Lepromin
Encyclopedia
The lepromin skin test is used to determine what type of leprosy
a person has. It involves the injection of a standardized extract of the inactivated "leprosy bacillus",(Mycobacterium leprae
or "Hansen's Bacillus") under the skin
. It is not recommended as a primary mode of diagnosis
.
has been injected at the correct depth. The injection site is labeled and examined 3 days and 28 days later to see if there is a reaction.
People with dermatitis
or other skin irritations should have the test performed on an unaffected part of the body. If a child needs to have this test performed, it may be helpful to explain how the test will feel, and even practice or demonstrate on a doll
. The more familiar the child is with what will happen and why, the less anxiety
he or she will feel. When the antigen is injected, there may be a slight stinging or burning sensation. There may also be mild itching at the site of injection afterwards.
By contrast, a positive Fernandez reaction
is seen in the skin of patients with tuberculoid and borderline tuberculoid Hansen's Disease. Patient's with this form of HD have an immune system that does not recognise the molecular parasite (plasmid) carried at the surface of the Hansen's bacillus lodged in their skin, but, instead, recognises the bacillus itself as foreign. Thus, the plasmid, with its replicator gene, is not prevented from moving out of the bacillus into neighboring human nerves where it replicates, damaging those nerves and causing the tuberculoid HD clinical picture. The bacillus, meanwhile, is rendered unable to divide (having lost its replicator gene) and is destroyed by the immune system in the normal way.
which may include itching and rarely hives.
published the first paper leading to the lepromin reaction. However, his original idea was to find a test which distinguishes leprosy patients from non-leprosy persons. During his study, he found that the test results differed depending on the types of leprosy. He reported it at the 3rd International Leprosy Congress in France in 1923 but it received little attention. Mitsuda stored the necessary materials in a regrigator and tried to persuade many doctors who came under him to study them, and finally he found Fumio Hayashi. The Mitsuda Test was at last completed by Fumio Hayashi.
, Baltimore
, Maryland
, USA. Review provided by VeriMed Healthcare Network. Text in the US Federal Government public domain.
Leprosy
Leprosy or Hansen's disease is a chronic disease caused by the bacteria Mycobacterium leprae and Mycobacterium lepromatosis. Named after physician Gerhard Armauer Hansen, leprosy is primarily a granulomatous disease of the peripheral nerves and mucosa of the upper respiratory tract; skin lesions...
a person has. It involves the injection of a standardized extract of the inactivated "leprosy bacillus",(Mycobacterium leprae
Mycobacterium leprae
Mycobacterium leprae, also known as Hansen’s coccus spirilly, mostly found in warm tropical countries, is a bacterium that causes leprosy . It is an intracellular, pleomorphic, acid-fast bacterium. M. leprae is an aerobic bacillus surrounded by the characteristic waxy coating unique to mycobacteria...
or "Hansen's Bacillus") under the skin
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
. It is not recommended as a primary mode of diagnosis
Diagnosis
Diagnosis is the identification of the nature and cause of anything. Diagnosis is used in many different disciplines with variations in the use of logics, analytics, and experience to determine the cause and effect relationships...
.
How the test is performed
An extract sample of inactivated Hansen's Bacillus is injected just under the skin, usually on the forearm, so that a small lump pushes the skin upward. The lump indicates that the antigenAntigen
An antigen is a foreign molecule that, when introduced into the body, triggers the production of an antibody by the immune system. The immune system will then kill or neutralize the antigen that is recognized as a foreign and potentially harmful invader. These invaders can be molecules such as...
has been injected at the correct depth. The injection site is labeled and examined 3 days and 28 days later to see if there is a reaction.
People with dermatitis
Dermatitis
-Etymology:Dermatitis derives from Greek derma "skin" + -itis "inflammation" and genetic disorder.-Terminology:There are several different types of dermatitis. The different kinds usually have in common an allergic reaction to specific allergens. The term may describe eczema, which is also called...
or other skin irritations should have the test performed on an unaffected part of the body. If a child needs to have this test performed, it may be helpful to explain how the test will feel, and even practice or demonstrate on a doll
Doll
A doll is a model of a human being, often used as a toy for children. Dolls have traditionally been used in magic and religious rituals throughout the world, and traditional dolls made of materials like clay and wood are found in the Americas, Asia, Africa and Europe. The earliest documented dolls...
. The more familiar the child is with what will happen and why, the less anxiety
Anxiety
Anxiety is a psychological and physiological state characterized by somatic, emotional, cognitive, and behavioral components. The root meaning of the word anxiety is 'to vex or trouble'; in either presence or absence of psychological stress, anxiety can create feelings of fear, worry, uneasiness,...
he or she will feel. When the antigen is injected, there may be a slight stinging or burning sensation. There may also be mild itching at the site of injection afterwards.
Normal values
People who don't have clinical leprosy (= Hansen's Disease, or HD) may have little or no skin reaction to the antigen, or may have a strong reaction to it. Patients with "lepromatous" (Virchowian) HD have no skin reaction to the antigen. This is because "lepromatous" patients' immune system specifically recognises, not the Hansen's bacillus, but instead the plasmid (or "transposon", or "ultravirus") that it carries attached to the inside of its cell wall. In other words, this group of the population has a specific anergy to Hansen's bacillus itself, the "price" for recognition of the associated neuron invasion threat that the bacillus carries. The plasmid harboured by Hansen's bacillus contains a replicator gene which it must share with its procaryote host, and a neuron invasion gene. Virchowian ("lepromatous") patients' macrophages (Virchow cells) stop the plasmid escaping from the bacillus into their peripheral nerves which would result in nerve damage. How does this immune defense system work? Once the Hansen's bacilli are engulfed by Virchow cells, the Virchow cell effects detachment of the plasmid from the bacterial cell wall, so that the threat of nerve invasion is averted. The detached plasmid re-integrates into the Hansen's Bacillus chromosome, allowing the bacillus to divide unchecked (resulting in "lepromatous" = Virchowian - skin nodules).By contrast, a positive Fernandez reaction
Fernandez reaction
The Fernandez reaction is reaction that occurs to signal a positive result in the lepromin skin test for leprosy. The reaction occurs in the skin at the site of injection if the body possesses antibodies to the Dharmendra antigen, one of the antigens found in Mycobacterium leprae, the bacteria that...
is seen in the skin of patients with tuberculoid and borderline tuberculoid Hansen's Disease. Patient's with this form of HD have an immune system that does not recognise the molecular parasite (plasmid) carried at the surface of the Hansen's bacillus lodged in their skin, but, instead, recognises the bacillus itself as foreign. Thus, the plasmid, with its replicator gene, is not prevented from moving out of the bacillus into neighboring human nerves where it replicates, damaging those nerves and causing the tuberculoid HD clinical picture. The bacillus, meanwhile, is rendered unable to divide (having lost its replicator gene) and is destroyed by the immune system in the normal way.
Risks
There is an extremely small risk of an allergic reactionAllergy
An Allergy is a hypersensitivity disorder of the immune system. Allergic reactions occur when a person's immune system reacts to normally harmless substances in the environment. A substance that causes a reaction is called an allergen. These reactions are acquired, predictable, and rapid...
which may include itching and rarely hives.
History
Kensuke MitsudaKensuke Mitsuda
was a Japanese leprologist and director of the Tama Zenshoen Sanatorium and the National Sanatorum Nagashima Aiseien. He had been at the frontier of leprosy policy of Japan. He was given the Order of Cultural Merits and Damien-Dutton Award...
published the first paper leading to the lepromin reaction. However, his original idea was to find a test which distinguishes leprosy patients from non-leprosy persons. During his study, he found that the test results differed depending on the types of leprosy. He reported it at the 3rd International Leprosy Congress in France in 1923 but it received little attention. Mitsuda stored the necessary materials in a regrigator and tried to persuade many doctors who came under him to study them, and finally he found Fumio Hayashi. The Mitsuda Test was at last completed by Fumio Hayashi.
Source
Lepromin skin test. Medline Plus Medical Encyclopedia. Update Date: 8/15/2003. By Daniel Levy, M.D., Ph.D., Infectious Diseases, Greater Baltimore Medical CenterGreater Baltimore Medical Center
Greater Baltimore Medical Center, known to many simply as GBMC, is a hospital located in the Baltimore suburb of Towson, Maryland. GBMC serves more than 26,700 inpatient cases and approximately 60,000 emergency room visits annually. GBMC’s main campus also includes three medical office...
, Baltimore
Baltimore
Baltimore is the largest independent city in the United States and the largest city and cultural center of the US state of Maryland. The city is located in central Maryland along the tidal portion of the Patapsco River, an arm of the Chesapeake Bay. Baltimore is sometimes referred to as Baltimore...
, Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...
, USA. Review provided by VeriMed Healthcare Network. Text in the US Federal Government public domain.