Specific testing for a rare type of multiple myeloma is available at a handful of reference labs across the country, but it takes extra time and expense that may not be necessary and likely will delay the start of treatment.
The broad range of nonspecific symptoms for multiple myeloma, like pain in your bones, weakness, fatigue, feeling very thirsty, frequent infections and fevers, changes in how often you pee, confusion, etc., tend to be the same across all types.
This type of blood cancer accounts for about 1% of multiple myelomas and has a worse prognosis. With multiple myeloma, the immune cells produce a single dysfunctional antibody, called an M spike, which leaves us vulnerable to infection and can even attack our bones.
Normally the antibody has two light chains, which is where healthy antibodies attach to whatever they are attacking. Light chains hook up with heavy chains, which are different, literally larger proteins that form the base of the Y.
Blood Cancer Eating Up Kidneys
While more light chains are always produced with this blood cancer, particularly with IgD, excessive numbers are produced that don’t pair up with heavy chains per usual and consequently end up moving freely about in the blood and inundating the kidneys, which normally filter about a half cup of blood every minute, according to the National Institute of Diabetes and Digestive and Kidney Diseases.
Dialysis with a special filter to capture light chains can prevent kidney damage and chemotherapy can further reduce the number of damaging light chains.
What’s So Special In Blood Cancer Testing?
In a retrospective review of more than 600 patients with multiple myeloma over 20 years at AU Medical Center, the adult teaching hospital affiliated with MCG, Singh and his colleagues identified only four patients with the rare IgD multiple myeloma.
But test findings were consistent in all four and are a red flag to physicians that it’s likely IgD myeloma and that aggressive treatment is urgently needed.
These patients had a mortality rate nearly three times that of patients with other forms of this blood cancer. They had higher rates of kidney damage and dialysis among the 600 patients whose courses were reviewed.
The patient will go ahead and start an antibiotic course but will still be given a test to determine the specific bacterium. Like that test for a specific bacterium, an IgD-specific test typically won’t alter, only delaying treatment.
The next steps should include clinical trials, comparing patient outcomes when the IgD specific testing is used and when these earlier indicators serve as clues to get started on treatment.
Source: Medindia
