The hyper-IgE syndromes (HIES; originally named Job's syndrome) are a collection of primary immunodeficiency syndromes resulting in elevated serum IgE levels and typified by recurrent staphylococcal skin abscesses, eczema and pulmonary infections. The disorder has autosomal dominant and recessive forms. Autosomal dominant HIES has been shown to be mainly due to STAT3 mutations and additionally results in connective tissue, skeletal, vascular and dental abnormalities. Autosomal recessive HIES has been shown to be mainly due to mutations in DOCK8; these patients are more prone to viral skin infections instead. This review article discusses the common clinical features of the syndrome, the genetic mutations responsible and the pathogenesis of the disease, as well as treatments currently used.

Background

Inherited deficiencies of IL-10 or IL-10 receptor (IL-10R) lead to immune dysregulation with life-threatening early-onset enterocolitis.

Objectives

We sought to gather clinical data of IL-10/IL-10R-deficient patients and devise guidelines for diagnosis and management, including hematopoietic stem cell transplantation (HSCT).

Methods

We enrolled 40 patients with early-onset enterocolitis and screened for mutations in IL10/IL10R using genetic studies, functional studies, or both of the IL-10 signaling pathway. Medical records of IL-10/IL-10R-deficient patients were reviewed and compiled.

Results

Of 40 patients, we identified 7 with novel mutations, predominantly in consanguineous families with more than 1 affected member. IL-10/IL-10R-deficient patients had intractable enterocolitis, perianal disease, and fistula formation. HSCT was carried out in 2 patients with IL-10 deficiency and 1 patient with IL-10R α chain deficiency and proved to be an effective therapy, leading to rapid improvement of clinical symptoms and quality of life.

Conclusion

Because the defect in patients with IL-10/IL-10R deficiency resides in hematopoietic lineage cells and their colitis is resistant to standard immunosuppressive therapy, HSCT should be considered early as a potentially curative therapeutic option.

Background

Recurrent bacterial and fungal infections, eczema, and increased serum IgE levels characterize patients with the hyper-IgE syndrome (HIES). Known genetic causes for HIES are mutations in signal transducer and activator of transcription 3 (STAT3) and dedicator of cytokinesis 8 (DOCK8), which are involved in signal transduction pathways. However, glycosylation defects have not been described in patients with HIES. One crucial enzyme in the glycosylation pathway is phosphoglucomutase 3 (PGM3), which catalyzes a key step in the synthesis of uridine diphosphate N-acetylglucosamine, which is required for the biosynthesis of N-glycans.

Objective

We sought to elucidate the genetic cause in patients with HIES who do not carry mutations in STAT3 or DOCK8.

Methods

After establishing a linkage interval by means of SNPchip genotyping and homozygosity mapping in 2 families with HIES from Tunisia, mutational analysis was performed with selector-based, high-throughput sequencing. Protein expression was analyzed by means of Western blotting, and glycosylation was profiled by using mass spectrometry.

Results

Mutational analysis of candidate genes in an 11.9-Mb linkage region on chromosome 6 shared by 2 multiplex families identified 2 homozygous mutations in PGM3 that segregated with disease status and followed recessive inheritance. The mutations predict amino acid changes in PGM3 (p.Glu340del and p.Leu83Ser). A third homozygous mutation (p.Asp502Tyr) and the p.Leu83Ser variant were identified in 2 other affected families, respectively. These hypomorphic mutations have an effect on the biosynthetic reactions involving uridine diphosphate N-acetylglucosamine. Glycomic analysis revealed an aberrant glycosylation pattern in leukocytes demonstrated by a reduced level of tri-antennary and tetra-antennary N-glycans. T-cell proliferation and differentiation were impaired in patients. Most patients had developmental delay, and many had psychomotor retardation.

Conclusion

Impairment of PGM3 function leads to a novel primary (inborn) error of development and immunity because biallelic hypomorphic mutations are associated with impaired glycosylation and a hyper-IgE-like phenotype.

Despite the known importance of zinc for human immunity, molecular insights into its roles have remained limited. Here we report a novel autosomal recessive disease characterized by absent B cells, agammaglobulinemia and early onset infections in five unrelated families. The immunodeficiency results from hypomorphic mutations of SLC39A7, which encodes the endoplasmic reticulum-to-cytoplasm zinc transporter ZIP7. Using CRISPR-Cas9 mutagenesis we have precisely modeled ZIP7 deficiency in mice. Homozygosity for a null allele caused embryonic death, but hypomorphic alleles reproduced the block in B cell development seen in patients. B cells from mutant mice exhibited a diminished concentration of cytoplasmic free zinc, increased phosphatase activity and decreased phosphorylation of signaling molecules downstream of the pre-B cell and B cell receptors. Our findings highlight a specific role for cytosolic Zn²⁺ in modulating B cell receptor signal strength and positive selection.