Bare lymphocyte syndrome: Difference between revisions
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{{SI}} | |||
{{Infobox medical condition | |||
| name = Bare lymphocyte syndrome | |||
| image = [[File:Autosomal_recessive_-_en.svg|200px]] | |||
| caption = Bare lymphocyte syndrome is inherited in an [[autosomal recessive]] pattern. | |||
| synonyms = MHC class II deficiency | |||
| field = [[Immunology]] | |||
| symptoms = [[Recurrent infections]], [[failure to thrive]], [[chronic diarrhea]] | |||
| complications = [[Severe combined immunodeficiency]] | |||
| onset = [[Infancy]] | |||
| duration = [[Lifelong]] | |||
| causes = Genetic mutations affecting [[MHC class II]] expression | |||
| risks = [[Consanguinity]] | |||
| diagnosis = [[Genetic testing]], [[flow cytometry]] | |||
| differential = [[Severe combined immunodeficiency]], [[DiGeorge syndrome]] | |||
| prevention = Genetic counseling | |||
| treatment = [[Hematopoietic stem cell transplantation]] | |||
| medication = [[Antibiotics]], [[immunoglobulin therapy]] | |||
| prognosis = Poor without treatment | |||
| frequency = Rare | |||
| deaths = High mortality without treatment | |||
}} | |||
{{Short description|A rare immunodeficiency disorder}} | {{Short description|A rare immunodeficiency disorder}} | ||
'''Bare lymphocyte syndrome''' (BLS) is a rare [[immunodeficiency disorder]] characterized by the absence or significant reduction of [[major histocompatibility complex]] (MHC) molecules on the surface of [[lymphocytes]]. This condition leads to severe immune system dysfunction, as MHC molecules are crucial for the immune system's ability to recognize and respond to foreign antigens. | '''Bare lymphocyte syndrome''' (BLS) is a rare [[immunodeficiency disorder]] characterized by the absence or significant reduction of [[major histocompatibility complex]] (MHC) molecules on the surface of [[lymphocytes]]. This condition leads to severe immune system dysfunction, as MHC molecules are crucial for the immune system's ability to recognize and respond to foreign antigens. | ||
==Classification== | ==Classification== | ||
Bare lymphocyte syndrome is classified into two main types based on the specific MHC molecules affected: | Bare lymphocyte syndrome is classified into two main types based on the specific MHC molecules affected: | ||
* '''Type I BLS''': This type involves a deficiency in MHC class I molecules. It is often associated with chronic [[lung infections]] and [[granulomatous skin lesions]]. | * '''Type I BLS''': This type involves a deficiency in MHC class I molecules. It is often associated with chronic [[lung infections]] and [[granulomatous skin lesions]]. | ||
* '''Type II BLS''': This type involves a deficiency in MHC class II molecules. It is more severe than Type I and is characterized by recurrent infections, failure to thrive, and often leads to early childhood mortality if untreated. | * '''Type II BLS''': This type involves a deficiency in MHC class II molecules. It is more severe than Type I and is characterized by recurrent infections, failure to thrive, and often leads to early childhood mortality if untreated. | ||
==Pathophysiology== | ==Pathophysiology== | ||
The pathophysiology of bare lymphocyte syndrome involves genetic mutations that affect the expression of MHC molecules on the surface of [[antigen-presenting cells]]. In Type I BLS, mutations typically occur in genes responsible for the transport and processing of MHC class I molecules. In Type II BLS, mutations affect the [[transcription factors]] necessary for the expression of MHC class II molecules. | The pathophysiology of bare lymphocyte syndrome involves genetic mutations that affect the expression of MHC molecules on the surface of [[antigen-presenting cells]]. In Type I BLS, mutations typically occur in genes responsible for the transport and processing of MHC class I molecules. In Type II BLS, mutations affect the [[transcription factors]] necessary for the expression of MHC class II molecules. | ||
==Clinical Features== | ==Clinical Features== | ||
Patients with bare lymphocyte syndrome present with a variety of clinical features depending on the type: | Patients with bare lymphocyte syndrome present with a variety of clinical features depending on the type: | ||
* '''Type I BLS''': Patients may experience recurrent [[respiratory tract infections]], [[bronchiectasis]], and skin lesions. Despite the absence of MHC class I molecules, these patients often have normal [[T-cell]] counts. | * '''Type I BLS''': Patients may experience recurrent [[respiratory tract infections]], [[bronchiectasis]], and skin lesions. Despite the absence of MHC class I molecules, these patients often have normal [[T-cell]] counts. | ||
* '''Type II BLS''': This type presents with severe combined immunodeficiency-like symptoms, including recurrent bacterial, viral, and fungal infections, [[chronic diarrhea]], and [[failure to thrive]]. | * '''Type II BLS''': This type presents with severe combined immunodeficiency-like symptoms, including recurrent bacterial, viral, and fungal infections, [[chronic diarrhea]], and [[failure to thrive]]. | ||
==Diagnosis== | ==Diagnosis== | ||
Diagnosis of bare lymphocyte syndrome involves a combination of clinical evaluation, laboratory tests, and genetic analysis. Key diagnostic tests include: | Diagnosis of bare lymphocyte syndrome involves a combination of clinical evaluation, laboratory tests, and genetic analysis. Key diagnostic tests include: | ||
* [[Flow cytometry]] to assess the expression of MHC molecules on lymphocytes. | * [[Flow cytometry]] to assess the expression of MHC molecules on lymphocytes. | ||
* Genetic testing to identify mutations in genes associated with MHC expression. | * Genetic testing to identify mutations in genes associated with MHC expression. | ||
* Immunological assays to evaluate the function of T-cells and other immune components. | * Immunological assays to evaluate the function of T-cells and other immune components. | ||
==Treatment== | ==Treatment== | ||
The treatment of bare lymphocyte syndrome is primarily supportive and may include: | The treatment of bare lymphocyte syndrome is primarily supportive and may include: | ||
* [[Antibiotic]] prophylaxis to prevent infections. | * [[Antibiotic]] prophylaxis to prevent infections. | ||
* [[Immunoglobulin replacement therapy]] to provide passive immunity. | * [[Immunoglobulin replacement therapy]] to provide passive immunity. | ||
* [[Hematopoietic stem cell transplantation]] (HSCT) is the only curative treatment, particularly for Type II BLS. | * [[Hematopoietic stem cell transplantation]] (HSCT) is the only curative treatment, particularly for Type II BLS. | ||
==Prognosis== | ==Prognosis== | ||
The prognosis for patients with bare lymphocyte syndrome varies depending on the type and severity of the condition. Type I BLS generally has a better prognosis with appropriate management, while Type II BLS often requires early intervention with HSCT to improve survival outcomes. | The prognosis for patients with bare lymphocyte syndrome varies depending on the type and severity of the condition. Type I BLS generally has a better prognosis with appropriate management, while Type II BLS often requires early intervention with HSCT to improve survival outcomes. | ||
==See also== | |||
== | |||
* [[Immunodeficiency]] | * [[Immunodeficiency]] | ||
* [[Major histocompatibility complex]] | * [[Major histocompatibility complex]] | ||
* [[Hematopoietic stem cell transplantation]] | * [[Hematopoietic stem cell transplantation]] | ||
[[Category:Immunodeficiency disorders]] | [[Category:Immunodeficiency disorders]] | ||
[[Category:Genetic disorders]] | [[Category:Genetic disorders]] | ||
Latest revision as of 19:21, 4 April 2025
Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
Founder, WikiMD Wellnesspedia &
W8MD medical weight loss NYC and sleep center NYC
| Bare lymphocyte syndrome | |
|---|---|
| |
| Synonyms | MHC class II deficiency |
| Pronounce | N/A |
| Specialty | N/A |
| Symptoms | Recurrent infections, failure to thrive, chronic diarrhea |
| Complications | Severe combined immunodeficiency |
| Onset | Infancy |
| Duration | Lifelong |
| Types | N/A |
| Causes | Genetic mutations affecting MHC class II expression |
| Risks | Consanguinity |
| Diagnosis | Genetic testing, flow cytometry |
| Differential diagnosis | Severe combined immunodeficiency, DiGeorge syndrome |
| Prevention | Genetic counseling |
| Treatment | Hematopoietic stem cell transplantation |
| Medication | Antibiotics, immunoglobulin therapy |
| Prognosis | Poor without treatment |
| Frequency | Rare |
| Deaths | High mortality without treatment |
A rare immunodeficiency disorder
Bare lymphocyte syndrome (BLS) is a rare immunodeficiency disorder characterized by the absence or significant reduction of major histocompatibility complex (MHC) molecules on the surface of lymphocytes. This condition leads to severe immune system dysfunction, as MHC molecules are crucial for the immune system's ability to recognize and respond to foreign antigens.
Classification[edit]
Bare lymphocyte syndrome is classified into two main types based on the specific MHC molecules affected:
- Type I BLS: This type involves a deficiency in MHC class I molecules. It is often associated with chronic lung infections and granulomatous skin lesions.
- Type II BLS: This type involves a deficiency in MHC class II molecules. It is more severe than Type I and is characterized by recurrent infections, failure to thrive, and often leads to early childhood mortality if untreated.
Pathophysiology[edit]
The pathophysiology of bare lymphocyte syndrome involves genetic mutations that affect the expression of MHC molecules on the surface of antigen-presenting cells. In Type I BLS, mutations typically occur in genes responsible for the transport and processing of MHC class I molecules. In Type II BLS, mutations affect the transcription factors necessary for the expression of MHC class II molecules.
Clinical Features[edit]
Patients with bare lymphocyte syndrome present with a variety of clinical features depending on the type:
- Type I BLS: Patients may experience recurrent respiratory tract infections, bronchiectasis, and skin lesions. Despite the absence of MHC class I molecules, these patients often have normal T-cell counts.
- Type II BLS: This type presents with severe combined immunodeficiency-like symptoms, including recurrent bacterial, viral, and fungal infections, chronic diarrhea, and failure to thrive.
Diagnosis[edit]
Diagnosis of bare lymphocyte syndrome involves a combination of clinical evaluation, laboratory tests, and genetic analysis. Key diagnostic tests include:
- Flow cytometry to assess the expression of MHC molecules on lymphocytes.
- Genetic testing to identify mutations in genes associated with MHC expression.
- Immunological assays to evaluate the function of T-cells and other immune components.
Treatment[edit]
The treatment of bare lymphocyte syndrome is primarily supportive and may include:
- Antibiotic prophylaxis to prevent infections.
- Immunoglobulin replacement therapy to provide passive immunity.
- Hematopoietic stem cell transplantation (HSCT) is the only curative treatment, particularly for Type II BLS.
Prognosis[edit]
The prognosis for patients with bare lymphocyte syndrome varies depending on the type and severity of the condition. Type I BLS generally has a better prognosis with appropriate management, while Type II BLS often requires early intervention with HSCT to improve survival outcomes.
