Cell counts after BAL showed predominant CD4 cells [8].In some cases, biopsy reveals pulmonary inflammation with features of lymphocyte predominance, desquamative alveolitis, histiocytosis, interstitial fibrosis, and non-necrotic granulomata that are overall non-specific findings suggestive of diffuse alveolar damage [1]. Here, CD4 is linked to hypersensitivity pneumonitis.