Pro-inflammatory genotype as a risk factor for aPL-associated thrombosis: Report of a family with multiple anti-phospholipid positive members

ObjectiveInflammation might represent a second hit for anti-phospholipid antibody (aPL)-mediated thrombosis. Inflammatory responses have been linked to gene polymorphisms of several cytokines and Toll Like Receptors (TLRs). We examined IL1β, TNFα, TGFβ, IL6, IFNγ, IL10, tlr4 gene polymorphisms in a family with several members positive for IgG anti-β2 glycoprotein I (β2GPI) antibodies but with recurrent thrombosis in one member only.MethodsLupus anticoagulant, anti-cardiolipin, anti-β2GPI IgG/IgM antibodies, IL1β, TNFα, TGFβ1, IL6, IL10, IFNγ, tlr4 gene polymorphisms (by allele-specific polymerase chain reaction) in addition to standard thrombophilic risk factors and cytokine serum levels (IL-1β, TNFα, IL-10) were evaluated.ResultsRecurrent thrombotic events was reported only in the proband, but not in three healthy siblings persistently positive for IgG anti-β2GPI antibodies, respectively. The wild type tlr4 gene and cytokine polymorphisms associated with a high pro-inflammatory response (IL-1β promoter-511 C/T; TNFα G/A; TGFβ + 10 T/C, +25 C/G; IL-6 −174 C/G) were found only in the proband. Serum cytokine levels were normal.ConclusionThis case report confirms that protective tlr4 gene polymorphisms are more frequent in asymptomatic aPL carriers. In line with the role of inflammatory mediators as second hits for aPL-associated thrombosis, the polymorphisms of cytokines linked to higher inflammatory response were found in the proband only.