The effects of ageing on the immune response to Schistosoma haematobium and hookworm by measuring circulating immune complexes, C3, IgG, IgA and IgM levels in residents of Omi dam area of Kogi State, Nigeria.

In this study, the effects of infestation (with Schistosoma haematobium or hookworm) during host ageing on the serum levels of circulating immune complexes (CIC), C3, IgG, IgA and IgM were examined in residents of Omi dam area of Kogi state, Nigeria. S. haematobium-infested and hookworm-infested individuals showed no significant alteration in the levels of CIC, C3, IgG, IgA and IgM in comparison with controls. These levels were the same in infested subjects and controls even when the patients were pooled. Infested old people had the same concentrations of serum CIC, C3 IgG and IgM in comparison with infested young people but IgA levels were higher in the aged group (t=2.100; P<0.05); and were significantly correlated with age (r=0.301; P<0.05). No significant increase in CIC levels with rising age (r=0.123; P>0.20) was observed in the overall population of infested subjects; and infestation in old age did not alter CIC, C3, IgG, IgA and IgM levels in comparison with uninfested young people. For the uninfested, IgG, IgA and IgM values were similar in the aged and the young but the levels of CIC were higher (t=2.156; P<0.05; r=0.280; P<0.05) and C3 lower (t=3.313; P<0.01; r=-0.236; P>0.10) in the aged. The results of this study suggest that the elevated CIC levels found in old people is age-related; and that the contribution of parasitic infestation to these raised levels is uncertain.