Single-Nucleotide Polymorphisms in NOD1, RIPK2, MICB, PLCE1, TNF, and IKBKE Genes Associated with Symptomatic Dengue in Children from Colombia

What is the association between the IL6-174 G > C (rs1800795) polymorphism and the risk of dengue? Evidence from a meta-analysis

The association of polymorphisms in genes responsible for immunological mediators with dengue allows the identification of certain genetic alterations that increase or decrease the development risk of the disease. A few number of studies that correlate the interleukin 6-174 G > C (IL6-174 G > C) polymorphism (rs1800795) with dengue. However, there is an inconsistency on the polymorphism influence on the disease which motivated this meta-analysis. So, this study aimed to evaluate the rs1800795 polymorphism with protection or susceptibility for development of dengue. A search of the literature was performed for studies published before 05 September 2020 in various databases. Calculations of Odds Ratio (OR) with 95% of Confidence Intervals (CI) and heterogeneity (I²) were assessed and publication bias was done by Begg' and Egger's test. The value of P < 0.05 was considered as significant. As results, five case-control studies were identified and included in the results. The analysis showed that the heterozygous genotype has a protective role against dengue without warning signs (DWOS) (OR = 0.57, p = 0.001), as well as the polymorphic C allele (OR = 0.77, p = 0.04). When unifying the data from the included studies, the GG genotype was more prevalent among individuals with dengue with warning signs (DWWS) when compared to the control group (p = 0.0221). GC genotype was more prevalent in the control group than in the DWWS group (p = 0.0119). Therefore, in our study we observed that the GC genotype and the C allele have a protective role against DWOS. Since this polymorphism is associated with low IL-6 expression, thus it is expected that there will be a decreased pro-inflammatory response. However, more studies regarding this thematic are necessary to have a consensus about this polymorphism and dengue.

Major Histocompatibility Complex Class I Chain-Related A and B (MICA and MICB) Gene, Allele, and Haplotype Associations With Dengue Infections in Ethnic Thais

BACKGROUND

Major histocompatibility complex class I chain-related (MIC) A and B (MICA and MICB) are polymorphic stress molecules recognized by natural killer cells. This study was performed to analyze MIC gene profiles in hospitalized Thai children with acute dengue illness.

METHODS

MIC allele profiles were determined in a discovery cohort of patients with dengue fever or dengue hemorrhagic fever (DHF) (n = 166) and controls (n = 149). A replication cohort of patients with dengue (n = 222) was used to confirm specific MICB associations with disease.

RESULTS

MICA*045 and MICB*004 associated with susceptibility to DHF in secondary dengue virus (DENV) infections (odds ratio [OR], 3.22; [95% confidence interval (CI), 1.18-8.84] and 1.99 [1.07-2.13], respectively), and MICB*002 with protection from DHF in secondary DENV infections (OR, 0.41; 95% CI, .21-.68). The protective effect of MICB*002 against secondary DHF was confirmed in the replication cohort (OR, 0.43; 95% CI, .22-.82) and was stronger when MICB*002 is present in individuals also carrying HLA-B*18, B*40, and B*44 alleles which form the B44 supertype of functionally related alleles (0.29, 95% CI, .14-.60).

CONCLUSIONS

Given that MICB*002 is a low expresser of soluble proteins, these data indicate that surface expression of MICB*002 with B44 supertype alleles on DENV-infected cells confer a protective advantage in controlling DENV infection using natural killer cells.

Towards Predicting Progression to Severe Dengue

There is an urgent need for prognostic assays to predict progression to severe dengue infection, which is a major global threat. While the majority of symptomatic dengue patients experience an acute febrile illness, 5-20% progress to severe infection associated with significant morbidity and mortality. Early monitoring and administration of supportive care reduce mortality and clinically usable biomarkers to predict severe dengue are needed. Here, we review recent discoveries of gene sets, anti-dengue antibody properties, and inflammatory markers with potential utility as predictors of disease progression. Upon larger scale validation and development of affordable sample-to-answer technologies, some of these biomarkers may be utilized to develop the first prognostic assay for improving patient care and allocating healthcare resources more effectively in dengue endemic countries.