Effect of long-term and low-dose administration of erythromycin on proliferation of T lymphocytes stimulated with mitogens.

The aim of the study was to assess the effect of long-term low-dose erythromycin (EM) treatment for chronic airway inflammation on proliferation of T cell subsets when stimulated with concanavalin A (Con A) and phytohemagglutinin (PHA). CD8+ cells are much more responsive to Con A compared to PHA. Ten patients with bronchiectasis were administered EM at 400 mg daily for 6 months. The extent of proliferation was assayed by [(3)H] thymidine incorporation and expressed as a stimulation index (SI). The lymphocyte subsets were analyzed including CD3+, CD4+ and CD8+ cells. The SI stimulated with Con A in the last month of therapy was significantly lower compared with that before the start of therapy (p=0.015) and 3 months after the end of therapy (p=0.002). However, EM therapy did not make a significant difference to the SIs when stimulated with PHA. CD3+, CD4+ and CD8+ cells in absolute numbers and CD4+/CD8+ ratios were not different among those harvested at the three time points. Long-term administration of EM may decrease the transformation response of CD8+ cells in patients.

High incidence of angiosarcomas in brown-fat tissue and livers of mice fed sterigmatocystin.

BDF1 female mice fed 30 or 120 ppm sterigmatocystin in their diet for 55 or 51 wk, respectively, developed angiosarcomas of the liver and of the dorsal brown-fat tissue. No tumours were observed in five mice from each group, including the controls, killed after 43 wk, but angiosarcomas were observed in mice from the test groups that died or were killed after more than 43 wk of treatment with sterigmatocystin. Thirty-four out of 53 mice (64.2%) fed 30 ppm sterigmatocystin developed hepatic angiosarcomas. Six (11.3%) of those fed 30 ppm sterigmatocystin and 27 out of the 51 mice (52.9%) fed 120 ppm developed angiosarcomas in the dorsal brown-fat tissue. Benign vascular lesions in the liver and a few angiosarcomas of the ovary and lung were also observed in mice of both test groups. No vascular changes were observed in control mice except for peliosis-like lesions in the spleens of two mice. Increases in the incidences of lung and hepatocellular adenomas were also observed in sterigmatocystin-treated mice.