Increased numbers of peripheral blood CD34+ cells in dogs with canine atopic dermatitis.

Abstract

The bone marrow may be involved in human atopic diseases, as shown by the release of CD34+ cells into the peripheral blood. The aim was to determine the numbers of CD34+ cells in atopic dogs. The following three groups of dogs were studied: 27 dogs with nonfood-induced atopic dermatitis (NFICAD); 16 dogs with nonallergic inflammatory diseases; and 13 healthy control dogs. Dogs with NFICAD were selected after fulfilment of Favrot's criteria and exclusion of other pruritic dermatoses, including flea infestation and adverse reaction to foods. The Canine Atopic Dermatitis Extent and Severity Index (CADESI)-03 and a Visual Analog Scale (VAS) score for pruritus were used to quantify clinical signs. A phycoerythrin-conjugated anticanine CD34 antibody was used to stain peripheral blood CD34+ cells, and these were enumerated using a flow cytometer. The CD34+ cell counts were compared between groups and tested (in the NFICAD group) for correlation with the severity of clinical signs. The numbers of peripheral CD34+ cells in dogs with NFICAD (median 1.7) were statistically higher than in dogs with other nonallergic inflammatory diseases (median 1.0; P=0.01) and healthy control dogs (median 0.9; P=0.009). In dogs with NFICAD, there was no correlation between CD34+ cell numbers and CADESI-03 scores or owner-assessed pruritus (VAS score). The results of this study suggest the possible involvement of CD34+ cells in dogs with NFICAD. The role of CD34+ cells in the aetiopathogenesis of canine atopic dermatitis remains to be determined.