Elevated anti-malarial IgE in asymptomatic individuals is associated with reduced risk for subsequent clinical malaria

Int J Parasitol. 2004 Jul;34(8):935-42. doi: 10.1016/j.ijpara.2004.04.007.

Abstract

Immunological characteristics were assessed for prospective risk of clinical malaria in a longitudinally followed population in a holoendemic area of Tanzania. Baseline characteristics including crude Plasmodium falciparum extract-specific IgE and IgG; total IgE; and parasitological indices, e.g. number of P. falciparum clones, were investigated among 700 asymptomatic individuals. Cox regression analysis estimated the risk of succumbing to a new clinical episode during a 40 weeks follow up. High anti-P. falciparum IgE levels were associated with reduced risk of acute malaria in all age groups independently of total IgE levels. Statistically significant reduced odds ratio of 0.26 (95% CI, 0.09-0.72, P=0.010) and 0.44 (95% CI, 0.19-0.99, P=0.047) for the two highest fifths, respectively was observed after adjustment for age, sex, total IgE, numbers of parasite clones per infection and HIV-1 seropositivity. In contrast, high levels of malaria specific IgG or total IgE were not associated with reduced risk to succumb to a new clinical episode. A protective effect of asymptomatic multiclonal P. falciparum infections was also confirmed. For the first time, anti-malarial IgE levels in asymptomatic individuals in endemic area are found to be associated with reduced risk for subsequent malaria disease. Specific IgE antibodies may play role in maintaining anti-malarial immunity, or indicate other aspects of immune function relevant for protection against malaria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Disease
  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Animals
  • Antibodies, Protozoan / blood
  • Antibodies, Protozoan / immunology
  • Child
  • Child, Preschool
  • Endemic Diseases*
  • Female
  • Humans
  • Immunoglobulin E / immunology*
  • Immunoglobulin G / immunology
  • Infant
  • Longitudinal Studies
  • Malaria, Falciparum / epidemiology
  • Malaria, Falciparum / immunology*
  • Male
  • Middle Aged
  • Plasmodium falciparum / immunology
  • Prevalence
  • Prognosis
  • Recurrence
  • Risk Factors
  • Tanzania / epidemiology

Substances

  • Antibodies, Protozoan
  • Immunoglobulin G
  • Immunoglobulin E