Cytokine Levels in the Sera of Patients with Idiopathic Pulmonary Fibrosis

Background: Idiopathic pulmonary fibrosis (IPF) is a fibroproliferative disorder. Cytokines contribute an important but yet undefined role to its pathogenesis.

Objectives: The present study aims to compare serum levels of cytokines involved in Th-1 and Th-2 immunity, such as interleukins (IL) IL-2, IL-4, IL-8, IL-10, interferon-gamma (IFN-gamma) and IL-12 (p40) in patients with IPF and healthy volunteers. Twenty patients with IPF and 40 healthy controls (HC) participated.

Methods: Cytokines were assessed by enzyme-linked immunoabsorbent assay (ELISA).

Results: Median values of serum IL-2, IL-8, IL-10, IL-12 (p40) were higher in the IPF than the control group: IPF group: 1.05 U/ml, 12.55, 10.13, 44.17 pg/ml; control group: 0.05 U/ml, 6.91, 0.75, 4.51 pg/ml, respectively (P<0.05). IFN-gamma serum levels were lower in the IPF (0.19 pg/ml) than in the control group (0.49 pg/ml). IL-4 values did not differ in a statistically significant way among the groups: 8.40 pg/ml in the IPF group, and 7.46 pg/ml in the control group (P>0.05). IL-4 positively correlated to fast expiratory volume in 1s (FEV1%) and forced vital capacity (FVC%), while IL-8 negatively correlated to the respective values (P<0.005).

Conclusions: IL-2, IL-8, IL-10 and IL-12 (p40) were found to be elevated in the sera of patients with IPF. IFN-gamma was found to be decreased in the sera of patients with IPF.