Characterization of the biological activity of Cryptococcus infections in surgical pathology. The Budding Index and Carminophilic Index.

The histologic spectrum of cryptococcosis varies greatly, including florid granulomatous reactions, necrotizing infections, fibrotic nodules or "cryptococcomas", and gelatinous reactions containing scant or absent inflammatory cells. These variants are thought to represent differences both in the duration and activity of the infection as well as the nature and extent of the immune response. However, there exists no method for the quantitation of these factors in tissue sections to form an estimate of the activity of the infection. This communication reviews 16 cases of cryptococcosis and describes a method for the estimation of the biological activity of cryptococcosis in tissue sections by determination of the percentage of budding organisms (Budding Index) and yeasts having carminophilic capsules (Carminophilic Index). These indices may be useful for the assessment of cryptococcal viability and divisional activity within a lesion, as well as estimation of the fungistatic or fungicidal effects of therapy.