The commonest reason for increase in no of white blood cells is any infection.
It is not common to have a leukemia and if you have family history and also altered cells in your blood report then only you suspect.
In leukemia the white blood cells are not formed completely and premature cells are released and you have to detect these.
Another thing for your Pylori treatment, is it is a risk for stomach ulcer/cancer if you do not get it treated and it is not related to Leukemia.
Do not worry and go for an annual checkup and follow whatever the clinician advices you.
I was treated for Pylori and over a year ago and do not have any symptoms,can I assume that the bacteria has been eradicated and will not return.
Thanks for the advice.