High ferritin and low glycosylated ferritin may also be a marker of excessive macrophage activation
A high serum ferritin concentration with a low percentage of glycosylated ferritin (< 20%) have been reported to be a specific marker of active adult Still's disease (ASD). However, high ferritin levels are found during hemophagocytosis syndrome (HS). We investigated the ferritin level and the percentage of glycosylation in a HS series of various causes. Diagnosis of HS was confirmed by erythrophagocytosis pictures on a bone marrow cytology or biopsy in all patients. Serum ferritin concentration was determined on a heterogenous immunoassay module. Glycosylated ferritin was separated using concanavalin A (Con-A) sepharose 4B chromatography. The nonglycosylated ferritin unbound to Con-A was recovered in the supernatant and quantified with the same procedure. Percentages of glycosylated ferritin less than 20% are considered to be usual in ASD, between 20 and 40% usual in inflammatory syndrome, and between 50 and 80% normal. In all cases tested during the acute phase of the disease, ferritin blood level was high and the percentage of glycosylated ferritin was low, less than 20%. The combination of high ferritin level and low percentage of glycosylation may be a marker of excessive macrophage activation.