Abnormal expression of CD54 in mixed reactions of mononuclear cells from hyper-IgE syndrome patients

Quantitative defects in invariant NKT cells and TLR responses in patients with hyper-IgE syndrome

BACKGROUND

Autosomal dominant hyper-IgE syndrome (AD-HIES) is a primary immunodeficiency mainly caused by mutations in STAT3, a signalling molecule implicated in the development of appropriate immune responses. We aimed to characterise the innate immune response in AD-HIES.

METHODS

The frequency of innate immune cells in peripheral blood (PB) from seven AD-HIES patients and healthy controls were determined. CD80/CD86 surface expression and cytokine levels in supernatants from PBMC after stimulation with TLR-2, -4 and -9 agonists were also measured by flow cytometry. In addition, several SNPs within these TLR genes in genomic DNA samples from patients and controls were examined.

RESULTS

A significantly reduced number of PB iNKT cells was observed in the AD-HIES group. CpG-stimulated pDC and mDC from patients exhibited a lower increase in the expression of the costimulatory molecule CD80. We also observed an increase in the secretion of IL-12p70, TNF-alpha and IL-10 in PBMC from HIES patients after LTA or LPS stimuli. No association was found between the different SNPs detected and the HIES phenotype.

CONCLUSIONS

These findings demonstrate that important mediators of the innate immunity responses are affected in AD-HIES. More studies are necessary to investigate how the STAT3 function interferes with development of iNKT cells and TLR-mediated responses.

No Indication for a Defect in Toll-Like Receptor Signaling in Patients with Hyper-IgE Syndrome

Hyper-IgE syndrome is a rare primary immunodeficiency of unknown etiology characterized by recurrent infections of the skin and respiratory system, chronic eczema, elevated total serum IgE, and a variety of associated skeletal symptoms. Recent reports about susceptibility to pyogenic bacterial infections and high IgE levels in patients and animals with defects in toll-like receptor (TLR) signaling pathways prompted us to search for TLR signaling defects as an underlying cause of hyper-IgE syndrome. Blood samples from six patients with hyper-IgE syndrome were analyzed for serum cytokine levels, intracellular cytokine production in T cells after stimulation with PMA/ionomycin, and cytokine production from peripheral blood mononuclear cells stimulated by TLR ligands and bacterial products including LPS (TLR4), peptidoglycan (TLR2), PolyIC (TLR3), R848 (TLR7/8), CpG-A, and CpG-B (TLR9), zymosan and heat killed Listeria monocytogenes. All results were compared to data from healthy controls. A reduction in IFN-gamma, IL-2, and TNF-alpha producing T cells after PMA stimulation suggested a reduced inflammatory T cell response in patients with hyper-IgE syndrome. Increased serum levels of IL-5 indicated a concomitant Th2 shift. However, normal production of cytokines (TNF-alpha, IL-6, IL-10, IFN-alpha, IP-10) and upregulation of CD86 on B cells and monocytes after TLR stimulation made a defect in TLR signaling pathways highly unlikely. In summary, our data confirmed an imbalance in T cell responses of patients with hyper-IgE syndrome as previously described but showed no indication for an underlying defect in toll-like receptor signaling.