DETECTION OF TUMOR-NECROSIS-FACTOR-ALPHA IN SARCOIDOSIS AND TUBERCULOSIS GRANULOMAS USING IN-SITU HYBRIDIZATION

Aims-To determine the site of tumour necrosis factor alpha (TNF alpha) product and mRNA in granulomas. Method-In situ hybridisation with dig oxigenin labelled or biotinylated oligonucleotide probes was used to d emonstrate the presence of total mRNA, and then the presence of TNF al pha mRNA in the biopsy specimens of 37 granulomas (31 sarcoidosis, six tuberculosis). Results-TNF alpha mRNA was detected in epithelioid cel ls, giant cells, and lymphocytes in the granulomas. Some sarcoidosis s pecimens did not contain detectable mRNA for TNF, but did contain TNF peptide in the epithelioid or giant cells on immunostaining. This may have been due to stored TNF present in cells in which mRNA for TNF is no longer being produced. Conclusion-The results suggest that giant ce lls should not be regarded as effete cells, as they contain large amou nts of mRNA and seem to be actively producing TNF alpha.