[What can be expected of biological tests in scleroderma?].

Biological investigations are useful from three main view points in systemic scleroderma: diagnosis: the demonstration of antinuclear antibodies which are quite specific for these conditions: antinuclear anti-ECT (nRNP, Scl 70, KU, PM 1) and anticentromere antibodies; prognosis: the presence of some antibodies is associated with a more favourable outcome: anti-nRNP and Sharp's syndrome, anti-centromere and the CREST syndrome, anti-KU and syndromes overlapping with polymyositis; pathogenic: the study of abnormalities of T-lymphocyte function, immunogenetic (HLA grouping) studies, cytotoxic factors for vascular endothelium, mitogenic factors of fibroblasts and the "chromosome breaking" factor.