Prognostic significance of subepidermal immune deposits in uninvolved skin of patients with systemic lupus erythematosus: a 10-year longitudinal study.

The detection by direct immunofluorescence of subepidermal immune deposits in clinically normal skin of patients with systemic lupus erythematosus has become known as a positive lupus band test (LBT). To gain a better understanding of the relation between the LBT and prognosis in systemic lupus erythematosus (SLE) a prospective longitudinal study has been carried out in 51 SLE patients covering a 10-year period. A total of 223 LBTs were obtained from clinically normal skin of the medial volar forearm on these 51 patients (average, 4.4 per patient) and the results correlated with clinico-pathologic features of the disease and outcome. Findings from the initial LBT (obtained while on no systemic therapy) were used to divide patients into LBT-positive and LBT-negative groups. With the exception of patients subsequently treated with daily doses of prednisone greater than 40 mg or cytotoxic agents, the patients in the LBT-positive group usually remained LBT-positive. The LBT-negative patients usually remained LBT-negative on repeated testing. A comparison of clinical features in the two groups revealed a 55% prevalence of lupus nephropathy in the LBT-positive group as opposed to 23% in the LBT-negative group (p = 0.025). Although the two groups had similar serum creatinine levels at the time of the initial LBT, the maximum serum creatinine (mean, 3.0 mg/dl) in the LBT-positive group was significantly higher than the maximum (mean, 1.2 mg/dl) in the LBT-negative group (p = 0.04). Furthermore, only 9% of renal biopsies in the LBT-negative group showed diffuse proliferative glomerulonephritis in contrast to 65% of biopsies in the LBT-positive group (p = 0.007). Lastly, the two groups were compared with regard to outcome; 10-year survival from the time of diagnosis was 95% in the LBT-negative group as opposed to only 54% in the LBT-positive group (p = 0.007). These findings indicate that a positive LBT has predictive value in that it identifies a subset of SLE patients with more aggressive renal disease and significantly decreased long-term survival.