Relationship between changes observed in nailfold capillaroscopy and serological profile, lung fibrosis, and elevated risk of pulmonary hypertension in patients with systemic sclerosis and mixed connective tissue disease

Introduction
Microvascular changes play a significant role in systemic sclerosis (SSc) and mixed connective tissue disease (MCTD). The most serious complications of SSc and MCTD are lung fibrosis (LF) and pulmonary hypertension (PH).

Aim
To determine the relationship of the changes observed in capillaries with the serological profile, LF, PH, and finger ulcerations in patients with SSc and MCTD.

Material and methods
The tested group comprised 80 persons (61 SSc, 19 MCTD); mean age 53.6 ±13.6 years. Patients were qualified to the LF group based on HRCT. Likelihood of PH was determined using echocardiography. The presence of antinuclear antibodies (ANA) was assessed using indirect immunofluorescence, while ANA profile, and sclerosis profile were assessed using EUROIMMUN kits, and antiphospholipid antibodies (aPL) using the ELISA method. Capillaroscopy was performed using the Nikon CPS 160 optical microscope.

Results
The following were found: a relationship between occurrence of anti-SS-A (p = 0.006) and anti-centromere B antibodies (p = 0.012) and ramified vessels, between anti-SS-B and capillary haemorrhages (p = 0.019), a positive correlation between NOR90 antibodies and winding loops (p = 0.021), PM-Scl 100 antibodies and enlarged vessels (p = 0.033), a negative correlation between Scl-70 antibodies and winding loops (p = 0.033), and a relationship between aCL and winding loops (p = 0.002). No relationship between the capillaroscopy image and PH risk was found. A positive correlation was found between avascularisation areas and LF and between giant capillaries and finger ulcerations. A negative correlation was found between U1-RNP antibodies and finger ulcerations (p = 0.009), and a positive correlation between antibodies to fibrillarin and ulcerations (p = 0.028).

Conclusions
SS-A, SS-B and anti-centromere antibodies are associated with the late phase of sclerodermic microangiopathy. Avascularisation areas significantly correlate with a higher prevalence of LF. U1-RNP antibodies have a protective role, while anti-fibrillarin antibodies are the risk factor for finger ulcerations.