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Combined Immunodeficiency in an Appaloosa Foal

1984; SAGE Publishing; Volume: 21; Issue: 5 Linguagem: Inglês

10.1177/030098588402100522

1544-2217

L E Perryman, C. R. Boreson, M. W. Conaway, Ron Bartsch,

Mycobacterium research and diagnosis

Combined immunodeficiency of Arabian horses, first described in 1973. is a primary immune deficiency disorder characterized by lymphopenia, absence of identifiable B and T lymphocytes. increased susceptibility to infections, and death. generally before five months of The disorder is inherited as an autosomal recessive trait and occurs with sufficient frequency to require consideration of this disease in all Arabian foals showing signs of infection.'.. I' The establishment of a diagnosis of combined immunodeficiency requires that three criteria be fulfilled: lymphopenia (less than lOOO/pl), absence of immunoglobulin M in serum. and demonstration of hypoplasia of lymphoid tissues.3..'.X To date. reported cases have been limited to foals for which both the dam and sire were of part or pure Arabian breeding.'.x.'3 In June. 1983. a two-month-old Appaloosa filly in Arizona was examined because of respiratory distress. The foal was lethargic. febrile (40. I C). had bilateral nasal discharge, and lung sounds indicative of bronchopneumonia. Bacteriologic culture of the nasopharynx revealed E.vclicvYchiu coli. The foal was treated with various antibiotics. expectorants. anti-inflammatory agents. and humidified oxygen. Analysis of blood samples revealed undetectable quantities of immunoglobulin M and an immunoglobulin G concentration of 640 mg/dl. Leukogram data on three different days were 4.700 leukocytes with 940 lymphocytes/pl: 3.900 leukocytes with 234 lymphocytes/pl: and 6.100 leukocytes with 437 lymphocytes/pl. Following death of the foal at three months of age. examination of tissues revealed focal accumulations of neutrophils. macrophages, and necrotic cells within alveoli and bronchioles. The spleen was nearly devoid of lymphocytes. There was absence of lymphoid follicles. and the connective tissue stromal framework for lymphoid follicles was not identifiable (fig. I ) . Multiple sections of adipose tissue from the anterior mediastinum were examined and one contained focal accumulations of epithelial cells with Hassall's corpuscles and few lymphocytes (figs. 2. 3). Lymph nodes were deficient in lymphocytes and lacked both lymphoid follicles and corticomedullary differentiation. The absence of immunoglobulin M. profound lymphopenia. and hypoplastic changes of spleen. thymus. and lymph nodes in this Appaloosa foal were identical to the findings in Arabian foals with combined immunodeficiency. and differed substantially from the diagnostic criteria for agammaglobulinemia. selective immunoglobulin M deficiency. and failure of colostral immunoglobulin transfer.X Because the data were compatible with a diagnosis of combined immunodeficiency.