A blood sample was collected just before the onset of anakinra treatment and total RNAs were extracted from the peripheral blood mononuclear cells. The [33P] radiolabeled mRNAs were hybridized (duplicate or triplicate) over a set of 10.000 human cDNA probes spotted at a high density on nylon membranes. Data were normalized and filtered to allow the comparison between RNA samples. Statistical analyses were performed with the R software and hierarchical clustering was performed with the Cluster and Tree View softwares.