Antiscorpionic Serotherapy: Clinical Efficacy, Preclinical Aspects, and Prospects for Future Nanotherapy

Djilani, Salma; Sadine, Salah Eddine; Kerboua, Kheir Eddine

Algerian Journal of Health Sciences
Volume 2, Numéro 2, Pages 112-117
2020-09-02

Antiscorpionic Serotherapy: Clinical Efficacy, Preclinical Aspects, And Prospects For Future Nanotherapy

Auteurs : Djilani Salma . Sadine Salah Eddine . Kerboua Kheir Eddine .

Résumé

Global incidence of scorpionism is estimated at more than 1 million cases of envenomation per year, with nearly 3.000 associated deaths. In Algeria, statistics of 2019 show 46797 cases of stings, including 39 deaths. The problem with antiscorpionic serotherapy is that antivenoms are generally very old products, so they rarely justify a clinical efficacy proven by controlled trials. Moreover, it has been controversial for several years.Algerian Antiscorpionic Serum, one of the few products with established clinical efficacy, has previously gone through clinical observations from all regions of the country, since its development from 1936 to 1946; Among 3089 patients, including 655 serious cases, and 148 cases of extreme severity, the success rate was 90.4% (No symptomatic treatment at that time). Facing the notable insufficiency of controlled clinical trials, many scientists rely on the neutralizing capacity of antivenom in mice to define the appropriate doses needed. However, several parameters limit the direct extrapolation of this parameter to an appropriate dose for humans. A prior incubation of the venom and antivenom before administration to mice rules out the test conditions of accidental envenomation; f(ab')2 immunoglobulin fractions have a poor diffusion due to their high molecular weight (∼ 100 KDa versus 3 to 7 KDa for scorpionic toxins) and the lethal median dose (LD50) remains a highly variable indicator. Currently, new approaches to antibody engineering have allowed development of new "Nanobodies" fragments without light chains, from camelid antibodies. They are not very immunogenic, and have a better affinity and a much lower molecular weight (11 to 15 KDa) giving them a very good tissue diffusion. An interesting perspective seems to be offered to antiscorpionic serotherapy.