Hemophagocytic lymphohistiocytosis in infancy and childhood

The current status of hemophagocytic lymphohistiocytosis (HLH) in infants and children has been studied.

Eighty-two cases of pediatric HLH, for which there was no confirmed familial inheritance, were comparatively studied between 36 patients less than 2 years of age and 46 patients more than 2 years of age.

In all cases, persistent fever, cytopenia, liver dysfunction, and hepatosplenomegaly were the most frequently noted symptoms. Hyperferritinemia (> 1000 micrograms/L) and elevated blood levels of lactate dehydrogenase (> 1000 IU/L) were observed in 90% and 89.7%, respectively. These figures were considerably higher than for either hypertriglyceridemia (> 2 mmol/L) (50%) or hypofibrinogenemia (< 1.5 gm/L) (57.4%), indicating that increased serum ferritin and lactate dehydrogenase concentrations might be good diagnostic parameters for HLH. These parameters are nonspecific but are of follow-up and prognostic value in these HLH cases. No differences were found in clinical signs and symptoms or other laboratory findings for the two age groups. Immunochemotherapy was administered in the similar regimens to patients in both groups. Of the 82 patients, 13 (15.9%) succumbed to a fatal course within 2 months after diagnosis, and Kaplan-Meir analysis for all cases predicted the overall disease-free patient survival at 4 years from the onset of disease to be 57.2% (95% confidence interval (CI), 45.1% to 69.3%). There was a slightly, but not statistically significant, poorer prognosis for the younger patients: 44.2% (95% CI, 26.0% to 62.4%) survival for the infant group versus 67.2% (95% CI, 51.8% to 82.6%) survival for the older group (p = 0.0569).

Refinement of the treatment is mandatory to improve the outcome of HLH in both infants and older pediatric patients.