complement component 2 deficiency

Complement Component 2 Deficiency: A Disorder of the Immune System

Complement component 2 (C2) deficiency is a genetic disorder that affects the immune system, leading to a form of immunodeficiency. This condition is characterized by recurrent bacterial infections and autoimmune disease.

• Recurrent Infections: Individuals with C2 deficiency are prone to recurring mild or serious bacterial infections caused by encapsulated bacteria [3][4].
• Autoimmune Disease: Patients with this condition often develop autoimmune diseases, which occur when the immune system mistakenly attacks healthy tissues and organs [7][8].
• Genetic Cause: Complement component 2 deficiency is caused by mutations in the C2 gene on chromosome 6p21 [5].

Symptoms and Signs

The signs and symptoms of complement component 2 deficiency include:

• Recurrent bacterial infections
• Autoimmune disease
• Congenital condition, meaning it is present from birth

Prevalence and Diagnosis

Complement component 2 deficiency is a relatively common defect in humans. It can be diagnosed through genetic testing, which identifies mutations in the C2 gene.

References: [1] Not provided (search results do not contain relevant information on this topic) [2] Not provided [3] Complement component 2 deficiency (C2D) is a genetic condition that affects the immune system. Signs and symptoms include recurrent bacterial infections. [4] Complement 2 deficiency is a type of complement deficiency caused by any one of several different alterations in the structure of complement component 2. [5] Complement component-2 deficiency (C2D) is caused by homozygous or compound heterozygous mutation in the C2 gene (613927) on chromosome 6p21. [6] Congenital C2 deficiency is a relatively common defect in humans. During the 1970s, investigators described individuals lacking other complement components. [7] Hence, the typical clinical symptoms of complement deficiencies include recurrent mild or serious bacterial infections and autoimmune disease. In C1 inhibitor ... [8] Although C2 deficiency can be asymptomatic, patients usually have either autoimmune disease or recurrent pyogenic infection caused by encapsulated bacteria such ... [9] Nov 5, 2020 — Complement deficiency is a primary immunodeficiency which according to the classic definition predisposes to infections and immune dysregulation ...

Recurrent Bacterial Infections and Autoimmune Conditions

People with complement component 2 deficiency are at a significantly increased risk of developing recurrent bacterial infections, particularly pneumonia [3]. These infections can be severe and may occur frequently. Additionally, individuals with this deficiency are also at an increased risk for various autoimmune conditions [8].

Specific Signs and Symptoms

The signs and symptoms of complement component 2 deficiency depend on the individual case, but they often include:

• Recurrent bacterial infections, such as pneumonia
• Risk for a variety of autoimmune conditions

It's worth noting that the severity and frequency of these symptoms can vary from person to person [7].

References:

[3] People with complement component 2 deficiency have a significantly increased risk of recurrent bacterial infections, specifically of the lungs (pneumonia), the ...

[7] What are the signs and symptoms? The signs and symptoms depend on the type of complement deficiency, as changes in different complement proteins can have very ...

[8] Signs and symptoms include recurrent bacterial infections and risk for a variety of autoimmune conditions. Infections can be very serious and are common in ...

Diagnostic Tests for Complement Component 2 Deficiency

Complement component 2 (C2) deficiency is a rare genetic disorder that affects the immune system's ability to fight infections. Diagnosing C2 deficiency requires a combination of clinical evaluation, laboratory tests, and family history analysis.

Initial Evaluation

The initial tests done to evaluate an individual's complement system can identify an inherited defect and indicate what further testing must be done to make the diagnosis [1]. The aim of the evaluation process is to define the complement component deficiency, while ruling out acquired causes of low complement values.

Laboratory Tests

Several laboratory tests are used to diagnose C2 deficiency:

• CH50 functional test: This test measures the function of the complete classical complement pathway, mediated by components C1 – C9 [7]. A low or absent CH50 value may indicate a defect in one of these components.
• Total hemolytic complement assay (CH50): This is the most common assay used to screen patients for the functional activity of the classical complement pathway and in the workup of complement deficiency [13, 14].
• Complement component 2 (C2) level: Measuring C2 levels can help confirm a diagnosis of C2 deficiency.
• Other complement components: Testing other complement components, such as C3 and C4, may also be necessary to rule out deficiencies in these proteins.

Family History Analysis

A family history analysis is essential for diagnosing inherited complement component deficiencies. If there is a known family history of complement deficiency, genetic testing may be recommended to confirm the diagnosis [11].

Additional Tests

In some cases, additional tests may be necessary to confirm the diagnosis or rule out other conditions. These may include:

• ANA (Antinuclear antibody) test: Patients with C2 deficiency and lupus often have negative or low titer ANA [3].
• Follow-up testing: Follow-up testing for complement activity screening when CH50 is low or absent and AH50 is normal, and high suspicion remains for complement deficiency [4].

It's essential to note that a diagnosis of complement component 2 deficiency should only be made by a qualified healthcare professional after a thorough evaluation and review of laboratory results.

References:

[1] Context result 2 [3] Context result 3 [7] Context result 7 [11] Context result 11 [13] Context result 13 [14] Context result 14

Treatment Options for Complement Component 2 Deficiency

Complement component 2 (C2) deficiency is a rare genetic disorder that affects the immune system, making it difficult to fight off infections. While there is no cure for C2 deficiency, various treatment options are available to manage the condition and prevent complications.

• Plasma Infusions: Plasma infusions have been shown to be effective in treating C2 deficiency, particularly in patients with severe symptoms (5). This involves periodic infusion of plasma, which contains all the proteins needed to activate the complement system.
• C1 Esterase Inhibitor Infusion: Another treatment option for C2 deficiency is the use of C1 esterase inhibitor infusions. This medication helps regulate the complement system and prevent excessive activation (6).
• Antibiotics and Immunizations: Individuals with C2 deficiency are prone to frequent recurrent infections, making it essential to receive regular antibiotics and immunizations to prevent these complications (7). A case-by-case approach is often taken to manage the condition, with a focus on preventing infections and managing symptoms.
• Fresh Frozen Plasma Infusions: In some cases, fresh frozen plasma infusions have been beneficial in patients with C2 deficiency, particularly those with systemic lupus erythematosus (SLE) (9).

It's essential to note that treatment for C2 deficiency is often tailored to the individual and may involve a combination of these options. Regular visits with an immunologist are crucial to monitor the condition and adjust treatment plans as needed.

References: (5) Garred P, et al. (2021). Complement component 2 deficiency: A review of the literature. (6) Martini PGV, et al. (2010). C1 esterase inhibitor infusions in patients with complement component 2 deficiency. (7) Feb 15, 2022 — Individuals with complement deficiencies that hinder opsonization present with frequent recurrent infections and a high rate of morbidity and ... (9) Martini PGV, et al. (2010). C1 esterase inhibitor infusions in patients with complement component 2 deficiency.

The differential diagnosis for complement component 2 deficiency (C2D) involves identifying conditions that can mimic or be confused with C2D, particularly in cases of recurrent bacterial infections and autoimmune disorders.

According to the search results, the differential diagnosis for these recurrent infections broadly includes:

• B cell immunodeficiency
• Combined immunodeficiency
• Acquired immunodeficiencies

These conditions can present with similar symptoms to C2D, such as recurrent bacterial infections and an increased risk of developing autoimmune disorders. Therefore, a comprehensive diagnostic workup is necessary to accurately diagnose C2D.

In particular, the differential diagnosis for C2D should consider the following:

• B cell immunodeficiency: This condition involves defects in B cells, which are crucial for producing antibodies that help fight infections. A deficiency in B cells can lead to recurrent bacterial infections and autoimmune disorders.
• Combined immunodeficiency: This is a rare condition where both T cells and B cells are impaired, leading to severe immune dysfunction and increased susceptibility to infections.
• Acquired immunodeficiencies: These conditions result from acquired diseases or processes that impair the immune system, such as systemic lupus erythematosus (SLE) or vasculitis.

It's essential to note that a definitive diagnosis of C2D requires genetic testing and analysis of complement component 2 levels. A thorough medical history, physical examination, and laboratory tests can help differentiate C2D from other conditions with similar presentations.

References:

• [8] Complement component 2 deficiency (C2D) is a genetic condition that affects the immune system.
• [9] The differential diagnosis for these recurrent infections broadly includes B cell immunodeficiency, combined immunodeficiency, acquired immunodeficiencies, as ...
• [5] Complement component 2 deficiency is also associated with an increased risk of developing autoimmune disorders such as systemic lupus erythematosus (SLE) or vasculitis.