FDA Approves Assay for Rare Cell Disorders

Lawrence Schwartz (Virginia Commonwealth University)

The U.S. Food and Drug Administration approved a new test to help physicians diagnose a group of rare cell disorders. The test, or assay, was developed by Lawrence Schwartz (pictured right), a medical school professor at Virginia Commonwealth University in Richmond and a researcher in the field of mast cells.

Mast cells are found in skin, lymph nodes, liver, spleen, and the linings of the lung, stomach, and intestine. They serve a number of functions in the body, including support for the immune system, defense mechanisms against parasitic infections, and tissue repair, and are vital to the inflammation process. They are derived from bone marrow and rely on stem cells for their survival.

When mast cells are activated, they release chemicals in the body including the enzyme tryptase and histamine. “Histamine,” says Schwartz, “causes itching, swelling, wheezing and sneezing and other signs and symptoms of allergic reactions.”

Mastocytosis is a disorder that can occur in both children and adults, and is caused by the presence of too many mast cells in the body. When there are too many mast cells, the increased burden of the chemicals released from these cells can cause several symptoms that range in intensity from mild to severe. These symptoms are often similar to allergic reactions, but mastocytosis can occur spontaneously rather than be triggered by an allergen.

Schwartz’s research includes development of immunoassays for tryptases as biomarkers of disorders involving mast cells. The ImmunoCAP Tryptase, a new diagnostic assay based on Schwartz’s research, measures the level of tryptase in the blood to help diagnose systematic mastocytosis. A persistently elevated baseline level of tryptase is an indicator of mastocytosis.

Virginia Commonwealth first licensed the assay in 1993 to a company that has become Thermo Fisher Scientific in Uppsala, Sweden. FDA approved the assay as a test for mastocytosis, but it has other potential applications, including an indicator of future episodes of systemic anaphylaxis, a severe, whole-body allergic reaction to a chemical that has become an allergen.

Read more:

• New Methods Proposed for Testing Allergens Without Animals
• FDA Approves First Treatment for Scorpion Stings

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