Review article: non-malignant haematological complications of anti-tumour necrosis factor alpha therapy

Background Tumour necrosis factor-alpha (TNF-a) is an important mediator of the molecular cascade leading to chronic inflammation. TNF-a inhibitors have proven their safety and efficacy in the treatment of inflammatory diseases. Aim To review the nonmalignant haematological adverse events, such as thrombocytopaenia, neutropaenia, hypercoagulability, pancytopaenia and aplastic anaemia in patients receiving TNF-a inhibitors. Methods We reviewed the literature by searching MEDLINE and EMBASE databases as well as references of all retrieved articles for the following terms: anti-tumour necrosis factor, anti-TNF, infliximab, adalimumab, certolizumab, etanercept, haematological complications, thrombocytopaenia, neutropaenia, anaemia, bone marrow and thrombosis. Results Thombocytopaenia is a very rare phenomenon and was associated with no serious adverse events. However, transient neutropaenia developed in up to 16% of cases. Patients with a previous history of neutropaenia on other therapies or baseline neutrophil count <4X109/L are at a particularly higher risk. The association between anti-TNF-a therapy and thrombosis is very nebulous due to the multitude of potential confounders. Only one case of primary eosinophilia has been reported with anti-TNF-a therapy. Conclusion Regular monitoring of the white blood cell count at baseline and with each infusion is recommended for patients on anti-TNF-a. Further studies to elucidate their interaction with the immune system are warranted.