Elevated immunoreactive tumor necrosis factor and interleukin-1 in sickle cell disease

Area of Science:

• Hematology
• Immunology
• Pathophysiology

Background:

• Sickle cell disease (SCD) is a genetic blood disorder characterized by abnormal hemoglobin.
• The role of inflammatory cytokines, such as TNF and IL-1, in SCD pathogenesis is not fully understood.

Purpose of the Study:

• To investigate the potential involvement of tumor necrosis factor (TNF) and interleukin-1 (IL-1) in the pathogenesis of sickle cell disease and its complications.
• To measure levels of TNF-alpha and IL-1-alpha in adult SCD patients.

Main Methods:

• Enzyme-linked immunosorbent assay (ELISA) was used to measure TNF-alpha and IL-1-alpha levels.
• Plasma samples were collected from 34 adult subjects with Hb SS or Hb SC, including those in steady state and painful crisis.
• Measurements were compared with coagulation markers and disease severity.

Main Results:

• Elevated TNF levels were observed in a majority of subjects (27/34), irrespective of disease state (steady state or crisis).
• Elevated IL-1 levels were found in a smaller subset of subjects (6/34), always co-occurring with elevated TNF.
• No significant correlation was found between cytokine levels and coagulation activation, overall disease severity, or specific vascular complications.

Conclusions:

• Plasma TNF is frequently elevated in sickle cell disease patients.
• IL-1 is also elevated in some patients, often alongside TNF.
• A direct role for TNF and IL-1 in the vascular occlusion of SCD was not demonstrated, but an indirect role remains possible.