Effects of circulating endothelial progenitor cells, serum vascular endothelial growth factor and hypogammaglobulinemia in Perthes disease.

Objective: The aim of this study was to investigate Legg-Calvé-Perthes disease (PD) pathogenesis by comparing absolute circulating endothelial progenitor cell (EPC) counts, serum levels of vascular endothelial growth factor-A (VEGF-A) and immunoglobulins between PD patients and controls.
Methods: The study included 28 PD cases (mean age: 8 ± 3.8) and 25 healthy age-matched control subjects. EPC, serum VEGF-A and immunoglobulin levels were measured in peripheral blood samples. Comparisons and correlation analysis were performed.
Results: In the PD group, 17 subjects were in the fragmentation stage and 11 in the healing stage. Four patients had bilateral disease and 14 had hypogammaglobulinemia. Median EPC count of the PD group was 80 and was significantly higher than those of the control group (p=0.011). No significant difference was determined in serum VEGF-A levels (p=0.354). EPC count were inversely correlated with serum IgG levels of the PD group (r=0.403, p=0.03). Absolute EPC count was also significantly higher in the fragmentation stage than in the healing stage and were also greater in bilaterally affected than in unilaterally affected patients. Circulating EPC count was correlated to the serum VEGF-A levels in patients with fragmentation stage of PD (r=0.605, p=0.01) and in those with hypogammaglobulinemia (r=0.599, p=0.001).
Conclusion: High EPC count at the fragmentation stage of PD and relatively higher counts in bilateral disease suggest that EPC may be a valuable marker in the diagnosis and follow-up of PD. Additional studies are needed to explain the strong correlation between EPC and serum VEGF-A level in the fragmentation stage and in the presence of hypogammaglobulinemia.