It should also be noted that the SSc-associated autoantibody group (Ab-Neg) remains a heterogeneous group of patients - as defined by the presence of other autoantibodies such as anti-fibrillarin, anti-PM-Scl or anti-Th/To [32] - and whether these less common subsets also have differences in the plasma cytokine profiles remains to be determined. This evidence concerns the gene TH and systemic sclerosis.