A patient with homozygous beta delta thalassemia developed a severe cold he
magglutinin disease with reticulocytopenia. Acute parvovirus B19 infection
was suspected because of the presence of anti-B19 IgM in serum and viral DN
A analysis in bone marrow. Evidence of recent B19 infection should be sough
t in patients with autoimmune hemolytic anemia and reticulocytopenia.