Serious neutropenia following etanercept administration in a 62 years female patient of rheumatoid arthritis.

Tumor necrosis factor (TNF) plays an important role in the inflammatory process of RA and the resulting joint pathology. Etanercept is a member of anti TNF family which is indicated in patients with moderate to severe active rheumatoid arthritis either alone or in combination with MTX. Very few cases of neutropenia with etanercept treatment have been reported worldwide so far. The mechanism of etanercept induced neutropenia is not yet established. We report a case of 62 year female patient, developing etanercept induced neutropenia after 1 month of starting treatment. The absolute neutrophil count (ANC) came down to 150/microl on the 6th day of diagnosis. Bone marrow examination revealed a maturation arrest of granulocytic cells. Other marrow components were normal. Causality assessment of adverse drug reactions was done as per Naranjo's Algorithm. It was a probable ADR. We propose the possible mechanism of neutropenia is bone marrow toxicity. This is contrary to a previous case report which suggested peripheral consumption of neutrophil as a cause of neutropenia. Recently, there are some reports of leukemia and other hematological malignancies associated with the use of etanercept and in those conditions neutropenia could be the first manifestation. Neither product label of the drug nor US FDA warns for periodic blood investigation during etanercept therapy. There is a definite need for total and differential count estimation at the beginning and regular interval during etanercept treatment to rule out possibilities of neutropenia.