Stem cell factor and its soluble receptor (c-kit) in serum of asthmatic patients- correlation with disease severity

Abstract

Background: SCF (stem cell factor) is a pleiotropic cytokine exerting its role at different stages of bone marrow development and affecting eosinophil activation, mast cells and basophil chemotaxis and survival. The aim of the study was to assess concentration of SCF and its soluble receptor c-kit (sc-kit) in peripheral blood of patients with asthma referring it to asthma severity and phenotype.

Methods: The study involved 107 patients with bronchial asthma, well characterized with respect to severity and 21 healthy controls. Concentration of SCF and sc-kit in the patients serum were measured by ELISA method.

Results: Mean serum SCF level in the group of asthmatics (n = 88) was significantly higher as compared to healthy controls (1010 pg/ml +/- 37 vs 799 +/- 33; p < 0,001). The level of SCF was higher in patients with severe asthma as compared to patients with non-severe asthma (1054 +/- 41 pg/ml vs 819 +/- 50; p < 0,01) and correlated with dose of inhaled glucocorticosteroids taken by the patients to achieve asthma control (R = 0,28; p < 0,01). The mean sc-kit serum level did not differ between asthmatic patients and healthy controls, however the level of sc-kit in non-severe asthmatics was significantly higher as compared to patients with severe asthma and healthy controls. In asthmatic patients (n = 63) the level of sc-kit correlated positively with FEV1% predicted value (R = 0,45; p < 0,001) and MEF25% predicted value (R = 0,33; p < 0,01). The level of sc-kit inversely correlated with the dose of inhaled glucocorticosteroids taken by the patients (R = -0,26; p < 0,01).

Conclusion: Serum levels of SCF and its soluble receptor c-kit seem to be reflect asthma severity suggesting a role for these molecules in asthmatic inflammation.

Figure 1

Serum SCF concentrations in patients with severe asthma (SA, n = 56) (* p < 0,001) and non-severe asthmatics (NSA, n = 32) (& p < 0,01) as compared to healthy controls (HC, n = 21).

Figure 2

Serum SCF level in patients with severe asthma treated (SA GCS+) and not treated (SA GSC-) with oral glucocorticosteroids as compared to mild asthmatics (MA) (* p < 0,01) and nonatopic healthy controls (HC) (& p < 0,01).

Figure 3

Correlation between SCF serum concentrations and dose of inhaled steroids taken by the patients (n = 88).

Figure 4

Soluble c-kit in serum non-severe asthmatics (NSA, n = 22) as compared to patients with severe asthma (SA, n = 41) (*p <0,05) and healthy controls (HC, n = 15) (& p < 0,01).

Figure 5

Serum sc-kit level in patients with severe asthma treated (SA GCS+) and not treated (SA GSC-) with oral glucocorticosteroids as compared to mild asthmatics (MA) (& p < 0,01). Sc-kit level in mild asthmatics as compared to healthy control subjects (* p < 0,01).

Figure 6

Correlation of FEV1 % of predicted value with sc-kit serum level in asthmatic patients (n = 63).

Figure 7

Correlation of MEF25% with serum soluble c-kit in patients with asthma (n = 63).

Figure 8

Correlation of the dose of inhaled budesonide with soluble c-kit serum levels in patients with asthma (n = 63).

Figure 9

Soluble c-kit in serum of patients with atopic and nonatopic asthma.

Figure 10

Soluble c-kit in serum levels in patients with asthma, aspirin hypersensitivity and nasal polyps (ASA group, n = 11) and in patients with asthma without aspirin hypersensitivity and nasal polyps (ATA group, n = 20) (* p < 0,05).