CD8+DR+ T-Cells and C3 Complement Serum Concentration as Potential Biomarkers in Thrombotic Antiphospholipid Syndrome

Abstract

Purpose. To assess complement factors and T lymphocyte activation subset abnormalities in patients with thrombotic antiphospholipid syndrome (APS) as potential biomarkers for development of clinical complications. Methods. We assessed C3, C4, factor B concentrations (nephelometry), complement haemolytic functional activity (CH100, radial immune diffusion), and the activation status of CD4+ and CD8+ T-cells (three-colour flow cytometry) in patients with thrombotic APS. Antiphospholipid (aPL) positive patients without APS-related clinical criteria, systemic lupus erythematosus (SLE) patients, and healthy individuals were evaluated as controls. A clinical followup was performed to assess the potential relationship between the immunological parameters and development of APS-related complications. Results. Lower concentrations of C3 and higher levels of CD8+DR+ cells were risk factors for development of APS-related complications during followup, including rethrombosis and neuropsychiatric symptoms. Patients with diagnosed thrombotic APS had significantly lower levels of C3, C4, and CH100 as well as higher percentages of activated CD4+DR+ and of CD8+DR+ T-cells than healthy controls but similar to that observed in autoimmune disease controls. Conclusion. Lower C3 and C4 complement levels and higher percentages of CD8+DR+ T-cells were observed in thrombotic APS patients. The potential role of these abnormalities as biomarkers of clinical outcome warrants further evaluation in a multicenter study.

BF*F allotype of the alternative pathway of complement: A marker of protection against the development of antiphospholipid antibodies in patients with systemic lupus erythematosus

“…However the presence of split products of BF, such as Bb, in early pregnancy of non-SLE patients with adverse fetal outcomes 31 is suggestive that the alternative pathway may be implicated in obstetric APS. Data from previous studies [26][27][28]30,31 indicate that evaluation of variants of BF in obstetrical APS may constitute an interesting approach; the present study, detecting an inverse relationship between BF SF phenotype and BF*F allotype and the presence antiphospholipid antibodies in SLE patients, corroborates this position.…”

“…Hypocomplementemia has been found in half of patients with primary APS, 24 and it is considered a prognostic factor for pregnancy outcome in lupus patients with obstetrical APS. 25 In humans and animal models with obstetrical APS, the lack and/or blockage of components of the complement common pathway, such as C3, 26 C5 27 and C6 28 avoid fetal wastage. Heparine is considered effective in APS treatment, not only because of its anticoagulant properties, but also because of its activity as a complement inhibitor.…”