Theterm primary immun odeficiencies (synonym: PID/immunodeficiency syndromes/immunodeficiency diseases) covers more than 400 different diseases of the immune system, which are characterized by a temporary or irreversible disturbance of the immune function, in which the immunodeficiency is congenital, occurs in families and/or can be inherited.
Secondary or acquired immunodeficiencies: The PID group with congenital defects is contrasted with acquired or secondary immunodeficiencies. The best known example of this is AIDS (acquired immune deficiency syndrome). Naturally, we are most often concerned with immunodeficiencies induced by immunosuppressive therapy.
Clinically, primary immunodeficiencies usually, but not always (e.g. fever syndromes), appear by a pathological susceptibility to infections, which can also be specific in the case of various mutations. E.g. IL-ILRA defect (chronic mucocutaneous candidiasis), interleukin-12/IL-23RB1 defects (medelian susceptibility to macobacerial diseases) or STAT1/STAT2 defects leading to a predisposition for severe viral infections.
Typical warning signs are hidden behind the acronyms:
- ELVIS(pathogen: unusual; localization: atypical; course: long; intensity: severe; sum: very common)
and
- GARFIELD(granulomas, autoimmunity, recurrent fever, eczema, lymphoproliferation, intestinal inflammation).
PID can manifest in all organs, but the surface epithelia of the skin, lungs, intestines, and genitourinary tract are most commonly affected.
For children, the following symptoms are considered warning signs(12 Warning Signs in Children):
- Positive family history of congenital immunodeficiency.
- 8 or more purulent otitis per year, mastoiditis
- 2 or more sinusitis per year
- 2 or more pneumonias within one year
- indicated antibiotic therapy for 2 or more months without effect
- Vaccination complications with live vaccinations (especially BCG, rotavirus and polio according to Sabin)
- recurrent or systemic infections with atypical mycobacteria
- recurrent deep skin or organ abscesses
- 2 or more visceral infections (meningitis, osteomyelitis, septic arthritis, empyema, sepsis)
- persistent Candida infections on skin or mucosa beyond 1 year of age
- unexplained erythema/erythroderma in newborns and young infants (e.g., chronic graft vs. host reaction, Omenn phenotype, etc.)
- Failure to thrive in infancy, with or without chronic diarrhea.
For adults, the following 6 warning signs are indicative:
- 4 or more infections within a year that had to be treated with antibiotics.
- Recurrent infections or an infection requiring prolonged antibiotic therapy
- 2 or more severe bacterial infections
- 2 or more radiologically proven pneumonias within three years
- Infection with unusual localization or with unusual causative agent
- Primary immunodeficiency in the family
The following table shows, based on the biological findings , the currently valid classification of primary immunodeficiencies according to the IUIS Classification 2021. It is constantly expanding, as about 10 new primary immunodeficiencies are described each year. The individual clinical pictures are summarized here in groups. The individual entities can be found under the linked group names.