Effect of SARS-CoV-2 and Toxoplasma gondii co-infection on IFN-γ and TNF-α expression and its impact on disease severity.

ABSTRACT

The symptomatology of COVID-19 is dependent on the immune status and the cytokine response of the host. The cytokine level of the host is influenced by the presence of chronic persistent or latent infections with co-pathogens. Parasitic diseases are known to induce host immune-modulation which may impact the response to co-infection. Toxoplasmosis is a widespread protozoal infection that remains quiescent in its latent form to be re-activated during states of immune depression. Clinical data on the relation between toxoplasmosis and COVID-19 cytokine profile and symptomatology are still insufficient. Seventy-nine subjects were included in this study. Patients were diagnosed with COVID-19 by PCR. Serological testing for toxoplasmosis was performed by the detection of anti-Toxoplasma IgG antibodies, in addition to IgG avidity testing. IFN-γ and TNF-α levels were determined by RT-PCR. Among patients diagnosed with COVID-19, 67.1% were seronegative for anti-Toxoplasma IgG, while 32.9% were seropositive. High avidity was found in 10 cases (40% of seropositive cases), 4 of whom required ICU administration, while low avidity was found in 15 cases (60%), 7 of which were administered to the ICU. TNF-α and INF-γ levels were significantly higher in COVID-19 patients than in healthy control subjects. No significant association was found between the seroprevalence of toxoplasmosis and the presence of COVID-19 and its severity. Cytokines were significantly higher in both seropositive and seronegative COVID-19 patients than in their control counterparts. The high prevalence of toxoplasmosis merits further exploration of its relation to COVID-19 by mass studies.