the short-term effects of sulfur mustard gas on the complement system

background: the serum levels of c 3 , c4, and the total hemolytic activity of complement system (ch50) of patients ex­posed to mustard gas (mg) in the battlefield were measured in this study. methods: c3 and c4 were measured by single radial immunodifusion and ch50 was evaluated according to total hemolytic activ­ity of the serum. results:   the serum levels of c 3 showed a significant increase on day 3 after exposure to mg. the serum levels of c 3 in the sera of patients collected during 4-18 and 19-31 days after exposure to mg were also found to have increased significantly com­paring to those of the controls. the levels of c 4 in the sera of patients collected from the patients during 4-18 and 19-31 days after exposure were also found to be significantly higher than those of the controls. however the increase in the serum lev­els of c 4 were not in the same magnitude as those of the c 3 . the serum ch50, which is a measure of the total hemolytic activ­ity of classical complement system also showed a significant increase in patients' sera on day 3 and in the sera collected dur­ing 4-18 days after exposure. however, the ch50 in the sera of patients showed a decrease in the sera collected during 19-31 days after exposure to mg. conclusion: since c3 is an acute phase protein as well as a complement component, these results are discussed in terms of a vigorous acute phase response and activation of the complement system.