Thymoma with immunodeficiency

Last updated
Thymoma with immunodeficiency
Other namesGood syndrome

Thymoma with immunodeficiency (also known as "Good syndrome") is a rare disorder that occurs in adults in whom hypogammaglobulinemia, deficient cell-mediated immunity, and benign thymoma may develop almost simultaneously. [1] :86Most reported cases are in Europe, though it occurs globally.

Hypogammaglobulinemia is a problem with the immune system in which not enough gamma globulins are produced in the blood. This results in a lower antibody count, which impairs the immune system, increasing risk of infection. Hypogammaglobulinemia may result from a variety of primary genetic immune system defects, such as common variable immunodeficiency, or it may be caused by secondary effects such as medication, blood cancer, or poor nutrition, or loss of gamma globulins in urine, as in nonselective glomerular proteinuria. Patients with hypogammaglobulinemia have reduced immune function; important considerations include avoiding use of live vaccines, and take precautionary measures when traveling to regions with endemic disease or poor sanitation such as receiving immunizations, taking antibiotics abroad, drinking only safe or boiled water, arranging appropriate medical cover in advance of travel, and ensuring continuation of any immunoglobulin infusions needed.

Cell-mediated immunity is an immune response that does not involve antibodies. Rather, cell mediated immunity is the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to antigen. Historically, the immune system was separated into two branches: humoral immunity, for which the protective function of immunization could be found in the humor and cellular immunity, for which the protective function of immunization was associated with cells. CD4 cells or helper T cells provide protection against different pathogens. Naive T cells, mature T cells that have yet to encounter an antigen, are converted into activated effector T cells after encountering antigen-presenting cells (APCs). These APCs, such as macrophages, dendritic cells, and B cells in some circumstances, load antigenic peptides onto the MHC of the cell, in turn presenting the peptide to receptors on T cells. The most important of these APCs are highly specialized dendritic cells; conceivably operating solely to ingest and present antigens.

Thymoma A thymus cancer that derives from epithelial cells located in the thymus. The tumor cells in a thymoma look similar to the normal cells of the thymus, grow slowly, and rarely spread beyond the thymus.

A thymoma is a tumor originating from the epithelial cells of the thymus that may be benign or malignant. Thymomas are frequently associated with the neuromuscular disorder myasthenia gravis; thymoma is found in 20% of patients with myasthenia gravis. Once diagnosed, thymomas may be removed surgically. In the rare case of a malignant tumor, chemotherapy may be used.

Contents

Dr. Robert Good was first to describe the association between thymoma and hypogammaglobulinemia in 1954. Much remains to be understood about its pathogenesis.


Signs and symptoms

Most patients present with an immunodeficient state and recurrent sinopulmonary infections in their sixth decade of life (later than other primary immunodeficient states). Few patients are diagnosed with thymoma prior to the manifestation of immunodeficiency.

Immunodeficiency involves both deficient humoral and cellular immunity. Patients have low total serum antibodies. The thymoma may inhibit the thymus’s normal role in production of self-tolerant T lymphocytes. These T-lymphocytes then attack the B cell precursors in the marrow, preventing maturation and ultimately resulting in hypogammaglobulinemia.

Good Syndrome is associated with other autoimmune conditions including pure red cell aplasia and myasthenia gravis.

Pure red cell aplasia (PRCA) or erythroblastopenia refers to a type of anemia affecting the precursors to red blood cells but not to white blood cells. In PRCA, the bone marrow ceases to produce red blood cells. There are multiple etiologies that can cause PRCA. The condition has been first described by Paul Kaznelson in 1922.

Myasthenia gravis Human disease

Myasthenia gravis (MG) is a long-term neuromuscular disease that leads to varying degrees of skeletal muscle weakness. The most commonly affected muscles are those of the eyes, face, and swallowing. It can result in double vision, drooping eyelids, trouble talking, and trouble walking. Onset can be sudden. Those affected often have a large thymus or develop a thymoma.

Pathogenesis

The cause of Good Syndrome is unknown. It is thought to be an autoimmune process affecting the bone marrow.

Diagnosis

Definition

There are no formal diagnostic criteria. Generally it can be defined as an adult-onset primary immunodeficiency associated with thymoma, hypogammaglobulinemia, diminished B and T cells, and inverted CD4/CD8+ ratio. Some consider Good Syndrome to be a subset of common variable immunodeficiency (CVID).

Common variable immunodeficiency (CVID) is an immune disorder characterized by recurrent infections and low antibody levels, specifically in immunoglobulin (Ig) types IgG, IgM and IgA. Generally symptoms include high susceptibility to foreign invaders, chronic lung disease, and inflammation and infection of the gastrointestinal tract. However, symptoms vary greatly between people. CVID is a lifelong disease.

Treatment

The mainstay of treatment consists of thymectomy and immunoglobulin replacement with intravenous immunoglobulin. Immunodeficiency does not resolve after thymectomy. Immunosuppression is sometimes used.

A thymectomy is an operation to remove the thymus. It usually results in remission of myasthenia gravis with the help of medication including steroids. However, this remission may not be permanent. Thymectomy is indicated when thymoma are present in the thymus. Anecdotal evidence suggests MG patients with no evidence of thymoma may still benefit from thymectomy, thus the procedure is commonly prescribed.

The Centers for Disease Control and Prevention recommend pneumococcal, meningococcal, and Hib vaccination in those with diminished humoral and cell-mediated immunity.

Centers for Disease Control and Prevention government agency

The Centers for Disease Control and Prevention (CDC) is the leading national public health institute of the United States. The CDC is a United States federal agency under the Department of Health and Human Services and is headquartered in Atlanta, Georgia.

Pneumococcal vaccine vaccine against Streptococcus pneumoniae

Pneumococcal vaccines are vaccines against the bacterium Streptococcus pneumoniae. Their use can prevent some cases of pneumonia, meningitis, and sepsis. There are two types of pneumococcal vaccines: conjugate vaccines and polysaccharide vaccines. They are given by injection either into a muscle or just under the skin.

Meningococcal vaccine refers to any of the vaccines used to prevent infection by Neisseria meningitidis. Different versions are effective against some or all of the following types of meningococcus: A, B, C, W-135, and Y. The vaccines are between 85 and 100% effective for at least two years. They result in a decrease in meningitis and sepsis among populations where they are widely used. They are given either by injection into a muscle or just under the skin.

Some have advocated prophylaxis with trimethoprim-sulfamethoxazole if CD4 counts are lower than 200 cells/mm^3, similar to HIV/AIDS patients.

See also

Related Research Articles

Thymus organ of the immune system

The thymus is a specialized primary lymphoid organ of the immune system. Within the thymus, T cells mature. T cells are critical to the adaptive immune system, where the body adapts specifically to foreign invaders. The thymus is composed of two identical lobes and is located anatomically in the anterior superior mediastinum, in front of the heart and behind the sternum. Histologically, each lobe of the thymus can be divided into a central medulla and a peripheral cortex which is surrounded by an outer capsule. The cortex and medulla play different roles in the development of T cells. Cells in the thymus can be divided into thymic stromal cells and cells of hematopoietic origin. Developing T cells are referred to as thymocytes and are of hematopoietic origin. Stromal cells include epithelial cells of the thymic cortex and medulla, and dendritic cells.

Autoimmunity is the system of immune responses of an organism against its own healthy cells and tissues. Any disease that results from such an aberrant immune response is termed an "autoimmune disease". Prominent examples include celiac disease, diabetes mellitus type 1, sarcoidosis, systemic lupus erythematosus (SLE), Sjögren's syndrome, eosinophilic granulomatosis with polyangiitis, Hashimoto's thyroiditis, Graves' disease, idiopathic thrombocytopenic purpura, Addison's disease, rheumatoid arthritis (RA), ankylosing spondylitis, polymyositis (PM), dermatomyositis (DM) and multiple sclerosis (MS). Autoimmune diseases are very often treated with steroids.

Immunosuppressive drug Agents that suppress immune function by one of several mechanisms of action. Classical cytotoxic immunosuppressants act by inhibiting dna synthesis. Others may act through activation of t-cells or by inhibiting the activation of helper cells. While

Immunosuppressive drugs or immunosuppressive agents or antirejection medications are drugs that inhibit or prevent activity of the immune system.

Lymphocyte subtype of white blood cell

A lymphocyte is one of the subtypes of a white blood cell in a vertebrate's immune system. Lymphocytes include natural killer cells, T cells, and B cells. They are the main type of cell found in lymph, which prompted the name "lymphocyte".

Immunodeficiency is a state in which the immune system's ability to fight infectious disease and cancer is compromised or entirely absent. Most cases of immunodeficiency are acquired ("secondary") due to extrinsic factors that affect the patient's immune system. Examples of these extrinsic factors include HIV infection, extremes of age, and environmental factors, such as nutrition. In the clinical setting, the immunosuppression by some drugs, such as steroids, can be either an adverse effect or the intended purpose of the treatment. Examples of such use is in organ transplant surgery as an anti-rejection measure and in patients suffering from an overactive immune system, as in autoimmune diseases. Some people are born with intrinsic defects in their immune system, or primary immunodeficiency. A person who has an immunodeficiency of any kind is said to be immunocompromised. An immunocompromised person may be particularly vulnerable to opportunistic infections, in addition to normal infections that could affect everyone. Immunodeficiency also decreases cancer immunosurveillance, in which the immune system scans the body's cells and kills neoplastic ones.

Immunodeficiency–centromeric instability–facial anomalies syndrome human disease

ICF syndrome is a very rare autosomal recessive immune disorder.

Evans syndrome is an autoimmune disease in which an individual's immune system attacks their own red blood cells and platelets, the syndrome can include immune neutropenia. These immune cytopenias may occur simultaneously or sequentially.

Omenn syndrome Human disease

Omenn syndrome is an autosomal recessive severe combined immunodeficiency. It is associated with hypomorphic missense mutations in immunologically relevant genes of T-cells such as recombination activating genes, Interleukin-7 receptor-α (IL7Rα), DCLRE1C-Artemis, RMRP-CHH, DNA-Ligase IV, common gamma chain, WHN-FOXN1, ZAP-70 and complete DiGeorge syndrome. It is fatal without treatment.

X-linked agammaglobulinemia Human disease

X-linked agammaglobulinemia (XLA) is a rare genetic disorder discovered in 1952 that affects the body's ability to fight infection. As the form of agammaglobulinemia that is X-linked, it is much more common in males. In people with XLA, the white blood cell formation process does not generate mature B cells, which manifests as a complete or near-complete lack of proteins called gamma globulins, including antibodies, in their bloodstream. B cells are part of the immune system and normally manufacture antibodies, which defend the body from infections by sustaining a humoral immunity response. Patients with untreated XLA are prone to develop serious and even fatal infections. A mutation occurs at the Bruton's tyrosine kinase (Btk) gene that leads to a severe block in B cell development and a reduced immunoglobulin production in the serum. Btk is particularly responsible for mediating B cell development and maturation through a signaling effect on the B cell receptor BCR. Patients typically present in early childhood with recurrent infections, in particular with extracellular, encapsulated bacteria. XLA is deemed to have a relatively low incidence of disease, with an occurrence rate of approximately 1 in 200,000 live births and a frequency of about 1 in 100,000 male newborns. It has no ethnic predisposition. XLA is treated by infusion of human antibody. Treatment with pooled gamma globulin cannot restore a functional population of B cells, but it is sufficient to reduce the severity and number of infections due to the passive immunity granted by the exogenous antibodies.

Primary immunodeficiencies are disorders in which part of the body's immune system is missing or does not function normally. To be considered a primary immunodeficiency (PID), the cause of the immune deficiency must not be secondary in nature. Most primary immunodeficiencies are genetic disorders; the majority are diagnosed in children under the age of one, although milder forms may not be recognized until adulthood. While there are over 300 recognized PIDs, most are very rare. About 1 in 500 people in the United States are born with a primary immunodeficiency. Immune deficiencies can result in persistent or recurring infections, autoinflammatory disorders, tumors, and disorders of various organs. There are currently limited treatments available for these conditions; most are specific to a particular type of PID. Research is currently evaluating the use of stem cell transplants (HSCT) and experimental gene therapies as avenues for treatment in limited subsets of PIDs.

An immune disorder is a dysfunction of the immune system. These disorders can be characterized in several different ways:

Humoral immune deficiency

Humoral immune deficiencies are conditions which cause impairment of humoral immunity, which can lead to immunodeficiency. It can be mediated by insufficient number or function of B cells, the plasma cells they differentiate into, or the antibody secreted by the plasma cells. The most common such immunodeficiency is inherited selective IgA deficiency, occurring between 1 in 100 and 1 in 1000 persons, depending on population.They are associated with increased vulnerability to infection, but can be difficult to detect in the absence of infection.They can be associated with increased risk of gastric cancer.

T cell deficiency Human disease

T cell deficiency is a deficiency of T cells, caused by decreased function of individual T cells, it causes an immunodeficiency of cell-mediated immunity. T cells normal function is to help with the human body's immunity, they are one of the two primary types of lymphocytes(the other being B cells).

Caspase-8 deficiency autoimmune lymphoproliferative syndrome that has material basis in homozygous mutation in the CASP8 gene on chromosome 2q33

Caspase-8 deficiency (CEDS) is a very rare genetic disorder of the immune system. It is caused by mutations in the CASP8 gene that encodes the protein caspase-8. The disorder is characterized by splenomegaly and lymphadenopathy, in addition to recurrent sinopulmonary infections, recurrent mucocutaneous herpesvirus or other viral infections, and hypogammaglobulinemia. Investigators in the laboratory of Dr. Michael Lenardo at the National Institutes of Health described this condition in two siblings from a consanguineous family in 2002, and several more affected family members have since been identified.

Immunoglobulin therapy, also known as normal human immunoglobulin (NHIG), is the use of a mixture of antibodies (immunoglobulins) to treat a number of health conditions. These conditions include primary immunodeficiency, immune thrombocytopenic purpura, chronic inflammatory demyelinating polyneuropathy, Kawasaki disease, certain cases of HIV/AIDS and measles, Guillain-Barré syndrome, and in certain other infections when a more specific immunoglobulin is not available. Depending on the formulation it can be given by injection into muscle, a vein, or under the skin. The effects last a few weeks.

References

  1. James, William D.; Berger, Timothy G.; et al. (2006). Andrews' Diseases of the Skin: clinical Dermatology. Saunders Elsevier. ISBN   0-7216-2921-0.
Classification
D
External resources