类风湿关节炎合并间质性肺病患者血清表面活性蛋白A和D水平及临床意义

Detection of serum surfactant protein A and D levels in serum of patients with interstitial lung disease associated with rheumatoid arthritis

目的探讨类风湿关节炎（RA）合并间质性肺病（ILD）患者的血清表面活性蛋白A（SP-A）和D（SP-D）水平及临床意义。方法采用双抗体夹心酶联免疫吸附试验（ELISA）法检测SP-A和SP-D，并比较单纯RA组、RA-ILD组、对照组血清样本SP-A和SP-D水平的差异，分析其与RA合并ILD的相关性。计算3组血清SP-A和SP-D阳性检出率。分析SP—A和SP-D与年龄、红细胞沉降率（ESR）、C反应蛋白（CRP）、类风湿因子（RF）、抗环瓜氨酸肽（CCP）抗体、抗核抗体、抗核周因子（APF）和抗角蛋白抗体（AKA）之间的相关性。多组间均数的比较采用方差分析，数据间的相关性分析采用Spearman等级相关。结果①RA—ILD组、单纯RA组、对照组的血清SP-A水平分别为（51．2±9．2）、（25．9±2．6）、（15．4±0．3）μg／L，SP—D水平分别为（42．5±8．1）、（20．8±1．5）、（16．6±0．8）μg／L。RA-ILD组患者血清SP-A和SP-D水平高于单纯RA组以及对照组（P〈0．05）。单纯RA组患者血清SP-A和SP-D水平和健康对照组比较差异无统计学意义（P〉0．05）。②RA-ILD组血清SP—A和SP-D的阳性率明显高于单纯RA组（χ^2=5．21，P=0．02；χ^2=4．79，P=0．01）和健康对照组（χ^2=4．96，P=0．03；χ^2=4．75，P=0．02），RA—ILD组血清SP-D的阳性检出率大于血清SP—A（χ^2=4．95，P=0．04）。③RA—ILD患者血清SP-A、SP—D水平与年龄、CRP呈正相关（r=0．687，P=-0．001；r=-0．571，P=-0．009）。④RA—ILD患者血清SP—D水平与RF、抗CCP抗体和AKA呈正相关，而血清SP—A、SP-D水平与抗核抗体、APF、ESR无相关性。结论①SP—A和SP—D可作为RA合并ILD的血清学标志；②SP-A和SP-D在早期诊断RA合并ILD方面有一定价值，SP-D更有效地提示RA合并ILD存在，判断肺损伤程度，预测疾病转归情况。

Objective To measure serum surfactant protein （SP） A and D levels in patients with inter- stitial lung disease associated with rheumatoid arthritis （RA）. Methods Serum SP-A and SP-D levels of RA, RA-ILD patients and healthy controls were assessed using a sensitive enzyme-linKed immunosorbent assay （ELISA）. The relationship between SP-A and SP-D and RA-ILD was analyzed. The serum SP-A and SP-D positive rate was calculated for the three groups. The correlation between SP-A and SP-D with RF, anti-CCP, antinuclear antibody, antikeratin antibody, anti-perinuclear factor, C-reactive protein, erythrocyte sediment- ation rate, were analyzed. Mean value of groups were compared with variance analysis, Spearmarn rank correlation test was used for correlation analysis. Results The levels of serum SP-A in RA-ILD patients and RA patients as well as in healthy controls were [ （51.2±9.2）, （25.9±2.6）, （15.4±0.3） μg/L ] respectively. The level of serum SP-D of the three groups was [ （42.5±8.1）, （20.8±1.5）, （16.6±0.8） μg/L] respectively. The levels of serum SP-A and SP-D in patients with RA complicated with ILD were higher than those simple RA patients and healthy controls （P〈0.05）. The levels of serum SP-A and SP-D in patients with RA were not significaritly higher than those in healthy controls （P〉0.05）. The positive rate of serum SP-A and SP-D in RA-ILD patients were significantly higher than those in simple RA patients and healthy controls. The positive rate of serum SP-D of RA-ILD patients was higher than that of SP-A. The levels of serum SP-A and SP-D in patients with RA complicated with ILD were correlated positively with age, C-reactive protein. The level of serum SP-D was correlated positively with RF, anti-CCP, antikeratin antibody. There was no correlation between the level of serum SP-A and SP-D with RA-ILD and antinuclear antibody,antiperinuclear factor, erythrocyte sedimentation rate. Conclusion The levels of serum SP-A and SP-D are correlated with RA-ILD and may be useful markers for ILD in patients with RA. These two paramenters may be helpful to early diagnosis of RA-ILD. The Serum SP-D levels are more sensitive in predicting the development of RA-ILD than other parameters and can help in assessing the severity of lung damage.