Spontaneous NBT reduction by monocytes as a marker of disease activity in children with histiocytosis

In an attempt to define a biological marker of monocyte hyperactivation in the course of infantile histiocytosis, the spontaneous nitroblue tetrazolium (NBT) reduction assay was applied to monocytes from 13 children with Langerhans cell histiocytosis (LCH), familial haemophagocytic lymphohistiocytosis (FHL), juvenile xanthogranuloma or malignant histiocytosis. Significant increase in NBT reduction was observed in the patients with both active LCH and FHL in comparison with control subjects, who were either healthy or affected by different conditions. A close relationship between spontaneous reduction rate and clinical condition of the patients was evident in patients tested at diagnosis, during remission and during the course of disease reactivation. Interleukin-1 (IL-1) production by monocytes was also evaluated: the patients with LCH and FHL displayed a significant increase in in vitro IL-1 production by lipopolysaccharide-stimulated monocytes. In our experience the spontaneous NBT reduction assay was a sensitive, quite specific, low-cost and reproducible test for the evaluation of children with histiocytosis. Useful information may be obtained at diagnosis but also during the clinical course of disease by using this marker of monocyte spontaneous activation.

Dyslipoproteinemia and xanthomatosis

The cutaneous markers associated with dyslipoproteinemia are reviewed in the context of the current view of lipid and lipoprotein metabolism. The utility of determining the plasma levels of lipoproteins and certain apoproteins in children or adults with xanthomas or xanthelasma is discussed. We hope that early identification and appropriate treatment of such patients will reduce the morbidity and mortality from the two major complications of dyslipoproteinemia--atherosclerotic cardiovascular disease and pancreatitis.

[Regression of xanthomas in endogenous hypertriglyceridemia under low carbohydrate diet]

Report on two patients with endogenous hypertriglyceridemia. In both patients normal serum lipid values were reached in a comparatively short time under a diet with reduced carbohydrates and calories. In one diabetic patient who needed insulin at the beginning of the treatment the disease could be controlled by dietary measures alone after a few days. Different biological half-life periods of the various serum lipid fractions explain why, under a reducing diet, the rate of decrease of lipids is variable according to the respective component. Thus, the ratio of triglycerides and cholesterol can vary in the same patient within a few days and may change his classification under different types of hyperlipidemia according to Fredrickson. It would appear that in these cases a classification based on etiological considerations is more recommendable.