A high white blood cell count is an indication of infection: an ‘infection marker’ as it’s called. White blood cells increase to fight infection. They remain high even after recovery from infection – except perhaps when antibiotics have been successfully used. In 2014, after a routine blood test for diabetes, it was found that June had a high white blood cell count. This eventually went back to normal. High white blood cell count can be caused by corticosteroids – but June wasn’t taking prednisolone in 2014. Can also be caused by antibiotics.