The mechanism of fibrosing vasculopathy in lung allograft is poorly understood. A 58 year old man received a bilateral lung transplant for interstitial lung disease. The patient's initial biopsies showed intermittent evidence of acute cellular rejection which was treated with rituximab and monthly intravenous immunoglobulin, followed by thymoglobulin which served to clear the histologic signs of rejection. Of note, his nine month post-transplant biopsy showed evidence of eosinophilic vasculitis. Subsequent testing with an ANCA panel was negative and the HLA donor-specific antibodies never showed a significantly high level. The patient continued to clinically decline with worsening spirometry readings and passed away seventeen months post-transplant. At autopsy, severe fibrosing vasculitis was noted most prominently in bilateral lower lobes. As ANCA, ANA, and HLA antibodies were negative, this was thought to be a case of de novo autoimmune vasculitis in the allograft. An immunohistochemical stain for alpha 1 chain of collagen V was performed and detected strong positivity predominantly in the tunica intima and focally in the media of pulmonary arteries (Fig. 1). Collagen V is a minor type of collagen essential for tissue elasticity and compliance and autoimmunity to collagen V, particularly to the alpha 1 subtype, has been recently implicated in the development of bronchiolitis obliterans in lung transplant patients. It is thought that in transplanted lung allografts the extensive repair may result in excess collagen V alpha one chain production/expression. Our findings suggest that overexpression of collagen V alpha one in the allograft arteries may explain the severity of the vasculopathy observed in this case. This highlights an rare but important potential cause for lung allograft failure.

CITATION INFORMATION: Daoud E, Butt Y, Torres F, Jose T. HLA, ANA, and ANCA Negative Vasculitis in Lung Transplantation Due to Overexpression of α1 Collagen V. Am J Transplant. 2017;17 (suppl 3).

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