Cyclic neutropenia in a basset hound

Abstract

A 6 month old, male basset hound was referred for intermittent malaise, and pyrexia that repeated every 10-11 days. Sequential blood counts and bone marrow aspirates demonstrated severe neutropaenia and increased myeloid precursor cells in the bone marrow from day two of each cycle. By day five the bone marrow had predominantly mature neutrophils and band cells, and by day 10 the myeloid precursors had decreased with a myeloid:erythroid of 0.4:1. During the same period the blood neutrophils had rebounded to normal counts by day five, and were declining by day 9 and 10. The monocytes and platelets were oscillating in an opposite phase to the neutrophils. The age of onset, regular cycle length, oscillation of neutrophil, platelet and monocyte counts and characteristic bone marrow cytology were diagnostic for cyclic neutropaenia. This syndrome has never before been described in any breed other than the grey collie. The grey collie gene mutation was not found in this dog. However, based on the clinical signs, and haematological and bone marrow results, it can be deduced that cyclic neutropaenia may develop as a result of other mutations in neutrophil elastase expression.