Components of the defense system - Phagocytic system (Neutrophils, Monocytes-Macrophages), accounts for 18% of ID cases.
- Complement system, for 2%, and
- The Immune System, for 80%, excluding solely IgA deficiency. (B-lymphocyte defects for 50%, T-lymphocyte defects for 10%, and Combined B- and T- cell defects for 20%.)
Types of ImmunodeficiencyCommon variable
Immunodeficiency (CVID) and Selective IgA deficiency are the commonest IDs and autoimmune problems appear frequently among them.
Phagocytic disorders: Aphthous ulcers of the mucus membranes, severe gingivitis, periodontal disease, life threatening pyogenic infections and Gram negative and Fungal infections.
Complement defects : C1q, r, s, C2, C4 (autoimmune disease e.g. SLE), C3b (pyogenic infections), C5-C8 (recurrent Neisserial infections)
B-cell defects : Onset of infection is after transplacentally acquired maternal IgG decreases i.e. after 6 months of age. Recurrent Respiratory Tract (Sino-Pulmonary) infections in 85%, persistent infectious diarrhea (giardia), meningitis, arthritis, pyoderma, perianal abscesses and Sepsis occur. Later, autoimmune signs and non-malignant lymphoid hyperplasia or malignant tumors, especially lymphorecticular complications are seen.
T-cell defects : Onset of symptoms is in the first few months of life with Chronic diarrhea (cryptosporidium, Giardia, Rota virus) and chronic lung disease (viruses, P.carinii), persistent cough, FTT persistent thrush, and extensive monilial diaper rash. These infants are at risk for graft-versus -host disease (GVHD) from transplacental acquisition of maternal T-cells, as evidenced in 40% of Severe Combined ID (SCID) babies because of failure to recognize and reject foreign maternal T-lymphocytes, leading to skin signs (commonly) and hepatic disease in 40%. Later, autoimmune signs (not in SCID) and malignancies may occur.