Evaluation of a tryptase depletion index for better pathologic identification of mast cell activation syndrome.

This study explores the development of a tryptase depletion index (TDI) as a potential diagnostic tool for Mast Cell Activation Syndrome (MCAS). Current diagnostic methods for MCAS involve detecting elevated mast cell mediators in blood or urine, which are expensive and technically challenging, or assessing mast cell counts in gastrointestinal (GI) tract tissues, which is controversial. By evaluating gastrointestinal biopsies from 251 MCAS patients and 95 controls using CD117 and tryptase antibodies, the researchers found that mean total mast cell counts did not significantly differ between patients and controls, but the mean TDI did. The TDI, with specific cut-off values, was shown to potentially distinguish between MCAS patients and controls. If validated by further studies, the TDI could serve as a useful minor diagnostic criterion for MCAS, offering a simpler and cheaper diagnostic method.