Immune response to melanoma extracts in three melanoma-prone families

Immune reactivity to melanoma extracts was measured by the leukocyte adherence inhibition (LAI) test in 40 members of 3 melanoma-prone families. The melanoma patients had a wide range of responsiveness to the extract, the highest responder being a 10-year survivor. As a group, family members (including spouses) without disease had significantly elevated LAI responses compared to those of unrelated controls (P less than 0.01). Within the families, members with close exposure to melanoma patients for 10 years or more had a significantly higher response to melanoma antigen than did members with 0-5 years of close exposure (P less than 0.05). Responses of spouses and members at high risk of developing melanoma (B-K mole syndrome) also correlated with length of exposure to patients, which suggests that the elevated LAI response was not genetically determined. The high frequency of positive responses to melanoma antigens in these families, particularly in spouses, suggests the presence of transmissible melanoma-associated material capable of immunizing persons in contact with melanoma patients.