[Immunologic profile of a patient with lymphocutaneous sporotrichosis]

Sporotrichosis is characterized by a wide range of clinical manifestations from mild fixed cutaneous forms to systemic dissemination of the disease, despite an apparent regular pattern of virulence of the etiological agent, S. schenckii. These facts suggest that immunological mechanisms of the host could play an important role on the pathogenesis of the mycosis. On this basis, an immunologic survey was carried out in patients with lymphocutaneous sporotrichosis. Cell-mediated immunity was evaluated by means of lymphocyte transformation stimulated with phytohaemagglutinin and the response to several intradermal reaction antigens. Lymphocyte blastic transformation was normal as compared with a control group. All patients were positive at least against one of the antigens tested. These results indicate that this group of patients did not show any cell-mediated immunity deficiency. Serum immunoglobulins (IgG, IgM, IgA), and C3 measured to evaluate humoral immunity, were also within normality. Since many cases of sporotrichosis cure with the administration of potassium iodine, whose mechanisms of therapeutic activity are unknown, a possible impairment in the management of iodine was investigated, with the premise that iodine enhances the host defenses rather than acting against the fungus. Thyroid function tests performed in all patients to support this hypothesis, gave normal results. These data permit to conclude that susceptibility to sporotrichosis in the affected patients does not depend on gross abnormal humoral and/or cell-mediated immunity, and their response to potassium iodine is not related to deficient thyroid function.