[Hyperimmunoglobulin D syndrome].

The hyper-IgD syndrome is a rare entity characterized by early onset of attacks of periodic fever. All patients have an elevated serum IgD (> 100 U/ml). Symptoms during attacks include joint involvements (arthralgias/arthritis), abdominal complaints (vomiting, pain, diarrhoea), skin lesions, swollen lymph nodes, and headache. In 1992 an International hyper-IgD study group was established, and to date the diagnosis has been made in 60, mainly European patients; 14 come from France. The disorder occurs in families and is transmitted by autosomal recessive inheritance. Linkage studies indicate that the gene encoding for familial Mediterranean fever is different from the gene for the hyper-IgD syndrome. In children the hyper-IgD syndrome should be distinguished from two other periodic febrile disorders. CINCA (chronic inflammatory, neurological, cutaneous and articular syndrome) and FAPA (periodic fever, adenopathies, pharyngitis, and aphtous stomatitis) share some symptoms with the hyper-IgD syndrome but in these syndromes serum IgD is normal. The pathogenesis remains to be elucidated but during attacks all patients have an acute-phase response with elevated C-reactive protein concentrations. During the febrile episodes, the inflammatory cytokines such as IL-6 TNF alpha, IFN gamma are increased together with natural occurring inhibitors such as IL-1ra and sTNFr. There is no therapy for the syndrome and patients will experience attacks during their entire life although frequency and severity tend to diminish with age.