G. D. Pegrum

Immune complexes in myelofibrosis: a possible guide to management.

Using a fluorescent technique intracellular immune complexes were found in the peripheral leucocytes in all of 12 patients with myelofibrosis studied. Fluorescent cells varied from 12% to 81%; with no relation to the total white count or any obvious clinical finding.

HL-A Antigens on Leukaemic Cells

Summary. The peripheral blood leucocytes from 26 leukaemic patients have been typed using alloantisera which recognize 13 HL‐A specificities. The results show a marked increase in the incidence of HL‐A 3, some increase in certain other HL‐A antigens, and a slighty reduced frequency of HL‐A 2, as compared with a population of healthy volunteers, kidney donors and patients awaiting renal transplantation.

TIMING OF CYCLOSPORIN-A THERAPY FOR ABROGATION OF HVG AND GVH RESPONSES IN RATS

Treatment with cyclosporin A was most effective in abrogating popliteal-lymph-node enlargement induced by host-versus-graft and graft-versus-host reactivity in rats when started before injection of donor-strain lymphocytes. Popliteal lymph-node enlargement was never completely abolished, and splenic lymphocytes from recipients treated with cyclosporin A showed no significant reduction in their response to donor-strain lymphocytes in mixed lymphocyte cultures, suggesting that clonal deletion had not taken place. Mixed lymphocyte cultures also indicated that cyclosporin treatment had not reduced the antigenicity of recipient lymphocytes towards donor strain.

Changes in Antigenic Nature of Lymphocytes Caused by Common Viruses

Healthy human lymphocytes were incubated in the presence of influenza A2/Singapore/57, herpes simplex type 1, or adenovirus type 2. After two days the cultures were inactivated by irradiation. Fresh lymphocytes taken from the same donor were then found to react to the virus-treated cells in short-term cultures. We suggest that this reactivity is due to a change in the surface characteristics of the lymphocytes brought about by the presence of the virus. This may account for anomalous reactions in mixed lymphocyte cultures, and a similar effect in vivo might cause accelerated graft rejection.

THE LYMPHOCYTE IN CHRONIC LYMPHATIC LEUKÆMIA

Abstract The morphological appearances and kinetics of lymphocytes in chronic lymphatic leukaemia are considered together with their reactivity in short-term culture. The findings are discussed with respect to the underlying mechanism of the disease and origin of the leukaemic cells. Despite the heterogeneous cell population, it is possible to demonstrate that the abnormal cells are capable of responding in vitro. Viability appears to be maintained by a factor which can be removed from the cell surface.

The in vitro Effect of Phytohaemagglutinin on Separated Human Bone Marrow Cells

Cells from 60 marrow aspirates were separated using columns of glass microspherules. The effect of PHA on the viability and synthesis of DNA and RNA by these cells was observed after 3 days growth. The synthesis of DNA and RNA was observed before and after culture by means of autoradiographs prepared after exposure to 3H thymidine or 3H uridine. 3H thymidine uptake was low in the initial suspensions and was not increased by the addition of PHA, 3H uridine uptake was increased in only four of 41 cultures stimulated with PHA, and there was a reduction in the number of viable cells in cultures containing PHA.

The effect of phytohaemagglutinin on human foetal cells grown in culture.

Cell suspensions of foetal thymus, liver, spleen and bone marrow have been grown in cell culture and the effect of adding PHA observed. 3H thymidine uptake by the cells after exposure for a measured time was quantitated by autoradiographic counts performed on the initial suspensions and following culture. The initial unstimulated liver and thymic cell suspensions had a high level of 3H thymidine uptake, while that of the spleen and bone marrow cells was low. After 3 days culture the unstimulated cells from the liver, thymus and bone marrow showed very little 3H thymidine uptake, while that of the spleen was slightly increased. Foetal thymic and splenic cells responded to PHA while liver and bone marrow cells did not. The findings suggest that foetal cells of similar morphology may have different origins in the reticulo‐endothelial system.

ASSESSMENT OF HUMAN RENAL TRANSPLANTATION

Abstract A renal-transplant unit was established to work with an existing haemodialysis unit; initially it was decided to adopt a policy of close HL-A matching. Most of the recipients had been on long-term haemodialysis and had received multiple transfusions in the past. Those patients who had not developed antibodies on this regimen had the best prognosis. It is suggested that good matching and prior exposure to blood-transfusion without antibody production are both factors indicating a favourable outcome in renal transplantation. Rejection episodes were also infrequent, and although several tests were used to determine early rejection none was entirely satisfactory. Estimation of urinary fibrinogen-degradation products generally gave the most helpful results.

The Haematological and Histological Findings in 18 Patients with Clinical Features Resembling those of Myelofibrosis

Summary. The presentation and haematological abnormalities in 18 patients with splenic and hepatic enlargement and a leukaemoid or leucoerythroblastic blood picture have been reviewed. The clinical features in each case were consistent with a diagnosis of myelofibrosis. Histological examination of the bone marrow showed myeloid proliferation of various types for which no underlying cause was apparent. On the basis of the bone marrow histology, it was possible to divide the 18 patients in this study into two groups.

In vitro stimulation of chronic lymphocytic leukaemic lymphocytes.

Summary. The response of chronic lymphocytic leukaemic (CLL) lymphocytes to various mitogens in 5‐day cultures has been studied. Concanavalin A (Con.A) and pokeweed mitogen (PWM) were not superior to phytohaemagglutinin (PHA) in their stimulatory activity. Suboptimal levels of PHA and PWM together caused greater RNA synthesis than either mitogen at their optimal levels. The response to PHA could be chanced by the addition of a specific number of red blood cells and by glutathione. Using transformed nuclear material a reaction approaching the level found in normal lymphocytes was attained clearly indicating marked stimulation of the leukaemic cell population.