The paucity of specific feline antibodies for flow cytometry (FC) is an ongoing challenge. Flow cytometrists must extrapolate information from relatively few markers. We evaluated the expression pattern of the panleukocyte markers CD18 and CD44 on leukocyte (white blood cell, WBC) subclasses in the peripheral blood (PB) of 14 healthy cats. The degree of expression of CD18 and CD44 was calculated as the ratio between the median fluorescence intensity (MFI) value of antibody-stained cells and autofluorescence. All samples were acquired with the same cytometer with constant photomultiplier setting and compensation matrices. Both molecules were expressed at higher levels on monocytes, intermediate levels on polymorphonuclear cells (PMNs), and lower levels on lymphocytes. CD18-MFI discriminated well among the 3 populations, whereas CD44-MFI mostly overlapped between monocytes and PMNs. However, CD44-MFI had a lower intra-population variability. Evaluation of CD18 and CD44, together with morphologic parameters, was useful for discriminating among WBC subclasses in healthy cats. This information may be helpful for future studies given that an increase in CD18-MFI may indicate reactive changes, whereas fluctuations in CD44-MFI may suggest neoplasia.

缺乏用于流式细胞术（FC）的特异性猫抗体是一项持续的挑战。流式细胞仪必须从相对较少的标记中推断信息。我们评估了14只健康猫的外周血（PB）中白细胞（白细胞，WBC）亚类上的全白细胞标记CD18和CD44的表达模式。CD18和CD44的表达程度计算为抗体染色细胞的中值荧光强度（MFI）值与自体荧光之间的比率。所有样品均使用具有恒定光电倍增器设置和补偿矩阵的相同细胞仪采集。两种分子在单核细胞上均以较高水平表达，在多形核细胞（PMN）上以中等水平表达，在淋巴细胞上以较低水平表达。CD18-MFI在3个人群中有很好的区别，而CD44-MFI主要在单核细胞和PMN之间重叠。但是，CD44-MFI的种群内变异性较低。CD18和CD44以及形态参数的评估对于区分健康猫的WBC亚类非常有用。鉴于CD18-MFI的增加可能表明反应性改变，而CD44-MFI的波动可能提示肿瘤，该信息可能对将来的研究有所帮助。