Retrospective analysis of globule leukocytes in parasite-free rumens of cattle: a histopathological research with literature review

Having previously been described by several researchers, an association of globule leukocytes with helminth infestation involving the gastrointestinal tracts has been well acknowledged in humans and animals; however, the appearance of globule leukocytes is less common in those disorders which are not associated with parasitism. It has been suggested that the appearance of globule leukocytes, which are probably derived from mast cells, may indicate a significant role in immune response. The present retrospective study of archived bovine cases with postmortem diagnosis of rumen disorder that was not associated with parasitism provides a histopathological description of the appearance of globule leukocytes, in connection with a review of relevant literature. Archival histopathological analysis of 20 adult Holstein-Friesian dairy cows (5–8 years of age) revealed six cows that showed eosinophilic inflammatory changes in the lamina propria and submucosa of the rumens. In addition to eosinophils, the rumens exhibited lesser numbers of 2 cell types: the mucosal epithelium was infiltrated by globule leukocytes; the underlying lamina propria and submucosa, by mast cells admixed with eosinophils. Less frequently, there were granular cells that probably exhibited intermediate cells between mast cells and globule leukocytes. Histochemical stains failed to reveal bacteria, parasites, protozoa, or fungi. It is likely that there was a close relationship between a triad of eosinophils, mast cells, and globule leukocytes in the lesional rumens. In the present six cattle, although they appeared at glance to be asymptomatic, histopathological features were suggestive of an immune reaction involving the rumens.