Life History, Immune Function, and Intestinal Helminths: Trade-Offs Among Immunoglobulin E, C-Reactive Protein, and Growth in an Amazonian Population

Objectives. Infection with helminths is associated with shifts in host immunity, including increased production of immunoglobulin E (IgE) and reduced inflammation. Given limited energy budgets, these shifts may involve changes in energy allocation toward competing demands. Here we test for potential trade-offs between growth, IgE, and the inflammatory marker C-reactive protein (CRP). Methods. Dried blood spots and anthropometrics were collected from 162 Shuar forager-horticulturalists from a village in southeastern Ecuador. Enzyme-linked immunosorbent assays (ELISAs) were used to measure IgE and CRP. Relationships among IgE, CRP, and anthropometrics were examined in three groups: children aged 2-7 years (n = 63), children aged 8-15 (n = 61), and adults over age 18 (n = 37). Results. Geometric mean IgE was 1,196 IU ml(-1) while geometric mean CRP was 1.33 mg l(-1). In children, IgE and CRP were negatively correlated (r = -0.21, P = 0.02, df = 122). Controlling for fat stores and age, IgE was associated with lower stature in children (t = -2.04, P = 0.04, df = 109), and adults (t = -3.29, P < 0.01, df = 33). In children there was a significant interaction between age and CRP, such that in younger children CRP was associated with shorter stature, but in older children was associated with greater stature (t = 2.15, P = 0.04, df = 109). Conclusions. These results suggest that infection with helminths may have hidden costs associated with immunological changes, and that these costs may ultimately affect growth and other life history parameters. Am. J. Hum. Biol. 22:836-848, 2010. (C) 2010 Wiley-Liss, Inc.