Can serum interleukin 34 levels be used as an indicator for the prediction and prognosis of COVID-19?

OBJECTIVE: Interleukin 34 (IL-34) is a molecule whose expression is increased in conditions such as autoimmune disorders, inflammation, and infections. Our study aims to determine the role of IL-34 in the diagnosis, follow-up, and prognosis of Coronavirus Disease-19 (COVID-19).

METHOD: A total of 80 cases were included in the study as 40 COVID-19 positive patient groups and 40 COVID-19 negative control groups. The COVID-19-positive group consisted of 20 intensive-care unit (ICU) patients and 20 outpatients. Serum IL-34, c-reactive protein (CRP), ferritin, D-dimer, troponin I, hemogram, and biochemical parameters of the cases were studied and compared between groups.

RESULTS: IL-34 levels were significantly higher in the COVID-19-positive group than in the negative group. IL-34 levels increased in correlation with CRP in predicting the diagnosis of COVID-19. IL-34 levels higher than 31.75 pg/m predicted a diagnosis of COVID-19. IL-34 levels did not differ between the outpatient and ICU groups in COVID-19-positive patients. IL-34 levels were also not different between those with and without lung involvement.

CONCLUSION: While IL-34 levels increased in COVID-19-positive patients and were successful in predicting the diagnosis of COVID-19, it was not found to be significant in determining lung involvement, risk of intensive care hospitalization, and prognosis. The role of IL-34 in COVID-19 deserves further evaluation.