Comment
Tumor necrosis factor α blockers are commonly used for moderate to severe plaque psoriasis. To our knowledge, there have been no reported human studies showing TNF-α blockade as a potential treatment of sickle cell disease. Increased levels of TNF-α have been shown to contribute to the onset of sickle cell crises and severity of sickle cell disease by playing an integral role in the development of vascular wall dysfunction and ischemia.3 Inflammatory mediators in HbSS disease, such as heparan sulfate from the endothelial glycocalyx and heme from hemolysis, act on monocytes to release TNF-α.1 Through this effect on the endothelium, TNF-α impedes blood flow during sickle cell crisis, leading to worsening ischemia and resultant painful infarction.3 Analysis of cytokine levels in HbSS patients showed significantly (P<.05) elevated levels of TNF-α during sickle cell crises and at baseline in comparison to nondiseased controls (HbAA), indicating a possible role of TNF-α in the pathogenesis of the crisis state.3 These studies suggest that TNF-α inhibition may reduce the initiation of vaso-occlusive crisis and decrease the subsequent ischemia related to a sickle cell crisis.
Although these findings were observational and limited to a single patient, the 50% decrease in pain level and use of pain medications reported to her hematologist independent of her dermatology visits coincided with the initiation of adalimumab. Although radiographs showed possible psoriatic changes of the distal metatarsal row, her described sickle cell pain and pain crises were atypical for psoriatic arthralgia. Tumor necrosis factor α inhibitors could be the drug of choice to treat patients with psoriasis with concomitant HbSS or HbSC disease due to the blockade of a common inflammatory mediator. Further studies are indicated to analyze the in vivo role of TNF-α inhibition in sickle cell disease.