Do all the immunosuppressants give you teeth and gums side effects?

Yes. Immunosuppressant drugs shut down the immune system such that the body has a harder time warding off infection. The teeth and gums can be afftected by an increase in cavities and dry, red gum tissues. Easily treated by a dentist with Fluoride treatments and saliva substitutes.
No. Cyclosporine is known to cause gingival hypertrophy and one may need a visit to an oral surgeon to have excess tissue removed. Other immunosuppressive medications usually do not have this side effect.
Pretty much. Immunosuppressants are a nasty class of drugs. They're necessary in certain circumstances, but they are really hard on your mouth. Meticulous oral hygiene and lots of Fluoride exposure are both important.