A major problem facing dermatologists is that DOCK8 deficiency shares many clinical and laboratory features with severe atopic dermatitis, making diagnosis in children confusing, especially when some features may be absent.
Both DOCK8 deficiency and classical hyper-IgE syndrome due to STAT3 mutations typically present with signs of atopic dermatitis, Staphylococcus aureus skin abscesses or soft tissue infections, pneumonias, elevated serum IgE and eosinophilia.
Researchers have recently identified biomarkers that may be used to distinguish DOCK8 deficiency from severe atopic dermatitis. Diagnosis relies on examining DOCK8 protein expression and sequencing the 48 exons in the DOCK8 gene, but these assays may not always be readily available.
Biomarkers routinely measured by flow cytometry on whole blood in clinical immunology laboratories can be used in distinguishing DOCK8 deficiency from severe atopic dermatitis. The use of these biomarkers may help dermatologists to identify those patients who are most likely to have DOCK8 mutations and would therefore benefit from further specialised diagnostic testing.
Janssen E, Tsitsikov E, Al-Herz W et al. Clin Immunol 2014; 150(2): 220-4.