Infections and associated diseases in patients with mannose-binding lectin deficiency, presenting to a tertiary care immunology clinic

Rationale: Clinical significance of mannose-binding lectin MBL deficiency (MBLd) has been argued. The role of mannose-binding lectin (MBL) as a disease modifier, causing other diseases to present with a more severe phenotype, has been suggested. Methods: We conducted a retrospective chart review of patients presenting to a tertiary immunology center with recurrent and/or severe infections. All patients underwent immune evaluation and were found to have undetectable MBL levels (<70ng/ml). Types of infections and associated diseases were recorded. Results: 53 patients with MBLd were identified. Most (47/53) had sinopulmonary infections (47/53) including sinusitis (40/53), viral upper respiratory infections (25/53), bronchitis (19/53), pneumonia (15/53), Streptococcal pharyngitis (9/53), otitis media (9/53). Other infections were skin infections (6/53), sepsis (2/53), meningitis (2/53). Among 33 patients with chronic sinusitis, 15/33 had chronic rhinosinusitis without polyps, 10/33 had aspirin exacerbated respiratory disease (AERD), 7/33 chronic rhinosinusitis with polyps (non AERD), 2/33 had allergic fungal sinusitis. Many were atopic (44/53) with allergic rhinitis (30/44), asthma (25/44), atopic dermatitis (7/44), and food allergy (7/44). Associated immunodeficiencies were (13/53) were with common variable immunodeficiency (7/13), IgG subclass deficiency (2/13), isolated IgM deficiency (2/13), other hypogammaglobulinemia (1/13), specific antibody deficiency (1/13), transient T cell lymphopenia of infancy (1/13). Rheumatologic disease was seen in 14/53 patients, hematologic disease in 8/53 and inflammatory bowel disease in 5/53. Other disease findings included bronchiectasis (8/53). Conclusions: Even in the absence of other immunodeficiency, people with MBLd have recurrent infections, most commonly sinopulmonary. Further research, comparing infections, severity and associated illnesses in those with patients with different MBL levels is warranted to define its clinical significance.