[Reflections on non-differentiated collagenosis or non-differentiated autoimmune syndrome]

The authors review the Non-Differentiated Collagenosis (NDC) described by Gyula Petrányi 29 years ago, and try to establish whether it is still necessary to maintain this clinical picture. Relying on data from special literature and on their own findings, the authors conclude that the maintenance of the NDC terminology is justified by the fact that poly-systemic autoimmune diseases take time to develop and that at certain stages of this development it is almost impossible to make a firm decision as to which clinical picture the process will lead to. The authors discuss the clinical and immunological features of NDC, the implications for the patients and things to be done in order to recognise the NDC disease process. They also emphasize a more frequent occurrence of the features of NDC than is generally stated, and that such patients need regular, competent and devoted medical attention.