Primary Immunodeficiency Syndromes (PIDs)

Patients with primary immunodeficiencies (PIDs) typically present with chronic and recurring infections any time between infancy and adulthood.
Hypogammaglobulinemia occurs in over 80% of patients with a PID.
Selective IgA deficiency is the most common immunodeficiency and is associated with a variety of autoimmune manifestations.
Common variable immunodeficiency (CVID) may present in early adulthood as an aseptic polyarthritis of the large and medium joints.
Early complement protein (C1, C4, C2) deficiencies are associated with autoimmune diseases whereas late (C5 to C8) deficiencies are associated with Neisseria infections.

Components of the immune system involved in PID syndromes:

B cells (humoral immunodeficiency): 55% of all immunodeficiencies

T cells and natural killer (NK) cells (cell-mediated immunodeficiency): 20%

Phagocytes (neutrophils, macrophages, dendritic cells): 20%

Complement proteins and mannose-binding lectin (MBL): 5%

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