Abnormal depolarizing patterns in three patients with filarial infection

Area of Science:

• Hematology
• Parasitology
• Clinical diagnostics

Background:

• Automated depolarization analysis, a component of the full blood count (FBC) using analyzers like Cell-Dyn 4000, has been recognized for its potential in detecting malaria infection.
• Abnormal depolarizing patterns in FBC are typically attributed to leukocyte-associated malaria hemozoin, a pigment that alters laser light depolarization.
• This method aids in identifying malaria by analyzing how cellular components interact with polarized light during routine blood tests.

Observation:

• This report details three patients presenting with abnormal depolarizing events in their FBC, despite lacking malaria infection.
• These unique depolarizing patterns were linked to infection by the nematode Mansonella perstans.
• The observed pattern included a normal eosinophil population alongside an abnormal depolarizing population with a linear relationship between granularity and lobularity.

Findings:

• The abnormal depolarizing pattern observed in Mansonella perstans infection is distinct from that caused by malaria hemozoin.
• The atypical population in M. perstans infected samples was smaller than typical leukocytes, aiding differentiation.
• The characteristic 'straight-line' scatter plot features may result from microfilaria fragmentation induced by erythrocyte-lysing agents used in leukocyte analysis.

Implications:

• Automated depolarization analysis may require careful interpretation to distinguish between malaria and other parasitic infections like Mansonella perstans.
• Understanding these distinct depolarizing patterns can improve diagnostic accuracy in parasitology and hematology.
• Further research into the effects of sample preparation agents on parasitic material is warranted for accurate automated blood analysis.