Background The association between antiphospholipid antibodies (aPL) and systemic sclerosis (SSc) and its clinical manifestations is controversial, but owing to some shared pathogenetic pathways one expects that SSc patients with aPL will have more severe vascular manifestations that SSc without aPL.
Objectives To evaluate whether different aPL are associated with SSc and some of its clinical manifestations and if so, whether aPL titre impact on the severity of those clinical manifestations.
Methods Systematic review of EMBASE and PubMed databases from inception to October 2015 followed by meta-analysis according to the PRISMA guidelines.
Results The relationship between between aCL (anticardiolipin) of IgG/IgM isotype and SSc was addressed in 8 studies yielding 725 controls and 484 SSc participants. The pooled prevalence of IgG aCL was 1.6% in controls and 15.4% in SSc patients with an odds ratio (OR) of 10.895 (95% CI 5.853, 20.282, I2 =19.5%, p=0.003) and that of IgM was 0.6% and 5.1% respectively with an OR of 7.843 (95% CI 2.981, 20.633, I2 =21.5%, p=0.002). The relationship between between IgG aβ2GPI of IgG/IgM isotype and SSc was addressed in 8 studies yielding 725 controls and 484 SSc participants. The pooled prevalence of IgG aβ2GPI was 1.6% in controls and 15.4% in SSc patients (OR 11.121, 95% CI 2.587, 47.812, I2 =35.6%, p=0.0003) while that of IgM was 0.6% and 5.1% respectively (OR 12.185, 95% CI 1.563, 94.948; I2 =67.5%, p=0.02). The relationship between aPL and thrombosis was addressed in 6 studies yielding 428 aCL negative and 88 aCL positive SSc: the pooled prevalence of thrombosis was 3.7% in the aCL negative group and 25% in the aCL positive group with a relative risk (RR) of 7.344 (95% CI: 4.089–13.191; I2 =29.5%, p =0.0001). The relationship between aPL and pulmonary arterial hypertension (PAH) was addressed in 7 studies yielding 1171 aCL negative SSc patients and 166 aCL positive SSc: the pooled prevalence of PAH in aCL negative patients was 11% and in aCL positive patients was 24.6% for a RR of 6.8 (95% CI: 3.110–12.280; I2 =4.18; p =0.0001). The relationship between aPL and renal involvement was investigated in 5 studies yielding 264 aCL negative and 83 aCL positive SSc patients: the pooled prevalence of renal involvement in aCL negative patients was 17% and in aCL positive patients was 40% for a RR of 1.993 (95% CI: 1.359–2.923; I2 =0%, p =0.0001).
Conclusions There is a strong association between aPL and SSc; within SSc per se, aPL, with varying heterogeneity, relate to some vascular manifestations of SSc, such as thrombosis, DI, PAH and renal involvement. The analysis was carried out on the percentage of positive aPL per group, as very few studies reported aPL titres, precluding further assumptions on the relationships found
Disclosure of Interest None declared