Background and aims Interleukin-1 receptor-associated kinase 4 (IRAK4) deficiency is a recently recognised immunodeficiency disorder that affects innate immunity through Toll-like receptors. Although < 100 patients have been reported, the clinical features are not fully clarified. We report here additional clinical information involving two Japanese siblings with IRAK 4 deficiency, who were successfully prevented by prophylactic treatment in the first few years of life (J Pediatr 2010;156:168).
Case report Case 1: A 9-year-old boy was diagnosed with IRAK4 deficiency, as characterised by an IRAK4 gene mutation. The boy received prophylactic treatment, as previously reported. He did not develop severe infections or pyrexia until 5 years of age; however, he subsequently had several episodes of curable bacterial infections without elevation of C-reactive protein (CRP). At present, he had developed normally and antibody production after the usual vaccinations has been normal. Case 2: A 7-year-old girl, the younger sister of case 1, was diagnosed with IRAK4 deficiency, as characterised by the same mutation and she received the same prophylactic treatment. She did not have pyrexia or severe infections until 4 years of age. She subsequently had several pyrexic episodes without elevation of CRP. The response to vaccinations was normal with the exception of rubella.
Conclusion The clinical course was favourable for both cases. Although they experienced some bacterial infections and pyrexia, the CRP were not elevated, which may reflect the basic mechanism of this disorder. Antibody production after vaccination was normal in both patients.