Low erythrocyte pyridoxal-kinase activity in Blacks: Its possible relation to falciparum malaria

Area of Science:

• Biochemistry
• Hematology
• Infectious Diseases

Background:

• Plasmodium falciparum malaria is a significant health concern, particularly in tropical regions.
• Red blood cell enzyme activities can be affected by parasitic infections and genetic factors.
• Glucose-6-phosphate dehydrogenase (G.-6-P.D.) and pyridoxal-kinase (P.L.K.) are key enzymes in red blood cells.

Purpose of the Study:

• To compare red-cell P.L.K. and G.-6-P.D. activity in Nigerian children with severe malaria versus healthy controls and White adults.
• To investigate the potential influence of falciparum malaria on red-cell enzyme activity and its implications for population genetics.

Main Methods:

• Enzyme activity assays for P.L.K. and G.-6-P.D. were performed on red blood cells.
• Subjects included Nigerian children with severe P. falciparum parasitaemia, healthy Nigerian children, and White adults.
• P.L.K.: G.-6-P.D. ratios were analyzed, correcting for red-cell age differences.

Main Results:

• Malaria patients exhibited significantly higher mean P.L.K. activity than healthy Nigerian controls.
• The P.L.K.: G.-6-P.D. ratio was higher in malaria patients and White adults compared to Nigerian controls.
• These findings were consistent after adjusting for reduced red-cell age in malaria patients.

Conclusions:

• Severe falciparum malaria is associated with altered red-blood cell enzyme activity, specifically increased P.L.K. levels.
• The observed differences suggest that falciparum malaria may have exerted selective pressure favoring lower red-cell P.L.K. activity in Black populations.
• This could explain the higher prevalence of low P.L.K. activity in individuals of Black African descent.