Protease inhibitors in serum and urine of snakebite victims.

In victims of poisonous snakebites, serum total antichymotryptic activity but not the antitryptic activity was found to be increased. In addition, urinary antitryptic activity was found to be markedly elevated. In nonpoisonous snakebite cases, no such differences were noted. Ion-exchange chromatographic analysis of serum protease inhibitors revealed the absence of inhibitory activity in the alpha 2-macroglobulin fraction and elevation of alpha 1-antichymotrypsin in poisonous bite cases. In addition, there was a significant increase in the ratio of cationic to anionic fraction of alpha 1-protease inhibitor compared to normals. Urinary antitryptic activity could serve as a reliable index in assessing clinical improvement in snakebite victims during treatment and in differentiating poisonous from nonpoisonous cases.