Autoantibodies against cytokines (c‐aAb) have been implicated in the pathophysiology of autoimmune diseases, and a variety of infections. In addition, several independent studies have detected elevated titers of c‐aAb in the circulation of healthy individuals. To further understand their impact on immune responses, we measured c‐aAb against IFN‐α, IFN‐γ, CSF2, IL‐1α, IL‐6, and IL‐10 in the plasma of 1000 healthy individuals of the Milieu Intérieur (MI) cohort. Focusing on donors above a defined positive cut‐off we observed significant age effects for c‐aAb against IL‐1α, but no major environmental or lifestyle associated factors were identified. Using TruCulture stimulation data from the MI cohort, we observed a strong association between induced IL‐1α and c‐aAb levels after LPS stimulation. For several other stimuli, c‐aAb against IL‐1α and IL‐10 were associated with decreased or increased proinflammatory gene expression, respectively. Finally, TruCulture assays supplemented with plasma containing high‐titer c‐aAb showed a strong influence of anti‐IFN‐α and anti‐IL‐6 c‐aAb on both baseline and induced gene expression. In summary, this study shows a widespread prevalence of anti‐cytokine autoantibodies in healthy donors with impacts on diverse immune responses, suggesting a significant contribution of c‐aAb to interindividual immune heterogeneity.