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Updated: Aug 12, 2026
Bronchoalveolar Lavage (BAL) for Research; Obtaining Adequate Sample Yield
Published on: March 25, 2014
Lymphocyte subsets in bronchoalveolar lavage fluid of children without bronchopulmonary disease
F Ratjen1, M Bredendiek, L Zheng
1Department of Pediatrics, University of Essen, Ruhrlandklinik, Germany.
Insights
Normal bronchoalveolar lavage fluid (BALF) values for lymphocyte surface markers are crucial for pediatric lung disease diagnosis. This study found lower CD4/CD8 ratios in children
Area of Science:
- Pediatric Pulmonology
- Immunology
- Clinical Chemistry
Background:
- Bronchoalveolar lavage (BAL) is a valuable diagnostic tool in pediatric pulmonology.
- Establishing normal reference values for BAL fluid (BALF) constituents in children is essential for accurate interpretation.
- Limited data exists on lymphocyte surface marker distributions in pediatric BALF.
Purpose of the Study:
- To define normal reference values for lymphocyte surface markers in pediatric BALF.
- To investigate the CD4/CD8 ratio in healthy children's BALF.
- To compare BALF and blood lymphocyte profiles in children.
Main Methods:
- BAL was performed on 28 children (3-16 years) undergoing elective surgery for non-pulmonary conditions.
- Lymphocyte surface markers (B-cells, pan T-cells, CD57, CD4, CD8) were analyzed in pooled BALF samples.
- Comparative analysis of BALF and peripheral blood lymphocyte subsets was conducted in a subgroup.
Main Results:
- The distribution of B-cells, pan T-cells, and CD57+ cells in pediatric BALF was similar to adult ranges.
- Pediatric BALF exhibited significantly lower CD4/CD8 ratios (0.7 ± 0.4) compared to adults, primarily due to increased CD8+ T-cells.
- CD4/CD8 ratios in children's blood were within normal ranges and significantly higher than in their BALF.
Conclusions:
- The normal CD4/CD8 ratio in pediatric BALF is lower than in adults.
- Increased CD8+ T-cells contribute to the lower CD4/CD8 ratio in healthy children's BALF.
- These findings necessitate consideration of age-specific reference ranges when interpreting pediatric BALF lymphocyte profiles in disease states.
Abstract:
Bronchoalveolar lavage (BAL) is increasingly used in the pediatric age group. However, normal values for BAL fluid (BALF) constituents are lacking. As part of an investigation to define reference values in children, we studied lymphocyte surface markers of BALF in 28 children 3 to 16 yr of age without bronchopulmonary disease. All of them were undergoing elective surgery for nonpulmonary illnesses. BAL was performed under general anaesthesia with tracheal intubation. A flexible bronchoscope (Pentax 3.5 or 4.9 mm) was wedged into the middle lobe or into one of its segments, and 3 x 1 ml/kg body weight normal saline warmed to body temperature were instilled and immediately withdrawn. The first sample was studied separately; subsequent samples were pooled for analysis. Studies on lymphocyte surface markers were performed on the pooled sample only. The distribution of B-cells, pan T-cells, and CD57 positive cells was within the range reported for adult subjects. However, CD4/CD8 ratios were lower than in adults (0.7 +/- 0.4, mean +/- SD). This decrease in the CD4/CD8 ratio was caused by an increase in CD8 cells. Comparative analysis of blood and BALF lymphocytes in a subgroup of children showed that CD4/CD8 ratios in blood were within the normal range reported for this age group and significantly higher when compared with BALF. The lower CD4/CD8 ratios in normal children have to be considered in the interpretation of BALF in children with pulmonary diseases.
