The Incidence of Thymic B Lymphoid Follicles in Healthy Beagle Dogs
2003; SAGE Publishing; Volume: 31; Issue: 2 Linguagem: Inglês
10.1080/01926230390183706
ISSN1533-1601
AutoresJan-Peter H. T. M. Ploemen, Wilma T.M. Ravesloot, Eric van Esch,
Tópico(s)Diabetes and associated disorders
ResumoThe incidence of thymic B cell lymphoid follicles was retrospectively studied in 62 male and 58 female healthy control beagle dogs (age 11.3 +/- 4.8, range 6 to 23 months). The animals were selected from toxicological studies performed in the period 1990-2001 at the Organon labs. The animals had received vehicle treatment. Thorough microscopic examination of the thymus in hematoxylin & eosin (H&E)-stained sections resulted in an unexpectedly high overall incidence of 70% of medullary lymphoid follicles. Occasionally, these lymphoid follicles contained germinal centers. With the use of a T- and B cell marker (respectively CD3 and CD79alpha) we confirmed that the lymphoid follicles exclusively contained large numbers of B lymphocytes. Moreover, with the use of the B cell marker, almost all animals (97%) prove to have B cell rich medullary areas. The study also confirmed that the dog thymus underwent progressive involution during the period from 6 to 23 months of age. As a consequence of the involution, B cell areas and lymphoid follicles may be obscured in some H&E sections. Results of this study indicated that dense B lymphocyte aggregates and/or B lymphoid follicles are a normal constituent of the canine thymus.
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