Comparative ultrastructure and immunolabeling of MHC-II antigens of alveolar macrophages obtained from patients with paracoccidioidomycosis and other lung diseases.

Samples of alveolar macrophages (AM) obtained by bronchoalveolar lavage from patients with either paracoccidioidomycosis, silicosis, sarcoidosis, or allergic alveolitis were investigated by electron microscopy and immunocytochemistry to compare cellular ultrastructure and expression of MHC-II antigens in the AM cell surface. All samples of AM obtained from patients with these pathologies showed heterogeneous structural features. Although, this morphological diversity is also present in AM of healthy donors, our observations seem to indicate that in the diseases studied this morphofunctional diversity is associated with additional ultrastructural characteristics inherent to each disease. In paracoccidioidomycosis the proportion of vacuolated macrophages is significantly lower than in other diseases; this might indicate that in paracoccidioidomycosis the proportion of activated AM is smaller. We observed significant differences in the expression of MHC-II antigens. Silicosis, sarcoidosis, and allergic alveolitis do not differ significantly in the quantity of immunolabeled AM or in the distribution of the label. The percentage of AM from paracoccidioidomycosis that exhibit the MHC-II molecule is very low with poor immunolabeling. In this disease the low expression of the MHC-II molecule could be related to a decrease of the antigen presenting function by AM.

American mucocutaneous leishmaniasis.

American mucocutaneous leishmaniasis is produced by several species of Leishmania. The microorganism lives in jungle reservoirs and is transmitted by sandflies. After infection, a complex set of immunologic phenomena takes place. Most lesions tend to heal, but some clinical forms are relentlessly progressive and resistant to available therapy. Diagnosis is usually possible with classical or modern techniques. Current treatment is effective in most cases, but it is expensive and difficult to manage under field conditions. Research on the immune response has been interesting, and vaccine prevention and treatment are objects of current interest. American leishmaniasis may not always remain a sylvan disease, and urban adaptation is a distressing possibility.