Positive Coombs test in acute leukaemia

Direct Antiglobulin Test Positivity in Children With Acute Lymphoblastic Leukemia at Diagnosis

Direct antiglobulin test positivity had been reported in the course of some lymphoproliferative neoplasms. However, there are a few case reports describing direct antiglobulin test (DAT) positivity in children with acute lymphoblastic leukemia (ALL). We herein report 8 patients who had positive DAT among 95 newly diagnosed children with ALL. None of these patients had evidence of hemolysis during the follow-up. An antibody was detected in 2 of 8 patients with positive DAT. These 2 children also had positive indirect antiglobulin test (IAT); an autoantibody that was reactive at 4°C, and an alloantibody (anti E) that was reactive at 37°C was detected. We believe DAT positivity in ALL without significant hemolysis is not a rare disorder, and a need for further prospective studies is apparent.

Autoimmune hemolytic anemia preceding T-ALL in a five-year-old girl

A 5-year-old girl developed acute lymphoblastic leukemia (T-ALL) 15 months after being diagnosed with autoimmune hemolytic anemia (AHA), while AHA was in partial remission. AHA was mediated by warm antibodies. Because AHA could not be controlled during the induction therapy of ALL, she was administered immunoglobulin G and plasmapheresis was performed. Hepatomegaly dissappeared in the 4th month. However, anemia requiring blood transfusion, positive direct Coombs' test, and splenomegaly dissappeared in the 13th month of the leukemia treatment; reticulocytosis and decreased haptoglobin level persisted. AHA exacerbated in the 24th month of the ALL therapy. Prednisolone was started but the family refused to continue the therapy. This case presents some features that were not reported before, such that ALL was preceded by AHA and involved T-cell lineage, AHA was mediated by warm antibodies, and the two disorders took place in childhood.

Positive direct antiglobulin test due to antiphospholipid antibodies in normal healthy blood donors

OBJECTIVES

Positive direct antiglobulin tests (DAT) occur occasionally, without obvious cause, among normal blood donors. This is sometimes associated with a false-positive serologic test for syphilis. Positive DATs due to antiphospholipid antibodies (APAbs) are well documented in the antiphospholipid syndrome with systemic lupus erythematosus and the primary antiphospholipid syndrome.

METHODS

Using conventional haematologic and serologic methods, we tested 474,545 normal blood donors in the west of Scotland during the years 1991 through 1993.

RESULTS

We identified 42 normal blood donors with a positive DAT and observed three who had positive DATs and false-positive VDRL tests, all of whom expressed raised APAbs.

CONCLUSION

APAbs may be an incidental cause of positive DATs among healthy blood donors.

Autoimmune hemolytic anemia in patients with de novo acute myelocytic leukemia

Autoantibody against erythrocytes has occasionally been observed in patients with de novo acute myelocytic leukemia (AML). However, it is not clear whether this autoantibody in AML patients induces frank hemolysis (autoimmune hemolytic anemia, AIHA), as seen in lymphoid neoplasms. We present two de novo AML patients who showed hemolysis due to antiglobulin test-positive and test-negative AIHA, respectively. AIHA should be considered as one cause of anemia in de novo AML patients, and blood transfusions should be given carefully in such cases to avoid harmful hemolysis.