Glomerular macrophage is an indicator of early treatment response in diffuse proliferative lupus nephritis

Patients with diffuse proliferative lupus nephritis (class IV) who responded to treatment within 6 months had better renal outcome than those who did not. Glomerular macrophage is known to be associated with poor renal outcome in glomerular diseases.

To evaluate association between glomerular macrophage number and early treatment response in lupus nephritis class IV patients.

Renal biopsies (n = 90, 86 females) diagnosed with lupus nephritis class IV were included in the study. The patients were divided into 2 groups (n = 45 each) according to response to treatment within 6 months. The treatment response group was defined as having decreased serum creatinine at least 25% from baseline and 24 hr urine protein or UPCR (urine protein creatinine ratio) < 1. The non-response group was defined as stable or increased serum creatinine and 24 hr urine protein or UPCR > or = 1. Immunohistochemistry for macrophage marker (CD68) was performed and the glomerular macrophages were counted on each biopsy. The relevant clinicopathologic data were collected.

The glomerular macrophage number in response and non-response group was 4.5 +/- 2.5 and 6.2 +/- 4.5 respectively (p = 0.029). The glomerular macrophage number was conversely and inversely correlated with activity (r = 0.281, p = 0.007) and chronicity (r = -0.358, p < 0.001) index, respectively

Lupus nephritis class IV patients who responded to treatment within 6 months had lower glomerular macrophages than those who did not. The glomerular macrophage number may be used to determine treatment response in lupus nephritis class IV patients.