Investigation of the cell mediated immune deficiency in rats with protein energy malnutrition

Previous studies indicated that lymphoid tissues, especially the thymus, be came atrophied and the proportion of sheep-erythrocyte-rosette-forming cell s declined in individuals with protein energy malnutrition (PEM). Neverthel ess, the mechanism of immune deficiency in malnutrition remains unclear. We hypothesized that the low proportion of rosette forming cells and dysfunct ion of lymphocytes may be caused by CD2 receptors that work improperly. 20 Wistar-albino rats received a diet containing 5.5% protein for 3 weeks. A c ontrol group was fed a normal diet containing 24% protein. By the end of 3 weeks there was a 18% weight loss, and serum total protein had decreased si gnificantly, in the protein deficient group. Lymphocyte sub-populations inc luding CD3+, CD19+, CD4+, CD8+ and CD2+ cells were investigated by immunofl uorescence. Immunoglobulin G (IgG), IgM and IgA levels were measured by rad ial-immunodiffusion plaques. The proportion of CD3+ cells did not change wh ile those of CD19+ and CD8+ cells increased significantly, with significant declines in CD4+ and CD2+, in peripheral blood. There was a moderate corre lation (r = 0.52) between the declines in IgG and IgM levels, and that in t he CD4+ cell proportion as well as the CD4/CD8 proportions. We believe that PEM causes a decrease in the number and/or function of lymphocyte subpopul ations. As a result cell activation and antibody production are impaired. M ed Sci Res 26:763-766 (C) 1998 Lippincott Williams & Wilkins.