RESUMO
120 patients with Giardia lamblia infection diagnosed by biliary drainage or jejunal mucosa smear are studied. 80 patients showed frequent reinfections by the parasites (recurrent giardiasis). A study is made of T and B lymphoid populations in peripheral blood, which were reduced in all patients with giardiasis in relation with the control group (p less than 0.01). Changes were more pronounced in relapsing than in non-relapsing patients. Retarded in vivo hypersensitivity tests with memory and recognizing antigens did not show significant differences between the experimental and control group. Serum levels of IgG, IgM, and IgA differed (p less than 0.01) between patients and controls at the expense of an IgA increase and IgG and IgM decrease, although these variations were not significant between relapsing and non-relapsing patients. It is concluded that the immunity status of the host is of interest in the clinical picture of patients with giardiasis and therefore must be a factor to be considered in the study of Giardia lamblia infected patients.