SPP1 and systemic sclerosis: Meanwhile they have been found also in systemic autoimmune disorders as for instance autoantibodies to the muscarinic acetylcholine receptors of the M3-type in primary Sjoegren syndrome (pSS) (10, 11) or to angiotensinII-type1- and endothelin-type-A-receptors (AT1R, ETA1) in SSc (12).