Anti-carbonic anhydrase antibody in collagen diseases and its clinical significance

八年前，我们发现了一种新的自身抗体；抗碳酸酐酶（CA）抗体在胶原蛋白疾病患者血清中的偶然发现。从那时起，抗体的分析和频率，抗原性质的分析在我们组和世界其他组不断探索。采用ELISA法对109例日本胶原蛋白病患者进行血清抗CA-Il抗体的筛选。SLE阳性率为24.1%，PSS阳性率为16.7%，干燥综合征阳性率为20.0%，皮肌炎阳性率为25.0%。为了探索ca - 1和ca - II的表位肽，我们进行了表位定位。我们制备了ca -1的P-1 ~ P-21和CA-II的P-1 ~ P-20的肽抗原。利用这些多肽，应用ELISA法在胶原蛋白疾病血清中筛选抗体。结果表明，ca -1的特异性抗体在SLE中针对P-1和2，在PSS中针对P-1，在干燥综合征中针对P-4。此外，利用CA-Il的肽检测SLE中P-2和8的抗体，PSS中P-8和15的抗体，Sjogrens综合征中的P-2和8的抗体，皮肌炎中的P-8的抗体。抗P-20抗体在胶原病血清和健康志愿者血清中是共同的表位。在两例SLE中，表位扩散是在几年的时间里观察到的。下一步是找出并分析这些疾病的一些致病表位。

Eight years ago, we discovered a novel autoantibody ; anti-carbonic anhydrase (CA) antibody in sera from patients with collagen diseases as a serendipitous finding. Since then, the analysis and frequency of antibody, the analyses of antigen natures have been continuously explored in our group and also in other groups -in the world. Using the ELISA method, we screened the serum anti CA-Il antibody in 109 Japanese collagen disease patients. The positive results were obtained in 24.1% of SLE sera, 16.7% of PSS, 20.0% of Sjogren's syndrome and 25.0% of dermatomyositis.To explore the epitope-peptides of CA-I and II, the epitope-mapping was performed. We prepared peptide-antigens from P-1 to P-21 of CA-I, and from P-1 to P-20 of CA-II. Using these peptides, antibody was screened in sera from collagen diseases, applying the ELISA method. As results, the specific antibodies of CA-I were presented against P-1 and 2 in SLE, against P-1 in PSS, and against P-4 in Sjogren's syndrome. Furthremore, antibodies were detected against P-2 and 8 in SLE, P-8 and 15 in PSS, P-2 and 8 in Sjogrens syndrome, and P-8 in dermatomyositis using peptides from CA-Il. The antibody against P-20 was common epitope among sera from the collagen diseases and healthy volunteers.In two cases of SLE, the epitope-spreading was observed in the course of several years. The next step is to find out and analyze some pathogenic epitopes in these diseases.