Human Genetics and the Immune System

Ronnee Yashon, Michael R. Cummings

• Éditeur: Momentum Press
• Année: 2019
• ISBN:
  9781946646576
• Sujet: Scienze biologiche
• Sous-sujet: Genetica e genomica

Illness is a part of life. For many years we have known about disease. But we were not always so smart. The Black Plague ravaged Europe between 1347-1352 and killed 30-80 MILLION people. No one knew how people caught the condition and lots of ideas failed–people just died. But not everyone died; possibly their immune systems help them fight off these "invaders".

Today we know about bacteria, viruses, cancers and other invaders and we usually let them run their course. That is because our bodies detect and fight them. That is immunity.

CHAPTER 1

General Information

Most of us do not think about the immune system, but it works defending us and keeping viruses, bacteria, and pollution at bay. History shows we have amazingly improved. From the times of the Black Plague (see Figure 1.1) where doctors wore masks to keep from getting sick, today, we have medications that boost and slow down our immune systems.

Figure 1.1 Plague Mask Worn by Doctors During the Black Plague

Active immune cells, B cells and T cells develop as white blood cells in the bone marrow. They both are lymphocytes. While B-cells mature in the bone marrow, T-cells travel through the bloodstream to the thymus gland—a small organ between the lungs and behind the sternum—and mature there.

This could explain where early in diagnosis of leukemia samples of bone marrow was taken from the sternum.

When your doctor takes a blood sample for testing, you may wonder what he or she is looking for (see Table 1.1).

Table 1.1 Components of blood

Test to find	Purpose	Normal	Abnormal
# of red blood cells	Carry oxygen to cells	4.1−5.1 million	High: Low: Anemia
# of white blood cells	Fight invaders (T and B cells)	45−10,000	High: active infection Low: difficulty healing
Amount of ­hemoglobin	How much oxygen is carried.	14−17 g/dl	Oxyhemoglobin carries the oxygen to the cells. Low: not enough oxygen goes to cell

If the numbers are low: serious anemia can cause a lack of oxygen and is treated by iron supplements or transfusions if necessary.

If the number is high, it signals that ...