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BACKGROUND:
Purine nucleoside analogs are a class of antineoplastic drugs with potent
lymphotoxicity against T and B lymphocytes, causing prolonged lymphopenia
and linked to delayed immune complications such as opportunistic infections
and more recently autoimmune hemolytic anemia (AIHA), seen mostly in
patients with chronic lymphocytic leukemia (CLL). A characteristic temporal
relation between fludarabine therapy and the appearance of a warm-reactive
immunoglobulin G (IgG)-mediated AIHA in patients with CLL has been observed
and, in some, the AIHA has been fatal. Whether both fludarabine and
cladribine cause AIHA is uncertain because AIHA is commonly seen in patients
with CLL without the use of these drugs. In contrast, AIHA is encountered in
Waldenstrom's macroglobulinemia (WM) much less frequently, and the
autoantibody is usually cold-reactive and IgM-mediated. In a few reported
cases of AIHA arising in patients with WM after cladribine therapy, there
was a latency of 24 to 60 months between therapy and the onset of AIHA,
three of which were warm-reactive and IgG-mediated.
CASE REPORT:
A warm-reacting IgG red cell autoantibody and evidence of hemolysis detected
1 month after completing cladribine therapy for WM, with warm antibody AIHA
developing 4 months later, are described.
CONCLUSIONS:
Cladribine, like fludarabine, is possibly able to produce this complication
during or early after therapy. Because the use of purine analogs is becoming
increasingly common, it is important to have an awareness of the
complications that can arise during and after treatment. Further
observations of warm AIHA during cladribine therapy are needed to establish
it as a distinct complication.
Reference:
Transfusion. 2006 Jan;46(1):90-4. |