Thanks for the clarification on some of the values.
So here's some more info for you, and I hope this makes sense. In the context of an autoimmune disorder, you could develop higher titers of antibodies to all sorts of different things, ranging from proteins in your cell, to proteins on your cell surface, to even DNA itself, which you definitely shouldn't have autoantibodies to. Now, it's certainly reasonable that you might also develop higher titers for antibodies against, say, the measles antigen too. HOWEVER, having this higher antibody titer ALONE does not cause disease, at least not for the measles antibody titer. It's merely an association, rather than a cause/effect relationship, as far as I know. Look at it like this: say you have an autoimmune disease like lupus, and I draw your blood and look at your antibody titers to 10 different molecules. They may be ALL really elevated, but that doesn't mean that having more antibodies (or having STRONGER antibodies) is associated with ANY of the disease process itself. They're simply markers that you have something going on with your immune system. But just because you have them, does NOT mean you are sick. Now, certain autoantibodies (like antibodies against your own DNA, or against certain proteins), we know those antibodies are destructive. However, higher than normal antibody titers for measles? That ALONE may not mean anything.
But, if you were to suddenly develop aching joints, or an unusual rash, or kidney failure, we'd start fishing for an autoimmune disease, and THEN the information might become more important (although it may or may not change how we manage the disease).
As it is, we really don't understand autoimmune diseases that well. There's so much research going on that looks at how we develop antibody responses to vaccines, and we're still working out how we know our own proteins from those of invaders, or from those of cancer cells, for instance. Autoimmune diseases are a pretty big black box, and when you get one, it can be pretty depressing because many of our therapies aren't very specific: they depend on knocking down your immune system with steroids to try and chill out your body from making antibodies against your own body, which is clearly not good. However, we don't know why people get them, nor how to treat them very well (although we're getting better).
Were I you, I'd chalk it up to having a pretty good immune response, and call it a day. Remember, the "norms" for any lab value are established like anything else: they look at where 95% of people fall, call that normal, and call everything else abnormal... even though it may be perfectly okay for you to have an even higher value. I wouldn't get any other lab tests, or work it up further.
And if you have the misfortune of developing an autoimmune disease, or symptoms of one, bring up our conversation and mumps and rubeola titers. It won't likely lead to any amazing diagnoses, but it can add a little more information to the picture.
And, 1 more thing... doesn't sound like you need a rubella shot either, which is great.
I hope all this makes sense. Please let me know if it doesn't.
-Phil
Hope this helps. If it did, please ACCEPT my answer, and leave me some feedback. Thanks!