Dermotossicità di una preparazione di nematocisti di Carybdea marsupialis

Carybdea marsupialis (Cnidaria, Cubozoa), a jellyfish found in the Adriatic Sea only in recent years, was previously considered innocuous and only recently has been described by us as dermotoxic to man. In the present study we evaluated the activity of a purified preparation of nematocysts of Carybdea marsupialis in men. A crude nematocystic fraction was tested by prick and patch test in 7 volunteers and by scratch-patch test in 20. In the prick test 0.1 ml of the suspension of nematocysts was applied on forearms, and then a slight prick was made with a needle at the centre of the drop. The reaction was read after 20 min. In the patch test 0.1 ml of nematocysts suspension were applied on forearms and covered by a suitable patch-tape. The reaction was read after 48 and 96 hrs. The scratch patch test consisted in producing a net (1 cm x 1 cm) of 3 vertical and 3 horizontal lines with a needle on the forearms without making it bleed. Then, 0.1 ml of the suspension were put on the scratched area and covered with a patch tape. The reaction was read after 48 and 96 hrs. All volunteers were also tested with distilled water. All the 7 subjects tested by prick and patch test resulted negative, while various degrees of erythema were observed only in 4 subjects tested by scratch-patch test. Our results confirm that Corybdea marsupialis is dermotoxic, even if only subjects with particularly sensitive skin suffer from its sting. This study shows that the procedure of purification we used is valid to maintain the dermotoxic activity of the preparation. The nematocysts separated from their cellular matrix appear unable to penetrate the intact skin, but maintain their capacity to release venom. In fact the purified preparation was inactive if tested in the prick and in the patch test. In contrast, its dermotoxic action was present when the skin barrier was altered as in the scratch-patch test. Therefore, scratch-patch test represents the most suitable method to evaluate the dermotoxicity of purified nematocysts.