DEPOSITION OF EOSINOPHIL GRANULE MAJOR BASIC-PROTEIN ONTO MICROFILARIAE OF ONCHOCERCA-VOLVULUS IN THE SKIN OF PATIENTS TREATED WITH DIETHYLCARBAMAZINE

  • 1 January 1984
    • journal article
    • research article
    • Vol. 50  (1) , 51-61
Abstract
The association between eosinophil degranulation, as evidenced by the deposition of granule major basic protein (MBP), and killing of microfilariae of O. volvulus in vivo following treatment with diethylcarbamazine (DEC) was investigated. Utilizing an immunofluorescence procedure for the cellular and extracellular localization of eosinophil MBP in formalin-fixed, paraffin-embedded tissues, skin biopsies were studied from onchocerciasis patients before and during treatment with topically or orally administered DEC. Before DEC, there was little or no inflammatory response in either dermis or epidermis and microfilariae were essentially intact. Immunofluorescent staining for MBP revealed some filamentous fluorescence associated with dermal collagen fibers, very few eosinophils, and no fluorescence in association with intact microfilariae. In contrast, during treatment with DEC, immunofluorescent staining for MBP revealed extensive eosinophil infiltrates in both dermis and epidermis with numerous intraepidermal eosinophil abscesses containing degenerating microfilariae. An intense extracellular immunofluorescence for MBP surrounded degenerating microfilariae in the dermis and epidermis in both the presence and absence of eosinophil infiltrates as early as 4.5 h after starting therapy. Many intact nondegenerating microfilariae were also present, but they did not show immunofluorescent staining for MBP nor a surrounding inflammatory infiltrate. Apparently, immediately following administration of DEC, eosinophils may localize and degranulate around microfilariae in the skin and release granule MBP onto or in close proximity to the parasite''s surface. Because of the striking association between eosinophil localization, degranulation, and deposition of MBP onto microfilarial surfaces, and the degeneration of microfilariae in the skin, these observations support the hypothesis that the eosinophil, through helminthotoxic granule proteins such as MBP, damages the microfilariae of O. volvulus.