

The online version of this article (doi:10.1186/s12985-017-0730-8) contains supplementary material, which is available to authorized users.