Findings indicated that longer disease duration, positive anti-Scl70 antibody titers, higher white blood cell and platelet counts, greater erythrocyte sedimentation rate (ESR) levels, and the presence of possible pulmonary hypertension (PH) were associated with ILD in SSc patients.
The study, “Clinical Characteristics of Systemic Sclerosis With Interstitial Lung Disease,” was conducted by researchers at Ajou University College of Medicine in Suwon, South Korea, and was published in the journal Archives of Rheumatology.
SSc can affect multiple organs, including the lungs, and ILD is a common condition that occurs in these patients.
According to the researchers, “the presence of ILD in SSc patients determines the severity and expected prognosis of the disease.” Therefore, early detection of ILD is needed to improve patient care and clinical outcomes.
In the study, they aimed to compare the clinical characteristics of SSc patients with or without ILD, and determine whether those differences could be useful in the detection of ILD in these patients.
The study involved 108 SSc patients, including 13 males and 95 females, ages 14 to 78 years. Of these patients, 49 (45.4%) had diffuse SSc, and 59 (54.6%) had limited SSc. ILD was confirmed by chest computed tomography.
Data showed that disease duration was significantly longer in SSc patients with ILD (mean of 6.72 years), than in those without ILD (4.28 years).
Researchers also found that more SSc patients with ILD had positive anti-Scl70 antibody titers (62.8%) than those without ILD (15.4%), making it an independent risk factor for ILD in SSc patients. The presence of these antibodies is known to be associated with immune disorders, including SSs.
In contrast, fewer patients with ILD were positive for another type of autoimmune-associated antibody, called anti-centromere antibody (9.3%) than those without ILD (50.8%).
SSc patients with ILD also had significantly higher white blood cell counts (mean 7,650.93 cells/microliter) and platelets (mean 282,100/microliter) counts than those without ILD (6,468.96 white blood cells/microliter, and 241,300 platelets/microliter).
Erythrocyte sedimentation rate, an inflammatory marker, was also significantly higher in patients with ILD patients (39.4 mm/hour) than in those without ILD (26.5 mm/hour).
Possible PH (defined as a right ventricular systolic pressure equal to or higher than 40 mm Hg) was also more common in SSc patients with ILD (25.6%) than in those without ILD (3.1%).
Researchers found that the incidence of ILD was higher in patients with diffuse SSc than in those with limited SSc, echoing the findings of previous studies.
Based on the results, the team concluded that “in SSc patients with ILD, disease duration was longer and positive titer of anti-Scl70 antibody was more frequent, positive titer of anti-centromere antibody was less frequent, and white blood cell and platelet counts, ESR levels, and incidence of possible pulmonary hypertension were significantly higher than in those without ILD.”
They suggested that “positive anti-Scl70 antibody, platelet count, ESR, and the development of PH were significantly associated with ILD in SSc patients.”