Brief Answer:
The increase and decrease in white blood cells affect immunity

Detailed Answer:
Hi XXXXXXX
Thanks for writing in to us.

I have read through your query in detail.
Please find my observations below.

1. Blood contains white blood cells which help in fighting disease conditions. The red blood cells are for transport of oxygen through hemoglobin.

2. The white blood cells are of different types and in this there is a group known as granulocytes (cells having granules) and lymphocytes.

3. Neutrophils are a type of white blood cells in group granulocytes and form the largest group and have a typical lobed nucleus. In acute infection and inflammation the neutropihils increase. The fight the disease causing bacteria and neutralize them.

4. When neutrophils decrease then it is called neutropenia and there can be many causes for this to happen including significant infection, viral and autoimmume infections, thyroid problems, bone marrow conditions and cancer.

5. Lymphocytes are a smaller group of white blood cells and they have sub groups of cells like B cells, T cells, NK cells. Due to their presence in lymph fluid they are called lymphocytes.

6. Lymphocytes increase in conditions like infection, cancer of white blood cell and autoimmune condition associated with chronic inflammation.

7. Lymphocyte is decreased in conditions like infections, autoimmune conditions, steroid treatment and conditions where there is bone marrow suppression like blood cancer and treatment.

Increase and decrease of neutrophils and lymphocytes affects our immunity. In cancers there is uncontrolled proliferation of abnormal cells. If the counts are decreased then our immunity decreases and diseases affect us easily.

Hope your query is answered.
Please do write back if you have any doubts.

Regards,

---