Atypical presentation of IL-12 receptor β1 deficiency with pneumococcal sepsis and disseminated nontuberculous mycobacterial infection in a 19-month-old girl born to nonconsanguineous US residents

Incubation of PBMCs with IFN-γ, LPS, and IL-12 demonstrates intact IFN-γ receptor signaling and aberrant IL-12 responsiveness in this patient. PBMCs were isolated from the patient and a control subject. A, Cells were stimulated with IFN-γ or LPS alone or the combination. Secreted IL-12p70 was measured by ELISA. B, PBMCs were stimulated with either phytohemagglutinin (PHA) or a combination of PHA and IL-12. Secreted IFN-γ was measured by ELISA.

Diminished phosphorylation of STAT4 after IL-12 stimulation in this patient. PBMCs from the patient and a control subject were stimulated for 5 days with phytohemagglutinin + IL-2. After stimulation, 10 ng/mL IL-12 was added for 20 minutes, and cells were fixed, permeabilized, and stained with anti-pSTAT4 antibody (BD Biosciences, San Jose, Calif). Unstimulated cells served as a control. The histogram for pSTAT4 staining in the IL-12–stimulated lymphocytes is shown in comparison with the unstimulated control. The mean fluorescence intensity (MFI) for pSTAT4 is shown for each sample.