Differential IgG responses to PfHRP2 across the malaria severity spectrum.

BACKGROUND

Severe malaria represent a leading cause of mortality in Plasmodium falciparum infections. Sequestered parasites release PfHRP2, which increases at schizont rupture. Thus, this study explored Pfhrp2 gene copy number variation and immune (IgG) response in mild (MM), severe (SM) and cerebral malaria (CM) cases.

METHODS

A total of 240 samples were collected and analysed further. Pfhrp2 gene copy numbers and IgG responses against the PfHRP2 peptide were assessed using real-time qPCR and ELISA-based assays, respectively.

RESULTS

Parasitaemia was significantly higher in MM cases compared with SM (P = .0009), and parasitaemia progressively increased from CM to SNCM to MM cases (P < .05). Pfhrp2 copy numbers were similar across all groups. However, IgG responses against the PfHRP2 peptide were notably higher in SM, CM and SNCM compared with MM cases( P < .0001). Positive correlations were observed between IgG response and age, as well as var P5 peptide (P < .01).

CONCLUSIONS

The absence of significant variation in Pfhrp2 gene copy numbers across severity groups indicates that it is not a reliable biomarker for disease severity. Conversely, the IgG response to PfHRP2 appears to be more critical, underscoring the importance of host -pathogen interactions in determining disease outcomes.