Introduction
The heterogeneity of anti-phospholipid antibodies can be manifested not only in different antigenic specificities, but also in their avidities. The aim of the study was to investigate the relationship between anti-cardiolipin antibody (aCL) IgG avidities and levels within the range of their titres, from very low to high ones.

Material and methods
We analyzed 78 serum samples from 60 patients by ELISA with chaotropic agents, using urea concentration of 6 and 8 mol/l and single diluted serum samples. The changes of aCL levels and avidities were explored during a long-term follow-up in 14 patients.

Results
The avidities of aCLs did not differ in the groups of patients classified according to aCL levels. The higher avidity antibodies predominated in our patients and the fluctuation of avidities in the longitudinal follow-up did not show significant differences. No relationship between aCL levels and their avidities was found.

Conclusions
aCL avidities seem to have no relationship with aCL levels and high-avidity aCLs; the potentially deleterious effects might be present also in patients with low and extremely low aCL levels. Avidity of aCLs



中文翻译：

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抗磷脂抗体的亲和力与其水平有关

引言
抗磷脂抗体的异质性不仅表现在不同的抗原特异性上，还表现在它们的亲和力上。该研究的目的是研究抗心磷脂抗体 (aCL) IgG 亲和力与其滴度范围内的水平之间的关系，从非常低到高。

材料和方法
我们通过 ELISA 分析了来自 60 名患者的 78 份血清样本，使用离液剂，使用浓度为 6 和 8 mol/l 的尿素和单一稀释的血清样本。在对 14 名患者的长期随访中探讨了 aCL 水平和亲和力的变化。

结果
在根据 aCL 水平分类的患者组中，aCL 的亲和力没有差异。在我们的患者中，较高的亲和力抗体占主导地位，纵向随访中亲和力的波动没有显示出显着差异。未发现 aCL 水平与其亲和力之间的关系。

结论
aCL 亲和力似乎与 aCL 水平和高亲和力 aCL 无关；在 aCL 水平低和极低的患者中也可能存在潜在的有害影响。aCL 的亲和力