Titers: chicken pox and measles

[Guest guest]

What does it mean when a child who had chicken pox as a child does not show it

in the titers?

My son was given the MMR vaccine and without us knowing was exposed to chicken

pox the same day.

He had chicken pox 2 weeks later and me and the rest of the family had the

chicken pox 2 weeks after that.

This was 16 yrs ago.

We had the titers for chicken pox and measles done recently and he shows NO

exposure to chicken pox. I am sure that it was chicken pox but the doctor

thinks it might have been measles. We are having my daughter tested to see if

she shows it in the titers.

Has anyone heard of a case like this? Does anyone have an idea why?