Background: Henoch-Schoenlein purpura is the one of most common types of systemic vasculitis that involves impaired renal function and Henoch-Schoenlein purpura nephritis (HSPN). The diagnosis of this condition is largely based on immunohistologic detection of immunoglobulin A1-containing immune complex in the glomerular deposits of mesangium. Despite clinical advances, the etiopathogenesis of HSPN is still largely unknown.
Methods: In this study, we enrolled 25 newly diagnosed HSPN patients and 14 healthy controls. Then, fractions of B cell subtypes were determined in venous blood using flow cytometry. The serum interleukin (IL)-10 concentration was determined by enzyme-linked immunosorbent assay.
Results: Compared to those in healthy controls, the numbers of CD38+CD19+, CD86+CD19+, CD38+CD86+CD19+, and CD95+CD19+ B cells per microliter of blood were significantly higher in HSPN patients. In contrast, the numbers of CD5+CD19+, IL-10+CD19+, CD5+CD1d+CD19+, and IL-10+CD5+CD1d+CD19+ B cells per microliter of blood and the serum IL-10 concentration were significantly lower in HSPN patients. Following treatment, the numbers of CD38+CD19+ and CD86+CD19+ B cells per microliter of blood were significantly reduced in HSPN patients. However, the numbers of CD5+CD1d+CD19+, CD5+CD1d+IL-10+CD19+, and IL-10+CD19+ B cells per microliter of blood and the serum IL-10 concentration were significantly increased in HSPN patients following treatment. The estimated glomerular filtration rate (eGFR) was negatively correlated with the number of CD38+CD19+ B cells but positively correlated with the numbers of IL-10+CD19+, CD1d+CD5+CD19+, and IL-10+CD1d+CD5+CD19+B cells per microliter of blood and the serum IL-10 concentration. The 24-h urinary protein concentration was positively correlated with the number of CD38+CD19+B cells but negatively correlated with the numbers of IL-10+CD19+, CD1d+CD5+CD19+, and IL-10+CD1d+CD5+CD19+B cells per microliter of blood and the serum IL-10 concentration.
Conclusion: Our results suggest that CD38+CD19+ and CD1d+CD5+CD19+ B cells (Bregs) contribute to the pathogenesis of HSPN.