Fc gamma receptor IIa (CD32) polymorphism and antibody responses to asexual blood-stage antigens of Plasmodium falciparum malaria in Sudanese patients

• In a prospective clinical study in New Halfa Teaching Hospital, the possible association between FcRIIa-R/H131 polymorphism and anti-malarial antibody responses with clinical outcome of Plasmodium falciparum malaria among Sudanese patients was investigated. A total of 256 individuals were consecutively enrolled, comprising 115 patients with severe malaria, 85 with mild malaria and 56 malaria-free controls. Genotyping of FcRIIa-R/H131 dimorphism was performed using gene-specific polymerase chain reaction (PCR) amplification with allele-specific restriction enzyme digestion of the PCR product. The antibody responses to asexual blood-stage antigens were assessed by an enzyme-linked immunosorbent assay. The frequency of the FcRIIa-R/R131 genotype was significantly higher in those with severe malaria when compared with patients with mild malaria, while the FcRIIa-H/H131 genotype showed a significant association with mild malaria. A reduced risk of severe malaria with IgG3 antibodies in combination with the H/H131 genotype was observed. Furthermore, low levels of IgG2 antibodies reactive with the Pf332-C231 antigen were also associated with lower risk of severe malaria in individuals carrying the H131 allele. The levels of IgG1 and IgG3 antibodies were statistically significantly higher in the mild malaria patients when compared with the severe malaria patients. Taken together, our study revealed that the FcRIIa-R/R131 genotype is associated with the development of severe malaria, while the H/H131 genotype is more likely to be associated with mild malaria. Our results also revealed that the natural acquisition of immunity against clinical malaria appeared to be more associated with IgG1 and IgG3 antibodies, signifying their roles in parasite-neutralizing immune mechanisms.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Infektionsmedicin (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Infectious Medicine (hsv//eng)

Keyword

Adolescent

Adult

Age Factors

Animals

Antibodies; Protozoan/*blood/immunology

Antigens; Protozoan/*immunology

Child

Child; Preschool

Enzyme-Linked Immunosorbent Assay

Female

Gene Frequency

Genetic Predisposition to Disease

Genotype

Humans

Immunoglobulin G/blood/immunology

Malaria; Falciparum/blood/*genetics/immunology

Male

Middle Aged

Plasmodium falciparum/*immunology

Polymerase Chain Reaction

Polymorphism; Genetic

Receptors; IgG/*genetics

Sudan

MEDICINE

MEDICIN

Infectious diseases

Infektionssjukdomar

Infektionssjukdomar

Infectious Diseases

Publication and Content Type

ref (subject category)

art (subject category)