Severe influenza pneumonitis in children with inherited TLR3 deficiency.

Lim HK, Huang SXL, Chen J, Kerner G, Gilliaux O, Bastard P, Dobbs K, Hernandez N, Goudin N, Hasek ML, García Reino EJ, Lafaille FG, Lorenzo L, Luthra P, Kochetkov T, Bigio B, Boucherit S, Rozenberg F, Vedrinne C, Keller MD, Itan Y, García-Sastre A, Celard M, Orange JS, Ciancanelli MJ, Meyts I, Zhang Q, Abel L, Notarangelo LD, Snoeck HW, Casanova JL, Zhang SY.

Source : J. Exp. Med.

2019 Nov 8

Pmid : 31217193


Autosomal recessive IRF7 and IRF9 deficiencies impair type I and III IFN immunity and underlie severe influenza pneumonitis. We report three unrelated children with influenza A virus (IAV) infection manifesting as acute respiratory distress syndrome (IAV-ARDS), heterozygous for rare TLR3 variants (P554S in two patients and P680L in the third) causing autosomal dominant (AD) TLR3 deficiency. AD TLR3 deficiency can underlie herpes simplex virus-1 (HSV-1) encephalitis (HSE) by impairing cortical neuron-intrinsic type I IFN immunity to HSV-1. TLR3-mutated leukocytes produce normal levels of IFNs in response to IAV. In contrast, TLR3-mutated fibroblasts produce lower levels of IFN-β and -λ, and display enhanced viral susceptibility, upon IAV infection. Moreover, the patients' iPSC-derived pulmonary epithelial cells (PECs) are susceptible to IAV. Treatment with IFN-α2b or IFN-λ1 rescues this phenotype. AD TLR3 deficiency may thus underlie IAV-ARDS by impairing TLR3-dependent, type I and/or III IFN-mediated, PEC-intrinsic immunity. Its clinical penetrance is incomplete for both IAV-ARDS and HSE, consistent with their typically sporadic nature.

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