Farmer’s lung with a high CD4/CD8 ratio lymphocytic alveolitis: A case report

Abstract

Background: Farmer’s lung is one of the most common forms of hypersensitivity pneumonitis (HP). It is a granulomatous inflammatory disease of the pulmonary parenchyma caused by the immune response to inhalatory antigens, mostly actinomycetes or moulds. The diagnostics range from imaging techniques to bronchoalveolar lavage, which demonstrates a typical lymphocytic alveolitis with a low CD4/CD8 ratio in only one third of patients. It is hypothesised that a low CD4/CD8 ratio predicts a prosperous course of the disease, but a high CD4/CD8 ratio lymphocytic alveolitis has yet to be determined to announce a more severe clinical course.

Case report: This case report presents a patient with farmer’s lung, with a high CD4/CD8 ratio lymphocytic alveolitis and the dynamics of her disease in relation to her environment and therapy. There was clinical improvement, even without therapy, each time the patient moved away from the risk home environment and a setback when she returned back home. Eventually, lung fibrosis with pulmonary hypertension developed.

Conclusion: Our case report does not only illustrate a clear etiological correlation between exposure to causative antigens and progression of farmer's lung, but also emphasises the necessity of early recognition and thorough sanitation of patients’ living space. Furthermore, a high CD4/CD8 ratio lymphocytic alveolitis, which is not typical for HP, is indicative of a continuous exposure to causative agents, leading to chronical inflammation and thus a worse clinical course of the disease.