The spectrum of lung involvement in collagen vascular-like diseases following allogeneic hematopoietic stem cell transplantation: report of 6 cases and review of the literature.

Multisystem autoimmune diseases occurring after allogeneic hematopoietic stem cell transplantation are infrequent, late-onset manifestations that resemble well-defined collagen vascular disorders. Because the lung is frequently involved in the course of connective tissue disorders, we focused on lung manifestations occurring in autoimmune diseases following allogeneic stem cell transplantation. In the present series, we report 6 patients with systemic lupus erythematous, mixed connective tissue disease, Sjögren syndrome, polymyositis, and ANCA-positive vasculitis who presented with a spectrum of pulmonary manifestations affecting the airways, lung parenchyma, and probably respiratory muscles. We identified 3 different histopathologic patterns of interstitial pneumonia consistent with the underlying autoimmune disorder: lymphocytic interstitial pneumonia and non-specific interstitial pneumonia in 2 patients with Sjögren syndrome and diffuse alveolar damage in 1 patient with ANCA-positive vasculitis. These lung manifestations had poor prognoses. Further studies are needed to determine the optimal therapy for these complications.