Aim and method: To address the clinical significance of lipoprotein (a) (Lp(a)) deposition in renal diseases of children, we examined renal localization of apolipoprotein (a) (apo(a)), which is the major apoprotein of Lp(a), using a new monoclonal antibody as a probe, and compared histological changes and clinical courses between the cases with and without apo(a) accumulation. Our study comprised 78 cases with various renal diseases.
Results: Of the 78 cases, 45 showed apo(a) deposition (group A) and the other 33 did not (group B). Nephrotic syndrome was similarly presented in groups A and B (46.7% vs 36.3%). Histological findings were analyzed in 62 proliferative and 16 non-proliferative original diseases separately. In the cases with proliferative diseases, severe histological changes were observed in group A more than in group B, severe proliferation (50.9% vs 26.1%: p < 0.01) and crescent formation (11.9% vs 5.1%: p < 0.01) were observed in group A over that of group B. However, the clinical status at the latest follow-up were quite similar, there was no difference of favorable (60.5% vs 62.5%) and unfavorable outcome (15.9% vs 16.7%) in groups A and B. In the cases with non-proliferative diseases, global sclerosis was more often encountered in group A than in group B (28.3% vs 6.5%). Group A carried poorer prognosis than group B in non-proliferative diseases.
Conclusion: These results suggest that apo(a) deposits just passively follow the histological injury, and they do not always accelerate it.