A quantitative assessment of the long-term prognostic value and clinical usefulness of recall antigen reactions in patients with malignant melanoma is not available. The authors evaluated longitudinal observations of survival made in 846 patients over a 12-year period. Each patient was initially studied with Mantoux-type recall antigen skin tests. The patients were categorized with respect to the following: high (greater than 5 mm) or low (less than or equal to 5 mm) averaged skin test reaction diameters at 48 hr; Clark level; tumor stage (I = localized tumor, II = local extension and/or region lymph node metastasis, III = systemic metastasis); ulceration; site of primary; histologic type; age; and sex. The percentage of high reactors in Stages I, II, and III were 44.3%, 37.4%, and 25%, respectively. Survival was evaluated with the Cox-Mantell hazard function model and the Cox regression model. The significant (chi-squared; probability) risk factors detected were tumor stage (94.58; less than or equal to 0.0001), Clark level (19.37; less than or equal to 0.0001), sex (16.97; less than or equal to 0.0001), and skin test reactivity (7.48; less than or equal to 0.0062). A significant relationship also was detected between skin test reactor status and the tumor stage (p less than or equal to 0.0330). When evaluated within each stage of disease, skin test reactivity predicted survival only in Stage II patients (p less than or equal to 0.0080). Five-year survival estimates among Stage II patients were 58% among high reactors and 38% among low reactors.(ABSTRACT TRUNCATED AT 250 WORDS)