medwireNews: Blood-cell markers of inflammation are elevated in children with Cushing’s syndrome (CS) and may offer useful diagnostic information, say researchers.
Christina Tatsi (Eunice Kennedy Shriver National Institute of Child Health & Human Development, Bethesda, Maryland, USA) and study co-authors compared the neutrophil-to-lymphocyte ratio (NLR), which they say “is a biomarker commonly used as a surrogate index of the inflammatory and immune system status”, in children with active CS and controls.
They found the median NLR was 2.47 in 117 children with active CS aged 6–12 years, which was significantly higher than the median of 1.35 found in 22 controls of similar age.
And in 188 CS patients aged 13–21 years the median NLR was 3.00, which was again significantly higher than the median of 1.80 in 71 controls.
The NLR was higher in patients than controls regardless of whether the patients had Cushing disease, adrenocorticotropic hormone-independent CS or ectopic CS.
The absolute neutrophil count was also significantly higher in CS patients than controls, at 5.54 versus 4.26 K/µL in the younger age group, for example, and the same was true for monocytes, at 0.81 vs 0.58 K/µL, whereas the absolute lymphocyte count was significantly lower, at 2.12 versus 2.80 K/µL in the younger group.
In addition, the monocyte-to-lymphocyte ratio was significantly higher in patients than controls, as was the platelet-to-lymphocyte ratio, despite there being no difference between the groups in the absolute platelet count.
Moreover, when the CS patients went into remission most of these differences disappeared and in many cases reversed.
In the younger children, the neutrophil count fell to significantly below that of the controls, resulting in a lower NLR. And in the older group, lymphocytes became elevated, but neutrophils and monocytes became significantly lower, leading to all lymphocyte ratios being significantly lower than in controls.
In the CS patients, the inflammatory biomarkers significantly correlated with several measures of cortisol secretion. NLR most reliably correlated, showing significant associations with morning serum cortisol, midnight serum cortisol and the fold increase in urinary free cortisol above the upper limit of normal, irrespective of the age group.
Tatsi and team suggest that these inflammatory biomarkers should be studied as potential diagnostic tools in paediatric CS.
Writing in the European Journal of Endocrinology, they stress that these would not replace currently recommended diagnostic tests, “whose accuracy is much higher, up to 90-95% in certain occasions”.
But the researchers say that “considering the ease and simplicity of a [complete blood count] test, this additional information may be used for the patient’s evaluation”, and they also suggest that the degree of inflammation might offer clues to disease severity or prognosis.
By Eleanor McDermid
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