Background and Importance The NF-KB essential modulator deleted exon 5 auto-inflammatory syndrome (NEMO-NDAS) is an X-linked auto-inflammatory disease belonging to the systemic auto-inflammatory diseases (SAIDs). NEMO-NDAS affects the skin (ectodermal dysplasia) and the immune system. A few cases have been reported in France.

Aim and Objectives The objective of this case report was to describe the use of infliximab and its safety in NEMO-NDAS.

Material and Methods We report a 9-month-old baby who initially presented a long-lasting fever and a panniculitis. No infectious nor autoimmune causes were found, and the interferon signature was low. A corticosteroid treatment was started. Further genetic analyses showed an anomaly of the NEMO gene compatible with a NEMO-NDAS. Several pathways are modified, including the interferon pathway, which was increased. No recommendations nor relevant literature for specific treatment was found.

Results Anti-TNF-alpha such as adalimumab or infliximab could be used to down regulate this interferon pathway. Infliximab was introduced at a dose of 5mg/kg every 15 days for a month and a half, then every month. After the first injection, no fever, infection nor cutaneous manifestation were reported by the parents. The patient seemed to suffer less. Following the second injection, the corticosteroid treatment was decreased and stopped over a 15-day period.

One month after the introduction of infliximab, the patient presented a total apyrexia and no clinical signs of infection. On clinical examination, a hypertrophy of the lymphatic system was found (bilateral painless mobile axillary adenopathies, anterior cervical and supra-clavicular adenopathies). In spite of this, the patient was considered to be in clinical and biological remission (C-reactive protein = 1 mg/L, sedimentation rate < 2 mm in the first hour, amyloid A serum < 6,4 mg/L, transcriptomic signature of negative interferon gamma). Infliximab is currently being continued.

Conclusion and Relevance Infliximab was used successfully in our case and led to remission in 1 month with good tolerance and no adverse effect. Infliximab seems to be a well-tolerated treatment option for NEMO-NDAS in infants.

Introduction of infliximab allowed a total remission in 1 month without any adverse effect on the patient.

Conflict of Interest No conflict of interest.