Genetic variation in toll like receptors 2, 7, 9 and interleukin-6 is associated with cytomegalovirus infection in late pregnancy

Influence of single-nucleotide polymorphisms in TLR3 (rs3775291) and TLR9 (rs352139) on the risk of CMV infection in kidney transplant recipients

Risk stratification for cytomegalovirus (CMV) infection after kidney transplantation (KT) remains to be determined. Since endosomal toll-like receptors (TLRs) are involved in viral sensing, we investigated the impact of common single-nucleotide polymorphisms (SNPs) located within TLR3 and TLR9 genes on the occurrence of overall and high-level (≥1,000 IU/ml) CMV infection in a cohort of 197 KT recipients. Homozygous carriers of the minor allele of TLR3 (rs3775291) had higher infection-free survival compared with reference allele carriers (60.0% for TT versus 42.3% for CC/CT genotypes; P-value = 0.050). Decreased infection-free survival was observed with the minor allele of TLR9 (rs352139) (38.2% for TC/CC versus 59.3% for TT genotypes; P-value = 0.004). After multivariable adjustment, the recessive protective effect of the TLR3 (rs3775291) TT genotype was confirmed (adjusted hazard ratio [aHR]: 0.327; 95% CI: 0.167–0.642; P-value = 0.001), as was the dominant risk-conferring effect of TLR9 (rs352139) TC/CC genotypes (aHR: 1.865; 95% CI: 1.170–2.972; P-value = 0.009). Carriers of the TLR9 (rs352139) TC/CC genotypes showed lower CMV-specific interferon-γ-producing CD4+ T-cell counts measured by intracellular cytokine staining compared with the TT genotype (median of 0.2 versus 0.7 cells/μl; P-value = 0.003). In conclusion, TLR3/TLR9 genotyping may inform CMV infection risk after KT.

TLR genetic variation is associated with Rotavirus-specific IgA seroconversion in South African Black infants after two doses of Rotarix vaccine

Live oral rotavirus vaccines have significantly reduced rotavirus-related diarrheal morbidity and mortality globally, but low efficacy of these vaccines is observed in low-income countries where disease burden is highest. The biological basis of rotavirus vaccine failure remains unknown but likely includes both microbial and host factors. We investigated associations between 19 candidate SNPs in the TLR3, TLR7, TLR8, DDX58 and IFIH1 genes that play a role in innate immunity, and seroconversion in Black South African infants after vaccination with Rotarix at 6 and 14 weeks of age. Rotavirus-specific IgA antibody titre was measured by ELISA before each vaccine dose and four weeks after the second dose, and seroconversion was defined as a four-fold or greater increase in IgA antibody titre at 18 weeks of age when compared to pre-vaccine titres. A total of 95/138 individuals seroconverted (68.8%) and seroconversion was significantly affected by birthweight (P = 0.010), pre-vaccine IgA and IgG titres (P = 0.0002 and P = 0.007 respectively). rs2159377 SNP in TLR8 was significantly associated with seroconversion in a univariate allelic model (P = 0.015) and was borderline significant in a multivariable logistic regression adjusted for birthweight and pre-vaccine titres (P = 0.071), although these values did not remain significant after Bonferroni correction. A haplotype of six SNPs on the X chromosome across TLR7 and TLR8, including rs179008 and rs5935438 minor alleles, was significantly associated with seroconversion in a univariate model (P = 0.042), but not in a multivariable model or after Bonferroni correction. Epistatic interaction between rs5743305 in TLR3 and rs55789327 in DDX58 was significantly associated with seroconversion (P = 0.034) but a genetic risk score constructed from all 19 minor alleles was not. Our results suggest that TLR variants may influence IgA antibody production and seroconversion to Rotarix vaccine in South Africans. Host genetic variation contributes to the varying immunogenicity of live oral rotavirus vaccines.

Cytomegalovirus pneumonia of infants in Africa: a narrative literature review

Cytomegalovirus pneumonia has repeatedly been described in the context of HIV-exposed uninfected and HIV-infected infants. Despite its significant role in the etiology of childhood pneumonia, there is still a paucity of literature generally, and specifically in Africa, suggesting that it might be a neglected disease. Emerging evidence highlights the importance of postnatal transmission through breastmilk. The pathogenetic significance of the multiplicity of strains acquired through repeated re-infections in early infancy is unknown. The development of cheap, accurate diagnostic tools and safe, effective antivirals and the maintenance of effective prevention and treatment of pediatric HIV are needed to manage cytomegalovirus pneumonia in low-resource settings.

The Limitations of Cytomegalovirus DNA Detection in Cerebrospinal Fluid of Newborn Infants With Congenital CMV Infection: A Tertiary Care Neonatal Center Experience

BACKGROUND

Congenital cytomegalovirus (cCMV) infection of the central nervous system (CNS) can cause ventriculomegaly, gliosis, calcifications and cortical defects. Detection of CMV DNA in cerebrospinal fluid by PCR (CSF-CMV-PCR) is a marker of CNS involvement.

OBJECTIVE

To evaluate a diagnostic value of the positive CSF-CMV-PCR in cCMV.

METHODS

Analysis of clinical, laboratory, neuroimaging and single-nucleotide polymorphisms (SNPs) data according to the results of CSF-CMV-PCR were performed in infants with cCMV.

RESULTS

A total of 168 infants were included; 145 (86.3%) had negative and 23 (13.7%) had positive CSF-CMV-PCR results. Associations between the positive CSF-CMV-PCR results and prematurity (odds ratio [OR] = 3.24; 95% confidence interval [CI]: 1.30-8.07), microcephaly (OR = 5.67; 95% CI: 2.08-15.41), seizures (OR = 4.15; 95% CI: 1.10-15.67), sensorineural hearing loss (OR = 6.6; 95% CI: 2.49-17.46), splenomegaly (OR = 8.13; 95% CI: 3.12-21.16), hepatitis (OR = 10.51; 95% CI: 3.31-33.35), petechiae (OR = 10.21; 95% CI: 3.78-27.57) and heterozygous T/C genotype at TLR4rs4986791 (OR = 7.88; 95% CI: 1.55-40.12) were observed. When using a multivariate logistic regression analysis, only the presence of severe sensorineural hearing loss (OR = 7.18; 95% CI: 1.75-29.34, P = 0.006), cystic lesions on MRI (OR 5.29; 95% CI: 1.31-21.36, P = 0.02), and calcifications on MRI (OR = 7.19; 95% CI: 1.67-30.97, P = 0.008) remained as the significant independent predictors of the positive CSF-CMV-PCR results.

CONCLUSIONS

The detection of CMV DNA in CSF is associated with a higher rate of CNS damage including abnormal MRI neuroimaging and severe hearing loss. Therefore, detection of CMV DNA in CSF may be considered as a marker of severe CNS injury in cCMV infection. However, the very low prevalence of the positive CSF-CMV-PCR results, even in infants with proven CNS involvement, may imply its limited role in clinical practice.