In a prospective study the efficacy of two regimens for selective decontamination of the digestive tract was studied in patients with acute leukaemia during remission induction therapy. Seventy-eight patients were randomized to receive either a combination of cotrimoxazole, polymyxin B and nystatin (group A) or a combination of nalidixic acid, polymyxin B, neomycin and nystatin. With both regimens the gastrointestinal tract could be decontaminated equally effectively from potential pathogens. In the oropharyngeal region the decontamination from Enterobacteriaceae was significantly better in group A (P less than 0.01). In both groups less than 10% of the acquired infections were caused by gram-negative bacilli and no gram-negative septicaemia occurred in either group. The median time interval until the first acquired infection was 17 days in group A and 36 days in group B, respectively (P less than 0.05). It is concluded that regimen A might be more effective than regimen B though both regimens prevent reliably severe gram-negative infections.

Bone-marrow transplantation (BMT) from an unrelated, HL-A-phenotype-identical, MLC-negative donor was performed in a 31 year old woman with severe longlasting aplastic anemia. In vitro assays failed to demonstrate humoral or cellular sensitization of the recipient against donor-type antigens. Following conditioning with cyclophosphamide, prompt but only transient engraftment of the transplant occurred accompanied by signs of mild graft-versus-host-disease (GVHD) of the liver. The results of a second bone marrow transplantation from the same donor cannot be evaluated due to early death of the recipient. It is concluded that bone marrow from unrelated, HL-A and MLC-identical donors may engraft without severe GVHD. Rejection of the graft in our patient may have been related to greater antigenic differences that can be expected to exist between HL-A and MLC-identical unrelated individuals than between HL-A and MLC-identical siblings. However, insufficient preparative immunosuppression with cyclophosphamide due to severe hepatic hemosiderosis appears equally likely as the cause of graft rejection. The possibly increased risk of graft rejection or severe GVHD should not preclude the use of unrelated HL-A and MLC-identical marrow donors, when histocompatible sibling donors are not available; but more potent immunosuppressive regimens than the cyclophosphamide protocol may be necessary to ensure permanent engraftment.

A simple continuous filtration leukapheresis has been devised whereby two Leuko-Pak filters can be charged and eluted within 5 h with approximately 121 of blood in a closed system of tubes. Blood flows by means of gravity without the use of pumps. Without premedication with prednisolone the average yield from 10 donors was 3.66 x 10(10) granulocytes per leukapheresis and after premedication with 150 mg prednisolone orally it was 6.44 x 10(10) granulocytes per leukapheresis. The in vitro function of filter granulocytes was not reduced even after premedication with prednisolone. In comparison with leukapheresis by blood cell separators this modified method of filtration leukapheresis offers the following advantages: 1) the granulocyte yield per litre of whole blood processes is higher, 2) technical assistants in a blood-bank can carry out the method on several donors simultaneously, 3) the method is more economical than leukapheresis by blood cell separators.

The pathogenicity of microorganisms isolated by surveillance cultures, the neutrophil count in the peripheral blood, and the interaction of the two factors were analyzed as risk factors for infections of the oropharynx and the respiratory tract in patients with acute leukemia being treated in strict reverse isolation under antimicrobial modulation. A statistical method was developed for the identification of bacteria, the presence of which was correlated with an increased risk of infection. A significantly increased risk was found mainly for species of Klebsiella, Enterobacter, Proteus, and Pseudomonas. The degree of neutropenia was significantly correlated with the risk of infection, which was influenced by the microbiologic state of the oropharynx. Thus, patients with gram negative bacilli had significantly more days with infection at all levels of neutropenia than patients without gram-negative bacilli. These two risks factors were additive but did not potentiate each other.

Hemopoietic stem cells were collected from blood by means of continuous-flow centrifugation. The therapeutic use of large quantities of autologous blood stem cells requires a suitable, reliable and easily practicable cryopreservation technique which prevents loss of cell number and viability. This paper describes a closed plastic bag system consisting of one part for the collection and freezing of blood-derived mononuclear cells (MNC), among them granulocyte/macrophage progenitor cells (CFUc), and of a second part for thawing the cryopreserved cells and washing them free of DMSO before transfusion to a patient. In a series of 20 leukaphereses, the average number of collected MNC and CFUc was about 11 x 10(9) and 8 x 10(5) respectively. The recovery rate of the leukapheresis derived MNC and CFUc after cryopreservation, thawing, and washing was demonstrated to be 90 per cent of better. Sequential leukaphereses in the same donor showed little effect on red and white blood cell concentration. However, there was a significant decrease in the donor's blood platelet concentration prior to the third leukapheresis.