Compositions and methods for the prevention and treatment of mast cell-induced vascular leakage

A method of inhibiting vascular leakage in a subject having a mild or severe form of Japanese encephalitis virus (JEV) infection, the method comprising:

• (a) obtaining a biological sample from the subject;
• (b) determining the level of chymase, tryptase, or a combination thereof in the biological sample from the subject;
• (c) comparing the level of chymase, tryptase, or a combination thereof in the biological sample to a first reference level of chymase, tryptase, or a combination thereof and a second reference level of chymase, tryptase, or a combination thereof;
• (d) correlating the level of chymase, tryptase, or a combination thereof in the biological sample with the mild or severe form of JEV infection in the subject, wherein if the level of chymase, tryptase, or a combination thereof is greater than the first reference level and the second reference level, the subject is diagnosed as having the severe form of JEV infection, and wherein if the level of chymase, tryptase, or a combination thereof is greater than the first reference level but less than the second reference level, the subject is diagnosed as having the mild form of JEV infection;
• and
• (e) administering a mast cell modulator with an aggressive treatment regimen to the subject identified as having the severe form of JEV infection or administering a mast cell modulator to the subject identified as having the mild form of JEV infection, wherein the mast cell modulator comprises cromolym, ketotifen, or montelukast.