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Virulence of malaria is associated with differential expression of Plasmodium falciparum var gene subgroups in a

Mirjam Kaestli1, Ian A Cockburn, Alfred Cortés

  • 1Swiss Tropical Institute, Basel, Switzerland.

The Journal of Infectious Diseases
|May 3, 2006
PubMed

Insights

Var gene expression in Plasmodium falciparum differs between clinical and asymptomatic malaria. Group B var transcripts are higher in clinical cases, while Group C transcripts are prevalent in asymptomatic infections.

Area of Science:

  • Malariology
  • Molecular Biology
  • Genetics

Background:

  • Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a key virulence factor in falciparum malaria, mediating cytoadherence.
  • PfEMP1 is encoded by approximately 60 var genes, classified into three main subgroups: A, B, and C.
  • Emerging evidence suggests that the differential expression of these var gene subgroups correlates with clinical outcomes.

Purpose of the Study:

  • To investigate the association between var gene subgroup expression and the clinical presentation of falciparum malaria in children.
  • To compare var gene expression profiles in parasites from children with severe, mild, and asymptomatic malaria.

Main Methods:

  • Quantitative polymerase chain reaction (qPCR) was used to determine the proportions of var group transcripts.
  • Field samples were collected from children in Papua New Guinea with varying malaria severity.

Main Results:

  • A significantly higher proportion of var group B transcripts was observed in children with clinical malaria (mild and severe).
  • Asymptomatic infections were characterized by a higher proportion of var group C transcripts.
  • Parasites forming rosettes showed a significant upregulation of var group A transcripts.

Conclusions:

  • Distinct var gene expression patterns distinguish parasites causing clinical malaria from those causing asymptomatic infections.
  • Var gene subgroup expression is a significant factor in the clinical manifestation of falciparum malaria.

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