IgG reactivities directed toward triosephosphate isomerase, superoxide dismutase mitochondrial precursor and heterogeneous nuclear ribonucleoprotein L. (A) areas of 2-D membranes with IgG reactivities directed toward triosephosphate isomerase (rectangles) and superoxide dismutase mitochondrial precursor (ovals) in sera from patients with different subsets of SSc and from healthy blood donors in total protein extract. (D) Areas of 2-D membranes with IgG reactivities directed toward heterogeneous nuclear ribonucleoprotein L in sera from SSc patients with unidentified ANA and from healthy blood donors in enriched nuclear protein extract. 2-D silver-stained gel of total (B) and nuclear (E) protein extracts from HEp-2 cells. First dimension (x-axis): pH range from 3 to 10; second dimension: range from 150 to 10 kDa (y-axis). The areas delineated by rectangles in B (pH 6.5 to 7.8; 22 to 28 kDa) and D (pH 7.1 to 7.7; 55 to 65 kDa) correspond to the region of membranes magnified in A and D, respectively. (C and F) 3-D representation of IgG reactivity peaks in a sera pool from three patients (left) and from the 12 healthy blood donors (right). ACA: anticentromere antibody; ANA: antinuclear antibody; ATA: antitopoisomerase I antibody; dcSSc: diffuse cutaneous systemic sclerosis; DU: digital ulcer; lcSSc: limited cutaneous systemic sclerosis; MW: molecular weight; PAH: pulmonary arterial hypertension; RNAP: anti-RNA polymerase III antibody; SRC: scleroderma renal crisis; SSc: systemic sclerosis.