Tryptase detection in bone-marrow blood: a new diagnostic tool in systemic mastocytosis

The condition mastocytosis includes a heterogenous group of disorders that are characterized by abnormal growth and accumulation of mast cells. The detection of serum tryptase, an essential mast cell enzyme, is a widely used tool in the diagnosis of mastocytosis. The diagnosis of systemic mastocytosis is substantially based on the histologic examination of bone-marrow biopsy specimens.

We hypothesized that the detection of tryptase in bone-marrow blood might provide additional, more sensitive information on the bone-marrow involvement of patients with mastocytosis.

Serum tryptase was monitored in patients with cutaneous symptoms (n = 17), patients with extracutaneous symptoms (n = 16), and healthy control subjects (n = 359). Bone-marrow biopsy specimens of patients with systemic mastocytosis (n = 7) and control subjects (n = 7) were investigated histologically and bone-marrow blood of these individuals was analyzed on the tryptase levels.

We could detect for the first time significantly elevated tryptase levels in bone-marrow blood of patients with systemic mastocytosis. Secondarily we could present a clear correlation between the level of serum tryptase and the clinical symptoms of mastocytosis.

With the present study, we establish a new diagnostic tool for systemic mastocytosis. Unfortunately, we can only present a limited number of cases, since systemic mastocytosis is a rare disease involving few patients.

Our results indicate that the measurement of tryptase in bone-marrow blood is a new, sensitive marker of the mast cell burden in bone marrow of patients with systemic mastocytosis.