Interleukin-1 Receptor-Associated Kinase 4 Deficiency in a Greek Teenager

Human interleukin- (IL-) 1 receptor-associated kinase 4 (IRAK-4) deficiency is a recently described primaryimmunodeficiency. It isa rare,autosomal recessiveimmunodeficiencythat impairs toll/IL-1R immunity,exceptfor thetoll-likereceptor (TLR) 3- and TLR4-interferon alpha (IFNA)/beta (IFNB) pathways.Case Report. We report the first patient in GreecewithIRAK-4deficiency.Fromtheageof8months,shepresentedwithrecurrentinfectionsoftheupperandlowerrespiratorytractandskinabscesses.Forthis,shehadbeenrepeatedlyhospitalizedandtreatedempiricallywithintravenousantibiotics.Nosevereviral, mycobacterial, or fungal infections were noted. Her immunological laboratory evaluation revealed low serum IgA andrestored in subsequent measurements; normal IgG, IgM, and IgE; and normal serum IgG subclasses. Peripheral bloodimmunophenotyping by flow cytometry and dihydrorhodamine (DHR) test revealed normal counts. She was able to makefunctional antibodies against vaccine antigens, including tetanus and diphtheria. She was administered with empirical IgGsubstitutionfor5yearsuntiltheageof12years,andshehasneverexperiencedinvasivebacterialinfectionssofar.DNAanalysisrevealed a heterozygous variant in the patient: c.823delT (p.S275fs∗13 at protein level) in the IRAK4 gene.Conclusions. *eimportance of clinical suspicion is emphasized in order to confirm the diagnosis by IRAK4 gene sequencing and provide theappropriate treatment for this rare primary immunodeficiency, as soon as possible.