Immune responses in the human body play a major role during disease or abnormality. The immune system responds according to the stimulus it receives from the brain either to fight a pathogen or to eradicate an unwanted cell in the body. Immunotherapy enhances or suppresses the immune system to act on the respective disease. Immunotherapy varies in types depending upon its administration requirements. In case of allergic reactions or autoimmune diseases, immunotherapy is used to suppress the immune response to control the adverse reactions caused by allergens and abnormal proteins.
Types of Immunotherapeutic Agents
Immunotherapy is selective for each disease. There are many types of immunotherapeutic agents available. Some are used to enhance the immune system in facilitating the process of phagocytosis and some are used to block the allergic reactions and autoimmune responses of the body.
Monoclonal antibodies which are prepared in the lab are used as anticancer agents. These antibodies are unique as they target specific locations of the cancer cells. Monoclonal antibodies can used in many ways depending upon the type of case. Some monoclonal antibodies can be used directly without any additives. Some are coated with a radioactive material or an additional anticancer drug to act on the cancer cells. These antibodies adhere to the target cell thus interfering with the cancer cell activity.
Many conditions such as Hodgkin’s Lymphoma, chronic lymphocytic leukemia have US FDA approved immunotherapy drugs. Rituxan and Campath are the first monoclonal immunotherapy FDA approved drugs in treatment of cancer. The common side effects noticed in the administration of monoclonal antibodies both as single and conjugated forms include fever, headaches, nausea, rash, low red blood cell count as it interferes with the marrow and also liver disorders. Monoclonal antibodies conjugated with radioactive material in case of radio immunotherapy may trigger severe allergic reactions.
Cytokines such as interferon and interleukin are generally used as immunotherapeutic agents because of their involvement with cell signaling pathways. They are naturally secreted by the body and they are also called nonspecific immunotherapeutic agents. They are predominantly used in treating infections, cancers and tumors. Alpha interferon is widely used in the treatment of cancers such as T-cell lymphoma, Chronic myelogenous leukemia and non-Hodgkin lymphomas. They inhibit the proliferation of cancer cells by interfering with the growth factors.
Interleukins are also used in the treatment of cancers such as lymphoma, leukemia and mylomas of various origins. Interleukin 2 (IL2) is a widely recommended agent for myelomas. Interleukin and interferon therapies have side effects such as extreme fluid accumulation, fever, chills and dizziness. Cytokine therapies based on lymphocyte infusion can cause graft versus host disease leading to the destruction of host cells by the induced lymphocyte cells.
Pruritus is a skin disease associated with conditions pertaining to autoimmune disorders and other advanced complications like liver cirrhosis. Pruritus cases vary from mild to complex as the symptoms associated with the condition generally aggravate with age. Untreated pruritus can be a big hindrance to an individual's normal life as it interferes with sleep patterns leading to irritability and stress. In some cases the causative agent for this disease is the Hepatitis C virus which accounts in 20% of the population.
Pruritus occurs mostly in the wrist and ankles as a scratch. The intensity of the itch facilitates other factors such as eczema, impetigo and induced urticaria. The immune response releases histamines causing allergic reactions. The association of pruritus with allergic reactions is identified by the presence of serotonin. The serotonin release caused because of pruritus occurs in case of preexisting medical conditions such as polycythemia, lymphoma and cholestasis.
The identification and diagnosis of pruritus is closely associated with the evaluation of dermatological condition of the patient. Progressive pruritus is noticed with contact dermatitis, urticaria, scabies, pediculous infections of the genital region, folliculitis and xerotic eczema.The factors associated with the respective causes along with pruritus are fomites, dust, bites, chemicals and photosensitivity. Atopic dermatitis induces aggressive form of pruritus. The intense forms of atopic dermatitis associated pruritus usually occur in pregnant women, infants and veterans. Systemic causes of pruritus involve preexisting conditions such as Hodgkin's lymphoma, HIV, scleroderma, multiple myeloma, chronic renal failure and many other conditions.
Pruritus diagnosis involves meticulous procedures in examining the exact history of the patient to rule out other forms of allergic reactions. The information pertaining to the patient history includes several factors such as travel zones, food and occupation. Differentiation of non-septic and septic forms is done to identify systemic involvement of the disease. Secondary infections and malignancies associated have to be identified. Specific sites are identified on the skin reaction to respective drug therapy is carefully monitored.
Avoid stress which delays the healing process. Topical creams are prescribed for allergic forms of pruritus. Skin cleansing is an important step. It is predominantly done to prevent secondary infections and conditions such as psoriasis. Patients who have history of sunburn and sensitivity to extreme temperatures need to relieve the stress upon immune system that reacts immediately to such conditions. Hydration of the skin helps in the restoration of the skin cells to facilitate the process of healing. Change of diet and lifestyle is prescribed to patients who are sensitive foods such as nuts, seafood etc. Patients with a history of contact dermatitis are advised to use skin safe deodorants, shampoos and bubble bath solutions. Oral antihistamines are recommended to ease the immune system's reactivity. Hot water bath and tight clothing are to be avoided in case of pruritus as it may aggravate the condition. Topical creams containing corticosteroids are recommended during the onset of a pruritic reaction. In case of secondary infections associated with pruritus, antibiotics are given.
Allergies are one of the most common types of acquired health conditions as the causes include various factors. Most of these factors are related to the environment such as dust, pollen, virus and chemicals. Allergic reaction signifies the defense mechanism of the immune system to a foreign particle. Allergic reactions if untreated can lead to bigger complications such as bronchitis and sinusitis. Antihistamines were first synthesized by Daniel Bovet. They play a major role in controlling the release of histamines in the body which are produced as response to an allergen. Histamines are chemicals which are released from the mast cell damage. These chemicals initiate the process of allergic reaction in the blood and tissues which causes discomfort. Histamines have three types of receptors H1, H2 and H3 which are specific for different organ systems. The H1 receptor is associated with vasodilation and smooth muscle stimulation, H2 receptor is associated with the cardiac stimulation and H3 is associated with the feedback inhibition process regulated by the central nervous system.
Types of antihistamines
Antihistamines mainly act upon the receptors of the type of histamine released. Each antihistamine has a tendency to compete in binding to the receptors to inhibit the process of allergic stimulation caused in the organ system. There are two major classes of antihistamines. The first generation and the second generation are classified based on their sedative effect on the patient during the course of their action. The first generation of antihistamines are sedatives as they act upon the parasympathetic nervous system in preventing the release of acetylcholine. Their anticholinergic properties enable them to act fast in providing relief within a few minutes. People who experience motion sickness are often suggested to take antihistamines because it suppresses the ear balance discomfort.
The most common ingredients present in these medications are chlorpheneramine, doxylamine, brompheneramine and dimenhydrinate. Most of these first generation antihistamines are recommended in allergic reactions such as hay fever, viral infection, pollen and dander as they suppress the central nervous system. Patients experience drowsiness for a period of time during the first generation antihistamine treatment.
Second generation antihistamines are not sedative in nature and they have large molecular size and electrostatic nature which makes them noncompeting to cross the blood and brain barrier. The response pertaining to their action is comparatively slow as they do not act upon the central nervous system. Studies have shown the increased administration of non-sedative antihistamines in the recent times. Some of these second generation antihistamines have been banned from the market due to their adverse side effects such as arrhythmia. Most of these antihistamines are prescribed during seasonal allergies.
Side effects of antihistamines
The common side effect of most first generation antihistamines is drowsiness or dizziness. The other side effects include nausea, feeling of dryness in mouth and nostrils and sometimes blurred vision. These happen because of the inhibition of secretions from salivary, nasal and lachrymal glands during the onset of an allergic response. The suppression of central nervous system activity may initiate confusion, disorientation and sometimes hallucination in patients.
Rashes, chest congestion and difficulty in breathing have also been reported as adverse effects of antihistamine administration. In case of H2 receptor antihistamines, diarrhea is significant side effect along with headache. Most of the side effects caused by antihistamine intake subside within a few hours. However increased sensitivity to a certain type of antihistamine has to be immediately reported to the physician.