A novel flow cytometry approach to quantify malaria-derived particles

Area of Science:

• Parasitology
• Flow Cytometry
• Diagnostic Development

Background:

• Accurate quantification of malaria parasite density is vital for effective diagnosis and treatment.
• Malaria-derived particles (MDPs) are implicated in malaria pathology, but a standardized quantification method is lacking.
• Existing methods for parasite quantification may not be suitable for routine laboratory use.

Purpose of the Study:

• To optimize a flow cytometry method for enumerating malaria-derived particles (MDPs) per microliter of blood.
• To establish a reliable and straightforward quantification technique for routine laboratory settings.
• To assess the correlation between MDP levels and parasite density in malaria infections.

Main Methods:

• Optimization of a flow cytometry protocol involving propidium iodide staining and red blood cell (RBC) lysis.
• Quantification of MDPs using a CytoFlex flow cytometer with size-standard and counting beads.
• Ultrastructural analysis of malarial parasites in lysed RBCs via electron microscopy.

Main Results:

• A significant increase in MDP levels was observed in blood samples from Plasmodium falciparum and Plasmodium vivax infections compared to controls.
• MDP concentration strongly correlated with infected red blood cell (iRBC) percentage (R² = 0.94) and parasite density (R² = 0.94 for P. falciparum, R² = 0.91 for P. vivax).
• Electron microscopy confirmed malarial parasites exist as membrane-bound spherical cells within lysed RBCs.

Conclusions:

• Flow cytometry provides a reliable and straightforward method for quantifying MDPs, offering a new tool for malaria diagnosis.
• The developed method demonstrates a strong association between MDP concentration and parasite density.
• This approach has the potential for routine laboratory use in managing malaria parasite infections.