2008.01.14 – Dr. Mehta-A new blood test-Do we know JAK?

Waukegan News Sun – Waukegan,IL,USA

Dr. Mehta: A new blood test: Do we know JAK?

January 14, 2008
BY NILESH MEHTA M.D. drnileshdmehta@gmail.com

As provocative as the title may sound, it was intriguing to the hematologists who attended the American Society of Hematology meeting in Atlanta last month. More importantly, it defines a new era of genetic advances in medicine which increases our ability to recognize hematological disorders. Specialized newer blood tests have improved our armamentarium for diagnostic accuracy in patients.

Mrs. D is a 76-year-old woman who was found to have “too many white blood cells and red blood cells” five years ago. In addition to a routine medical evaluation, Mrs. D also had a blood test — JAK2 mutation.

This blood test is now being used in diagnostic algorithms for patients with blood disorders, particularly those with too many white blood cells, red blood cells and platelets. In patients with polycythemia vera (too many red blood cells), JAK2 mutation is found in 90 percent of patients, whereas in patients with too many platelets (thrombocythemia), JAK2 is found to be positive in 60 percent of patients.

Even though this blood test does not replace the gold standard — bone marrow examination — it has added significant value to this group of disorders collectively called as MyeloProliferative disorders (MPDs or bone marrow proliferative disorders). This mutation has been scientifically evaluated and the next step for researchers is to look into the development of a new treatment with anti-JAK2 or JAK2 inhibitors.

At the Atlanta meeting, there was a plethora of activity in the field of MPDs with several scientists presenting their new information. These disorders are often clinically suspected on a routine blood test (CBC — complete blood count) done in doctors’ offices. Patients can have symptoms like fatigue, abdominal pain due to enlargement of spleen, headaches, weakness, dizziness, itching particularly after bathing, redness of the skin particularly face, easy bruising and bleeding. Primary care doctors would refer patients for further testing if they are found to have an abnormality on their routine blood tests.

Mrs. D had a positive JAK2 mutation and was diagnosed to have polycythemia vera — a bone marrow condition where too many red blood cells are manufactured in the bone marrow. Her treatment includes phlebotomy (removal of her blood) on a regular basis. It is important to follow these patients since there is a chance that the blood disorder can transform into leukemia or cause other fatal complications which would require an entirely different approach.

Mrs. D is doing quite well and comes to my office on a monthly basis for her blood tests.

Dr. Nilesh D. Mehta is a board certified medical oncologist practicing in Gurnee. He is clinical associate professor at Rosalind Franklin University in North Chicago.