When incompatible blood is given, antibodies and complement in the recipient plasma attack the antigens on the donor RBC. Hemolysis ensues The antigen-antibody complex activate the Hageman factor (factor XII), which acts on the kinin system to produce bradykinin
Still it is not advisable to take it after the expiry date written on the bottle. This is just for your information to let you know that you are safe. Anyway Saline Nasal spray is not going to do any harm even if you used an expired one. So forget about it.
Salt, like a lot of other spices, may have a best before date but does not have an expiration date. You may safely use table or sea salt for your flavoring needs and your body needs after a best before date has lapsed. Other types of salt like Rock, Pickling and Bath salts can also be used for extended amounts of time.