Erythrocyte enzyme abnormalities in leukemias.

Red cell enzymes were assayed in a total of 67 patient including 24 patients with AML (19 relapse, 5 remission), 16 patients with ALL (10 relapse, 6 remission), 22 patients with CML and 5 patients with blastic CML. Diagnosis of leukemia was based on clinical presentation, peripheral blood smear and bone marrow examination (as per FAB classification). PK activity was significantly high in case of CML and blastic CML (p<0.01). Red cell HK was high in all leukemia subtypes. There was no alteration in red cell G6PD. Notably there was no PK deficiency in AML or G6PD deficiency in ALL. Activities of G6PD and PK could be correlated in cases of CML, AML, (p<0.05) and ALL (p<0.01) i.e. when there was increased activity of G6PD, PK activity also tended to be higher. HK activity showed a positive correlation with PK and G6PD activity in cases of CML (p<0.05), however in acute leukemia there was no such correlation. Alteration of enzyme activities among red cells in leukemia occurred only during relapse. At the time of remission there has been no significant alteration in any of the enzyme activities. It would therefore, appear that enzyme alterations seen in leukemia patients is due to abnormal pluripotent stem cell that has given to a leukemia cell. The fact that enzyme alterations have primarily occurred at the time of relapse would further substantiate that abnormalities of red cell enzymes may be the result of a derivation some circulating red cells from the abnormal pluripotent stem cell. With the recovery of normal stem cells function during remission, enzyme abnormalities tend to become normal.

Rapid screening of PNH red cell populations using the gel test.

Paroxysmal nocturnal hemoglobinuria (PNH), an acquired clonal hematopoietic stem cell defect is underdiagnosed because of its atypical symptoms in some patients and because available methods, which are time consuming and complicated, are not widely used. The purpose of this study is to compare the results of the detection of PNH red cell populations using the PNH gel test and the Ham test. Fifty-eight blood samples obtained from 35 patients and 23 healthy blood donors were tested for PNH by the PNH gel test and the Ham test. It was found that 7 (20%) of the patients were positive for PNH by both tests. Twenty-three blood samples from healthy donors were all negative for PNH by both tests. The overall sensitivity and specificity of the gel test were 100%. This study showed that the PNH gel test was simple and could replace the Ham test as a screening test for PNH. This test would be especially easy to introduce in laboratories that are already using this system for blood grouping and antibody detection.

Laboratory and field comparisons of adenosine influx in Plasmodium falciparum and Plasmodium vivax infected erythrocytes with genetic abnormalities from patients in Myanmar.

Influx of the purine nucleoside, adenosine, was assessed in erythrocytes from both normal subjects and from subjects with a range of genetically determined erythrocyte disorders from Myanmar. The latter included alpha-thalassemia major (Myanmar variant), beta-thalassemia major (Myanmar variant), beta-thalassemia trait, HbEE and HbAE erythrocytes and two variants of glucose-6-phosphate dehydrogenase (G6PDH) deficiency. Significant reductions (p < 0.01) of adenosine influx were observed in erythrocytes from individuals with alpha- and beta-thalassemia major and severe G6PDH deficiency. Abnormal erythrocytes infected with the malarial parasites, Plasmodium falciparum or Plasmodium vivax, demonstrated a reduction in adenosine transport which correlated with the proportion of abnormal erythrocytes present in the samples obtained. The effect of nitrobenzylthioinosine (NBMPR) on adenosine influx was explored in normal and abnormal erythrocytes. In all these cases, NBMPR completely inhibited the transport of adenosine. However, transport of adenosine into P. falciparum and P. vivax-infected normal erythrocytes and abnormal cells was only inhibited 50-60% by NBMPR. The combination of tubercidin and NBMPR completely blocked adenosine transport into both normal and abnormal erythrocytes infected with either P. falciparum or P. vivax.