Pure red cell aplasia (PRCA) or erythroblastopenia refers to a type of aplastic anemia affecting the precursors to red blood cells but usually not to white blood cells. In PRCA, the bone marrow ceases to produce red blood cells.
PRCA is a normochromic, normocytic anemia associated with an extremely low reticulocyte count, with virtual absence of red blood cell precursors in the bone marrow.
It is defined by bone marrow examination and has many different clinical contexts and manifestations.
Incidence only 1 to 2 cases per million per year.
The etiologies that can cause PRCA:
Causes of PRCA include:
Autoimmune disease
Thymoma
Viral infections such as HIV, herpes, parvovirus B19 (Fifth disease), hepatitis, COVID-19, and COVID-19 vaccination.
Lymphoproliferative: T-cell large granular lymphocyte leukemia.
Idiopathic.
Drugs such as mycophenolic acid or erythropoietin.
Congenital-Diamond–Blackfan anemia.
Pregnancy
Primary PRCA is also known as antibody mediated PRCA and is caused by an antibody against the red blood cell progenitors.
Secondary PRCA is almost always a result of an abnormality of the immune system, with many causes.
Diagnosis is suspected when a patient has anemia and an extremely low reticulocyte count of less than 1%, and frequently less than 0.1%.
Bone marrow biopsy is characteristic and shows absence of erythroid precursors, accounting for fewer than 1% of nucleated cells in the bone marrow, and less than 5% of basophilic arrhythmia blasts.
Treatment
Considered an autoimmune disease as it will respond to immunosuppressant treatment such as cyclosporine.
Cyclosporine response rates are roughly 75%.
Corticosteroids may produce responses and 40 to 50% of cases.
It has also been shown to respond to treatments with rituximab and tacrolimus/sirolimus.
In cases caused by parvovirus intravenous immunoglobulins produce a response in more than 9% of patients, although one third of patients will have a relapse.
In Thymoma surgical reception of the thimis leads to a response in approximately one third of cases.
Patients with CLL and lupus require specific therapies.
In refractory PRCA hematopoietic stem cell transplant has been reported.