Comorbid connective tissue diseases and autoantibodies in lymphangioleiomyomatosis: a retrospective cohort study

BACKGROUND: Lymphangioleiomyomatosis (LAM) and connective tissue diseases (CTDs) occur more frequently among women than men. We investigated the frequency of comorbid CTD and positive serum autoantibody findings in patients with LAM. METHODS: A total of 152 patients with LAM were prospectively and consecutively registered in the National Hospital Organization Kinki-Chuo Chest Medical Centre cohort. The clinical data were retrospectively analysed, and patients were categorised into the following three groups: a CTD group, a non-CTD-autoantibody-positive group, and a non-CTD-autoantibody-negative group. RESULTS: All patients were women. We identified five patients with comorbid CTDs (3.3%): Sjögren’s syndrome (SjS) (n = 3), systemic lupus erythematosus (n = 1), and rheumatoid arthritis (n = 1). One patient with SjS was also diagnosed with antiphospholipid antibody syndrome. The positive rate for anti nuclear antibody was 31.5% and 6.9% at dilution of 1:40 or higher, and those of 1:160 or higher, respectively. It tended to be lower in patients with LAM than in healthy women. The positive rate for anti-SS-A and anti-SS-B antibody was 7.9% and 1.8%, respectively. No significant differences in age, type of LAM, smoking status, serum vascular endothelial growth factor D level, respiratory function, treatment, or prognosis were observed among the three groups. CONCLUSIONS: Comorbid CTDs, especially SjS, in LAM patients should be considered.