he Mita clinic in Kodaira city, Tokyo, has carried out blood examination and thyroid ultrasound examination on 1,500 patients, including children. Mamarevo Magazine here interviews Dr. Mita, the head of the clinic, about what he has seen through the blood exam.
What is a ‘differential white blood cell count’? What can we learn from checking it?
Q: Please tell us about the examinations that are conducted by the Mita clinic.
A: Since October 2011, we have carried out blood examinations, which include ‘differential white blood cell count’, and thyroid ultrasound examinations. The WBC (white blood cells) consist of 5 different kinds of cells: neutrophil, lymphocyte, eosinocyte, basophil, and monocyte. The ‘differential WBC count’ consists of comparing the ratio of occurrence between these five cell types. Workers who work in environments with high radiation levels have to take ‘ionized radiation health checks’, which particularly focus on ‘differential WBC count’.
In the current situation, thyroid ultrasound examinations have been getting a lot of attention, but I consider differential WBC count to be rather important as well, for assessing the effects of radiation.
Q: Do you mean that we can understand the impact of radiation on humans by checking differential WBC count?
Mita: Yes. Blood is produced in the bone marrow which is one of the organs that are most vulnerable to radiation. If the bone marrow is exposed to high doses of radiation, the quality and ratio of blood corpuscle cells can be changed. The values of differential WBC count can be affected easily by even tiny inflammation in the body. So, in our clinic, we first take a close look at patient’s condition such as the symptom of inflammation and liver function. If a patient is diagnosed with such conditions, we ask him/her to undergo the blood examination only after full recovery.
It is possible to see tendencies of areas by evaluating the data of hundreds and thousands of people.
So, if the mean value of the result of the collective blood exams is not very good, it can indicate the need for decision-making of whether one should keep living in the area.
By the way, in the ongoing Fukushima Health Management Survey in Fukushima prefecture, the differential WBC counts have been conducted only on residents who have resided in the evacuation zone. But I think that all the residents in Northern Kanto and Metropolitan Tokyo areas should be encouraged to take this examination.
Q: You have found changes in the children’s differential WBC counts. Could you tell us about it?
Mita: Yes. Our patients mostly come from Tokyo, Chiba, Kanagawa, Saitama, and other Northern Kanto areas. I have found an obvious decline of neutrophil value in leukocyte (WBC) of these children.
The pediatricians’ general textbook says that reference value of neutrophil for healthy children (6-12 years old) is between 3000 and 5000. 3000 is considered as the threshold value. But the mean number of neutrophil values of the children who have visited our clinics since the accident has decreased to 2500. The mean value should normally be 4000, but it has shifted to 2500. It is lower than the threshold value of 3000. I think this points at a serious problem.