DIFFERENTIAL CYTOLOGY OF BRONCHOALVEOLAR LAVAGE FLUID IN NORMAL-CHILDREN

Bronchoalveolar lavage (BAL) is increasingly used in the assessment of pulmonary diseases in children. However, reference values for cellula r and noncellular constituents of BAL fluid in children are lacking. W e have studied the differential cytology of BAL fluid in 48 children a ged 3-16 years (mean age+/-SD 7.9+/-3.5 yrs) undergoing elective surge ry for nonpulmonary illnesses. A flexible bronchoscope (Pentax 3.5 or 4.9 mm) was wedged in the middle lobe or one of its segments. BAL was performed with 3x1 ml.kg(-1) body weight of normal saline warmed to bo dy temperature. The first sample was studied separately; subsequent sa mples were pooled for analysis. The mean recovery was 58+/-15%. Signif icantly more granulocytes and less lymphocytes were found in the first , as compared to the pooled, sample. Total cell counts were highly var iable and ranged from 0.5-57.1 x 10(4).ml(-1). Macrophages were the pr edominant cell type, with a mean percentage of 81.2+/-12.7% The relati ve proportion of lymphocytes was higher than that reported in most stu dies of adult volunteers (16.1+/-2.4%). No age dependency was observed for either cell type. The mean percentage of granulocytes was 2.5+/-3 .3%. Absolute granulocyte counts were significantly higher in children under 8 yrs of age. This study provides the first reference data on B AL differential cytology in children without pulmonary disease and wil l be the basis for future investigations of BAL in paediatric lung dis eases.