Objective: To determine the significance of hepatitis B virus (HBV)-associated antigen deposition in renal tissue from patients with systemic lupus erythematosus (SLE).
Methods: The medical records of 166 inpatients with lupus nephritis and 384 controls without SLE were analyzed retrospectively. Patients with SLE were classified as positive or negative depending on whether HBV-associated antigen deposition was detected in renal biopsies.
Results: HBV-associated antigen deposition was mainly detected in renal tissue from patients with SLE (50.6%), primary renal glomerular disease (20.8%), and allergic purpura (21.7%). It was not detected in renal tissue from patients with diabetic nephropathy, hypertensive nephrosclerosis, thin basement membrane nephropathy, or Alport syndrome. Hepatitis B surface antigen and core antigen were deposited in the mesangial region and vascular loops. The positive group had a significantly higher frequency of IgG, IgA, and IgM deposition than the negative group (53.6% vs 30.5%; p < 0.01). There was no significant difference in the types of lupus nephritis observed between the 2 groups.
Conclusion: There was a high prevalence of HBV-associated antigen deposition in renal tissue of patients with SLE by indirect immunofluorescence, which may result mainly from the cross-reactivity with deposited immunoglobulins.