I am currently being tested for Lupus and MCTD variations and had my flu shot at my GPs when I went uo for a chest infection as I have lower immunity as am on azathioprine. The flu shot we have in UK is the 'dead' version so no live vaccine. I have it every year since 1995, prior to that would get flu every year without fail just after New Year, all that chime of midnight kissing, but since I have had my shot only have caught swine flu and that was when pandemic started and they hadn't developed vaccine for it at the time.
I don't know about whether it would interfere with the medication you are taking but would say of you are in the risk group and doctor says it is ok then I'd have it.
Crohn's, antiphospholipid syndrome, Crohn's arthritis, very low blood pressure, low kidney function, ezcema, asthma, ileostomy, numerous surgeries for abscessses & strictures. Humira - very bad permanent side effects incl joint pain, hair loss, fatigue & nreve damage. Azathioprine, immodium, simethicone, fludrocortisone, oxycodone, gabapentin, tramadol, amitriptyline, Folic acid, vit d & calcium.