Peter W. Marks, MD, PhD
2009-12-05
Those who attend the Education Program Session on hemolytic anemias today from
9:30 to 11:00 a.m. or tomorrow from 7:30 to 9:00 a.m. in room E-3 of the Ernest
N. Morial Convention Center will have the opportunity to learn about the impact
of drugs and bugs on the red blood cell.
Drug-induced immune hemolytic anemia (DIIHA) can occur with a broad range
of pharmacologic agents — more than one hundred specific compounds have
now been implicated. Dr. George Garratty of the American Red Cross Blood Service,
Southern California Region, will review the drugs involved and mechanisms of
DIIHA. In addition to reviewing well-described drug-dependent and drug-independent
mechanisms, Dr. Garratty will also discuss a more recently identified mechanism
of hemolysis: non-immune protein absorption (NIPA). In this case, modification
of the red blood cell membrane surface by pharmacologic agents leads to coating
of the red blood cells non-specifically with immunoglobulins or other plasma
proteins ultimately leading to hemolysis. Dr. Garratty will also provide some
clinical pearls regarding specific offending agents; as he notes in the ASH
Education
Book, "Cefotetan represents more than 50 percent of the DIIHA that you
are likely to encounter."
Dr. Philip Hoffman of the University of Chicago will discuss selected topics
regarding immune hemolytic anemias. The hot topics in the field that he has
selected include: 1) unusual aspects of the epidemiology of autoimmune
hemolytic anemia
(AIHA), such as the association with fludarabine therapy, allogeneic stem
cell transplantation, or blood transfusion; 2) complications of autoimmune
hemolytic
anemia; and 3) therapy of refractory cases of autoimmune hemolytic anemia.
Dr. Hoffman will highlight the relative frequency and morbidity of venous
thromboembolic
events in patients with AIHA and the importance of considering strategies
to prevent VTE in this setting. Finally, he will review treatment of refractory
cases of AIHA, covering some things old and some things new: from immune
globulin
and danazol, to rituximab and mycophenolate mofetil.
The session will conclude with a discussion of malaria, erythrocytic infection,
and anemia. Dr. Kasturi Haldar of the Center for Rare and Neglected Diseases
at University of Notre Dame will describe how malaria parasites remodel the
red cell for their own use, leading to a "chronic dynamic imbalance of
immune and erythropoietic response." An exacerbation of the hemolytic anemia
by suppression of red cell production also appears likely, mediated by cytokines
and other mediators of inflammation rather than erythropoietin deficiency.
The
anemia of malaria may also be exacerbated by co-infections, such as those with
helminths or HIV.
Those who attend this session will have a better appreciation of the relevance
of hemolytic anemias across the field of hematology, from those caused by
drugs to those by bugs.
Dr. Marks indicated no relevant conflicts of interest.
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