Search tips
Search criteria 


Logo of thoraxThoraxVisit this articleSubmit a manuscriptReceive email alertsContact usBMJ
Thorax. 1992 January; 47(1): 25–29.
PMCID: PMC463545

Use of induced sputum cell counts to investigate airway inflammation in asthma.


BACKGROUND: Airway inflammation is considered to be important in asthma but is relatively inaccessible to study. Less invasive methods of obtaining sputum from patients unable to produce it spontaneously should provide a useful investigational tool in asthma. METHODS: A method to induce sputum with inhaled hypertonic saline was modified for use in 17 asthmatic patients and 17 normal subjects who could not produce sputum spontaneously. The success rate and safety of the method, the reproducibility of cell counts, and differences in cell counts between the asthmatic and normal groups were examined. Hypertonic saline solution 3-5% was inhaled for up to 30 minutes after inhalation of salbutamol. Subjects were asked to expectorate sputum every five minutes. The quality of the sample was scored on the volume of plugs and the extent of salivary contamination. Plugs from the lower respiratory tract were selected for a total cell count and for differential cell counts of eosinophils and metachromatic cells (mast cells and basophils) in direct smears. RESULTS: Adequate samples from the lower respiratory tract were obtained in 76% of first attempts. The mean fall in the forced expiratory volume in one second (FEV1) during inhalation of saline was 5.3% and the maximum fall 20%. Eosinophil and metachromatic cell counts were reproducible (reliability coefficient 0.8 and 0.7 respectively). When compared with sputum from normal subjects sputum from asthmatic patients contained a significantly higher proportion of eosinophils (mean 18.5% (SE 3.8%) v 1.9% (0.6%)) and metachromatic cells (0.50% (0.18%) v 0.039% (0.014%)). In the asthmatic group the differential eosinophil count correlated with the baseline FEV1. CONCLUSION: Induced sputum is capable of detecting differences in cell counts between normal and asthmatic subjects and merits further development as a potential means of assessing airway inflammation in asthma.

Full text

Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (876K), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References.

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Kirby JG, Hargreave FE, Gleich GJ, O'Byrne PM. Bronchoalveolar cell profiles of asthmatic and nonasthmatic subjects. Am Rev Respir Dis. 1987 Aug;136(2):379–383. [PubMed]
  • Wardlaw AJ, Dunnette S, Gleich GJ, Collins JV, Kay AB. Eosinophils and mast cells in bronchoalveolar lavage in subjects with mild asthma. Relationship to bronchial hyperreactivity. Am Rev Respir Dis. 1988 Jan;137(1):62–69. [PubMed]
  • Beasley R, Roche WR, Roberts JA, Holgate ST. Cellular events in the bronchi in mild asthma and after bronchial provocation. Am Rev Respir Dis. 1989 Mar;139(3):806–817. [PubMed]
  • Dark J, Corris PA. The current state of lung transplantation. Thorax. 1989 Sep;44(9):689–692. [PMC free article] [PubMed]
  • Leigh TR, Parsons P, Hume C, Husain OA, Gazzard B, Collins JV. Sputum induction for diagnosis of Pneumocystis carinii pneumonia. Lancet. 1989 Jul 22;2(8656):205–206. [PubMed]
  • Bigby TD, Margolskee D, Curtis JL, Michael PF, Sheppard D, Hadley WK, Hopewell PC. The usefulness of induced sputum in the diagnosis of Pneumocystis carinii pneumonia in patients with the acquired immunodeficiency syndrome. Am Rev Respir Dis. 1986 Apr;133(4):515–518. [PubMed]
  • Pitchenik AE, Ganjei P, Torres A, Evans DA, Rubin E, Baier H. Sputum examination for the diagnosis of Pneumocystis carinii pneumonia in the acquired immunodeficiency syndrome. Am Rev Respir Dis. 1986 Feb;133(2):226–229. [PubMed]
  • Crapo RO, Morris AH, Gardner RM. Reference spirometric values using techniques and equipment that meet ATS recommendations. Am Rev Respir Dis. 1981 Jun;123(6):659–664. [PubMed]
  • Hargreave FE, Dolovich J, Newhouse MT. The assessment and treatment of asthma: a conference report. J Allergy Clin Immunol. 1990 Jun;85(6):1098–1111. [PubMed]
  • Kramer MS, Feinstein AR. Clinical biostatistics. LIV. The biostatistics of concordance. Clin Pharmacol Ther. 1981 Jan;29(1):111–123. [PubMed]
  • Anderson SD, Schoeffel RE, Finney M. Evaluation of ultrasonically nebulised solutions for provocation testing in patients with asthma. Thorax. 1983 Apr;38(4):284–291. [PMC free article] [PubMed]
  • Boulet LP, Legris C, Thibault L, Turcotte H. Comparative bronchial responses to hyperosmolar saline and methacholine in asthma. Thorax. 1987 Dec;42(12):953–958. [PMC free article] [PubMed]
  • Araki H, Sly PD. Inhalation of hypertonic saline as a bronchial challenge in children with mild asthma and normal children. J Allergy Clin Immunol. 1989 Jul;84(1):99–107. [PubMed]
  • Godard P, Aubas P, Calvayrac P, Taib J, Michel FB. Endoscopie et lavage bronchiolo-alvéolaire chez l'asthmatique allergique. Nouv Presse Med. 1981 Oct 24;10(38):3141–3148. [PubMed]
  • Flint KC, Leung KB, Hudspith BN, Brostoff J, Pearce FL, Johnson NM. Bronchoalveolar mast cells in extrinsic asthma: a mechanism for the initiation of antigen specific bronchoconstriction. Br Med J (Clin Res Ed) 1985 Oct 5;291(6500):923–926. [PMC free article] [PubMed]
  • Wardlaw AJ, Cromwell O, Celestino D, Fitzharris P, Geddes DM, Collins JV, Kay AB. Morphological and secretory properties of bronchoalveolar lavage mast cells in respiratory diseases. Clin Allergy. 1986 Mar;16(2):163–173. [PubMed]
  • Kelly C, Ward C, Stenton CS, Bird G, Hendrick DJ, Walters EH. Number and activity of inflammatory cells in bronchoalveolar lavage fluid in asthma and their relation to airway responsiveness. Thorax. 1988 Sep;43(9):684–692. [PMC free article] [PubMed]
  • Lundgren R, Söderberg M, Hörstedt P, Stenling R. Morphological studies of bronchial mucosal biopsies from asthmatics before and after ten years of treatment with inhaled steroids. Eur Respir J. 1988 Dec;1(10):883–889. [PubMed]
  • CHODOSH S, ZACCHEO CW, SEGAL MS. The cytology and histochemistry of sputum cells. I. Preliminary differential counts in chronic bronchitis. Am Rev Respir Dis. 1962 May;85:635–648. [PubMed]

Articles from Thorax are provided here courtesy of BMJ Publishing Group