T and B lymphocytes, immunoglobulins and complement components in bronchial asthma

Area of Science:

• Pediatric immunology
• Respiratory medicine
• Clinical immunology

Background:

• Bronchial asthma is a common chronic respiratory disease in children.
• Understanding lymphocyte subsets and complement pathways is crucial for asthma pathogenesis.
• Previous research has yielded conflicting results on immune cell profiles in pediatric asthma.

Purpose of the Study:

• To investigate the percentage and total counts of T and B lymphocytes in children with bronchial asthma.
• To analyze these immune cell populations based on asthma type (extrinsic atopic, mixed, intrinsic) and clinical severity (mild, severe).
• To correlate lymphocyte levels with immunoglobulin and complement component levels.

Main Methods:

• Studied 60 children with asthma (7-15 years) and 44 healthy controls (12-14 years).
• Assessed T lymphocytes via nonimmune rosettes with sheep red blood cells (total and active).
• Estimated B lymphocytes using antibody-complement coated sheep erythrocytes.
• Measured immunoglobulin (IgA, G, M, D, E) and complement (C1q, C4, C3, C3 proactivator, C5) levels using radial immunodiffusion tests.

Main Results:

• No decrease in T lymphocyte percentage or count; active T cells increased in severe extrinsic atopic asthma.
• B cell percentage decreased in severe atopic, mild intrinsic, and mild mixed asthma; total B cell count lowered only in mild mixed asthma.
• Elevated C4 in mild extrinsic, C5 in severe extrinsic, and C3 in severe mixed asthma observed. Decreased C3 proactivator noted in mild extrinsic and mixed asthma, with concurrent C3 reduction in intrinsic asthma, suggesting alternative complement pathway activation.

Conclusions:

• T lymphocyte levels are not diminished in pediatric asthma, with potential increases in active T cells in severe extrinsic atopic cases.
• B lymphocyte alterations are present in specific asthma subtypes and severity levels.
• Complement component changes, particularly involving C3 proactivator and C3, indicate possible alternative pathway activation in certain pediatric asthma phenotypes.