How can I help my child who has a low white blood cell count?

Follow up. The best answer I can give is to be sure to follow up with appointments and blood tests. There could be a number of reasons for low white blood count, some of them serious and some not, and the best thing one can do is to be sure the child has close follow-up with the pediatrician. If the cause is known to be an immune deficiency, then keeping good hygiene is very important.