OBJECTIVES The purpose of this study was to evaluate the value of serum krebs von den lungen-6 (KL-6) level as a diagnostic indicator for connective tissue disease associated with interstitial lung disease (CTD-ILD). METHODS One hundred fifty five patients with newly diagnosed CTD in our hospital were enrolled and divided into two groups by their ILD manifestations, the CTD-ILD group and the CTD group. In parallel, 61 patients with pulmonary infection and 60 cases of healthy subjects were also enrolled into the study. The difference of serum KL-6 level among the four groups were compared. In CTD-ILD group, carbon monoxide diffusing capacity (DLCo) and high-resolution computed tomography (HRCT) of lung were also tested. The serum KL-6 level of 32 patients from the CTD-ILD group who received cyclophosphamide (CTX) pulse therapy were sampled and measured, by enzyme linked immunosorbent assay (ELISA), at three time points: before treatment, 3 months after treatment and 6 months after treatment. RESULTS The serum KL-6 level in the CTD-ILD group (1004.9 (676.41738.1) IU/ml) is significantly higher than three other groups (χ2 = 72.29, P < 0.001). In the CTD-ILD group the level of serum KL-6 was positively correlated with disease severity on HRCT (r = 0.75, P <  0.001), while was negatively correlated with DLCo (r = - 0.50, P <  0.001). In 32 patients who received CTX pulse therapy, the level of serum KL-6 was gradually decreased in 20 cases whose lesions were absorbed within 6 months (F = 13.67, P <  0.001), whereas it remained unchanged in the rest of 12 patients (Z = -1.328, P = 0.198). CONCLUSIONS Serum KL-6 level can potentially serve as a diagnostic marker for CTD-ILD and be utilized to evaluate the effectiveness of CTX pulse therapy.

中文翻译：

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血清克雷布斯·冯·登·弗伦6在诊断与间质性肺疾病相关的结缔组织疾病中的价值。

目的本研究的目的是评估血清克雷布斯冯登肺6（KL-6）水平作为与间质性肺病（CTD-ILD）相关的结缔组织病的诊断指标的价值。方法将我院155例初诊CTD患者按ILD表现分为两组，即CTD-ILD组和CTD组。同时，本研究还纳入了61名肺部感染患者和60例健康受试者。比较了四组之间的血清KL-6水平的差异。在CTD-ILD组中，还测试了肺的一氧化碳扩散能力（DLCo）和高分辨率计算机断层扫描（HRCT）。通过酶联免疫吸附测定（ELISA），在三个时间点：治疗前，治疗后3个月和接受治疗的3个时间点，对来自CTD-ILD组的32例接受环磷酰胺（CTX）脉冲治疗的患者的血清KL-6水平进行采样和测量。治疗后6个月。结果CTD-ILD组的血清KL-6水平（1004.9（676.41738.1）IU / ml）明显高于其他三个组（χ2= 72.29，P <0.001）。在CTD-ILD组中，血清KL-6水平与HRCT上的疾病严重程度呈正相关（r = 0.75，P <0.001），而与DLCo呈负相关（r =-0.50，P <0.001）。在接受CTX脉冲治疗的32例患者中，在6个月内吸收了病灶的20例患者中，血清KL-6水平逐渐降低（F = 13.67，P <0.001），而其余12例患者则保持不变（Z = -1.328，P = 0.198）。结论血清KL-6水平可潜在地作为CTD-ILD的诊断指标，并可用于评估CTX脉冲疗法的有效性。