title: Acquired immunodeficiency in a seven-year-old horse.
abstract: A 7-year-old horse with no previous history of illness was determined to have a systemic infection of Rhodococcus equi. Rhodococcus equi was isolated from blood, tracheal fluid, and feces. Lymphopenia, failure to respond to concanavalin A and phytohemagglutinin lymphocyte stimulation testing, decreased concentrations of immunoglobulin (Ig)M, IgA, and IgG, low R equi antibody titer, histologic depletion of lymphoid tissue, and a failure to respond to antigenic stimulation led to the conclusion that both humoral and cell-mediated immunity were compromised. No cause for the acquired immunodeficiency could be determined.
mesh_terms: D000193:Actinomycetales Infections / Q000150:complications / Q000662:veterinary; D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D004406:Dysgammaglobulinemia / Q000662:veterinary; D006734:Horse Diseases; D006736:Horses; D017098:IgA Deficiency; D017099:IgG Deficiency; D007108:Immune Tolerance; D007075:Immunoglobulin M / Q000172:deficiency; D007153:Immunologic Deficiency Syndromes / Q000150:complications / Q000662:veterinary*; D008213:Lymphocyte Activation; D008231:Lymphopenia / Q000662:veterinary; D008297:Male; D012240:Rhodococcus / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D007075:Immunoglobulin M