effects of acute or chronic exposure to Lewisite from experimental situations.

There is a wealth of information on the acute and short-term effects of sulfur mustard on human and animal skin. However, there is a paucity of literature describing delayed or long-term effects. Based on a small body of information derived from fairly crude data, observation periods as long as 35-45 years may be required to produce meaningful human data. To our knowledge, the only prospective study of long-term cutaneous effects of acute sulfur mustard exposure on human skin is that of Balali (1986). This study is now in its fourth or fifth year and should provide very valuable information in 15-20 years.

Human data derived from patients previously treated in Russian and Eastern European studies of the agent psoriasin may also be useful in determining the delayed effect of short-term  administration of suberythema dosages of sulfur mustard. We are now approaching 20 to 25 years from the beginning of these studies. Follow-up of those participants, if properly done, now would be of invaluable help in determining delayed effects of acute sulfur mustard exposure. It is possible that some studies were designed using chronic dosing and adequate control populations. If so, patients in this category may aid in determining if chronic sulfur mustard administration in subinjury dosages, like nitrogen mustard, may lead to the development of cutaneous cancer.

Ideally, if one were able to determine successfully who participated, and when, in the variety of experiments carried out by the U.S. Armed Forces and its Allies in World War II, an examination of this group, potentially numbering in the thousands, would serve as an excellent source of data on the long-term effects of sulfur mustard on the skin.

There are also numerous gaps in the literature relative to the acute and long-term effects of Lewisite skin exposure. Lewisite has been subjected to much less intense investigation than sulfur mustard. Very little is known regarding its specific effect on skin; data on such basic areas as absorption, disposition, and excretion after skin exposure are minimal. Although much is known of Lewisite's biochemical interactions, little is known of the morphologic sites of these interactions. Microscopic examination of affected skin has yet to be pursued in depth. Most studies have been impaired, as has been work on sulfur mustard exposure, by the lack of good animal model systems.

Studies on the carcinogenicity or noncarcinogenicity of Lewisite