Sensitisation of neuroblastoma patients and related and unrelated contacts to neuroblastoma extracts.

Sensitisation to neuroblastoma extracts was tested by the leucocyte migration inhibition technique in 8 neuroblastoma patients, 22 relatives, and 49 unrelated contacts. All three groups showed a high frequency of positive reactions compared with 61 controls having no exposure to neuroblastoma. The frequency of sensitisation could be related to closeness of contact, but the nature of the sensitising material and its mode of transmission are unknown. Virus studies by the sensitive techniques of tumour virology are suggested. The absence of case clustering and the low familial incidence of neuroblastoma indicate that simple exposure to the tumour is not a major oncogenic factor.