[Periodic fever with increased IgD]

Periodic fever or hereditary inflammatory fevers are characterized by intermittent inflammatory attacks. Many entities are well recognized today such as familial mediterranean fever (FMF) and hyperimmunoglobulinemia D syndrome (HIDS). We report on the case of a 6-year-old boy referred for evaluation of a recurrent fever associated with chest pain, pneumonitis, or pleuritis since the age of 5 years. Laboratory data showed leukocytosis, a high erythrocyte sedimentation rate, and C-reactive protein; however, a permanent high serum level IgD was noted. Stereotypical episodes of fever appeared every 4-6 weeks, while infectious, malignant, and auto-immune causes were eliminated. A search for the most common mutations of the FMF gene in Tunisian patients (M694V, M680I, V726A, E148Q, M694I, and A744S) were negative. Likewise, urinary leukotriene E(4), which may be increased in HIDS, was normal in this patient. Mevalonate kinase activity in lymphocytes was not assayed. Ethnic origin and clinical presentation suggest FMF with an increased IgD rather than authentic HIDS, in spite of the lack of improvement under colchicine treatment and the negativity of the main mutations involved in FMF.