Boarding passes disappeared from Passbook

Hi everyone

I plugged my iphone 5 to an old mac pro I have and for some reason all the boarding passes are gone. only a few left from random dates. I checked the itunes on my old mac and no backup has taken. I plugged the iphone on my new macbook pro and it synced. so the last sync has no boarding passes. I never synced to icloud so cant retrieve it from there. Could you please let me know if these boarding passes are gone or if there is a way I can get them back?

Thank you for the help