Infectious Mononucleosis: Increase of High-Affinity E-Receptor-Bearing Lymphocytes

The increase of T lymphocytes in infectious mononucleosis (IM) is shown to be due to an increase of ‘active’ (early erythrocyte rosette-forming) T cells: 67.2 ± 18.3% of IM lymphocytes were ‘active’ versus 34.7 ± 14.9% of control lymphocytes. IM was also associated with an increase of lymphocytes demonstrating E receptors at 20°C (E&lt;sub&gt;20&lt;/sub&gt;-R)·This phenomenon was not related to the heterophile antibody titre and could not be demonstrated with ox or rabbit erythrocytes. Patients with other lymphoproliferative diseases did not show an increase of E&lt;sub&gt;20&lt;/sub&gt;-R-positive cells or of ‘active’ erythrocyte rosette-forming cells (E-RFC). Re-rosetting experiments indicated that E20-R and ‘active’ E-RFC belong to overlapping populations of cells. A double-gradient separation technique was shown to be superior to the conventional Ficoll-Isopaque method for the demonstration of ‘active’ and total T cells. A high proportion of T lymphocytes were also recovered in the granulocyte layer by this technique, indicating a selective loss of these cells by the conventional technique.</jats:p

Light-induced release of protoporphyrin, but not of zinc protoporphyrin, from erythrocytes in a patient with greatly elevated erythrocyte protoporphyrin

Abstract A patient with greatly increased erythrocyte protoporphyrin, but normal porphyrins in urine and feces, is described. The patient later developed a malignant lymphoma, and the reason why she accumulated protoporphyrin in her erythrocytes is not known. The protoporphyrin in the erythrocytes consisted of two types of protoporphyrin, free protoporphyrin (30%) and zinc protoporphyrin (70%). Upon irradiation of erythrocytes in the absence of albumin, protoporphyrin and zinc protoporphyrin, which were both bound to hemoglobin, were released. In contrast, when the irradiation was carried out in the presence of albumin, the photohemolysis was negligible, and there was release of free protoporphyrin, but not of zinc protoporphyrin, from the erythrocytes. In vivo albumin is present in the plasma and the results may help to explain why patients with erythropoietic protoporphyria (erythrocytes containing free protoporphyrin) are photosensitive, whereas patients with lead intoxication and iron deficiency (erythrocytes containing zinc protoporphyrin) are not.</jats:p

Sideroblastic anemia with markedly increased free erythrocyte protoporphyrin without dermal photosensitivity

Abstract A patient with idiopathic sideroblastic anemia and atypical clinical and biochemical findings is described. He had a greatly increased erythrocyte and plasma protoporphyrin, but normal urine and fecal porphyrins. The erythrocyte protoporphyrin had a fluorescence spectrum typical of free protoporphyrin, but caused no photosensitivity. Bone marrow metal chelatase activity was normal. There were no clinical signs of liver disease. The abnormal porphyrin metabolism in this patient is not known though a number of explanations are discussed.</jats:p

Light-induced release of protoporphyrin, but not of zinc protoporphyrin, from erythrocytes in a patient with greatly elevated erythrocyte protoporphyrin

A patient with greatly increased erythrocyte protoporphyrin, but normal porphyrins in urine and feces, is described. The patient later developed a malignant lymphoma, and the reason why she accumulated protoporphyrin in her erythrocytes is not known. The protoporphyrin in the erythrocytes consisted of two types of protoporphyrin, free protoporphyrin (30%) and zinc protoporphyrin (70%). Upon irradiation of erythrocytes in the absence of albumin, protoporphyrin and zinc protoporphyrin, which were both bound to hemoglobin, were released. In contrast, when the irradiation was carried out in the presence of albumin, the photohemolysis was negligible, and there was release of free protoporphyrin, but not of zinc protoporphyrin, from the erythrocytes. In vivo albumin is present in the plasma and the results may help to explain why patients with erythropoietic protoporphyria (erythrocytes containing free protoporphyrin) are photosensitive, whereas patients with lead intoxication and iron deficiency (erythrocytes containing zinc protoporphyrin) are not.</jats:p