Complement Components in Peripheral Blood from Adult Patients with IDH Wild-Type Glioblastoma

Background: The complement system seems to influence cancer pathophysiology. The primary aim of this study was to explore complement components associated with the classical pathway (CP) of the complement system in peripheral blood from patients with IDH–wild-type (IDH-wt) glioblastoma. Methods: Patients undergoing primary surgery due to glioblastoma in the years 2019–2021 were prospectively included in the present study. Blood samples were collected prior to surgery, and analyzed with regard to CP complement components, as well as standard coagulation tests. Results: In total, 40 patients with IDH-wt glioblastomas were included. C1q was reduced in 44% of the cases compared to the reference interval. C1r was reduced in 61% of the analyzed samples. Both C1q and C1r are parts of the initial steps of the classical complement activation pathway, which, however, was not correspondingly altered. Activated pro-thromboplastin time (APTT) was shorter in 82% of the analyzed samples compared to the reference interval. APTT was shorter in those with reduced C1q and C1r levels. C1q is an important link between the innate and acquired immunity, and C1q and C1r also interact with the coagulation system. Patients who displayed reduced levels of both C1q and C1r preoperatively had a significantly shorter overall survival compared with the rest of the cohort. Conclusions: Our findings demonstrate that there are alterations in C1q and C1r concentrations in peripheral blood from patients with IDH1-wt glioblastoma compared with the normal population. Patients who displayed reduced C1q and C1r levels had a significantly shorter survival.