Procalcitonin and minimal-change nephropathy: a pilot study.

Introduction: This study assessed the role of procalcitonin (PCT) in the differentiation of minimal-change nephropathy (MCN) relapses from infections co-existent with proteinuria flares in children.

Methods: Data on the PCT levels of patients with MCN who were on follow-up were retrospectively gathered at relapse (Group I), during proteinuria attacks co-existent with intercurrent infection (Group II) and at remission (Group III). The results of these three groups were then prospectively compared with nephrologically healthy patients who had infections that were similar to those in Group II (Group IV), and controls (Group V).

Results: Significant differences in PCT level were noted between patients of Groups I, II and IV and the other two groups. A 93% reduction in proteinuria was achieved for Group II patients following an antibiotic regimen. The difference in PCT level between Groups I and II was significant. PCT showed a higher diagnostic predictability than C-reactive protein (CRP) in Group I patients, and was as good as CRP for those with infection and infection-related proteinuria. Sensitivity × specificity in relapse and infection-related states for PCT were 0.472 and 0.628, respectively, and those for CRP were 0.183 and 0.762, respectively.

Conclusion: A combined approach with CRP and PCT readings may be beneficial in discriminating proteinuria attacks co-existent with intercurrent infection from sole relapses of nephrotic syndrome. PCT may be a part of the wide spectrum of immune abnormalities seen in patients with MCN.