Increased serum ferritin levels in patients with Crimean-Congo hemorrhagic fever: can it be a new severity criterion?

Objectives: Serum ferritin is one of the markers indicating hemophagocytosis that may have a role in the pathogenesis of Crimean-Congo hemorrhagic fever (CCHF). This study was designed to determine any correlation between serum ferritin and routine diagnostic laboratory markers of CCHF, and to investigate the relationship between serum ferritin levels and disease severity. Methods: Sixty-six patients with CCHF admitted to the hospital during the spring and summer months of 2006 and 2007 were included in the study. Serum ferritin levels were measured in sera obtained during the initial days of hospitalization. Data from 53 patients showing decreasing platelet counts over the first three days were used for further analysis and these patients were divided into two groups according to disease severity: group A included severe cases with lowest platelet counts <= 20 x 10(9)/l and group B included mild cases with lowest platelet counts > 20 x 10(9)/l. Results: Forty patients (60.6%) were male (mean age 43 +/- 17 years). Three patients died, thus the fatality rate was 4.5%. Fifty-one patients (77.3%) had abnormal serum ferritin levels, with levels above 500 ng/ml in 62.1%. There was a significant negative correlation between ferritin levels and concordant platelet counts (p < 0.001; r = -0.416) and ferritin was also found to be positively correlated with aspartate aminotransferase (p < 0.001; r = 0.625), alanine aminotransferase (p < 0.001; r = 0.479), and lactate dehydrogenase (p < 0.001; r = 0.684). Group A had higher ferritin levels than group B (p < 0.001). Receiver operating characteristic analysis revealed that a ferritin level of >= 1862 ng/ml had a sensitivity of 87.5% and a specificity of 83.8% in differentiating severe cases from mild ones. Conclusions: Increased serum ferritin levels may suggest a significant role of hemophagocytosis in the pathogenesis of CCHF and may be a useful marker for diagnosis, disease activity, and prognosis. (C) 2009 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.