# Expression and clinical significance of S100A8/9 in adults with secondary phagocytic lymphohistiocytosis

## TL;DR

This study shows that S100A8/9 levels in blood can help diagnose and predict outcomes in patients with a rare inflammatory disease called secondary phagocytic lymphohistiocytosis.

## Contribution

The study identifies S100A8/9 as a potential biomarker for diagnosing and predicting prognosis in sHLHa patients.

## Key findings

- Serum S100A8/9 levels were higher in sHLHa patients compared to healthy controls.
- High S100A8/9 levels and low ANC were independent risk factors for poor prognosis in sHLHa patients.
- S100A8/9 levels showed a nonlinear correlation with survival and a threshold effect at 2.44 µg/mL.

## Abstract

The study aimed to investigate the diagnostic and prognostic value of serum S100A8/9 levels with sHLHa, a high-mortality multiorgan inflammatory syndrome with no reliable clinical biomarkers, where calreticulin’s role is unclear.

This was a study of 67 newly diagnosed sHLHa patients. 48 patients met criteria and were analyzed. ELISA detected S100A8/9 levels in patients and controls. The optimal classification threshold for S100A8/9 was determined to be 2.44 µg/mL by restricted cubic spline (RCS) curve analysis. Patients were categorized. Correlations, diagnostic efficacy, survival differences, and prognosis impacts were analyzed.

Serum S100A8/9 levels in sHLHa patients were greater than in healthy controls. Various analyses showed its diagnostic and prognostic value. ANC<1.0 × 109/L and high S100A8/9 expression group were independent risk factors for poor prognosis in patients with sHLHa. It’s correlated with liver function indicators and HScore.

This study evaluates S100A8/9 in sHLHa diagnosis and prognosis. S100A8/9 levels are useful for differentiating patients, providing etiologic and survival info. They show a nonlinear positive correlation with survival and a threshold effect. Serum S100A8/9 levels offer potential biomarkers, and further studies are needed.