What Is Autoimmune Neutropenia? What Are the Symptoms? How Is It Treated?

Who Is Eligible for Autoimmune Neutropenia? What Are the Symptoms? How Is It Treated? In this article, we will examine the details of the subject. Autoimmune neutropenia is a blood disorder in which the immune system attacks white blood cells (neutrophils) that fight infections. Autoimmune neutropenia can be primary or secondary. Primary autoimmune neutropenia mostly affects infants and young children and resolves spontaneously. Secondary autoimmune neutropenia stems from another condition and most commonly affects children and adults. It is usually a lifelong condition.

What Is Autoimmune Neutropenia? Autoimmune neutropenia is a blood disorder that involves the immune system attacking the body's neutrophils (a type of white blood cell). Neutrophils are an essential part of the immune system. They destroy harmful foreign agents that cause infections, such as fungi and bacteria. In autoimmune neutropenia, the immune system mistakenly attacks these white blood cells. As a result, lower-than-normal levels of neutrophils are found in the blood.

Autoimmune neutropenia can be primary or secondary.

• Primary Autoimmune Neutropenia: Primarily affects infants and young children. It involves a low neutrophil count that cannot be explained by other causes. Primary neutropenia usually resolves on its own within a few years.
• Secondary Autoimmune Neutropenia: More common in older children and adults. It involves a low neutrophil count resulting from another condition, such as infections, blood disorders, etc. Other autoimmune diseases often cause neutropenia. In an autoimmune disease, instead of protecting the body, the immune system mistakenly attacks the body itself. Secondary autoimmune neutropenia is generally chronic (long-term).

How Low Must the Neutrophil Level Be to Be Considered Neutropenia? Autoimmune neutropenia is just one type of neutropenia. Neutropenia is classified as mild, moderate, or severe depending on the number of neutrophils in a microliter (microL) of blood.

• Mild neutropenia: 1,000 – 1,500 microL.
• Moderate neutropenia: 500 – 1,000 microL.
• Severe neutropenia: Less than 500 microL.

How Does Autoimmune Neutropenia Affect the Body? The experience of autoimmune neutropenia depends on multiple factors, which should be discussed with a doctor. Having very few neutrophils can increase the risk of developing infections. These infections can be life-threatening without prompt medical attention. In other cases, autoimmune neutropenia may cause mild infections or no symptoms at all (asymptomatic).

You should work with a doctor to determine what is causing the neutropenia. Depending on the causes, the doctor may monitor the condition to keep infections under control.

Who Does Autoimmune Neutropenia Affect? Primary autoimmune neutropenia mostly affects infants and young children. On average, it is diagnosed at around eight months of age. Secondary autoimmune neutropenia often results from another autoimmune disease, such as lupus or rheumatoid arthritis. Most children with secondary autoimmune neutropenia are diagnosed at an average age of about 10 years. Most adults diagnosed with secondary autoimmune neutropenia are between 40 and 60 years old.

How Common Is Autoimmune Neutropenia? Primary autoimmune neutropenia is rare, occurring in approximately 1 in 100,000 children under the age of 10.

What Are the Symptoms of Autoimmune Neutropenia? Autoimmune neutropenia does not always cause noticeable symptoms. Instead, signs of infection may be observed. These include:

• Ear infections (most common).
• Respiratory tract infections (most common).
• Oral infections (ulcers, gingivitis).
• Skin infections.
• Pneumonia.
• Meningitis.
• Urinary tract infections.
• Sepsis.

Infections associated with primary autoimmune neutropenia are usually mild. More serious infections such as pneumonia, meningitis, and sepsis are more frequently associated with secondary autoimmune neutropenia compared to primary autoimmune neutropenia.

What Are the Causes of Autoimmune Neutropenia? Autoimmune neutropenia is classified as primary or secondary depending on what causes the low neutrophil levels.

What Are the Causes of Primary Autoimmune Neutropenia? In primary autoimmune neutropenia, antibodies target and destroy neutrophils. Antibodies are immune system proteins that destroy harmful foreign agents like viruses and bacteria. Researchers do not know for certain why antibodies in the body attack neutrophils.

What Are the Causes of Secondary Autoimmune Neutropenia? The low neutrophil count associated with secondary autoimmune neutropenia stems from another cause or condition that leads the immune system to destroy neutrophils. Causes may include:

• Autoimmune diseases (rheumatoid arthritis, lupus, autoimmune hemolytic anemia).
• Cancer (large granular lymphocytic leukemia).
• Infections (HIV, Parvovirus, hepatitis B).
• Tumors (Wilms tumor, Hodgkin's disease).
• Neurological diseases (multiple sclerosis).
• Kidney or bone marrow transplants.
• Medications, including certain chemotherapy drugs.

How Is Autoimmune Neutropenia Diagnosed? A doctor may notice low neutrophil levels during blood tests performed to investigate possible causes of an infection or fever. Because autoimmune neutropenia can have multiple causes, making a diagnosis can be challenging. The doctor may reach a diagnosis after ruling out other conditions that could cause low neutrophil levels.

The doctor may perform the following tests to diagnose or monitor autoimmune neutropenia:

• Complete Blood Count (CBC): Shows the number of neutrophils in the blood. These levels can fluctuate. To confirm neutropenia, the doctor will likely perform multiple CBCs to check if neutrophil levels are persistently low. Frequent CBC tests can show whether autoimmune neutropenia is chronic.
• Peripheral Blood Smear: Examining the blood under a microscope allows for the evaluation of neutrophil morphology and the identification of findings that may point to a diagnosis.
• Vitamin B12, Folate, and Copper Tests: These tests can reveal deficiencies associated with neutropenia. The body needs these to produce neutrophils.
• Liver Function Tests: The doctor may evaluate liver function and screen for viral hepatitis.
• HIV and Other Viral Screenings: HIV and other viral infections can cause low white blood cell counts and may therefore be part of the initial evaluation process.
• Flow Cytometry: A laboratory test that allows the doctor to examine cells for signs of disease. It can be used to determine whether an autoimmune condition is causing the neutropenia.
• Imaging: If the doctor suspects that lymphoma may be causing autoimmune neutropenia, an MRI or CT scan may be performed.
• Bone Marrow Aspiration and Biopsy: During a bone marrow aspiration and biopsy, the doctor takes a small sample of bone marrow to examine for signs of disease. These procedures can show whether the neutropenia is related to a blood cancer like leukemia.

The doctor may request a blood test to check for signs of antibodies in the blood attacking neutrophils. The most common tests are:

• Indirect Granulocyte Immunofluorescence Test (I-GIFT).
• Granulocyte Agglutination Test (GAT).

Unfortunately, these tests are not always reliable in diagnosing autoimmune neutropenia. Depending on what is causing the neutropenia and the timing of the test, they may fail to detect antibodies or produce false-positive results. A false-positive means the test detects antibodies even though they are not present.

If the doctor suspects that neutropenia is caused by a specific condition, additional tests may be ordered.

How Is Autoimmune Neutropenia Treated? Treatment depends on how severe the condition is. For example, asymptomatic infants with neutropenia may require more frequent CBCs to monitor neutrophil levels, but may not need immediate treatment. If a child frequently gets infections, the doctor may prescribe prophylactic antibiotics. While antibiotics treat infections, prophylactic antibiotics prevent them.

In secondary autoimmune neutropenia, the doctor will treat the underlying condition causing the low neutrophil count to prevent infections. They may also prescribe:

• Granulocyte Colony-Stimulating Factor (G-CSF): The primary treatment for more severe forms of neutropenia. It stimulates the body to produce more neutrophils. G-CSF can also prevent frequent infections associated with primary autoimmune neutropenia.
• Corticosteroids: Corticosteroids like prednisone can limit the body's immune response so that antibodies do not attack neutrophils.
• Other Treatments: Additional agents such as IVIG, rituximab, and alemtuzumab have also been used to treat individuals in critical condition due to severe autoimmune neutropenia.

What Is Expected If You Have Autoimmune Neutropenia? Primary autoimmune neutropenia usually resolves spontaneously. In about 95% of children with autoimmune neutropenia, neutrophil counts return to normal by age two or three. Almost all cases of primary autoimmune neutropenia resolve by age 11.

Otherwise, the course depends on multiple factors, such as the underlying condition that may be causing the neutropenia. Treating the underlying disease and preventing infections can help neutrophil levels rise to normal.

How Can Autoimmune Neutropenia Be Prevented? Neither primary nor secondary autoimmune neutropenia can be prevented. However, taking precautions to avoid infections makes it possible to prevent complications associated with autoimmune neutropenia.

When Should You Seek Medical Attention? If you have a severe form of autoimmune anemia and develop a fever, you should contact a doctor immediately. Sometimes, the doctor may prescribe antibiotics to have on hand in case a fever develops. Treatment will most likely be administered in a hospital.

If you have a severe, chronic form of autoimmune neutropenia, the doctor can explain the symptoms to be aware of and what needs to be done to prevent complications.

You should work with the doctor to determine what an autoimmune neutropenia diagnosis means for you or your child. Although symptoms and causes vary, the good news is that treatments like G-CSF are highly effective at raising neutrophil levels. If a child has autoimmune neutropenia, the doctor's guidance regarding how often blood tests should be performed should be followed. Be vigilant for signs of infection and seek treatment as soon as possible to prevent potential complications.