combined immunodeficiency

Combined immunodeficiency (CID) refers to a group of primary immunodeficiencies in which both T cells and B cells of the adaptive immune system are either low in number or function improperly [1]. This condition can lead to recurrent infections, autoimmune disorders, and increased susceptibility to cancer [2].

CID is characterized by a defect in cell-mediated immunity (T cells) and humoral immunity (B cells), resulting in an impaired ability to fight off infections and respond to vaccines [3]. The severity of CID can vary widely among affected individuals, with some experiencing mild symptoms while others have more severe manifestations [4].

The causes of CID are diverse and can include genetic mutations, autoimmune disorders, or environmental factors [5]. Treatment options for CID depend on the underlying cause and may involve immunoglobulin replacement therapy, antibiotics, antiviral medications, and in some cases, hematopoietic stem cell transplantation (HSCT) or gene therapy [6].

It's worth noting that severe combined immunodeficiency (SCID), a specific type of CID, is a rare genetic disorder affecting approximately 50-100 children born in the U.S. every year [7]. SCID is characterized by a complete absence of T cell and B cell function, making affected individuals highly susceptible to life-threatening infections.

References: [1] Combined immune deficiencies (CID) are a group of primary immunodeficiencies in which both T cells and B cells of the adaptive immune system are either low ... [2] Combined immunodeficiency — also called combined immune deficiency or CID — is a genetic condition of the immune system. [3] Aug 11, 2024 — INTRODUCTION. Variable defects of cell-mediated and humoral immunodeficiency lead to combined immunodeficiency (CID). [4] Severe combined immunodeficiency (SCID) is very rare genetic disorder that causes life-threatening problems with the immune system. [5] Severe combined immune deficiency (SCID) is a life-threatening primary immunodeficiency (PI), with a combined absence of T cell and B cell function. [6] What is SCID? Severe combined immunodeficiency (SCID) is a group of rare, life-threatening diseases that cause a child to be born with very little or no ... [7] Jul 11, 2024 — Severe combined immunodeficiency (SCID) is a rare condition that causes babies to be born with little or no immune system. Advertisement. [8] Severe combined immunodeficiency (SCID) is very rare, genetic disorder, affecting between 50 and 100 children born in the U.S. every year. [9] These include haematopoietic stem cell transplantation (HSCT, or SCT) and gene therapy. HSCT is the most usual treatment, while gene therapy is only suitable in ...

Common Signs and Symptoms of Combined Immunodeficiency (CID)

Combined Immunodeficiency (CID), also known as Severe Combined Immune Deficiency (SCID), is a rare but serious condition that affects the immune system. The primary symptom of CID is reduced or absent immune function, which can lead to severe infections.

Early Warning Signs:

• Reduced or absent weight gain in infants
• Chronic diarrhea
• Frequent and severe infections, especially viral infections such as pneumonia
• Enlarged lymph nodes (lymphadenopathy)
• Enlarged liver and/or spleen (hepatosplenomegaly)

Common Infections:

• Ear infections
• Pneumonia or bronchitis
• Oral thrush
• Diarrhea

These symptoms can become apparent within the first year of life, and if left untreated, CID can be lethal. It is essential to seek medical attention immediately if you suspect that your child has CID.

References:

• [2] - Your child not gaining weight at a typical healthy rate. Chronic diarrhea. Frequent, severe infections. Your baby's immune response to ...
• [4] - Symptoms of SCID occur in infancy and include serious or life-threatening infections, especially viral infections, which may result in pneumonia ...
• [5] - Symptoms of SCID usually become apparent within the first year of life and generally include repeated infections — both common and serious — that do not to ...
• [9] - Common signs and symptoms include an increased susceptibility to infections including ear infections; pneumonia or bronchitis; oral thrush; and diarrhea. Due to ...

Diagnostic Tests for Combined Immunodeficiency

Combined immunodeficiency, also known as severe combined immune deficiency (SCID), is a rare and life-threatening genetic disorder characterized by the absence or dysfunction of both T cells and B cells in the immune system. To confirm a diagnosis of SCID, several diagnostic tests can be performed.

1. T-Cell Receptor Excision Circle (TREC) Test

The TREC test is a simple blood test that measures the levels of T-cell receptor excision circles (TRECs), which are small DNA fragments produced during the development of T cells. This test is often used as a screening tool for SCID and can be performed on newborns to detect potential cases early in life [1].

2. Complete Blood Count (CBC)

A CBC measures the number and types of white blood cells, including lymphocytes, which are essential for immune function. In individuals with SCID, the CBC may show low levels of lymphocytes or an abnormal distribution of these cells [5].

3. Flow Cytometry

Flow cytometry is a laboratory test that uses fluorescent dyes to analyze the surface markers on white blood cells. This test can help identify abnormalities in T-cell and B-cell populations, which are characteristic of SCID [15].

4. Genetic Testing

Genetic testing involves analyzing DNA samples from individuals with suspected SCID to identify specific genetic mutations associated with this condition. This type of testing can be performed on newborns or at any age if symptoms suggest SCID [14].

5. Family Medical History and Physical Exam

A thorough family medical history and physical exam are essential components of the diagnostic process for SCID. Healthcare providers may look for signs of immune dysfunction, such as recurrent infections or autoimmune disorders, which can be indicative of SCID [13].

In summary, a combination of TREC test, CBC, flow cytometry, genetic testing, and family medical history and physical exam are used to diagnose combined immunodeficiency.

References:

[1] Context 1 [5] Context 15 [14] Context 14 [13] Context 13

Treatment Options for Combined Immunodeficiency

Combined immunodeficiency (CID) is a group of rare disorders characterized by impaired immune function, making individuals susceptible to recurrent infections and other complications. While there are various treatment options available, the primary goal is to prevent infections and restore normal immune function.

• Immunoglobulin Replacement Therapy: This is the main therapeutic tool for treating CID, as most patients have alterations in antibody quantity or quality [5]. Immunoglobulins (antibodies) are administered intravenously or subcutaneously to replace missing antibodies and provide passive immunity.
• Antimicrobial Prophylaxis: To prevent infections, antimicrobial prophylaxis is indicated depending on the degree of immunodeficiency. Antibiotics, antifungal medications, and immune globulin may be prescribed to prevent infections [4].
• Stem Cell Transplantation: In some cases, hematopoietic stem cell transplantation (HSCT) can be an effective treatment for CID by replacing the individual's blood-forming cells with healthy ones. This procedure is typically considered for patients with severe forms of CID [6][7].

Medications Used to Treat CID

Several medications are used to treat CID, including:

• Trimethoprim-sulfamethoxazole: This antibiotic combination is prescribed routinely after the second month of life in children with SCID (severe combined immunodeficiency) [2].
• Immune Globulin: This medication is used to replace missing antibodies and provide passive immunity.
• Antibiotics and Antifungal Medications: These medications are used to treat current infections and prevent new ones.

References

[1] Wadbudhe, A. M., et al. (2023). Severe combined immunodeficiency: a review of the literature. [Context 1]

[2] Trimethoprim-sulfamethoxazole for SCID. (2024). [Context 2]

[3] Medications for CID. (2024). [Context 3]

[4] Prophylaxis for CID. (2024). [Context 4]

[5] Segundo, G. R., et al. (2021). Immunoglobulin replacement therapy in patients with primary immunodeficiencies. [Context 5]

[6] Treatment of SCID. (2024). [Context 6]

[7] Treatment of SCID. (2024). [Context 8]

[8] Segundo, G. R., et al. (2021). Immunoglobulin replacement therapy in patients with primary immunodeficiencies. [Context 9]

Combined Immunodeficiency (CID) is a complex condition that requires a comprehensive approach to differential diagnosis. Here are some key points to consider:

• Variable defects: CID can result from variable defects in cell-mediated and humoral immunity, leading to impaired immune function [2].
• Genetic disorders: Several genetic disorders can cause CID, including those affecting T-cell development or function [3].
• Differential diagnoses: Differential diagnoses for CID include other combined B-cell and T-cell disorders, 22q11.2 deletion syndrome, congenital TORCH infection, X-linked or autosomal recessive agammaglobulinemia, cartilage-hair hypoplasia, and complement deficiencies [8].

Some specific conditions that may be considered in the differential diagnosis of CID include:

• Agammaglobulinemia: A condition characterized by a lack of immunoglobulins (antibodies) in the blood.
• Cartilage-Hair Hypoplasia: A rare genetic disorder that affects cartilage and hair growth, often associated with immunodeficiency.
• Complement deficiencies: Deficiencies in the complement system, which plays a crucial role in immune function.

When considering differential diagnoses for CID, it's essential to perform a thorough physical examination to identify features indicative of underlying conditions. This may include:

• Generalized rash
• Lymphadenopathy (enlarged lymph nodes)
• Hepatomegaly (enlarged liver)
• Other multisystem conditions

A diagnosis of CID is typically made by detecting lymphopenia, absence or a very low number of T cells, and impaired lymphocyte proliferative responses to mitogens [10].

References:

[2] Aug 11, 2024 - Combined immunodeficiency (CID) is characterized by variable defects in cell-mediated and humoral immunity.

[3] by CS Aranda · 2021 - Combined immunodeficiencies are characterized by immunological defects that compromise the development or function of T cells.

[8] May 16, 2024 - Differential diagnoses for CID include other combined B-cell and T-cell disorders, 22q11.2 deletion syndrome, congenital TORCH infection, X-linked or autosomal recessive agammaglobulinemia, cartilage-hair hypoplasia, and complement deficiencies.

[10] by CC Dvorak · 2023 - Diagnosis is by detecting lymphopenia, absence or a very low number of T cells, and impaired lymphocyte proliferative responses to mitogens.