Cytokine profiles and antibody responses to Plasmodium falciparum malaria infection in individuals living in Ibadan, southwest Nigeria.
BACKGROUND
The ability of the host immune system to efficiently clear Plasmodium falciparum parasites during a malaria infection depends on the type of immune response mounted by the host.


METHODS
In a cross-sectional study, we investigated the cellular-and antibody responses in individuals with P. falciparum infection, in an attempt to identify immunological signs indicative of the development of natural immunity against malaria in Ibadan, Nigeria. Levels of IL-10, IL-12(p70), IFN-gamma, and IgM, IgG and IgG1-4 subclasses in the serum of 36 symptomatic children with microscopically confirmed malaria parasitaemia and 54 asymptomatic controls were analysed by ELISA.


RESULTS
IFN-gamma and IL-10 were significantly higher in the symptomatic children (p=0.009, p=0.025 respectively) than in the asymptomatic controls but no differences were seen for IL-12(p70). Estimated higher ratios of IFN-gamma/IL-10 and IFN-gamma/IL-12 were also observed in the symptomatic children while the asymptomatic controls had higher IL-12/IL-10 ratio. The mean concentration levels of anti-P. falciparum IgG1, IgG2, IgG3 antibodies were statistically significantly higher in the individuals >5 years of age than <5 years while anti-P. falciparum IgG3 antibodies were notably low in <5 years category. Children <5 years had higher IgM antibodies than IgG and the expression of IgG subclasses increased with age.


CONCLUSIONS
Taken together, malaria infection is on a delicate balance of pro- and anti-inflammatory cytokines. The higher levels of IFN-gamma seen in the symptomatic children (<6 months) may be instrumental in immune-protection against malaria by limiting parasite replication. The observed variations in immunoglobulin subclass levels were age-dependent and exposure-related.
Iriemenam
Nnaemeka C
NC
Tropical Diseases Research Laboratory, Department of Medical Microbiology & Parasitology, College of Medicine of the University of Lagos, Idi-araba, P.M.B. 12003 Lagos, Nigeria. iriemeka@yahoo.co.uk
Okafor
Christian M F
CM
Balogun
Halima A
HA
Ayede
Idowu
I
Omosun
Yusuf
Y
Persson
Jan-Olov
JO
Hagstedt
Margareta
M
Anumudu
Chiaka I
CI
Nwuba
Roseangela I
RI
Troye-Blomberg
Marita
M
Berzins
Klavs
K
D000293:Adolescent; D000328:Adult; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood* / Q000276:immunology; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D016207:Cytokines / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D007371:Interferon-gamma / Q000097:blood; D016015:Logistic Models; D016778:Malaria, Falciparum / Q000097:blood / Q000276:immunology* / Q000469:parasitology; D008297:Male; D009549:Nigeria; D010963:Plasmodium falciparum / Q000235:genetics / Q000276:immunology*; D055815:Young Adult
D000913:Antibodies, Protozoan; D016207:Cytokines; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007371:Interferon-gamma