A glossary of commonly used terms associated with pemphigus, pemphigoid, their treatment and diagnosis.
Acantholysis: Separation of cells; a term to describe a blister formation.
Amino acids: Small molecules that are the building blocks of proteins.
Antibody: A protein produced by a B cell in response to a specific foreign substance. The antibody can bond with the antigen enabling an immune response. Antibodies are the “soldiers” which protect us against bacteria and viruses that are free in the body (not inside cells) and parasitic infections.
Antigen: A substance recognized by the immune system as foreign or toxic which elicits an immune response. Antigens include bacteria, viruses, and chemicals. If the antigen is part of the body, it is called a self antigen. An antigen is any protein that can be recognized as foreign and that will generate an immune response.
Autoantibody: An antibody that is produced by a B cell against a self-antigen. In pemphigus, the self-antigen is a protein in the glue that keeps skin cells together.
Autoimmune disease: An immunological disease caused by the immune system attacking the body's own organs or tissues.
Autoimmune bullous skin diseases: Autoimmune blistering diseases are defined by antibodies attacking the glue (desmoglein) that keep the skin cells together. Two types are pemphigus and pemphigoid.
Basal layer: The lowest layer of the epidermis.
B cell: A type of lymphocyte (white blood cell) that develops in the bone marrow and produces antibodies that brings about an immune response. B-Cells make antibodies also called immunoglobulins.
Biopsy: The removal of a small piece or sample of tissue or organ for pathologic examination. Biopsies containing both healthy and diseased tissue in the same sample are often helpful in establishing a diagnosis.
Bullous: an adjective that describes something that blisters.
Cell: The basic unit of life. Within the cell is a nucleus and cytoplasm. The cytoplasm contains organelles that carry out the cell's functions. The nucleus contains the genetic material, DNA. The cell membrane which surrounds the cell has receptors on its surface which have unique functions and identifying properties.
Desmogleins: These are some of the proteins that make up the glue that keep the skin cells together.
Desmoglein 1 (dsg 1) is a protein more common in the upper layers (or granular layer) of the epidermis. It is the autoantigen in the superficial form of pemphigus - pemphigus foliaceus.
Desmoglein 3 (dsg 3) is a protein in the basal layer of the epidermis. It is the antigen in the deeper form of pemphigus - pemphigus vulgaris.
ELISA: Acronym for Enzyme-Linked ImmunoSorbent Assay. This is a sensitive and highly specific assay for antibodies. It is used to detect autoantibodies against desmoglein 1 and desmoglein 3.
Epidermis: The upper covering layer of the body, and with the underlying dermis, is referred to as the skin. The upper-most part of the epidermis is called the stratum corneum, composed of dead cells. Immediately below that is the area of living epidermal cells. It is within this layer that the various pathologic changes of pemphigus take place. Superficial separation is seen more in pemphigus foliaceus while slightly deeper separation is seen in pemphigus vulgaris. In bullous pemphigoid the separation occurs below the epidermis - between the epidermis and dermis.
Gene: The functional unit of DNA (deoxyribonucleic acid). Genes are segments of chromosomes found in the nucleus of cells. This hereditary information directs many aspects of human life – for ex. hair and eye color.
Human leukocyte antigens (HLA): A set of genes specific to the immune system that ideally should match when someone has an organ transplant. Certain HLA types can predispose individuals to develop particular diseases, especially autoimmune diseases. For example, HLA class II gene DRB1*0402 is recognized in people with Pemphigus Vulgaris.
Immune system: This system protects the body from infectious and foreign substances. T-cells tell B-cells to produce antibodies or autoantibodies to protect the body. White blood cells are another name for antibodies that protect us.
Immunofluorescence testing: A test used to detect the presence of antibodies. In the direct immunofluorescence test (DIF) a skin biopsy is treated with immunofluorescent antibodies. In pemphigus it looks specifically for anti-IgG, anti-IgM, anti-IgA. The Anti-C3 will be present also only in pemphigoid patients. The presence and location helps differentiate pemphigus from pemphigoid. In indirect immunofluorescence test (IDIF) the patient's serum is treated and placed on monkey esophagus and then examined for the presence and location of fluorescing autoantibodies.
Immune response: The body's reaction to a foreign substance.
Immunosuppressants: Drugs which reduce or eliminate the body's ability to make an immune response. Azathioprine and cyclophosphamide are examples of immunosuppressants.
Keratinocyte: These are the majority of cells in the epidermis and make keratins. They separate in pemphigus.
Keratins: A group of highly insoluble fibrous proteins.
Lymphocyte: White blood cell. Those that develop in the bone marrow are called B cells and those that develop in the thymus are called T cells. The B cells make the antibodies that are important in pemphigus.
Macrophage: A type of white blood cell.
Molecule: Two or more atoms chemically bound to one another. Includes chemical substances which are the building blocks of cells such as proteins, sugars and fats.
Mucous membrane: The moist lining of the mouth, nose, eyes (conjunctiva), genitals, and other areas.
Pathogen: Virus, bacterium, fungus or microorganism which produces a disease.
Pemphigoid: an autoimmune blistering disease with two main categories –bullous pemphigoid (BP) and cicatricial (or mucous membrane) pemphigoid (CP or MMP).
Pemphigus: An autoimmune blistering skin disease
Peptide: A molecule derived from two or more amino acids. In the human body, they can be obtained by the partial digestion of proteins.
Protein: Any of numerous, naturally occurring complex combinations of amino acids containing the elements carbon, hydrogen, nitrogen, oxygen, usually sulfur, and occasionally other elements. Proteins are essential elements of all living cells.
Receptor: A site on the surface of a cell which in a lock and key fashion fits into a complementary site on another cell or protein, as in the binding of an antibody to an antigen.
Systemic: Involving the entire system or body. Medications taken orally are systemic because they are distributed to the entire body.
T-cell: A type of lymphocyte that matures under the influence of the thymus gland. Comprised of three subsets: killer T cells, helper T cells, and suppressor T cells.
Killer (cytotoxic) T cells destroy cells marked by antibodies or specific antigens.
Helper T cells stimulate B cells to make antibodies in respond to proteins (antigens).
Suppressor T cells diminish the immune response, helping to regulate it.
Titer: The concentration of a substance in solution. Used to describe circulating antibodies in pemphigus or pemphigoid. Antibody concentrations are measured this way. Titers are often listed as dilutions like 1:20, the higher the dilution the greater the amount that was originally present.
Topical: Applied directly to the surface of area to be treated. This tends to localize the treatment and minimize side effects.
Glossary of Terms 
