Levels of PFOA significantly correlated with the production of IFNɣ of ex-vivo lymphocytes after stimulation with tetanus (r = − 0.33, p = 0.01) and diphtheria (r = − 0.24, p = 0.08) toxoid (n = 55 only, see also Table 3). The gene discussed is IFNA1; the disease is tetanus.