The discovery that loss-of-function mutations in the gene DOCK8 are responsible for most forms of autosomal recessive hyper-IgE syndrome and some forms of combined immunodeficiency without elevated serum IgE has led to studies into the immunopathogenesis of this disease. In this review, we relate the clinical features of this disease to studies using patients' cells and a mouse model of Dock8 deficiency, which have revealed how DOCK8 regulates T and B cell numbers and functions. The results of these studies help to explain how the absence of DOCK8 contributes to patients' susceptibility to viral, fungal, and bacterial infections. However, unanswered questions remain regarding how the absence of DOCK8 also leads to high IgE and allergic disease, predisposition for malignancy, and unusual clinical features, such as CNS abnormalities and autoimmunity, observed in some patients.
- [Show abstract] [Hide abstract] ABSTRACT: Knowing the clinical warning signs of immunodeficiency (ID) in adulthood is crucial for early detection of the over 200 forms of primary ID known to date. Many of these congenital diseases with a genetic background already manifest in childhood. Antibody deficiency diseases represent an important exception, with common variable immunodeficiency (CVID) being the most common form of ID. The median age of onset of CVID is 24 years. Unfortunately, the delay in diagnosis is still in excess of 4 years. General practitioners as well as allergists play a particularly important role in early detection. ID patients who present primarily with signs of immune dysregulation pose an even greater diagnostic challenge. Thus, autoimmune cytopenia, inflammatory bowel diseases, or sarcoid-like granulomatous inflammation can be the first manifestation in up to 20 % of ID patients. Secondary forms of ID [e. g., due to long-term corticosteroid treatment, HIV-infection, leukemia, lymphoma, nephrotic syndrome, malabsorption syndrome] need to be differentiated from primary antibody deficiency. Considering the overlap with allergic symptoms [ID accompanied by a susceptibility to eczema, elevated total IgE, blood eosinophilia], the present article discusses, the clinical warning signs of ID, the first diagnostic steps required and the option of further diagnostic work up at specialist centers for complex cases, as well as the treatment options for such cases.0Comments 2Citations
- [Show abstract] [Hide abstract] ABSTRACT: Deficiency of dedicator of cytokinesis 8 (DOCK8) is a newly described combined primary immunodeficiency disease. It was found to account for 15% of combined immune deficiency cases in the National Primary Immunodeficiency Disorders Registry in Kuwait, a country with high prevalence of consanguinity. We present the clinical, immunologic and molecular characteristics of 9 Kuwaiti patients with DOCK8 deficiency and discuss differences that distinguish DOCK8 deficiency from atopic dermatitis. Clinical immunologists in areas with high incidence of consanguinity should have a high index of suspicion of DOCK8 deficiency in children with recalcitrant eczema, recurrent non-cutaneous infections and lymphopenia.0Comments 22Citations
- [Show abstract] [Hide abstract] ABSTRACT: We describe seven Turkish children with DOCK8 deficiency who have not been previously reported. Three patients presented with typical features of recurrent or severe cutaneous viral infections, atopic dermatitis, and recurrent respiratory or gastrointestinal tract infections. However, four patients presented with other features. Patient 1-1 featured sclerosing cholangitis and colitis; patient 2-1, granulomatous soft tissue lesion and central nervous system involvement, with primary central nervous system lymphoma found on follow-up; patient 3-1, a fatal metastatic leiomyosarcoma; and patient 4-2 showed no other symptoms initially besides atopic dermatitis. Similar to other previously reported Turkish patients, but in contrast to patients of non-Turkish ethnicity, the patients' lymphopenia was primarily restricted to CD4(+) T cells. Patients had homozygous mutations in DOCK8 that altered splicing, introduced premature terminations, destabilized protein, or involved large deletions within the gene. Genotyping of remaining family members showed that DOCK8 deficiency is a fully penetrant, autosomal recessive disease. In our patients, bone marrow transplantation resulted in rapid improvement followed by disappearance of viral skin lesions, including lesions resembling epidermodysplasia verruciformis, atopic dermatitis, and recurrent infections. Particularly for patients who feature unusual clinical manifestations, immunological testing, in conjunction with genetic testing, can prove invaluable in diagnosing DOCK8 deficiency and providing potentially curative treatment.0Comments 29Citations