Alterations in peripheral blood leukocytes functions during enzootic bronchopneumonia of calves. Effect of treatment with antibiotics and immunomodulators.

Twelve calves from over veal calf farm were divided into two groups: group I-6 calves which developed typical signs of enzootic bronchopneumonia and group II-6 calves with no symptoms of the disease. Both groups of calves were compared with respect to changes in several hematological parameters. Some functions of peripheral blood leukocytes as random migration, phagocytic index, percent of phagocytic cells and percent of NBT positive cells were also scored. In addition, changes in serum levels of interferon (IFN) and tumor necrosis factor (TNF) and the ability of peripheral blood leukocytes (PBL) to produce IFN and TNF were quantitated by biological methods. On the day of diagnosis, in group I of calves a significant increase in the total serum protein concentration, hemoglobin content, red and white blood cells counts in comparison to control calves (group II) was observed. The increased number of NBT positive neutrophils and moderate levels of serum IFN and TNF correlated with elevated body temperature, breathing and heart rates. Calves with bronchopneumonia (group I) after diagnosis of the disease were treated with Tylbian (tylosine derivative), Flumetazon (glucocorticoid), Emulselvet (immunomodulator), bromhexinum and sulphonamides. Seven days after the beginning of treatment with medicaments a significant improvement in clinical symptoms was observed, however, the ability of PBL to cytokine production increased significantly 2 weeks after beginning of treatment and correlated with significant increase in random migration of neutrophils and their phagocytic activity, measured by the percent of phagocytic cells. Unexpectedly, in control calves (group II), not exhibiting any symptoms of bronchopneumonia at the beginning of experiment, high serum IFN titers were detected which decreased significantly during the first week of observation. In contrast to that the ability of PBL of control calves to produce IFN increased significantly within 3 weeks of observation. The correlations between the ability of PBL to produce cytokine and the development of clinical symptoms of bronchopneumonia are discussed.