In the plasma of TBE and co-infected patients (TBE1 and co-infection1), there was a significant increase in the level of the product of PUFAs oxidative fragmentation—malondialdehyde (MDA) and the product of oxidative cyclization—neuroprostanes (NPs) compared to the concentration in the plasma of healthy people (Fig. 2). The gene discussed is MMP2; the disease is tick-borne encephalitis.