ICD-10: D81.7

Clinical Description of ICD-10 Code D81.7: Major Histocompatibility Complex Class II Deficiency

Overview

ICD-10 code D81.7 refers to Major Histocompatibility Complex (MHC) Class II deficiency, a rare genetic disorder that affects the immune system. This condition is characterized by the inability of the body to produce MHC class II molecules, which are crucial for the immune response, particularly in the activation of T-helper cells. The deficiency leads to severe immunodeficiency, making individuals highly susceptible to infections.

Pathophysiology

MHC class II molecules are essential for presenting antigens to CD4+ T-helper cells, which play a pivotal role in orchestrating the immune response. In individuals with MHC class II deficiency, mutations in genes responsible for the expression of these molecules result in a lack of functional MHC class II on the surface of antigen-presenting cells (APCs). This impairment disrupts the normal activation of T-helper cells, leading to a compromised immune response against pathogens, particularly extracellular bacteria and viruses.

Clinical Features

Patients with MHC class II deficiency typically present with:

• Recurrent Infections: Frequent and severe infections, particularly from opportunistic pathogens, due to the inability to mount an effective immune response.
• Failure to Thrive: Infants may exhibit poor growth and development due to chronic infections and malnutrition.
• Autoimmunity: Some patients may develop autoimmune conditions as a result of dysregulated immune responses.
• Lymphadenopathy: Swollen lymph nodes may be observed due to the accumulation of immune cells attempting to respond to infections.

Diagnosis

Diagnosis of MHC class II deficiency involves a combination of clinical evaluation and laboratory tests, including:

• Genetic Testing: Identification of mutations in genes associated with MHC class II expression, such as the HLA-DP, HLA-DQ, and HLA-DR genes.
• Flow Cytometry: Assessment of the expression of MHC class II molecules on the surface of APCs.
• Immunological Evaluation: Testing for specific antibody responses to vaccines and infections to assess the functionality of the immune system.

Management

Management of MHC class II deficiency focuses on preventing infections and may include:

• Prophylactic Antibiotics: To reduce the risk of bacterial infections.
• Immunoglobulin Replacement Therapy: To provide passive immunity.
• Hematopoietic Stem Cell Transplantation (HSCT): This is the only potential curative treatment, particularly in severe cases, as it can restore normal immune function.

Prognosis

The prognosis for individuals with MHC class II deficiency varies depending on the severity of the condition and the timeliness of diagnosis and intervention. Early diagnosis and appropriate management can significantly improve outcomes, but untreated individuals may face life-threatening infections and complications.

Conclusion

ICD-10 code D81.7 encapsulates a critical immunological disorder that requires prompt recognition and management to mitigate the risks associated with severe immunodeficiency. Understanding the clinical features, diagnostic criteria, and treatment options is essential for healthcare providers to improve patient outcomes in those affected by MHC class II deficiency.

Major Histocompatibility Complex Class II Deficiency, classified under ICD-10 code D81.7, is a rare genetic disorder that significantly impacts the immune system. This condition is characterized by a lack of functional MHC class II molecules, which are crucial for the immune response, particularly in presenting antigens to CD4+ T cells. Below is a detailed overview of the clinical presentation, signs, symptoms, and patient characteristics associated with this condition.

Clinical Presentation

Immune Dysfunction

Patients with MHC class II deficiency exhibit profound immunodeficiency, leading to increased susceptibility to infections. This is primarily due to the inability to mount effective immune responses against pathogens, particularly those requiring T-helper cell activation.

Age of Onset

The clinical manifestations of MHC class II deficiency typically present in infancy or early childhood. Symptoms may arise shortly after birth or within the first few months of life, often coinciding with the introduction of environmental pathogens.

Signs and Symptoms

Recurrent Infections

One of the hallmark features of MHC class II deficiency is recurrent and severe infections. These may include:
- Bacterial Infections: Patients are particularly vulnerable to encapsulated bacteria such as Streptococcus pneumoniae and Haemophilus influenzae.
- Viral Infections: There is an increased risk of severe viral infections, including those caused by cytomegalovirus (CMV) and Epstein-Barr virus (EBV).
- Fungal Infections: Opportunistic fungal infections may also occur due to the compromised immune system.

Failure to Thrive

Children with this condition often experience failure to thrive, which can be attributed to chronic infections and the body's inability to mount an adequate immune response. This can lead to malnutrition and growth delays.

Autoimmune Manifestations

Some patients may develop autoimmune conditions due to dysregulation of the immune system, although this is less common compared to the infectious complications.

Lymphadenopathy and Splenomegaly

Patients may present with lymphadenopathy (swollen lymph nodes) and splenomegaly (enlarged spleen) as a result of chronic immune activation and infection.

Patient Characteristics

Genetic Background

MHC class II deficiency is often inherited in an autosomal recessive manner, with mutations affecting genes responsible for the expression of MHC class II molecules. This can include defects in the transcription factors necessary for MHC class II gene expression, such as CIITA.

Family History

A family history of immunodeficiency or related conditions may be present, as this disorder can be part of a broader spectrum of primary immunodeficiencies.

Ethnic and Demographic Factors

While MHC class II deficiency can occur in any ethnic group, certain genetic backgrounds may predispose individuals to this condition. The prevalence is generally low, making it a rare diagnosis.

Conclusion

Major Histocompatibility Complex Class II Deficiency (ICD-10 code D81.7) presents a significant challenge due to its profound impact on the immune system, leading to recurrent infections and associated complications. Early recognition and management are crucial for improving outcomes in affected individuals. Treatment often involves immunoglobulin replacement therapy, prophylactic antibiotics, and in some cases, hematopoietic stem cell transplantation to restore immune function. Understanding the clinical presentation and patient characteristics is essential for healthcare providers to diagnose and manage this rare immunodeficiency effectively.

ICD-10 code D81.7 refers to Major Histocompatibility Complex Class II Deficiency, a condition characterized by a lack of functional MHC class II molecules, which are crucial for the immune system's ability to present antigens to T cells. This deficiency can lead to severe immunodeficiency, making individuals more susceptible to infections.

Alternative Names

1. MHC Class II Deficiency: A more concise term that directly refers to the lack of MHC class II molecules.
2. Bare Lymphocyte Syndrome: This term is often used interchangeably with MHC class II deficiency, as it describes a condition where T lymphocytes are unable to respond to antigens due to the absence of MHC class II molecules.
3. Class II Immunodeficiency: A simplified term that highlights the immunodeficiency aspect related to class II molecules.
4. Congenital MHC Class II Deficiency: This term emphasizes that the condition is present from birth.

Related Terms

• Primary Immunodeficiency: A broader category that includes various genetic disorders affecting the immune system, including MHC class II deficiency.
• T-cell Immunodeficiency: Since MHC class II molecules are essential for T-cell activation, this term is relevant in discussing the consequences of the deficiency.
• HLA Class II Deficiency: Referring to the human leukocyte antigen (HLA) system, which includes MHC class II molecules, this term is often used in clinical contexts.
• Immunologic Deficiency Disorders: A general term that encompasses various disorders, including those affecting MHC class II function.

Conclusion

Understanding the alternative names and related terms for ICD-10 code D81.7 is essential for accurate diagnosis, coding, and communication among healthcare professionals. These terms help clarify the specific nature of the immunodeficiency and its implications for patient care. If you need further information on this topic or related conditions, feel free to ask!

Major Histocompatibility Complex Class II Deficiency (MHC Class II Deficiency), classified under ICD-10 code D81.7, is a rare genetic disorder that affects the immune system. This condition is characterized by the absence or dysfunction of MHC class II molecules, which are crucial for the immune system's ability to present antigens to T cells, leading to impaired immune responses. The diagnosis of MHC Class II deficiency involves several criteria and diagnostic steps.

Diagnostic Criteria for MHC Class II Deficiency

1. Clinical Presentation

Patients typically present with recurrent infections, particularly with opportunistic pathogens. Common clinical features include:
- Severe recurrent bacterial infections: These may include pneumonia, sepsis, and infections caused by encapsulated organisms.
- Failure to thrive: Infants and children may exhibit poor growth and development due to chronic infections.
- Autoimmune manifestations: Some patients may develop autoimmune conditions due to dysregulated immune responses.

2. Immunological Evaluation

A comprehensive immunological assessment is essential for diagnosis:
- Lymphocyte subset analysis: Flow cytometry is used to evaluate the distribution of T cells, B cells, and natural killer (NK) cells. Patients with MHC Class II deficiency often show a reduced number of CD4+ T cells.
- T cell function tests: These tests assess the ability of T cells to respond to antigens. A lack of response to T cell-dependent antigens is indicative of MHC Class II deficiency.
- B cell function tests: Evaluation of antibody production in response to vaccinations can help determine B cell functionality, which is often impaired in these patients.

3. Genetic Testing

Genetic testing is crucial for confirming the diagnosis:
- Identification of mutations: Genetic analysis can reveal mutations in genes responsible for MHC Class II expression, such as the CIITA gene, which is a key regulator of MHC class II gene expression.
- Family history: Since MHC Class II deficiency is often inherited in an autosomal recessive manner, a detailed family history may provide insights into genetic predispositions.

4. Exclusion of Other Conditions

It is important to rule out other immunodeficiencies that may present similarly:
- Other forms of severe combined immunodeficiency (SCID): Conditions like X-linked SCID or adenosine deaminase deficiency should be considered.
- Common variable immunodeficiency (CVID): This condition can also lead to recurrent infections and should be differentiated from MHC Class II deficiency.

Conclusion

The diagnosis of Major Histocompatibility Complex Class II Deficiency (ICD-10 code D81.7) relies on a combination of clinical evaluation, immunological testing, genetic analysis, and exclusion of other immunodeficiencies. Early diagnosis is critical for managing the condition effectively, as patients are at high risk for severe infections and may benefit from interventions such as immunoglobulin therapy or hematopoietic stem cell transplantation. If you suspect MHC Class II deficiency, a referral to a specialist in immunology or genetics is recommended for comprehensive evaluation and management.

Major Histocompatibility Complex Class II (MHC II) deficiency, classified under ICD-10 code D81.7, is a rare immunodeficiency disorder characterized by the absence or dysfunction of MHC II molecules, which are crucial for the immune system's ability to present antigens to T cells. This deficiency can lead to severe immunological consequences, including increased susceptibility to infections and autoimmune diseases. Here, we will explore the standard treatment approaches for managing this condition.

Overview of MHC II Deficiency

MHC II deficiency is primarily caused by genetic mutations affecting the genes responsible for the expression of MHC II molecules. Patients typically present with recurrent infections, failure to thrive, and may develop autoimmune conditions due to the impaired immune response. Diagnosis is often confirmed through genetic testing and immunological assessments, including flow cytometry to evaluate T cell function and MHC II expression.

Standard Treatment Approaches

1. Immunoglobulin Replacement Therapy

One of the primary treatment modalities for patients with MHC II deficiency is immunoglobulin replacement therapy. This therapy aims to provide the patient with the necessary antibodies to help combat infections. Intravenous immunoglobulin (IVIG) or subcutaneous immunoglobulin (SCIG) can be administered regularly to maintain adequate antibody levels and reduce the frequency and severity of infections[1][2].

2. Antibiotic Prophylaxis

Due to the increased risk of infections, prophylactic antibiotics are often prescribed to prevent bacterial infections. This approach is particularly important in young children or those with a history of recurrent infections. The choice of antibiotics may be tailored based on the patient's specific risk factors and previous infection history[3].

3. Hematopoietic Stem Cell Transplantation (HSCT)

For patients with severe forms of MHC II deficiency, hematopoietic stem cell transplantation may be considered. This treatment can potentially restore normal immune function by providing the patient with healthy stem cells that can produce functional immune cells. HSCT is typically reserved for patients with life-threatening infections or those who do not respond adequately to other treatments[4][5].

4. Supportive Care

Supportive care is crucial in managing MHC II deficiency. This includes regular monitoring for infections, nutritional support to address failure to thrive, and management of any autoimmune complications that may arise. Patients may also benefit from consultations with specialists in immunology, infectious diseases, and nutrition[6].

5. Gene Therapy (Emerging Approach)

While still largely experimental, gene therapy holds promise for treating genetic immunodeficiencies, including MHC II deficiency. Research is ongoing to develop techniques that could correct the underlying genetic defects, potentially offering a long-term solution for affected individuals. However, this approach is not yet standard practice and remains in the research phase[7].

Conclusion

Management of Major Histocompatibility Complex Class II deficiency requires a comprehensive approach that includes immunoglobulin replacement therapy, antibiotic prophylaxis, and potentially hematopoietic stem cell transplantation for severe cases. Supportive care plays a vital role in improving the quality of life for patients. As research progresses, emerging therapies such as gene therapy may offer new hope for those affected by this challenging condition. Regular follow-up with healthcare providers is essential to tailor treatment plans to individual patient needs and to monitor for complications.

References

1. Article - Billing and Coding: Immune Globulin (A57778).
2. Immunoglobulin replacement therapy.
3. Clinical Policy: Immune Globulins.
4. Systematic review of literature and analysis of big data from immunology studies.
5. Subject: Immune Globulin Therapy.
6. Immunoglobulin Medicare Guidelines.
7. ALYGLO® (immune globulin intravenous, human-stwk).