FASLG and Henoch-Schoenlein purpura: If we consider positive serum aPL antibody as a predictable factor of renal involvement in IgA vasculitis, our study shows a sensitivity of 64.3%, a specificity of 82.4%, a Positive Predictive Value (PPV) of 60.0% and a Negative Predictive Value (NPV) of 84.8%, showing that a positive serum aPL antibody can be used to positively predict the renal involvement, while a negative result is not strong enough to rule out future renal involvement.