Genetic associations of fatigue and other symptom domains of the acute sickness response to infection.
The acute sickness response to infection is a conserved set of changes in physiology and behaviour, featuring fever, fatigue, musculo-skeletal pain, disturbed mood, and cognitive difficulties. The manifestations differ somewhat between individuals, including those infected with pathogens which do not have genetic variability--suggesting host determinants. Principal components analysis (PCA) was applied to acute phase, self-report symptom data from subjects in the Dubbo Infection Outcomes Study (n=296) to empirically derive indices of fatigue, pain, neurocognitive difficulties, and mood disturbance, as well as overall illness severity. Associations were sought with functional single nucleotide polymorphisms (SNPs) in the cytokine genes, interleukin (IL)-6, tumour necrosis factor (TNF)-α, interferon (IFN)-γ, and IL-10. The summed individual symptom indices correlated with overall severity and also with functional status. The relative contribution of individual symptom domains to the overall illness was stable over time within subjects, but varied between subjects with the same infection. The T allele of the IFN-γ +874 T/A SNP was associated with increased fatigue (p=0.0003; OR: 3.3). The C allele of the IL-10 -592 C/A SNP exerted a protective effect on neurocognitive difficulties (p=0.017; OR: 0.52); while the A allele for the IL-10 -592 SNP was associated with increased mood disturbance (p=0.044; OR: 1.83), as was the G allele of the IL-6 -174 G/C SNP (p=0.051; OR: 1.83). The acute sickness response has discrete symptom domains including fatigue, which have unique genetic associations. These data provide novel insights into the pathophysiology of fatigue states.
Inflammation and Infection Research Centre, School of Medical Sciences, University of New South Wales, Australia.
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Piraino
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Vollmer-Conna
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Lloyd
D000328:Adult; D018354:Alphavirus Infections / Q000235:genetics / Q000503:physiopathology; D016207:Cytokines / Q000235:genetics*; D020031:Epstein-Barr Virus Infections / Q000235:genetics / Q000503:physiopathology; D005221:Fatigue / Q000209:etiology / Q000235:genetics*; D005260:Female; D056726:Genetic Association Studies; D005838:Genotype; D006801:Humans; D007239:Infections / Q000150:complications / Q000235:genetics* / Q000503:physiopathology*; D008297:Male; D010146:Pain / Q000209:etiology / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D025341:Principal Component Analysis; D011778:Q Fever / Q000235:genetics / Q000503:physiopathology; D012398:Ross River virus; D012720:Severity of Illness Index
D016207:Cytokines