Lymphocytes: Understanding Their Functions, Levels and Associated Disorders

Dr.Roshan Dikshit, 3 mins read

With evolution, humans have developed extra defence systems, including specialised immune cells called lymphocytes. These cells are a type of white blood cells that help the body’s immune system fight foreign viruses and bacteria. Thanks to these cells because they help the body remember past infections, allowing for a stronger immune response when encountering the same infection again.

Lymphocytes originate in the bone marrow and circulate in the body through the bloodstream and lymphatic system. They are essential for maintaining a balanced immune response.

Types

Primarily, there are two types of lymphocytes, T lymphocytes (T cells) and B lymphocytes.

1. T Lymphocytes (T Cells)

There are several subtypes of T cells with specialised functions:

• Helper T cells: Activate B cells to produce antibodies and stimulate macrophages to destroy ingested microbes.
• Cytotoxic (Killer) T cells: Remove intracellular and extracellular pathogens and destroy mutated or cancerous cells.
• Regulatory (Suppressor) T cells: These inhibit the activity of other lymphocytes to prevent an overactive immune response.

2. B Lymphocytes (B Cells)

B cells develop in the bone marrow and are responsible for producing antibodies that bind to pathogens or foreign substances, such as toxins, and neutralise them.

• Plasma B Cells: These cells produce large amounts of antibodies to fight infections and diseases.
• Memory B Cells: These provide long-term immunity by producing antibodies during future exposures to the same pathogen.

Function

Lymphocytes are responsible for producing antibodies, which kill virus-infected and tumour cells and regulate the immune response. T cells help kill infected cells and control the body's immune response to foreign substances. B cells have receptors on their surfaces where antigens attach. They then produce specific antibodies to target each antigen.

Levels of Lymphocytes

The normal range of lymphocytes depends on age, race, sex, altitude, lifestyle and various other factors. In adults, the normal range of lymphocytes in every 1 microliter of blood is between 1,000 and 4,800 lymphocytes. In children, the normal range of lymphocytes in every 1 microliter of blood is between 3,000 and 9,500 lymphocytes.

Associated Disorders:
Lymphocytes help fight off diseases. It is common for the lymphocyte count to rise after an infection. However, a high rise in lymphocyte count can lead to more serious conditions.

If the lymphocyte count is higher than the normal range, then that condition is termed lymphocytosis. It can be caused due to:

• An infection or inflammatory condition
• Stress and anxiety
• Reactions to certain medicines
• Serious conditions like leukaemia and non-Hodgkin lymphoma
• Bacterial diseases, such as syphilis and cat-scratch disease
• HIV/AIDS

Lymphocytosis is managed by treating the underlying cause. For example, in cancer cases, treatment involves chemotherapy, stem cell transplantation, immunotherapy, or targeted cell therapy.

If lymphocyte count is lower than normal, the condition is termed lymphopenia.
It occurs in adults when the lymphocyte count becomes less than 1,000 lymphocytes per microliter of blood. Children below two years of age have lymphopenia if they have less than 3,000 lymphocytes per microliter of blood.

There are many factors that cause lymphopenia. The most common among them are infections, medications and nutritional deficiencies. Foods containing beta-carotene like carrots, sweet potatoes, spinach, broccoli, onions, peas, lettuce, tomatoes, pumpkin, cantaloupe, dried apricots and mango are helpful in increasing the number of lymphocytes.

Foods which are high in trans fats, junk and oily foods containing high levels of low lipoprotein cholesterol, can decrease the number of lymphocytes.

A well-functioning lymphocyte system plays a vital role in providing short-term protection and long-term immunity. You can monitor your lymphocyte count through a normal blood test at your nearest healthcare facility or laboratory.