Multiple myeloma is a form of blood cancer that affects the plasma cells. In some cases, plasma cells gradually decline and cause a condition called hypogammaglobulinemia.

Plasma cells are white blood cells that produce antibodies that protect the body. In multiple myeloma, the cancerous plasma cells grow rapidly and destroy the healthy plasma cells in the bone marrow.

When plasma cells gradually decline, they can cause hypogammaglobulinemia, a reduced level of antibodies in the blood. This makes individuals especially prone to infections.

This article discusses multiple myeloma with hypogammaglobulinemia, including the symptoms, diagnosis, and treatment options.

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Hypogammaglobulinemia is a clinical condition that doctors characterize by low blood levels of antibodies.

The plasma cells in a person with hypogammaglobulinemia cannot produce sufficient antibodies to protect the body against disease-causing microorganisms. Consequently, individuals with the condition become prone to opportunistic viral and fungal infections.

Blood cancers, such as multiple myeloma, are common causes of hypogammaglobulinemia.

Multiple myeloma is one of the secondary causes of hypogammaglobulinemia.

According to research, 45–83% of people with multiple myeloma develop secondary antibody deficiency or hypogammaglobulinemia during the course of the disease.

In addition to depleting healthy plasma cells, treating multiple myeloma can trigger or worsen the degree of antibody deficiency.

Doctors may combine chemotherapy medications, such as cyclophosphamide or etoposide, with corticosteroids for multiple myeloma treatment. These chemotherapy medications may help suppress immune function, further reducing antibody blood levels.

The immunosuppression in hypogammaglobulinemia typically leads to mixed infections with multiple strains of infectious organisms.

Individuals with immunodeficiency due to multiple myeloma do not usually have any specific symptoms. The first sign that they have hypogammaglobulinemia is typically an infection.

These infections could be widespread or local to organs, resulting in any of the following:

  • respiratory tract infections, such as pneumonia
  • recurrent ear infections
  • acute or chronic sinus infections
  • urinary tract infections
  • chronic diarrhea due to gastrointestinal disorders
  • multiple enlarged lymph nodes
  • enlarged spleen

Also, these individuals may have the following symptoms of multiple myeloma:

Diagnosing multiple myeloma with hypogammaglobulinemia requires clinical examinations with laboratory tests.

After a multiple myeloma diagnosis, the following blood tests are essential in confirming the condition:

  • Serum immunoglobulin concentrations: A significant decline in the blood levels of IgM, IgG, IgA antibodies, or immunoglobulin suggest hypogammaglobulinemia.
  • Complete blood count: A decrease in the blood level of other immune cells, such as lymphocytes and neutrophils, may indicate the condition.

Hypogammaglobulinemia may not occur early in some cases of multiple myeloma. For example, some individuals may develop the condition shortly after chemotherapy.

Therefore, regular monitoring and evaluation of serum immunoglobulin levels are essential for early diagnosis and prompt treatment.

Treatment for hypogammaglobulinemia aims to replace the depleted antibodies in the blood and to decrease the burden of infections.

Immunoglobulin replacement therapy is the main method of treatment. This involves administering antibodies from the blood of healthy donors. Healthcare professionals administer the immunoglobulin intravenously or under the skin.

They will thoroughly screen individuals in need of immunoglobulin replacement therapy because of the risk of allergic reactions to the donor immunoglobulins.

Some possible side effects and complications of therapeutic immunoglobulin include:

  • anaphylaxis
  • headache
  • acute kidney injury
  • hemolytic anemia, a condition where the body destroys red blood cells in the body faster than it produces them
  • neutropenia, a significant reduction in neutrophils, a type of white blood cell

During the course of immunoglobulin replacement therapy, doctors typically monitor the antibody level for dose adjustment and to further reduce the risk of adverse reactions. They may also prescribe antimicrobial medications, such as antibiotics, antifungals, or antivirals, to individuals with active infections.

Combining immunoglobulin replacement therapy and antimicrobials helps reduce the risk of infection.

Recurrent infections are typically an indication of hypogammaglobulinemia in multiple myeloma. Therefore, it is crucial to consult a doctor when a person notices signs of infections such as:

  • recurrent cough
  • unexplained fever
  • yellowish nasal and or ear discharges

The disease progression of multiple myeloma and its treatment may reduce the blood level of antibodies, which can cause a clinical condition called hypogammaglobulinemia.

People with hypogammaglobulinemia are vulnerable to severe infections due to inadequate antibodies to protect the body. Therefore, these individuals could present with widespread or organ-specific infections such as chest or urinary tract infections.

Immunoglobulin replacement therapy and antimicrobials are common treatment methods for hypogammaglobulinemia.