The association of Tn and leukemia.

Tn polyagglutination or persistent mixed field polyagglutination is a rare acquired erythrocytic state which has been associated with haematologic abnormalities including four reported cases of acute leukaemia. Recent information has proven that the abnormality is clonal and the haematologic findings suggest a mutation of a somatic stem cell. The red cell membrane defect results from a deficiency of B-3-D galactosyltransferase. Tn polyagglutination has been described in patients presenting with acute leukaemia and has preceded acute leukaemia. The Tn syndrome has similarities to other forms of preleukaemic syndromes including paroxysmal nocturnal haemoglobinuria. Patients with Tn should be carefully monitored, although there is little justification for any specific therapy at the present time.