Granulomatous and lymphocytic interstitial lung disease: a spectrum of pulmonary histopathologic lesions in common variable immunodeficiency--histologic and immunohistochemical analyses of 16 cases.

Common variable immunodeficiency is a primary immunodeficiency of unknown etiology characterized by low serum immunoglobulin G, a decreased ability to make specific antibodies, and variable T-cell defects. Approximately 10-30% of patients with common variable immunodeficiency develop clinical evidence of a diffuse parenchymal lung disease with a constellation of histopathologic findings termed granulomatous and lymphocytic interstitial lung disease. In this study, we characterized the histologic and immunohistochemical features in a series of 16 cases diagnosed by open lung biopsy. Peribronchiolar and interstitial lymphocytic infiltration, granulomatous inflammation, and organizing pneumonia were consistent features; interstitial fibrosis with architectural remodeling was also found in a subgroup of patients. By immunohistochemistry, a predominance of CD4+ T lymphocytes with variable numbers of CD8+ T cells and B cells was present, with a striking absence of FOXP3-positive T-regulatory cells. This heretofore unrecognized immunohistochemical finding needs further investigation for a potential role in the pathogenesis of the condition. The presence of interstitial fibrosis with or without architectural remodeling in a subset of patients also needs additional study, for effect on prognosis.