Myd88 Is Required for an Antibody Response to Retroviral Infection

Although retroviruses have been extensively studied for many years, basic questions about how retroviral infections are detected by the immune system and which innate pathways are required for the generation of immune responses remain unanswered. Defining these pathways and how they contribute to the anti-retroviral immune responses would assist in the development of more effective vaccines for retroviral pathogens such as HIV. We have investigated the roles played by CD11c+ dendritic cells (DCs) and by Toll-like receptor (TLR) signaling pathways in the generation of an anti-retroviral immune response against a mouse retroviral pathogen, Friend murine leukemia virus (F-MLV). Specific deletion of DCs during F-MLV infection caused a significant increase in viral titers at 14 days post-infection, indicating the importance of DCs in immune control of the infection. Similarly, Myd88 knockout mice failed to control F-MLV, and sustained high viral titers (107 foci/spleen) for several months after infection. Strikingly, both DC-depleted mice and Myd88 knockout mice exhibited only a partial reduction of CD8+ T cell responses, while the IgG antibody response to F-MLV was completely lost. Furthermore, passive transfer of immune serum from wild-type mice to Myd88 knockout mice rescued control of F-MLV. These results identify TLR signaling and CD11c+ DCs as playing critical roles in the humoral response to retroviruses

A saturated map of common genetic variants associated with human height.

Common single-nucleotide polymorphisms (SNPs) are predicted to collectively explain 40-50% of phenotypic variation in human height, but identifying the specific variants and associated regions requires huge sample sizes1. Here, using data from a genome-wide association study of 5.4 million individuals of diverse ancestries, we show that 12,111 independent SNPs that are significantly associated with height account for nearly all of the common SNP-based heritability. These SNPs are clustered within 7,209 non-overlapping genomic segments with a mean size of around 90 kb, covering about 21% of the genome. The density of independent associations varies across the genome and the regions of increased density are enriched for biologically relevant genes. In out-of-sample estimation and prediction, the 12,111 SNPs (or all SNPs in the HapMap 3 panel2) account for 40% (45%) of phenotypic variance in populations of European ancestry but only around 10-20% (14-24%) in populations of other ancestries. Effect sizes, associated regions and gene prioritization are similar across ancestries, indicating that reduced prediction accuracy is likely to be explained by linkage disequilibrium and differences in allele frequency within associated regions. Finally, we show that the relevant biological pathways are detectable with smaller sample sizes than are needed to implicate causal genes and variants. Overall, this study provides a comprehensive map of specific genomic regions that contain the vast majority of common height-associated variants. Although this map is saturated for populations of European ancestry, further research is needed to achieve equivalent saturation in other ancestries

Prevalence of restless legs syndrome and associated factors in an otherwise healthy population: results from the Danish Blood Donor Study

$\textit{Objective}$ Restless legs syndrome (RLS) is a neurological sensorimotor disorder characterized by uncomfortable sensations in the legs. RLS often occurs as a comorbid condition. Besides an increased risk of iron deficiency, blood donors are considered to be generally healthy. Blood donors are therefore an ideal population for studying factors associated with RLS occurrence, herein the role of iron. It is suggested that RLS is linked to sex, age, low socioeconomic status, unhealthy lifestyle, and iron deficiency. The objective of this study is therefore to estimate the RLS prevalence and identify associated biological, sociodemographic, economic, and lifestyle factors in a population of blood donors. $\textit{Methods}$ A total of 13,448 blood donors enrolled in the Danish Blood Donor Study from May 2015 to May 2016. RLS cases were identified using the validated Cambridge–Hopkins RLS-questionnaire. Logistic regression models were applied to assess the relationship between RLS and data on socially related factors collected using questionnaires and population registers. $\textit{Results}$ In this study, 7.2% women and 4.5% men were classified with RLS. RLS was associated with: female sex, high age, smoking, frequent alcohol consumption, and low education. RLS-related symptoms were associated with obesity, parity and donation intensity 3 years prior to inclusion among women. RLS was not related to: reduced plasma ferritin, employment status, and income. $\textit{Conclusions}$ RLS is a frequent disorder in otherwise healthy individuals. The associations discovered in this study can be utilized in preventing or reducing RLS symptoms.The Danish Council for Independent Research - Medical Sciences, The Danish Administrative Regions, The Danish Blood Donor Research Foundation, The Danish Bio- and Genome bank, and The Brothers Hartmann Foundation