Research
Hormonal
The cellular composition of peripheral blood changes seasonally, with white blood cell counts and specific lineages (lymphocytes, monocytes, neutrophils) varying significantly by season in temperate regions.
Your blood cell counts are not static; they fluctuate with the seasons. This is a normal physiological variation, not necessarily a sign of disease, but it contributes to the overall seasonal immune profile.
GoodSupportsHIGH confidence
We also find the cellular composition of blood to vary by season, and these changes, which differ between the United Kingdom and The Gambia, could explain the gene expression periodicity.
Why this rating
Large cohort (7,343 healthy adults) with statistically significant p-values for multiple cell types.
Source
Widespread seasonal gene expression reveals annual differences in human immunity and physiology
Xaquín Castro Dopico et al. · Nature Communications · 2015
DOI 10.1038/ncomms8000
cohortCited 534×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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- Human immune function exhibits significant seasonal variation, with a pro-inflammatory transcriptomic profile and increased circulating levels of risk biomarkers (sIL-6R, CRP) during winter months in temperate climates.Good
- Seasonal gene expression patterns in the immune system are inverted between the Northern and Southern hemispheres, indicating a photoperiod-driven circannual rhythm.Good
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