Previous Article | Next Article ![]()
Infection and Immunity, January 2001, p. 123-128, Vol. 69, No. 1
U.S. Army Medical Research Unit-Kenya and
Kenya Medical Research Institute, Kisumu, Kenya
Received 7 June 2000/Returned for modification 4 August
2000/Accepted 6 October 2000
Immunity to Plasmodium falciparum develops slowly in
areas of endemicity, and this is often ascribed to poorly immunogenic or highly variant parasite antigens. However, among populations newly
exposed to malaria, adults acquire immunity more rapidly than children.
We examined the relationship between pubertal development and
resistance to P. falciparum. During two transmission
seasons in western Kenya, we treated the same cohort of young males to eradicate P. falciparum and then obtained blood smears each
week for 4 months. We determined pubertal development by Tanner staging and by levels of dehydroepiandrosterone sulfate (DHEAS) and
testosterone in plasma. In multivariate and age-stratified analyses, we
examined the effect of pubertal development on resistance to malaria.
In both seasons (n = 248 and 144 volunteers,
respectively), older males were less susceptible than younger males.
Age-related decreases in the frequency and density of parasitemia were
greatest during puberty (15- to 20-year-olds). DHEAS and testosterone
were significant independent predictors of resistance to P. falciparum parasitemia, even after accounting for the effect of
age. Fifteen- to 20-year-old males with high DHEAS levels had a 72%
lower mean parasite density (P < 0.01) than
individuals with low DHEAS levels. Similarly, 21- to 35-year-old males
with high DHEAS levels had a 92% lower mean parasite density
(P < 0.001) and 48% lower frequency of parasitemia (P < 0.05) than individuals with low DHEAS levels.
These data suggest that the long period needed to attain full immunity
could be explained as a consequence of host development rather than as
the requirement to recognize variant or poorly immunogenic parasite antigens.
0019-9567/01/$04.00+0 DOI: 10.1128/IAI.69.1.123-128.2001
Human Resistance to Plasmodium falciparum Increases
during Puberty and Is Predicted by Dehydroepiandrosterone Sulfate
Levels

*
Corresponding author. Present address: Walter Reed Army
Institute of Research, Department of Immunology, Bldg. 503, Rm. 3W53, 503 Robert Grant Ave., Silver Spring, MD 20910. Phone: (301) 319-9551. Fax: (301) 319-7358. E-mail:
patrick.duffy{at}na.amedd.army.mil.
Present address: International Health Institute and Department of
Pathology & Laboratory Medicine, Brown University School of Medicine,
Providence, RI 02912.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»