Lymphocyte transformation tests in workers with occupational exposure to spiramycin

By Valentino, M. - Monaco, F. - Provinciali, M. - Di Stefano, G. - Fabris, N. - Governa, M.

Pharmaceutical industry employees are exposed to drugs which can stimulate allergic reactions. Other authors have found that, in workers of pharmaceutical companies exposed to spiramycin, spiramycin-induced asthma can be diagnosed only on the basis of spiramycin inhalation tests, because IgE specific antibodies, as well as skin and patch tests, are often negative. Since lymphocytes from humans sensitised to various agents undergo morphological transformation on exposure to sensitising antigen in culture, we used a lymphocyte transformation test (LTT) following in vitro exposure to spiramycin of cells collected from healthy workers occupationally exposed or not exposed to this antibiotic. LTT was measured by [3H]-thymidine uptake into DNA of lymphocytes cultured for three days in medium containing 0-500micrograms/ml spiramycin. The number of lymphoblasts was also counted on cell smears. Lymphocytes from spiramycin-exposed subjects, incubated with spiramycin, demonstrated a statistically significant increase of [3H]-thymidine incorporation; the presence of lymphoblasts in the cultures was only slightly increased. Although other experiments with lymphocytes obtained from patients with spiramycin-induced asthma need to be performed, this pilot study suggests that LTT may be able to be used to detect early immune response changes caused by chemical agents in occupationally exposed workers.