Antiendothelial Cell Antibodies: Useful Markers of Systemic Sclerosis

BACKGROUND: Systemic sclerosis (SS) encompasses a wide spectrum of clinical presentations. Antiendothelial cell antibodies (AECA) in patients with primary Raynaudʹs phenomenon (PRP), limited SS (lSSc), or diffuse SS (dSSc) may help to determine the long-term prognosis of the disease. METHODS: Twenty-seven normal controls, 13 patients with PRP, 36 with lSSc, and 31 with dSSc were included in the study. Sera were examined for the presence of AECA, using a cellular enzyme-linked immunosorbent assay (ELISA). Angiotensin-converting enzyme (ACE) activity, plasma von Willebrand factor antigen (vWfAg), and thrombomodulin (Tm) concentrations were also evaluated. The medical records of 50 of the lSSc and dSSc patients were reviewed and the organ system involvement noted. RESULTS: Antiendothelial cell antibodies were present in 3 patients with PRP, 16 patients with lSSc, and 26 patients with dSSc. These autoantibodies were mainly of the IgG isotype. There was no difference in ACE activity between patients and controls. In contrast, vWfAg and Tm concentrations were higher in patients with PRP relative to controls, and higher in patients with lSSc compared with those with PRP. The presence of AECA was associated with digital scars and ulcers (P< 0.004 and P< 0.003, respectively), severe RP (P< 0.01), grade 3 tortuosity of vessels (P< 0.0004), and lung involvement (P< 0.02). CONCLUSION: The significant trend for AECA to increase with disease severity across the three groups of patients studied suggests that the AECA test can identify subsets of SSc with differing prognoses.