A 46-year-old man was admitted to our hospital with severe anemia and mild jaundice. The patient's poor state of health continued over the past several years. The erythrocytes were revealed to include spherocytes or stomatocytes under an electron scanning microscope with marked fragility against changes in the osmotic pressure, suggesting the presence of in vivo hemolysis. The leucocyte count was decreased, but 11% of myeloblasts were observed as well as a number of normoblasts. In spite of a pancytopenia in the peripheral blood, marked hyperplasia of erythroid cells with a normal differentiation was observed in the bone marrow. Mature granulocytes, however, were not found in it though 4.8% of myeloblasts were observed. The following tests, were negative: Coombs test, Ham test and antinucleic factor. From these findings, he was thought to have myelodysplastic syndrome. The true blood group was verified to be of an A-type from examinations of A-transferase and saliva, though the erythrocytes were not agglutinated by 33 out of 60 normal sera with A- or B-type randamly sampled. Confirmation of Th-polyaggulutination was established by the reaction with lectins and the erythrocytes, an agglutination with Arachis hypogaea and Polybrene.
This is the second case in Japan which showed Th-polyagglutination of erythrocytes accompanied by myelodysplastic syndrome. The appearance of the Th-antigen on the erythrocyte membranes seems to be associatd with the transformation at the stem cell level.