title: Two populations of women with high and low spleen rates living in the same area of Madang, Papua New Guinea, demonstrate different immune responses to malaria.
abstract: Specific malaria and total IgM antibody responses were measured in 2 linguistically distinct coastal Papua New Guinean populations living in the same endemic malarious area, but exhibiting different adult female spleen rates (51% and 30%), in order to establish whether the higher spleen rates in the former group were due to hyper-reactive malarious splenomegaly (HMS). Malaria parasite rates were comparable, and geometric mean titres of IgG malaria antibody were the same, in both groups, indicating comparable exposure to malaria. A higher mean total IgM was observed in the high spleen (HS) rate group (6.07 g/litre, compared with 4.62 g/litre), a higher proportion was seropositive for IgM antibody to Plasmodium falciparum (63% compared with 54%), and HMS was found rather more frequently (4.7% compared with 2.6%). In both groups total IgM concentrations increased significantly with rising parity, and the mean level of 5.27 g/litre in young nulliparous women from the HS group suggested that IgM levels in this group at least were elevated from childhood. In both groups a rise in total IgM was associated with higher P. falciparum IgM geometric mean titres of antibody activity, a fall in parasite rates (HS group: 30% to 15%, P = 0.02; LS group: 24% to 0%, P = 0.034), and higher spleen rates (HS group: 38% to 65%, P = 0.001; LS group: 20% to 67%, P = 0.00012). It is concluded that the difference in spleen rates between the 2 groups was the result of differing degrees of acquired immunity to malaria, probably due to genetic differences in immune responses.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Papua New Guinea Institute of Medical Research, Madang.
authors.forename: B J
authors.initials: BJ
authors.lastname: Brabin
authors.forename: L
authors.initials: L
authors.lastname: Brabin
authors.forename: G
authors.initials: G
authors.lastname: Crane
authors.forename: K P
authors.initials: KP
authors.lastname: Forsyth
authors.forename: M P
authors.initials: MP
authors.lastname: Alpers
authors.forename: H J
authors.initials: HJ
authors.lastname: van der Kaay
mesh_terms: D000328:Adult; D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000096:biosynthesis*; D008288:Malaria / Q000150:complications / Q000276:immunology*; D010219:Papua New Guinea; D010298:Parity; D010963:Plasmodium falciparum / Q000276:immunology*; D013154:Spleen / Q000473:pathology; D013163:Splenomegaly / Q000150:complications / Q000276:immunology*
chemical_list: D000913:Antibodies, Protozoan; D007074:Immunoglobulin G; D007075:Immunoglobulin M