Effect of cyclophosphamide on cytokines in patients with primary Sjögren’s syndrome-associated interstitial lung disease in South China

The objective of the study is to investigate the mechanisms of cyclophosphamide sequential therapy for patient with primary Sjögren’s syndrome-associated interstitial lung disease (PSS-ILD). This was a retrospective review of 15 patients (2005–2008) with PSS-ILD who underwent cyclophosphamide sequential therapy. Peripheral blood and bronchoalveolar lavage (BALF) were obtained before and 3, 6, 12 and 24 months after the treatment. The TNF-α and TGF-β1 mRNA levels in peripheral blood were measured using reverse transcription polymerase chain reaction. Serum and BALF TNF-α, TGF-β1 and MMP-9 levels were measured using sandwich enzyme-linked immunosorbent assay. The average levels of serum TNF-α (0.39 ± 0.22) and TGF-β1 (0.31 ± 0.18) mRNA in patients with PSS-ILD were higher compared with that in patients with PSS without ILD. TNF-α level (0.23 ± 0.19) was significantly decreased 3 months after cyclophosphamide treatment (t = 2.533, p < 0.05), and TGF-β1 (0.31 ± 0.18) level markedly decreased after 6 months of treatment (t = 2.617, p < 0.05). The levels of serum TNF-α (11.2 ± 2.6) μg/L, TGF-β1 (72 ± 19) μg/L and MMP-9 (38 ± 9) μg/L in patients with PSS-ILD were higher than that in patients with PSS without ILD. TGF-β1 (36 ± 12) μg/L level decreased significantly after 3 months of treatment (t = 2.526, p < 0.05), and TNF-α level (7.1 ± 1.3) μg/L markedly decreased after 6 months of therapy (t = 2.578, p < 0.05). MMP-9 level (18 ± 4) μg/L decreased significantly after 12-month treatment (t = 2.329, p < 0.05). The levels of BALF TNF-α (17.1 ± 3.5) μg/L, TGF-β1 (36 ± 17) μg/L and MMP-9 (27 ± 10) μg/L in patients with PSS-ILD were higher than that in patients with PSS without ILD. TGF-β1 (21 ± 14) μg/L level decreased significantly after 3-month treatment, and TNF-α level (9.4 ± 1.7) μg/L was decreased after 6 months of cyclophosphamide treatment that may be associated with its inhabitation on production of TNF-α, TGF-β1 and MMP-9.