Immunohistochemical Analysis of Granulomatous Lung Lesion in Primary Pulmonary Cryptococcosis

Abstract

Immunohistochemical analysis was performed in a case of pulmonary cryptococcosis that showed granulomatous pneumonia. The patient had no immunologic defects or other diseases. To cryostat sections, the immunocytes in granulomatous lesion were examined by application of monoclonal antibodies for T-lymphocytes, B-lymphocyte, macrophage series cells, lymphokines containing gamma interferon (γIFN), interleukin 1 (IL-1) and interleukin 2 (IL-2), and interleukin 2 receptor (IL-2R).
CD2⁺ cells, CD3⁺ cells and CD4⁺ cells were in and around the granulomas. On the other hand, CD8⁺ cells were around the granulomas. In granulomatous lesions, the CD4/CD8 ratio was 2.0. Some T-lymphocytes were considered as activated lymphocytes showing OKDR⁺, IL-2⁺, γIFN⁺ or IL-2R⁺. The lymphoid cells that aggregated near the granulomas were B-lymphocytes showing CD21⁺, CD24⁺, s-IgD⁺, s-IgM⁺, OKDR⁺. According to these results they were mature B lymphocytes. Alveolar macrophages (AMs) were CD11⁺, CD36⁺, IL-1⁺, OKDR⁺. Epithelioid cells were CD4⁺, CD11⁺, CD36⁺, OKDR⁺, IL-1⁺, IL-2R⁺. CD1⁺ cells showing dendritic forms were scattered in granulomas. They were recognized to be Langerhans giant cells.
These results suggest that in pulmonary cryptococcosis the formation of epithelioid cell granulomas is mainly induced by CD4⁺ cells (helper/inducer T-lymphocytes). Additionally, Langerhans giant cells and mature B lymphocytes may be related to humoral immunity in pulmonary cryptococcosis.