AB0938 EFFICACY AND SAFETY OF BIOLOGICAL THERAPY WITH ETANERCEPT IN A CASE OF SEVERE POLIARTHRITIS ASSOCIATED TO HARLEQUIN ICHTIOSIS

Background Harlequin Ichthiosis ( HI) is a rare autosomical recessive congenital disease, due to mutations of gene ABCA12.The estimated incidence is approximately 1 in 300,000 births, and approximately 200 cases have been reported worldwide. Typical manifestations of the disease at birth are the presence of hyperkeratotic plates with erythematous fissures, ectropion (eversion of the lower eyelids) and eclabium (eversion of the lips), rudimentary ears and nasal hypoplasia, and articular contractures. Babies who survive into infancy tend to loose hyperkeratotic plaques in favour of generalized scaling and erythroderma. Mental retardation is present in about 2/3 of cases.The association between HI and inflammatory joint involvement has been reported only in few patients since now. Objectives We are describing the case of a 6 years old kid with HI that at the age of 4 developed arthritis with severe impact on his quality of life. Methods We report clinical and laboratory findings, treatment choices and outcomes of young boy with HI who developed polyarthritis. Results A 6 years old kid with HI (the genetic test showed homozigous mutation of ABCA12) came to our attention with an history of chronic arthritis. Since he was 4, he developed bilateral knee arthritis. At first, he was treated with antimicrobial drugs, without improvement, in suspect of septic arthritis. In the following two years, he developed severe chronic poliarthtritis.At the first visit in our center, he showed the classical clinical feature of HI (severe ectropion, contracture and generalized erythroderma), and had history of multiple severe infections and sepsis. Arthritis affected both hips, knees, ankles, wrists, elbows, shoulders and all the feet joints. He lost the ability to walk since the onset of arthritis. Laboratorial features showed negative anti nuclear antibodies (ANA) and anti. extractable nuclear antigen antibodies ( ENA), anti ciclic citrullinated peptide and rheumatoid factor. No signs of uveitis were present at ophtalmological evaluation. The patient was treated with intraarticular corticosteroid injections (IACI) into knees, wrists, elbows and ankles, and then oral methotrexate (MTX) was started. The clinical response was initially good, with partial recovery of deambulation in the 4 months following the intrarticular injection treatment. After 7 months ankles and wrists showed swelling and tenderness, and IACI were repeated, with clinical improvement. Nonetheless, two months later, due to the persisting arthitis activity, anti TNF therapy was started. Etanercept at the dose of 0,8 mcg/week was found to be effective and safe, allowing the patient to walk again. Since the therapy onset, no severe adverse reaction was observed. Conclusion This is the first case of a kid with HI and poliarthritis treated with IACI and anti-TNF agent in combination with MTX. This clinical case shows the efficacy of IACI as a safe and powerful mean, with fast clinical response, in the treatment of arthritis in those patients. Furthermore, we observate the efficacy and safety of anti-TNF agents as baseline therapy for arthritis in patients with HI. References [1] Raghuvanshi S, et al. Harlequin Ichthyosis and Inflammatory Arthritis: Case Reports of a very Rare Combination. Rheumatology2015; 54, suppl_1, i55 [2] Clement S A, et al. Harlequin ichthyosis and juvenile idiopathic arthritis: a rare combination. Clin Rheumatol2007; 26: 460–462. [3] Chan YC, et al. Harlequin Ichthyosis in Association with Hypothyroidism and Juvenile Rheumatoid Arthritis. Pediatr Dermatol 2003; 20: 421–426. Disclosure of Interests None declared