Interferons - First Line Defense of Body Immunity

What Are Interferons?

Interferons are proteins that belong to the group of cytokines (tiny proteins that play an essential role in cell signaling) and regulate the immune response. These glycoproteins have antiviral properties and are the first line of host defense against invading pathogens. The natural substance helps the body’s immune system fight infection and other diseases such as cancer. The interferons are secreted by white blood cells, fibroblasts, and epithelial cells.

How Do Interferons Work?

Interferons are produced by the cells in the body in response to a virus or other foreign substance. There are three classes of interferons - alpha, beta, and gamma. The alpha Interferon is produced in the leukocytes infected with the virus, while the beta is from the fibroblasts infected with a virus. The gamma interferon is induced by stimulation of the sensitized lymphocytes with antigen or non-sensitized lymphocytes with mitogens (a tiny bioactive protein).

Interferons work in different ways. They alert the immune system when attacked by a virus or cancer and stop the virus and cancer cells from growing and dividing. The Interferons help the immune system to recognize the cancer cells and help the healthy cells to fight infection.

What Do Interferons Treat?

• The alpha-interferons treat microbial infections, particularly viral infections like Hepatitis B and C, hairy cell leukemia (a cancer type where the bone marrow produces the excess lymphocytes-a form of white blood cell), Kaposi's sarcoma (a type of cancer occurring in the lining of the lymph and blood vessels) caused by acquired immunodeficiency syndrome (AIDS), and chronic myelogenous leukemia (a condition where the bone marrow produces excess white blood cells). It is used to treat lymphoma, genital warts, and malignant melanoma (a severe type of skin cancer).

• Beta-Interferon is used to reduce episodes of symptoms in patients with relapsing multiple sclerosis (a disease affecting the central nervous system). It reduces inflammation in the brain and spinal cord and prevents nerve damage.

• Interferon-gamma treats a chronic granulomatous disease affecting the working of the immune system, and severe malignant osteopetrosis (an uncommon disorder that results in abnormal bone growth and increased bone density) affecting the bones.

How to Take Interferons?

Interferon is available only with a doctor’s prescription and in powder form or a solution. Interferon-alpha is given as a shot under the skin, into the muscle or vein. It may be given through vein infusion. The number of shots depends on the condition being treated. It is usually given three times a week. However, treating cancer may require infusions for weeks or months.

What Is the Dosage of Interferons?

What Precautions Should Be Taken When Taking Interferons?

• Pregnancy and Breastfeeding - Pregnant women exposed to interferon-beta can have an increased risk for fetal loss and low birth-weight infants. Lactating mothers should consult the doctor before breastfeeding.

• Allergies - It is important to tell the doctor if you have ever had allergic reactions to interferons or other medicines.

• Geriatrics - Elderly patients are likely to have age-related liver, kidney, bone marrow, or heart problems and should be administered cautiously by adjusting the doses.

• Alcohol - Interferon-beta may cause liver problems and increase the risk of liver damage. Alcohol should be avoided with these medications.

• Pediatrics - Children may be more sensitive to side effects of interferons such as mood changes and attempts of suicide. It may also slow down the rate of growth in children.

• Increased Blood Pressure - Interferons can cause an increase in blood pressure and heart rate and increase the risk of stroke.

• Liver Disease - Interferon may lead to severe liver injury with jaundice.

• Renal Dysfunction - Interferon can cause renal dysfunction and acute tubular necrosis (damage to the tubular cells of the kidneys resulting in lack of oxygen supply).

• Anemia - Interferon should be cautiously administered in people with anemia as it reduces the platelet count.

• Eye Disease - People with diabetic retinopathy (a complication of diabetes that affects the eyes) should get regular eye checkups while being treated with interferons as it may worsen the disease.

What Are the Side Effects of Interferons?

Common side effects of Interferon include

• Dizziness.

• Pain and swelling at the site of injection.

• Loss or thinning of hair.

• Reduced appetite and weight loss.

• Breathlessness.

• Easily bruised or bleeding.

• Weakness.

• Flu-like symptoms.

• Stomach ache.

• Diarrhea.

• Headache.

• Cough.

• Skin rash.

Serious side effects are

• Depression.

• Infertility and early menopause.

• High blood pressure.

• Tightness in the chest.

• Difficulty breathing.

What Are the Interactions of Interferons?

Drug Interactions:

The following drugs interact with interferon:

• Barbiturates such as Phenobarbital.

• Colchicine.

• Aldesleukin.

• Cyclosporine.

• Hydroxyurea.

• Telbivudine.

• Aminophylline.

• Live vaccines like live bacille Calmette-Guerin (BCG).

• Immunomodulators like Efalizumab, Natalizumab, Cladribine, Siponimod, and Fingolimod.

• Immunosuppressants like Talimogene laherparepvec and Acyclovir (antiviral).

Disease Interactions:

• Renal Dysfunction - Therapy with interferon should be administered cautiously to patients with severe renal dysfunction as there is an increased risk of renal toxicity.

• Autoimmune Disease - Antiviral interferons may exacerbate autoimmune disorders such as myositis (weakness or inflammation in the muscles), thyroiditis (inflammation of the thyroid gland), systemic lupus erythematosus (an autoimmune disease in which the immune system mistakenly attacks its own healthy tissues), rheumatoid arthritis (a chronic inflammatory disorder affecting mainly the joints of hands and feet), or autoimmune hepatitis (condition caused when body's immune system attacks the liver cells). Therapy should be avoided or administered with caution in patients with autoimmune disorders.

• Hepatic Dysfunction - Therapy with Interferon should be administered with caution in patients with liver disease and should be avoided in patients with autoimmune hepatitis.

• Cardiac Disease - Interferons should be administered with caution in patients with compromised cardiac function.

• Central Nervous System dysfunction - Seizures, manic behavior, psychotic reaction, and dizziness can occur in patients taking interferon therapy.

• Depression - Therapy with interferons should be administered cautiously in patients with mental depression and may require clinical monitoring.

• Thyroid Dysfunction - Interferons should be discontinued in patients with thyroid abnormalities as they can alter the activity of the thyroid gland.

• Colitis - Treatment with interferon should be discontinued in patients with ulceration or hemorrhagic or ischemic colitis as it may cause abdominal pain, bloody diarrhea, and fever.

• Diabetes Mellitus - Interferon therapy may precipitate ketoacidosis (when body produces excess blood acids) in diabetic patients. These patients should be monitored for blood glucose concentrations.

• Myelosuppression - Therapy with interferon may cause leukopenia (low white blood cells in the blood) and thrombocytopenia (low platelet level) in patients with bone marrow suppression.

• Peripheral Neuropathy - Interferon should be administered cautiously in patients with peripheral neuropathy (weakness or numbness caused from nerve damage) as it may cause paresthesia and numbness during the therapy.

• Lung Disease - Interferons can worsen lung problems like shortness of breath, pneumonia (infection in the lungs caused by bacteria), and bronchitis (inflammation of the lining of bronchi in the lungs) and should be discontinued in patients with symptoms like cough and shortness of breath.

Conclusion:

Interferon therapy has therapeutic value for autoimmune diseases, viral diseases, multiple sclerosis, chronic granulomatous disease (condition in which the white blood cells are unable to protect the body), and cancer. However, given the potential for hepatotoxicity, renal toxicity, myelosuppression (decreased bone marrow activity), and other adverse outcomes, it is important to routinely monitor blood count tests, liver function tests, and blood sugar levels of patients undergoing Interferon therapy. The healthcare teams should work as a cohesive unit to educate the patients about the importance of medication adherence and provide regular reminders to these patients.