Increased prevalence of gastrointestinal viruses and diminished secretory immunoglobulin a levels in antibody deficiencies

PURPOSE

Gastrointestinal disease occurs frequently in antibody deficiencies. This study aims to explore the relation between gastrointestinal infections and mucosal homeostasis in patients with antibody deficiencies.

METHODS

We performed an observational study including 54 pediatric antibody deficient patients (48 % CVID, 41 % CVID-like, 11 % XLA) and 66 healthy controls. Clinical symptom scores and stool samples were collected prospectively. Stool samples were evaluated for bacteria, parasites, viruses, secretory IgA- and for calprotectin levels. Results were compared between patients and controls.

RESULTS

24 % of antibody deficient patients versus 9 % of healthy controls tested positive for gastrointestinal viruses (p = 0.028). Fecal calprotectin levels were significantly higher in virus positive patients compared to virus negative patients (p = 0.002). However, in controls, fecal calprotectin levels were similar between virus positive and virus negative controls. Moreover, gastrointestinal virus positive patients had low serum IgA levels in 13/14 cases (94 %) versus 40/62 (62 %) patients in the virus negative patient group (p = 0.04). The virus positive patient group also displayed significantly lower secretory IgA levels in stool (median 13 ug/ml) than patients without gastrointestinal viruses detected or healthy controls (median 155 ug/ml) (p = 0.046).

CONCLUSION

We here report an increased prevalence of gastrointestinal viruses and gastrointestinal complaints in antibody deficient patients. Patients that tested positive for gastrointestinal viruses showed diminished serum- and secretory IgA levels, and only in patients, virus positivity was associated with signs of mucosal inflammation. These findings suggest that particularly patients with low IgA are at risk for longstanding replication of gastrointestinal viruses, which may eventually result in CVID-related enteropathy.

High-resolution computed tomography and pulmonary function in children with common variable immunodeficiency

High-resolution computed tomography (HRCT) may be useful to monitor lung disease in children with common variable immunodeficiency disorder (CVID). We evaluated interobserver agreement and correlation with pulmonary function tests (PFTs) for automated quantification and visual scoring of air trapping and airway wall thickening on HRCT in paediatric CVID patients. In a cohort of 51 children with CVID, HRCT was analysed visually and automated for presence of air trapping and airway wall thickening. PFTs were expressed as % predicted. Disease duration, physician-diagnosed pneumonias and antibiotic prophylaxis were recorded. Interobserver agreement for automated airway wall thickening was good with an intra-class correlation coefficient of 0.88, compared with 0.51 for visual scoring. Presence of air trapping on HRCT correlated significantly with PFTs and disease duration, but was not associated with previous pneumonias. Airway wall thickening did not correlate significantly with PFTs or disease duration and was not associated with previous pneumonias or prophylactic antibiotic use. In children with CVID disorders, HRCT air trapping measurements are significantly correlated with PFTs and disease duration. Quantitative air trapping is a feasible and promising technique for small airway disease quantification that may be applied to monitor (silent) disease progression in CVID.

Airway and interstitial lung disease are distinct entities in paediatric common variable immunodeficiency

Common variable immunodeficiency (CVID) is a common primary immune deficiency, caused by undefined defects in lymphocyte function, and is treated routinely by immunoglobulin substitution. CVID complications include airway disease (AD) and interstitial lung disease (ILD). It was not known if AD and ILD in CVID have a common immunological aetiology and should be considered separate features of the same disease, or as distinct syndromes that require specialized monitoring and treatment. We used high-resolution computed tomography (CT) to diagnose AD or ILD in paediatric CVID patients. Spirometry and body plethysmography did not differentiate between ILD and AD. Patients with AD (n = 11, 20%) developed more pneumonias while children with ILD (n = 8, 15%) showed immune dysregulation characterized by autoimmune complications, more severe memory B cell reduction and expansion of non-naive cytotoxic T cells. In conclusion, ILD and AD in CVID have dissimilar clinical and immunological characteristics, suggesting distinct aetiology requiring tailored monitoring and treatment of these patient subgroups.