Concomitant appearance of anti-cardiolipin, anti-β₂-glycoprotein I, anti-prothrombin and anti-annexin V antibodies

Background

Anticardiolipin (aCL), anti-β₂-glycoprotein I (anti-β₂-GPI), anti-prothrombin (aPT) and anti-annexin V (aANXV) antibodies are anti-phospholipid antibodies (aPL) with different antigenic and diagnostic specificities.

Objective

To ascertain a simultaneous appearance of antigenically undefined aCL and antigenically distinct anti-β₂-GPI, aPT and aANXV.

Methods

Sera from 92 patients (87 female, five male) were studied (63 SLE, 19 sAPS [SLE with APS] and 10 pAPS). IgG, IgM and IgA isotypes of aPL were determined using relevant ELISAs.

Results

IgG was the most frequently detected isotype in all four analyzed aPL subtypes. According to diagnostic criteria, aCL were more frequently found in patients with pAPS and sAPS than in those with SLE. Similarly, aPT were more often elevated in patients with pAPS (7/10) and sAPS (6/19) than in SLE (16/63; P < 0.05). The prevalence of anti-β₂-GPI and aANXV antibodies did not differ between patient groups. Regardless of diagnosis, aPT were always detected in combination with aCL and/or anti-β₂-GPI. aPT and aANXV were regularly present in the sera positive also for aCL and/or anti-β₂-GPI. aANXV was detected as a single antibody in only one patient. In the pAPS group concurrent multiple aPL varieties (three or four) were significantly more frequently present than one or two types (8/10 versus 2/10; P < 0.05). Statistically significant associations of particular aPL with clinical symptoms were as follows: elevated IgG anti-β₂-GPI with arterial thromboses, thrombocytopenia and foetal loss; IgG aPT with arterial thromboses; and IgG aCL with venous thrombosis. IgA isotype did not improve the clinical significance of the four analyzed aPL.

Conclusion

In patients with SLE and/or APS, individual aPL were found infrequently. Almost half of them had three or more aPL subsets elevated at the same time.