Raynaud’s phenomenon (RP) is a cold-induced vasoconstriction that affects mainly the fingers but can occur in other locations such as toes, nose, ears and nipples as well. Raynaud attacks are characterized by a color change of the skin that goes from white to blue and red. Clinically, RP is classified into primary RP, which is idiopathic and secondary RP, which is associated with an underlying disease process. Physiologically, the cold-induced vasoconstriction is mediated by an interaction of noradrenaline with G protein-coupled receptors such as α-adrenoceptors of vascular smooth muscle cells. There are three subtypes of α1-adrenoceptors (α1A,α1B, α1D) and three subtypes of α2-adrenoceptors (α2A, α2B, α2C). Further, there is evidence that α2C-adrenoceptors play a relevant role in the cold-induced vasoconstriction.

The aim of my study is to analyze the expression of leukocytic α-adrenoceptors as well as circulating anti-α1- and anti-α2-adrenoceptor autoantibodies in primary RP. Combined with clinical parameters (nailfold capillaroscopy; interview) I want to find out if it is possible to distinguish primary from secondary RP and to understand underlying mechanisms of primary RP.