目的　探讨系统性红斑狼疮 (SLE)的发病与MHCⅠ类分子的相关性。方法　选择41例住院的SLE ,用放射免疫法分别测定血清和尿中的 β2 微球蛋白 (β2 MG)的水平 ,观察治疗前后的变化及与病情活动指标间的相关性。结果　SLE组血清和尿的 β2 MG水平分别为 (3 0± 2 2 )μg/ml和 (2 2 0± 38 0 ) μg/ml,均显著高于正常 (P <0 0 5和P <0 0 1) ,治疗 1个月后血、尿β2 MG的下降不明显 ,而狼疮活动评估 (SLAM)积分却显著下降 (P <0 0 1) ,抗dsDNA抗体升高组血、尿β2 MG的水平较抗dsDNA非升高组高 ,但差异无显著性。血 β2 MG狼疮肾炎组显著高于非肾炎组。相关分析表明 β2 MG和抗dsDNA、SLAM积分显著正相关 ,尿 β2 MG和SLAM也显著正相关 ,血、尿β2 MG和 2 4h尿蛋白都不相关 ,尿 β2 MG和血清IL 4、IFN α水平显著正相关 ,和血清IL 8显著负相关。结论　SLE患者T细胞 β2 MG的表达高于正常 ,人类狼疮的发病和MHCⅠ类分子相关 ,治疗后血、尿 β2 MG的水平滞后于抗dsDNA和SLAM积分的下降。 Objective To investigate the relationship between the pathogenesis of systemic lupus erythematosus (SLE) and MHC class I molecules. Methods 41 cases of hospitalized SLE were selected. The levels of β2 microglobulin (β2 MG) in serum and urine were determined by radioimmunoassay. The changes before and after treatment were observed and the correlations were analyzed with the index of disease activity. Results Serum and urinary levels of β2 MG in SLE group were (30 ± 2 2) μg / ml and (220 ± 38 0) μg / ml, respectively, which were significantly higher than those in normal group (P <0 05 and P 0 0 1). After 1 month of treatment, the decline of blood and urine β2 MG was not obvious, while the score of lumbar activity assessment (SLAM) was significantly decreased (P <0.01). The anti-dsDNA antibody increased blood and urine β2 MG The level of anti-dsDNA non-elevated group was higher, but no significant difference. Serum β2 MG lupus nephritis group was significantly higher than non-nephritis group. Correlation analysis showed that there was a significant positive correlation between β2 MG and anti-dsDNA, SLAM score, urinary β2 MG and SLAM, blood and urine β2 MG and 24 h urine protein, urinary β2 MG and serum IL 4 and IFN α Significant positive correlation, and serum IL 8 significant negative correlation. Conclusions The expression of β2 MG in T cells of SLE patients is higher than that of normal and human lupus. The levels of β2 MG in blood and urine lag behind the decrease of anti-dsDNA and SLAM scores.