From the Rugbyologist's blog:  St. Louis Hero Needed

There is a 14 month old child in St. Louis in desperate need of an AB negative blood donor.

Hospitals in St. Louis are in desperate need of AB negative blood.

If you have this rare blood type, please contact Josh Witten immediately either by email or facebook or twitter (@rugbyologist).

Edit: a note from Josh Witten

Fortunately, it appears that enough donors have been identified.

I would, again, encourage everyone, regardless of blood type to donate as often as possible.