Radiological incomplete thymus involution in systemic sclerosis.

OBJECTIVE Thymus plays a crucial role in immune system homeostasis, and thymic abnormalities have been previously reported in many autoimmune diseases, including SSc. The aim of this study is to evaluate the frequency of radiological thymus abnormalities in SSc patients and its relationship with various clinical and laboratory features. METHODS Sixty-three female SSc patients (diffuse/limited: 49/14), all having pulmonary high-resolution CT (HRCT) scans, taken previously for evaluating lung involvement were included. At the time of the scans, mean age and disease duration of the patients were 50.1 +/- 8.5 and 10.2 +/- 7.8 years, respectively. As the control group, 45 age-matched female patients, having normal pulmonary HRCT scans taken previously for evaluating non-specific symptoms, were included. RESULTS Frequency of incomplete thymus involution was significantly higher in SSc patients (12/63; 19%) compared with the control group (2/45; 4.4%; P = 0.022). In SSc patients with pulmonary fibrosis, incomplete thymus involution was significantly lower (3/38; 7.9%) than those without pulmonary fibrosis (9/25; 36%; P = 0.007). CONCLUSION The present study shows significantly higher frequency of radiological incomplete thymus involution in SSc compared with normal controls. Furthermore, less common occurrence of pulmonary fibrosis in SSc patients with incomplete thymus involution deserves attention. These findings may have some implications regarding the possible role of thymic abnormalities at least in some patients with SSc.