Observational Study on Dual Marker of T Cell Activation for Early Diagnosis of Hemophagocytic lymphohistiocytosis (HLH) on Peripheral Blood

Introduction: Hemophagocytic lymphohistiocytosis (HLH) is a fatal disorder, characterized by a cytokine storm due to cytotoxic T cell activation, the causes of which are various. Its detection is first on clinical awareness and proved by several tests. However, there is not one specific test to diagnose HLH. We present an observational study to assess T cell activation dual marker (CD 38 high/ HLA -DR) as one of the important diagnostic parameters for HLH for an early rapid diagnosis for this condition.

Methodology: This is a retrospective observational study conducted in 22 patients. Demographic information, clinical characteristics, diagnostic impressions, pathological features, and laboratory values were collected for each patient. Flow cytometric immunophenotyping for dual positive markers was performed. The panel included antibodies specific for CD45, HLA-DR, CD3, CD4, CD8 and CD 38 T-cell receptor (TCR).

Results: Routine markers such as soluble CD 25, CRP, LDH, triglycerides, LDH and ferritin were unable to differentiate between HLH and other similar conditions. T-cell activation panel performed in these patients showed that 63.64% patients were positive and 36.36% negative for dual markers ((CD 38 high/ HLA -DR)).

Conclusion: T cell activation marker CD 38 high/ HLA -DR was found to be a rapid marker for identification of HLH. This will aide clinicians with a rapid specific diagnosis although the benefit of an early diagnosis did not yield a better outcome indicating that a larger study is needed.