Hyperferritinemia (ferritin ) was associated with higher plasma levels of the neutrophil degranulation products MPO and proteinase 3 (both constituents of azurophilic granules) but not higher levels of NGAL (derived from secondary granules) [22]; neutrophil counts did not differ between groups (Table 1). The gene discussed is PRTN3; the disease is isolated hyperferritinemia.