In vitro immune responses to PPD, extracts from Raji cells and nasopharyngeal carcinoma biopsies in NPC leucocytes.

Peripheral leucocytes from nasopharyngeal carcinoma (NPC) patients and control subjects, which included healthy subjects and patients with other cancers, have been tested against PPD and a panel of extracts from Raji cells and pooled NPC biopsies, using the blast transformation and the macrophage migration inhibition assays. The results of both assays indicated that the in vitro cell-mediated immune (CMI) responses to the Raji-cell extracts and NPC-biopsy extracts were associated with NPC. However, the peripheral leucocytes from NPC patients and control subjects responded similarly to PPD. These results are in general accord with the skin tests reported by Levine et al. (1976) and Ho, Ng and Kwan (1977b). The antigenic specificity of the NPC-associated CMI responses remains, however, to be resolved, as the extracts used in these or in the in vivo CMI studies were heterogeneous mixtures.