P. TangteerawatanaS. M. MontgomeryH. PerlmannS. LooareesuwanM. Troye-BlombergS. KhusmithMahidol UniversityKarolinska University HospitalOrebro Lans LandstingImperial College LondonStockholms universitet2018-08-242018-08-242007-09-01Parasite Immunology. Vol.29, No.9 (2007), 475-48313653024014198382-s2.0-34548165206https://repository.li.mahidol.ac.th/handle/20.500.14594/24516The aim of this study was to assess the immunoglobulin (Ig)-subclass distribution of antimalarial antibody responses in 110 and 169 Thai patients with complicated and uncomplicated Plasmodium falciparum malaria, respectively. Antimalarial plasma IgG subclasses and IgE antibody levels against a crude malaria blood stages, and antigen preparation were determined using enzyme-linked immunosorbent assay (ELISA). On admission, the levels of anti-P. falciparum IgG1, IgG2 and IgG3 were significantly lower in patients with complicated malaria than uncomplicated malaria (IgG1, P < 0.0001; IgG2, P < 0.0001; IgG3, P < 0.0001). The levels of antimalarial IgE were slightly lower, but not statistically significant (P = 0.389) in the complicated malaria. After adjusting all antibody levels and age, anti-P. falciparum IgG3 levels remained significantly associated with complicated malaria. None of the other antibody concentrations showed statistically significant associations with complicated malaria. The anti-P. falciparum IgG3 levels were related to the IgG1 as well as IgG2 levels. A correlation between anti-P. falciparum IgG2 and IgE was observed in the complicated malaria group, and this may indicate their roles in the severity of disease. Our data suggest that anti-P. falciparum IgG3 is associated with a reduced risk of complicated malaria and that antimalarial Ig-subclasses are differently regulated in patients with complicated and uncomplicated malaria. © 2007 Mahidol University.Mahidol UniversityImmunology and MicrobiologyArticleSCOPUS10.1111/j.1365-3024.2007.00965.x