The role of tumor necrosis factor-α in Henoch-Schönlein purpura

Henoch-Schönlein purpura (HSP) is one of the most common types of vasculitis disorders in childhood and is characterized by a rash, arthritis, abdominal pain, and renal involvement. The factors that determine and mediate the severity of HSP and its renal involvement remain poorly understood, although it is likely that pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), are involved in the pathogenesis. Serum and urine levels of TNF-α were measured in children with HSP in the acute and convalescent phases by ELISA. Serum TNF-α levels were significantly higher in proteinuric HSP in the acute phase (36.6±8.5 pg/ml) compared with those with HSP without renal involvement and those with hematuric HSP (25.4±4.5 and 27.1±3.9 pg/ml) (P<0.005). However, these significantly higher levels disappeared in the convalescent phase. Using matched serum samples from the same patients, serum TNF-α levels of proteinuric HSP patients were significantly lower in the convalescent phase (29.9±4.6 pg/ml, P <0.05) than in the acute phase (39.1±8.2 pg/ml). Although urine TNF-α levels were higher in proteinuric HSP in the acute phase and reduced in the convalescent phase, there were no significantly high or low levels. These results suggest that increased TNF-α levels in the serum induce a series of functional and morphological changes in the glomerular cells in the acute phase and may be used as markers for monitoring the disease activity of HSP with severe renal involvement.