Hyperzincaemia and hypercalprotectinaemia: a new disorder of zinc metabolism

Calprotectin (complex of S100A8 and S100A9) is the major calcium and zinc-binding protein of phagocytes. We report a new syndrome with recurrent infections, inflammation, and hyperzincaemia associated with excessively high plasma concentrations of calprotectin. We measured calprotectin in plasma and protein fractions by ELISA assay and zinc by atomic absorption spectrometry. Plasma proteins were fractionated by size exclusion chromatography and electrophoresis. Mass spectra of purified proteins were determined by MALDI-TOFMS. We assessed five patients, two of whom are related. All patients had much the same biochemical findings of hyperzincaemia (77–200 μmol/L, reference range 11–18 μmol/L) and raised plasma calprotectin concentrations (1·4–6·5 g/L, reference range