Dysfunctional LAD-1 neutrophils and colitis.

Area of Science:

• Immunology
• Gastroenterology
• Genetics

Background:

• Leukocyte adhesion deficiency 1 (LAD-1) is a primary immunodeficiency caused by absent or dysfunctional beta2 integrin (CD18).
• Defective CD18 impairs neutrophil function, including chemotaxis, adherence, and bacterial killing, leading to recurrent infections.
• Colitis is an uncommon manifestation of LAD-1, with only rare reports of necrotizing intestinal events.

Observation:

• This report details a case of moderate LAD-1 in an adult patient presenting with chronic colitis.
• The colitis was characterized by extensive inflammation and ulceration in the right colon and terminal ileum.
• Clinical and pathological findings led to adhesions and strictures, mimicking features of Crohn's disease.

Findings:

• The chronic colitis associated with dysfunctional neutrophils in LAD-1 represents a distinct pathology compared to typical forms of inflammatory bowel disease (IBD).
• This case demonstrates active IBD in the context of impaired CD18/CD11(a-b) intercellular adhesion molecules (ICAM-1) interaction.
• Neutrophil dysfunction in LAD-1 contributes to significant gastrointestinal inflammation and structural damage.

Implications:

• Understanding LAD-1-associated colitis is crucial for accurate diagnosis and management of IBD-like conditions in patients with primary immunodeficiencies.
• The findings suggest that neutrophil adhesion molecules play a critical role in the pathogenesis of gastrointestinal inflammation.
• Targeting ICAM-1 interactions, a strategy being explored for Crohn's disease, may need careful consideration in patients with underlying integrin deficiencies.