A lack of white blood cells can have many different reasons. Such as chemotherapy, malnutrition and a number of diseases, such as leukemia.
A lack of platelets can also be caused by chemotherapy and certain diseases such as leukemia. In addition, it can also be caused by the use of certain medication or excessive alcohol consumption.
If no cause for the leukopenia or thrombocytopenia is found, we call it unexplained.