INTESTINAL IMMUNE CELLS IN STRONGYLOIDES-STERCORALIS INFECTION

Background-Strongyloides stercoralis can cause a wide spectrum of dise ase in man, ranging from a chronic asymptomatic infection to a hyperin fective, often fatal syndrome. In rodents, spontaneous expulsion of St rongyloides spp occurs after experimental infection. Mast cells, goble t cells, and eosinophils have been identified as possible effecters of this expulsion. Aims-To investigate intestinal histopathology and muc osal immunity in immunocompetent patients with chronic S stercoralis i nfection. Methods-Jejunal biopsies were performed in 19 immunocompeten t patients with a positive stool examination for S stercoralis and few or no symptoms, and in seven healthy controls. Specimens were process ed for histopathological analysis and stained by the immunoperoxidase technique, using the following monoclonal antibodies: CD2, CD3, CD4, C D8, anti-T cell receptor (TcR) gamma/delta, RFD1 and RFD7 (two differe nt macrophage markers), Ki67+ (proliferating) cells, antihuman leucocy te antigen (HLA)-DR, and anticollagen IV. In addition, CD25+ cells, ma st cells, IgE expressing cells, calprotectin containing cells, and neu trophil elastase positive cells were stained by the alkaline phosphata se method. Results-Jejunal morphology and the numbers of different T c ell subsets, mast cells, IgE expressing cells, eosinophils, and goblet cells were unaffected by S stercoralis infection. Conversely, the num bers of mature macrophages and dividing enterocytes in the crypts were reduced significantly. Crypt enterocytes did not express HLA-DR in bo th groups. The expression of HLA-DR by villus enterocytes was also com parable in patients and controls. There were no activated (Cd25+) cell s in the mucosa of either patients or controls. Conclusions-Compared w ith seven healthy uninfected volunteers, a group of 19 Brazilians with clinically mild strongyloides infection showed no abnormality of muco sal structure and no increase in nonspecific inflammatory cells. Likew ise, there was no increase in mucosal T cells or macrophages.