Secondary immunodeficiencies also known as acquired immunodeficiencies are a group of conditions in which there is impaired immune function caused by acquired or external factors.¹ Secondary immunodeficiencies are different from primary immunodeficiencies which are genetic disorders.²  Secondary immunodeficiencies can be transient (lasting for a short time) or persistent.³ Some secondary immunodeficiencies are more common, but there are also rare secondary immunodeficiencies such as:

• Adult-onset immunodeficiency with anti-interferon-gamma autoantibodies (ORPHA:306431)
• Acquired angioedema (ORPHA:91385)
• Acquired neutropenia (ORPHA:178996)
• AIDS wasting syndrome (ORPHA:90081)
• Atypical hemolytic uremic syndrome (ORPHA:2134)
• Chronic Epstein-Barr virus infection syndrome (ORPHA:2566)
• Good syndrome (ORPHA:169105)
• Pulmonary alveolar proteinosis (ORPHA:420259)

This list does not cover all rare secondary immunodeficiencies. A list of rare secondary immunodeficiencies that resemble primary immunodeficiencies is included in table 10 of Human Inborn Errors of Immunity: 2024 Update on the Classification from the International Union of Immunological Societies Expert Committee.

Synonyms: acquired immunodeficiencies, SID/s, SI.¹

ORPHA:310050 Acquired immunodeficiency

ICD-11:4A20 Acquired immunodeficiencies

Universal rare disease classifications provide a common language for recording, reporting and monitoring diseases. Please visit the Rare Disease Classifications page for more information about these internationally recognised classifications.

Secondary immunodeficiencies vary widely between individuals.¹ The symptoms of secondary immunodeficiencies may be similar to primary immunodeficiencies.⁴

Some common signs and symptoms of secondary immunodeficiencies may include: ⁴

• recurrent infections that are unusually persistent, severe or resistant to treatment
• recurrent deep skin or organ abscesses (build-up of pus)
• persistent thrush

Please speak to your medical team to learn more about the signs and symptoms of secondary immunodeficiencies.

Rare diseases are often serious and progressive, exhibiting a high degree of symptom complexity, leading to significant disability. Majority of the estimated two million Australians living with a rare disease meet the Australian Government’s definition for disability (in accordance to the Australian Public Service Commission and Australian Bureau of Statistics), and many experience severe and permanent disability impacts. If you or someone you care for is experiencing disability-related impacts from a rare condition, please speak with a health or disability professional for advice. Information about relevant disability support can be found at the RARE Portal’s Disability Support Information page.

Secondary immunodeficiencies can be caused by a wide range of factors including malnutrition, infections, metabolic diseases, autoimmune diseases, cancers, medications or therapies that are immunosuppressive, premature or aging, and environmental stress.^1-3

Diagnosis of secondary immunodeficiencies may be made based on medical history especially patterns of infections, physical examination, and laboratory tests to test for immune function such as: ^1,3

• complete blood count to look for cytopenia (deficiency in blood cells)
• quantitative immunoglobulin tests to measure levels of antibodies
• protein electrophoresis and serum albumin and total protein levels tests to look for abnormal protein production which may indicate malnutrition or other protein-losing disease
• immunophenotyping to determine the type and make up of white blood cells that are present

Due to the similarities between primary and secondary immunodeficiencies, distinguishing between the two different groups of immunodeficiencies is important to establish appropriate treatment and management.^2,3

Please speak to your medical team to learn more about the available diagnostic pathways for secondary immunodeficiencies.

For most secondary immunodeficiencies, treating the underlying cause of the immunodeficiency or removing the causal agent may restore the immune function.¹ Other treatments are targeted at managing symptoms and reducing the risk of infections. These include prophylactic (prevention measures) antibiotics, immunoglobulin replacement therapy (IRT) to restore antibodies level, and immunisations.¹

More information about secondary immunodeficiencies and vaccination can be found at:

• Australian Immunisation Handbook: Vaccination for people with secondary (acquired) immunodeficiency due to medical conditions
• Australian Immunisation Handbook: Vaccination for people with secondary (acquired) immunodeficiency due to medical therapies

Please speak to your medical team to learn more about the possible treatment or management options for your condition. Treatment will depend on an individual’s specific condition and symptoms. It is also important to stay connected to your medical team so that you can be made aware of any upcoming clinical trial opportunities.

Clinical care for rare diseases often involves a multidisciplinary team of medical, care and support professionals. Please note that the information provided here is as a guide and that RVA does not necessarily monitor or endorse specific clinics or health experts.

Healthcare professionals involved in the treatment of secondary immunodeficiencies may include general practitioners (GP), clinical immunologists, haematologists, oncologists, pulmonologists, rheumatologists and gastroenterologists.^1,2 The need for different healthcare professionals may change over a person’s lifetime and extend beyond those listed here.

We are not aware of any clinical care guidelines for secondary immunodeficiencies in Australia. If you know of any relevant care guidelines, please let us know via the Contribute page.

The following guidance is available from international experts outside Australia for some types of secondary immunodeficiencies; however, there may be information that is not relevant or applicable to the Australian context, and may not be up to date:

• Practical guideline for the diagnosis and management of secondary hypogammaglobulinemia: A Work Group Report of the AAAAI Primary Immunodeficiency and Altered Immune Response Committees (2022) developed by the American Academy of Allergy, Asthma and Immunology.
• Treating secondary antibody deficiency in patients with haematological malignancy: European expert consensus (2021) developed by European haemato-oncologists and immunologists on the use of IRT in the treatment of hypogammaglobulinemia in individuals with haematological malignancies.

Individuals living with rare diseases may have complex medical issues and disabilities, which are not always visible. It is often useful to refer to their medical history as well as personal information such as a medical card, doctor’s letter, or if available, a rare disease passport, for relevant information.

There are specific considerations around participating in rare disease research, including clinical trials. It is important to be mindful of issues such as data privacy, research ethics, consent and differences in research regulations between Australia and other countries.

If you are interested in finding clinical trials for your condition, please visit the following websites; however, there may not be any clinical trials available:

• Australian Clinical Trials
• ClinicalTrials.gov

It is best to discuss your interest in any clinical trials with your medical team to determine suitability and eligibility.

Please note that RVA does not necessarily monitor or endorse each group/organisation’s operational governance and activities.

Australian Organisation:

Immune Deficiencies Foundation Australia (IDFA)

Website: https://www.idfa.org.au/

IDFA is a national not-for-profit and leading peak body offering education, advocacy and awareness for Australians living with primary or secondary immunodeficiencies.

Please note that RVA does not monitor or endorse each group/organisation’s operational governance and activities. When engaging with a group, please consider the information on the RARE Portal’s Finding Helpful Peer and Community Supports page.

Secondary immunodeficiencies vary between individuals, and each person’s experience is unique.

Please visit Immune Deficiencies Foundation Australia: Member Stories to read the personal stories of living with secondary immunodeficiencies.

If you would like to share your personal story with RVA, please visit the Rare Voices Australia: Share Your Story page. RVA will consider your story for publishing on our website and inclusion on the RARE Portal.

Immune Deficiencies Foundation Australia: Community Events has information about peer support and community groups for people living with immunodeficiency.

Immune Deficiencies Foundation Australia: Member Toolkits has resources tailored for child, young adults, adults, carers and health professionals.

Immune Deficiencies Foundation Australia: Self-Advocacy Tools

Immune Deficiencies Foundation Australia: Immunodeficiencies and Applying for the NDIS

For information on available government and social services that provide support for individuals with a rare disease, please visit the National and State Services pages.

People living with a rare disease, including families and carers, often face unique challenges such as diagnostic delays, misdiagnoses, limited treatment options, and limited access to rare disease specialists and support. These challenges may impact people’s emotional wellbeing and quality of life. Many people find it helpful to seek mental health and wellbeing support to cope with ongoing stress and uncertainty. Connecting with people who have shared experiences through a support group may also be helpful. Information about relevant mental health and wellbeing support can be found at:

• Mental Health and Wellbeing Support for Australians Living with a Rare Disease
• The National and State Services pages underneath the ‘Mental Health’ sections listed

Further information on secondary immunodeficiencies can be found at:

• Immune Deficiencies Foundation Australia: Secondary Immunodeficiency
• Immune Deficiencies Foundation Australia: Publications
• Australasian Society of Clinical Immunology and Allergy (ASCIA): Immunodeficiencies and SCIg Therapy

Australasian Society of Clinical Immunology and Allergy (ASCIA): Resources for health professionals – Immunodeficiency and Autoimmunity

ASCIA Immunodeficiency Strategy for Australia and New Zealand

Orphanet: Acquired immunodeficiency

This page has been co-developed by Rare Voices Australia (RVA)’s RARE Portal team in consultation with Immune Deficiencies Foundation Australia (IDFA).

If you are aware of any additional information that may benefit stakeholders with an interest in this page, or if you notice any broken links or inaccurate information, please let us know via the Contribute page.