White Blood Cells

Leukocyte Differential

•Done by evaluation of blood film or smear •In most cases, count 100 cells •Reported as a percentage of Total WBCs •What % of Total WBC are each type of WBC

Monocytes

•Primary Function: Migrate to tissues and to act as a macrophage •Phagocyte •Large cell with discrete vacuoles •Involved in tissue repair, immune response, RBC turnover, among other things •Basically clean up debris, foreign substances •Circulate in low numbers •Increase in chronic inflammatory disease, also stress in dogs •Can look like an immature Neutrophil (Band) •Nucleus of Monocyte more pleomorphic

Eosinophils

•Primary Function: Not clearly understood •Red cytoplasmic granules •Very few found in peripheral blood •Most commonly seen in response to: •Allergies •Parasites

Bosophils

•Primary Function: Not really known •Deep purple granules, lighter in cats •Rare in peripheral circulation •Involved in inflammatory and allergic responses •Granules contain histamine and heparin

Neutrophils = PMN Polymorphonuclear

•Primary Function: defense against bacteria, viruses •Phagocytize Most abundant WBC in dogs and cats Changes in indicate: infection, inflammation and stress Granules in cytoplasm don't stain red or blue (neutral)!

Lymphocytes

•Primary Function: participate in acquired immunity; •Circulate throughout body looking for trouble makers (antigens) •Second most common WBC in dog, cat and horse •Most common in ruminants •Produced in bone marrow, but migrate to other tissues •Spleen, lymph nodes, thymus, lungs, intestine, etc. •Lymphatic system: travel in ducts to go from tissues back into circulation •Two types •B-cell: produce antibodies •T-cell: regulates immune response, cell-mediated immunity