Quantitation of the third component of complement on stored red cells

Area of Science:

• Immunology
• Hematology
• Biochemistry

Background:

• The third component of complement (C3) plays a crucial role in immune responses.
• Understanding C3 behavior during blood storage is vital for transfusion medicine.
• Previous methods for quantifying C3 on red blood cells (RBCs) have limitations.

Purpose of the Study:

• To quantify C3 molecules accumulating on RBCs during liquid whole-blood storage.
• To characterize the C3 fragments bound to stored RBCs.
• To assess the correlation between cell-bound C3 and RBC agglutination.

Main Methods:

• Utilized an automated anti-C3c consumption technique to measure C3 on RBCs.
• Employed calibrated C3-sensitized zymosan particles (ZyC3) as standards.
• Analyzed dose-response curves and sigmoidal curve shapes for antigenic differences.

Main Results:

• Quantified C3 accumulation on RBCs stored at 4°C.
• Detected an average of 48 C3 molecules per RBC after 21 days of storage.
• Observed continuous C3 accumulation and subsequent C3c fragment cleavage on RBCs.
• Found a direct proportion between cell-bound C3 and RBC agglutination with anti-C3c.

Conclusions:

• The automated anti-C3c consumption technique adequately quantifies C3 on stored RBCs, despite antigenic differences.
• C3 continuously accumulates on RBCs during cold storage, leading to C3c fragment formation.
• The level of C3 on stored RBCs correlates with their agglutination properties.