Clinical and cellular characteristics of the TYK2 deficient patient. (A) Family pedigree showing the segregation of the TYK2 mutant (MT) allele. Double lines connect the two consanguineous parents. The closed black symbol indicates the proband (patient 1, P1) with TYK2 deficiency, and the open symbols indicate healthy family members. WT: wildtype. (B) Western blotting of the EBV-B cells from P1, showing TYK2 deficiency. The TYK2, STAT1, STAT3, pSTAT1, pSTAT3, and GAPDH proteins are shown. The response to IFN-α, IL-23 and IL-10 was similar to that in patients with complete TYK2 deficiency. MW, molecular weight in kD. (C) Computed tomography of P1 showing bilateral lung opacities. (D) Initial outcome before mepolizumab treatment. RSV: respiratory syncytial virus; BAL: bronchoalveolar lavage; NIV: noninvasive ventilation; IV: intravenous. AOM: acute otitis media. ARDS: acute respiratory distress syndrome. VZV: varicella zoster virus. (E) Outcome after mepolizumab treatment. IV IgG: intravenous immunoglobulin; TMP-SMX: trimethoprim-sulfamethoxazole. Source data are available for this figure: SourceData F1.