ABSTRACT
Connective tissue disorders (CTDs), which are also referred to as collagen vascular diseases, comprise a heterogeneous group of systemic autoimmune disorders characterized by immune-mediated end-organ dysfunction. CTDs include systemic sclerosis (scleroderma), rheumatoid arthritis, systemic lupus erythematosus, primary Sjögren syndrome, polymyositis and dermatomyositis, mixed CTDs, and undifferentiated CTDs. Consensus statements on the criteria for diagnosis of each of the aforementioned disorders now exist. 1 , 2 A common feature uniting this heterogeneous group is autoimmune-mediated organ damage, with the lungs being a frequent target. 3 Lung involvement may include the parenchyma, pleura, airways, or vasculature and combinations thereof. All patients with CTDs are at risk for the development of interstitial lung disease (ILD); however, ILD is more likely to occur in patients with systemic sclerosis and rheumatoid arthritis than in those with other CTDs. 4 Many patients have a subclinical form of ILD that although evident on a high-resolution computed tomography (HRCT) scan, may remain asymptomatic for decades. The ILD associated with CTDs generally has a better prognosis than does idiopathic interstitial pneumonia of equivalent severity. 5 Which patients with CTD-associated lung diseases should receive therapy is unknown. No data to support initiation of any type of immunosuppressive therapies in patients with CTD and asymptomatic or mild ILD exist. In cases involving more severe forms of ILD or symptomatic patients, the following factors are usually considered when starting immunosuppressive therapies: severity of lung disease, rate of progression, underlying CTDs and extrapulmonary disease activity, patients’ age and comorbid conditions, and likelihood of a response (assessed on the basis of radiographic patterns). Although these factors may reflect expert opinion and guidelines, little or no robust evidence-based data on when and how to treat patients with CTD and advanced or symptomatic ILD are available. 6 An exception is the body of data on patients with systemic sclerosis, who constitute a population that is discussed further in the following section. Patients with CTD refractory end-stage ILD are considered for lung transplantation. Historically, such patients were considered poor candidates for lung transplantation because of the systemic nature of their disease and the advanced stages of presentation (characterized by debilitation and overt immunosuppression). With the improved outcomes in lung transplantation and some success in the management of extrapulmonary diseases, lung transplantation is increasingly being considered for selected patients with CTDs who otherwise meet the criteria for lung transplantation. Most of the data on lung transplantation in cases involving CTDs concern patients with systemic sclerosis. Consequently, this chapter focuses on lung transplantation in patients with systemic sclerosis.
