The use of induced sputum in the assessment of pulmonary involvement in Crohn's disease

Am J Gastroenterol. 2000 Mar;95(3):730-4. doi: 10.1111/j.1572-0241.2000.01843.x.


Objective: Our aim was to evaluate lung involvement in Crohn's disease (CRD) patients by induced sputum (IS). Extraintestinal manifestations are frequent in CRD, but lung involvement is rare. Induced sputum is a reliable noninvasive method of investigating the pathogenesis, pathophysiology, and treatment of lung disease.

Methods: Twenty-four CRD patients and nine control subjects (all nonsmokers) without respiratory symptoms were tested. Sputum was induced by 20' inhalation of 3.5% saline using ultrasonic nebulizer. Samples were studied by differential counts of 200 cells on cytopreps stained by Giemsa. T-lymphocyte subset analyses were done by FACS using three monoclonal antibodies: CD3 = total T cells, CD4 = T helper cells, and CD8 = T suppressor-cytotoxic cells. CD4/CD8 >2.5 was considered abnormal.

Results: Four patients did not produce sputum. Of the remaining 20 patients, seven had active CRD and 13 were in remission. They were divided into two groups: Group A patients had abnormal CD4/CD8 ratio of 6.7 +/- 2.5; Group B (seven patients) had normal CD4/CD8 ratio of 1.7 +/- 0.52 (p = 0.0001). The differential counts of IS samples were similar in both groups, but lymphocyte count was significantly higher in CRD patients than in the control group (13.2 +/- 11.2 vs 4.8 +/- 3.6, p = 0.036). There were no differences in spirometry, treatment, extent, or activity of CRD.

Conclusion: Using a simple noninvasive method, we found that among CRD patients without respiratory symptoms there was a high (65%) incidence of lung involvement.

MeSH terms

  • Adolescent
  • Adult
  • CD4-CD8 Ratio
  • Crohn Disease / diagnosis*
  • Crohn Disease / immunology
  • Female
  • Humans
  • Immunophenotyping
  • Lung / immunology
  • Lung Diseases / diagnosis*
  • Lung Diseases / immunology
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Sputum / immunology*
  • T-Lymphocyte Subsets / immunology*