Hypersensitivity syndrome (HSS) usually refers to severe drug eruption associated with systemic symptoms and eosinophilia. Interleukin (IL)-5 regulates eosinophil counts with the help of IL-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF). Blood IL-5 levels have been reported to be increased in patients with eosinophilia secondary to parasitic infections or idiopathic eosinophilia, but have never been evaluated in drug-induced eosinophilia. The aim of our study was to determine whether IL-5, IL-3 and GM-CSF are involved in eosinophilia in patients with drug-induced HSS. Plasma levels of IL-3, IL-5 and GM-CSF were assayed by ELISA in seven patients with drug-induced HSS, in eight patients with cutaneous adverse drug reactions not associated with eosinophilia, and in five patients with eosinophilia unrelated to drug treatment. IL-5 levels were normal in all eight patients with drug eruptions without eosinophilia, and increased in five of the seven patients with HSS. In the latter patients, IL-5 levels peaked several days before highest eosinophil counts were noted, and returned to normal within a few days, even when eosinophilia persisted. In patients with eosinophilia unrelated to drug treatment, IL-5 levels, although significantly increased remained lower than in HSS patients. IL-3 and GM-CSF could not be detected in any group, at any time. Our results show that IL-5 is involved in drug-related eosinophilia. As IL-5 production was only involved in the early stages of the reaction, it is suggested that IL-5 mainly derives from activated lymphocytes rather than eosinophils. Our results support the clinical relevance of previous in vitro findings. Further studies are needed to test whether assays of IL-5 production by lymphocytes of patients stimulated by the suspected drug and/or its metabolites, are useful in establishing causality in drug-induced reactions associated with eosinophilia.
While germ cell regulation of Sertoli cells has been extensively explored in adult rats in vivo, in contrast, very little is known about germ cell influence on Sertoli cell function at the time when spermatogenesis begins and develops. In the present study various Sertoli cell parameters (number, testicular androgen binding protein (ABP) and testin, serum inhibin-B and, indirectly, follicle-stimulating hormone (FSH)) were investigated after the exposure of 19-day-old rats to a low dose of 3 Grays of gamma-rays. Differentiated spermatogonia were the primary testicular targets of the gamma-rays, which resulted in progressive maturation depletion, sequentially and reversibly affecting all germ cell classes. Testicular weight declined to a nadir when pachytene spermatocytes and spermatids were depleted from the seminiferous epithelium and complete or near complete recovery of spermatogenesis and testicular weight was observed at the end of the experiment. Blood levels of FSH and ABP were normal during the first 11 days after irradiation, when spermatogonia and early spermatocytes were depleted. While the number of Sertoli cells was not significantly affected by the irradiation, from days 11-66 after gamma-irradiation, ABP production declined and FSH levels increased when pachytene spermatocytes and spermatids were depleted and the recovery of these parameters was only observed when spermatogenesis was fully restored. Comparison of the pattern of change in serum levels of inhibin-B and testicular levels of testin and of germ cell numbers strongly suggest a relationship between the disappearance of spermatocytes and spermatids from the seminiferous epithelium and the decrease in levels of inhibin-B and increase in levels of testin from 7 to 36 days post-irradiation. Levels of testin and inhibin-B were restored before spermatogenesis had totally returned to normal. In conclusion, this in vivo study shows that pre-pubertal Sertoli cell function is under the complex control of various germ cell classes. This control presents clear differences when compared with that previously observed in adult animals and depends on the Sertoli cell parameter of interest, as well as on the germ cell type.
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