IgG4-related disease is a group of pathologies characterized by chronic inflammation, fibrosis, and the presence of IgG4-positive plasma cells in various organs. This disease, known as IgG4-associated disease, covers a wide range of clinical manifestations, including pancreatitis, unappreciated fibrotic processes in the lungs, kidneys, salivary and lacrimal glands, and systemic disorders. The underlying mechanism of this pathology is autoimmune reactions that are formed due to the inactivation of IgG4, which leads to the formation of a predominance of IgG4 antibodies and an active fibrotic process.
History of the disease and interesting historical facts
The generation of knowledge about IgG4 disease began in the early 21st century, when researchers first noted clinical manifestations and serologic markers associated with high levels of IgG4 in patients’ plasma. In 2003, a team of Japanese scientists led by Dr. Tazumasa Ueno published a paper describing new clinical features of IgG4-associated conditions. This work initiated further studies that demonstrated the relationship of IgG4 with various organ systems. Since then, our knowledge of the diagnosis and treatment of IgG4-associated diseases has expanded significantly.
Epidemiology
According to the available data, IgG4-associated diseases are observed in different regions of the world, but the exact statistics of prevalence remain uncertain. Medical groups in various countries report prevalence of the disease at the level of 0.2-0.6 cases per 100,000 population, with the highest number of cases recorded in Japan, where the rates can reach 5-10 cases per 100,000 population. A higher risk of the disease is registered in men compared to women, as well as in older patients. It is also important to know that the disease can often remain undiagnosed, which makes it difficult to compile accurate statistics.
Genetic predisposition to this disease
Studies have shown that there is a genetic predisposition to IgG4-associated diseases, but the specific genes and mutations responsible for the risk of developing the disease are still being actively studied. First of all, the attention of researchers is focused on heme associated with autoimmune processes, such as HLA-DRB1 and HLA-DQB1, which are associated with an increased risk. The conducted studies have also shown that a unique combination of polymorphisms of various genes associated with the immune response can significantly increase the likelihood of developing IgG4-associated diseases.
Risk factors for the development of this disease
Several risk factors have been identified that contribute to the development of IgG4-associated diseases, including:
- Chronic infectious diseases such as viral hepatitis.
- Long-term exposure of the body to chemicals, in particular silicates.
- The patient has other autoimmune diseases (eg, systemic lupus erythematosus or thyroid disease).
- Age (most often middle-aged and elderly patients are affected).
- Gender (men are more susceptible to the disease than women).
These factors can act individually or in combination, which may predispose to more severe forms of the disease.
Diagnosis of this disease
Diagnosis of IgG4-associated diseases involves a comprehensive approach that takes into account clinical manifestations and the results of laboratory and radiological examination. The main steps in the diagnostic process are:
- Clinical symptoms: Patients may complain of fatigue, weight loss, abdominal pain, among others. Symptoms may vary depending on the organs involved.
- Laboratory tests: serum IgG4 levels, as well as associated markers of inflammation and autoimmune response.
- Radiological examinations: ultrasound, MRI and CT are used to visualize affected organs and assess the degree of fibrosis.
- Other types of diagnostics: a biopsy may be prescribed for histological analysis of tissue.
- Differential diagnosis: it is necessary to exclude other diseases with a similar clinical picture, such as cancer, chronic pancreatitis and systemic diseases.
Treatment
Treatment of IgG4-associated diseases depends on the severity of clinical symptoms and organ involvement. Teams of doctors work in multidisciplinary groups to ensure the best treatment outcome:
- General treatment: includes lifestyle changes, diet and exercise.
- Pharmacological treatment: glucocorticosteroids are used as the main means to control the inflammatory process.
- Surgical treatment: If the obstruction is significant or there are other complications, surgery may be required.
- Other therapies: Immunosuppressant drugs may be prescribed if there is no response to standard therapy.
List of medications used to treat this disease
The main drugs used in the treatment of IgG4-associated diseases include:
- Prednisolone
- Mycophenolate mofetil
- Methotrexate
- Azathioprine
- Rituximab
These drugs help in reducing inflammatory activity and improving the general condition of the patient.
Disease monitoring
Monitoring the patient's condition requires regular check-ups and controlled tests. Important steps include:
- Monitoring the level of IgG4 in the blood.
- Assessment of clinical symptoms and patient's condition.
- Radiological monitoring of the dynamics of changes in organs.
- Prognosis: In most cases, the prognosis is favorable with adequate treatment, but acute and chronic relapses are observed.
- Complications: Possible complications include the development of infections and exacerbation of other chronic diseases.
Age-related features of the disease
IgG4-associated diseases may present differently in different age groups:
- Less severe forms are more common among young people.
- In middle-aged people, diseases can join existing pathologies.
- In older people, the course of the disease may be more severe, with multiple exacerbations and involvement of various organs.
These factors require an individual approach to diagnosis and treatment depending on the patient's age.
Questions and Answers
- What are the main symptoms of IgG4-associated diseases? The main symptoms include enlarged salivary glands, swelling, aspiration pneumonia, abdominal pain, loss of appetite, and general weakness.
- How is this disease diagnosed? Diagnosis includes blood tests to determine IgG4 levels, imaging studies (CT, MRI) and sometimes biopsy of affected tissue.
- What treatment is prescribed for IgG4-associated diseases? The main treatment methods are corticosteroids and drugs that suppress the immune response.
- Is it possible to prevent the development of this disease? Unfortunately, specific measures to prevent IgG4-associated diseases have not been established, but avoiding known risk factors may help.
- How often should patients be monitored? It is recommended to carry out monitoring every 3-6 months depending on the patient's condition and the severity of the disease.
Advice from Dr. Oleg Korzhikov:
"It is important to pay attention to any changes in health that may indicate the development of IgG4-associated diseases. Regular medical examinations and laboratory tests will play a key role in early diagnosis and successful treatment. In addition, harmony in nutrition and lifestyle will help maintain the immune system in proper condition. Do not neglect specialist consultations and inform your doctor about any alarming symptoms!"
