Comparative analysis of the Immunoglobulin G antibodies (IgG and IgG subclass) responses in children (≤15 years) with severe and uncomplicated malaria in Buea, South West region, Cameroon

Abstract

Studies assessing the immunoglobulin G (IgG) antibody responses in severe malaria are not readily available. This study was designed to compare the IgG and IgG1-4 antibody responses in severe malaria and its major clinical presentations (cerebral malaria, severe malarial anemia and respiratory distress) in children (≤15 years) in Buea, Cameroon. In a hospital-based cross-sectional comparative study, children presenting for consultation at the outpatient department/Emergency unit of the Buea Regional Hospital were enrolled and assigned into one of three groups: severe malaria, uncomplicated malaria and negative controls. Baseline characteristics were determined; blood glucose level was measured by glucometer, complete blood count was performed using an automated heamatology analyser and participants were screened for malaria parasites by light microscopy and severe malaria was categorized based on WHO criteria. Total IgG and IgG1-4 antibodies were measured using standard ELISA with Plasmodium falciparum 19-KDa C-terminal region of merozoite surface protein 1 (P.fMSP-119) antigen as capture antigen. A total of 236 participants were enrolled comprising: 66 severe malaria, 70 uncomplicated malaria and 100 negative controls. The participants in the different groups were similar with regards to their ages (p=0.06) and gender (p=0.900). Children with severe malaria had significantly higher levels of anti-P.fMSP-119 IgG4 (p<0.0001) antibodies and significantly lower levels of anti-P.fMSP-119 IgG1 (p<0.0001) and IgG3 (p<0.0001) antibodies. There was no significant variation in the IgG antibody responses between the major clinical forms of severe malaria. The study finding of significantly higher levels of the non-cytophilic antibody IgG4 is suggestive of the role the antibody plays in the pathogenesis of severe malaria. Larger studies investigating how these immune effector cells vary in the major phenotypes of severe malaria are recommended.

Keywords

• Severe malaria
• uncomplicated malaria
• Immunoglobulin G antibodies
• children
• comparative analysis