Induced sputum cellularity. Reference values and distribution in normal volunteers

Area of Science:

• Pulmonary Medicine
• Respiratory Cell Biology
• Clinical Immunology

Background:

• Sputum induction is a noninvasive method for assessing airway inflammation.
• Defining reference values for induced sputum cell counts in healthy populations is crucial for accurate diagnosis.
• Previous studies lacked comprehensive data on cell distribution in healthy subjects.

Purpose of the Study:

• To establish reference values for induced sputum cell counts in a healthy, non-hyperresponsive, non-smoking population.
• To characterize the distribution of various cell types in induced sputum from healthy volunteers.
• To provide a baseline for comparing sputum cell profiles in patients with airway inflammatory diseases.

Main Methods:

• Recruitment of 114 healthy, nonatopic, nonsmoking volunteers without airway hyperreactivity.
• Sputum induction procedure to obtain airway samples.
• Differential cell count analysis of induced sputum samples.

Main Results:

• Ninety-six (84%) subjects provided adequate sputum samples for analysis.
• Induced sputum primarily consisted of macrophages (69.2% ± 13%) and neutrophils (27.3% ± 13%).
• Eosinophils (0.6% ± 0.8%), lymphocytes (1.0% ± 1.2%), and epithelial cells (1.5% ± 1.8%) were found in low proportions.
• Macrophages and neutrophils exhibited normal distribution patterns, unlike other cell types.

Conclusions:

• Established reference ranges for induced sputum cell differential counts in healthy adults.
• These findings provide essential normative data for diagnosing and monitoring airway inflammation.
• The data facilitate the comparison of sputum cell profiles between healthy individuals and those with respiratory conditions.