title: Lymphopenia and lymph node histology following repetitive extracorporeal irradiation of blood in normal and thymectomized calves.
abstract: Repetitive extracorporeal irradiation of the circulating blood (RECIB) in normal or thymectomized calves and RECIB plus Imuran were used for comparative studies on the depletion of blood and lymph node lymphocytes. Elimination of the easily mobilizable pool of lymphocytes was almost complete within approximately 6 days after commencing RECIB and was reflected by a reduction of approximately 50% in the numbers of paracortical lymphocytes. Blood lymphocyte counts were reduced to approximately 1/3 to 1/4 of the pre-irradiation values. Thymectomized calves had lower pre-irradiation blood lymphocyte counts than non-operated controls, however, the reduction in the number of blood lymphocytes was proportionally similar. Continuation of RECIB beyond one week did not result in a further depletion of blood lymphocytes. The lymphocyte counts in the follicular cortex and in the medulla of lymph nodes were not significantly changed by the various procedures. RECIB of 8-16 days duration did not alter the number of germinal centers in non-thymectomized calves, however, in thymectomized animals treated with Recib, the number of germinal centers was reduced.
mesh_terms: D000818:Animals; D001769:Blood / Q000528:radiation effects*; D002417:Cattle; D005260:Female; D007958:Leukocyte Count; D008198:Lymph Nodes / Q000473:pathology*; D008231:Lymphopenia / Q000209:etiology*; D008297:Male; D011833:Radiation Injuries, Experimental / Q000097:blood / Q000150:complications*; D013934:Thymectomy; D013997:Time Factors