Krebs von den Lungen-6 (KL-6) may be effective in predicting the prognosis of patients with primary Sjögren’s syndrome-associated ILD (SJS-ILD), according to a recent study published in Scientific Reports-Nature.
The retrospective study carried out in 46 patients diagnosed with primary SJS-ILD evaluated the plasma biomarker levels of KL-6, CC chemokine ligand 18 (CCL18), chitinase-3-like-1 (YKL-40), interleukin-4 receptor alpha (IL-4Ra), and matrix metalloproteinase-7 (MMP-7) using the multiplex Luminex assays. The study carried out for a median follow-up length 69 months noted that the level of KL-6 was significantly higher in non-survivors than in survivors (119.6 vs 59.5 pg/mL, P = 0.037). The receiver operating characteristic analysis for 10-year survival demonstrated that KL-6 is a significant predictor of survival (AUC= 0.705, P = 0.037), with 66.7 percent sensitivity and 79.4 percent specificity, and an appropriate cut-off value of 53.5 pg/mL.
Patients in the high KL-6 group (> 53.5 pg/mL, n = 15) had lower lung functions and exercise capabilities as opposed to low KL-6 group (53.5 pg/mL, n = 31). Patients with high KL-6 levels also had increased adverse events (27% vs. 3%, P = 0.017) and reduced survival rate (5-year survival: 64% vs. 96%; 10-year survival: 30% and 75%, respectively; P = 0.001).
The prevenance of ILD in patients with SJS is estimated to be around 10–20% and the occurrence of this extraglandular complication increases the risk of mortality. Hence, identification of predicting factors that could distinguish patients with progressive disease from slow or stable disease assists in conferring appropriate intervention. Further studies are warranted to corroborate the usefulness of KL-6 in predicting the prognosis of patients with SJS-ILD,
Reference: Kim YJ, Choe J, Moon SJ, Song JW. Blood KL-6 predicts prognosis in primary Sjögren’s syndrome-associated interstitial lung disease. Sci Rep. 2022 Mar 29;12(1):5343.