First Case of Patient With Two Homozygous Mutations in MYD88 and CARD9 Genes Presenting With Pyogenic Bacterial Infections, Elevated IgE, and Persistent EBV Viremia

Maria Chiriaco, Gigliola Di Matteo, Francesca Conti, Davide Petricone, Maia De Luca, Silvia Di Cesare, Cristina Cifaldi, Rita De Vito, Matteo Zoccolillo, Jessica Serafinelli, Noemi Poerio, Maurizio Fraziano, Immacolata Brigida, Fabio Cardinale, Paolo Rossi, Alessandro Aiuti, Caterina Cancrini, Andrea Finocchi

Research output: Contribution to journalArticle


We described for the first time a female patient with the simultaneous presence of two homozygous mutations in MYD88 and CARD9 genes presenting with pyogenic bacterial infections, elevated IgE, and persistent EBV viremia. In addition to defective TLR/IL1R-signaling, we described novel functional alterations into the myeloid compartment. In particular, we demonstrated a defective production of reactive oxygen species exclusively in monocytes upon E. coli stimulation, the inability of immature mono-derived DCs (iDCs) to differentiate into mature DCs (mDCs) and the incapacity of mono-derived macrophages (MDMs) to resolve BCG infection in vitro. Our data do not provide any evidence for digenic inheritance in our patient, but rather for the association of two monogenic disorders. This case illustrates the importance of using next generation sequencing (NGS) to determine the most accurate and early diagnosis in atypical clinical and immunological phenotypes, and with particular concern in consanguineous families. Indeed, besides the increased susceptibility to recurrent invasive pyogenic bacterial infections due to MYD88 deficiency, the identification of CARD9 mutations underline the risk of developing invasive fungal infections emphasizing the careful monitoring for the occurrence of fungal infection and the opportunity of long-term antifungal prophylaxis.

Original languageEnglish
Pages (from-to)130
JournalFrontiers in Immunology
Publication statusPublished - Feb 14 2019


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