To answer this we need to remember how the inflammatory process works, a cut is open where the pathogen enters the body, and the histamine is released creating vasodilation, which increases the blood flux, redness, and swelling Leucocytes like phagocytes arrive and platelets start to seal the broken capillaries. Therefore the order is as follows.
Pathogens enter the body (1)
White blood cells travel to the area (4)
Histamine is released (2)
Cell recognizes invader (5)
Redness and swelling occur (3)
