Which scleroderma patients are at particularly high risk for progressive ILD?
Patients at highest risk for progressive ILD are those with:
• Positive anti-Scl-70 antibody
• Isolated nucleolar-staining ANA—that is a nucleolar-staining ANA with a negative anti-Scl-70. These patients frequently have an anti–U3 RNP or anti-Th/To antibody. Pm-Scl antibody is a less common autoantibody but can result in an isolated nucleolar-staining pattern as well.
However, all SSc patients are at some level of risk for the development of ILD, and therefore, monitoring should not be restricted to those with high-risk features only. When assessed by thoracic HRCT, approximately 75% patients with SSc have evidence of bibasilar ILD. Clinically significant ILD (presence of symptoms, restrictive defect on PFT, or extensive disease by HRCT) warranting immunosuppressive therapy is identified in only about 20% to 30% patients. Patients with a positive ACA rarely develop progressive ILD.