DETECTION OF INTERLEUKIN-5 MESSENGER-RNA AND INTERLEUKIN-5 PROTEIN INBRONCHIAL BIOPSIES FROM ASTHMA BY NONRADIOACTIVE IN-SITU HYBRIDIZATION AND IMMUNOHISTOCHEMISTRY

Recently direct evidence for the role of interleukin-5 (IL-5) in eosin ophilic inflammation in the radioisotope-labeled IL-5 complementary RN A probes. Radioisotope-labeled probes, although we attempted to detect IL-5 messenger RNA in the bronchial biopsy specimens from patients wi th asthma using nonradioactive in situ hybridization, which gives rapi d results. Bronchial biopsy specimens were obtained from eight patient s with asthma and seven diseased control subjects. IL-5 complementary DNA probes were labeled with digoxigenin-deoxyuridine an immunohistoch emistry technique. Positive hybridization signals were observed in sir of the eight biopsy specimens fi om patients with asthma. Pretreatmen t with ribonuclease or hybridization with an unrelated probe produced negative results. Immunohistochemical staining of serial sections with a monoclonal antibody to IL-5 revealed that a few cells within the mu cosa positively stained, suggesting active synthesis of IL-5. Biopsy r esults from the seven diseased control subjects did not show any hybri dization signal. These results confirm and asthma, and suggest that di goxigenin-labeled IL-5 complementary DNA probes would be a powerful re search tool.