Relationship between macrophage phenotype and kidney survival in patients with lupus nephritis

Aims

To determine the possible relationship between macrophage phenotypes and the progression of kidney disease in patients with lupus nephritis (LN).

Methods

Using immunohistochemistry, CD68⁺ and CD163⁺ cells were counted per glomerulus and per high-power field in the tubulointerstitium. Progression was defined as a doubling of the serum creatinine level and/or progression to end-stage kidney disease.

Results

Among the 21 patients, 52% had class III or IV LN. During the median follow-up of 88 months, 5 (23.8%) patients experienced progression. In terms of clinical and pathological markers, the only significant difference between progressors and nonprogressors was the number of interstitial CD163⁺ cells (median 4 versus 2.4, respectively; p = 0.025). A cutoff value of 2.7 for the mean number of CD163⁺ cells in the interstitium yielded a sensitivity of 80% and specificity of 75% for progression. The estimated median time to progression among patients with ≥2.7 CD163⁺ cells was shorter (median 136 versus 202 months, p = 0.023). A greater number of CD163⁺ cells in the kidney interstitium was associated with the progression of kidney disease (HR 2.88, 95% CI 1.22–6.80; p = 0.016). Class III–IV LN was associated with a higher median number of glomerular CD163⁺ cells (OR 1.96, 95% CI 1.1–3.49, p = 0.023). Endocapillary hypercellularity and extracapillary proliferation were associated with greater number of CD163⁺ cells in the glomerular area. Among patients with class III-IV LN, the number of interstitial CD68⁺ cells was greater in those who experienced progression of kidney disease (p = 0.012).

Conclusion

A greater number of CD163⁺ cells in the kidney interstitium was associated with the progression of kidney disease in patients with LN, while a greater number of CD68⁺ cells in the interstitium was associated with progression in the subgroup of patients with class III-IV LN.