We are grateful to Dr Marco Conti from Stanford University, CA, USA, for providing us with AC55 and K118 antibodies, to Dr Ted J. Torphy from SmithKline Beecham Pharmaceuticals, King of Prussia, PA, USA, for providing human PDE4 subtypes, to Pr Jean Sibilia from Strasbourg University Hospital Center of Hautepierre for access to lupus patients' samples, to Monique Duval and Hélène Justiniano for technical assistance. This evidence concerns the gene PDE4A and systemic lupus erythematosus.