Methotrexate and citrovorum factor after histoincompatible allogeneic bone marrow transplants in dogs.

Methotrexate (MTX) followed by citrovorum factor (CVF) rescue was evaluated for its effectiveness in reducing graft-versus-host disease (GVHD) in lethally irradiated dogs transplanted with bone marrow from unrelated histoincompatible donors. Animals were given no immunosuppressive therapy (group A) or a combined regimen of MTX and CVF (group AMC). These two groups were compared with a group of animals transplanted earlier given MTX alone (group AM). Ainmals in the AMC group lived significantly longer than the A group (p less than 0.05). Engraftment rate, hematopoietic recovery and incidence of GVHD were similar in all three groups. Incidence of early deaths was significant in the AM group (p less than 0.05). It is concluded that MTX combined with CVF increases survival and is an effective posttransplantation immunosuppressive regimen with minimal toxicity.

Canine migration inhibitory factor: effect of Corynebacterium parvum administration.

Peripheral blood lymphocytes from dogs sensitized to streptolysin O (SLO) were assayed for migration inhibitory factor (MIF) production by the indirect MIF test, using guinea pig peritoneal exudate cells as the source of macrophages. A specific direct correlation was established between the degree of inhibition of migration and the concentration of SLO-stimulated supernatants from lymphocyte cultures (SLO-S) of untreated normal dogs. Undiluted SLO-S inhibited migration by 66.8%, whereas a dilution of 1:64 elicited a 3% inhibition. In parallel tests, purified protein derivative stimulation of lymphocytes from BCG-vaccinated dogs produced 92.6% inhibition. The effect of Corynebacterium parvum on SLO-specific MIF production was evaluated in three groups of dogs administered a single intramuscular injection of C. parvum at 5 or 50 mg/m(2) or 50 mg/m(2) in suspension with 10 mg of methylprednisolone. Inhibition of migration of macrophages exposed to a 1:4 dilution of SLO-S from dogs inoculated with C. parvum (5 mg/m(2)) was 33% greater (mean inhibition, 75%) than the same SLO-S dilution from uninoculated normal dogs (mean inhibition, 42%) (P < 0.0002). Similarly, lymphocytes from dogs administered 50 mg/m(2) caused an enhancement of migration inhibition, with a mean increase of 26% over controls (P < 0.002), whereas a dose of 50 mg/m(2) with methylprednisolone produced a 16% increase in migration inhibition (P < 0.05). The administration of C. parvum resulted in a three- to fourfold increase in the SLO-S dilution, which would reduce migration by 20% (MIF titer). This increase peaked between days 20 and 30 and lasted over 50 days post-C. parvum inoculation. These findings indicate that C. parvum specifically increases MIF production by canine lymphocytes in a linear correlation with SLO concentration and suggest its use as a stimulant of canine immunity.

Successful granulocyte transfusion therapy for gram-negative septicemia. A prospectively randomized controlled study.

We prospectively randomized 27 granulocytopenic patients who experienced a total of 30 episodes of gram-negative septicemia. The control group received an appropriate antibiotic regimen alone, whereas the "transfusion" group received infusions of granulocytes in addition to the antibiotics. Five of 14 controls survived, and 12 of 16 in the transfusion group survived, and 12 of 16 in the transfusion group survived (P less than 0.04). An important factor in the outcome of treatment was the recovery of bone-marrow function (return of peripheral granulocyte count greater than or equal to 1000 per microliter). Eighty-three per cent (five of six) of the control group and all (four of four) of the transfusion group with recovery of granulocyte levels survived the episode of sepsis. In contrast, none of the eight control patients, as compared to 67 per cent (eight of 12) of the transfusion group, survived persistent granulocytopenia (P less than 0.005). Granulocyte transfusions appear to complement appropriate antibiotic treatment of gram-negative-septicemia due to granulocytopenia.

Canine allogeneic bone marrow transplantation. Technique and variables influencing engraftment.

We have studied the toxicity and immune suppression of supralethal total body irradiation (800-2000 rads, 60Co) at three dose intensities (10 rads/min, 49 rads/min, and 100 rads/min). In 79 intensively supported radiation control animals, the LD50(5) (tn 5 days) for these dose intensities is estimated to be 1556, 941, and 921 rads, respectively. A biomodal pattern of early (median 4 days) and late (median 9 days) deaths was observed corresponding to histopathological evidence of the intestinal and hematopoietic radiation syndromes. Random donor bone marrow transplants were performed in 83 animals to test immune suppression afforded by 800 rads and 1000 rads at dose intensities of either 10 rads/min or 49 rads/min. Bone marrow cell dose was varied to analyze its effect on engraftment. A greater degree of immunosuppression with less toxicity was achieved at the lower dose intensity. A minimum dose of 3-5 X 10(8) nucleated allogeneic bone marrow cells/kg (readily obtainable from living donors) resulted in a high percentage of engraftment with lethal graft-versus-host disease following conditioning with 1,000 rads midplane at 10 rads/min, the optimum regimen employed.

Correction of poor platelet transfusion responses with leukocyte-poor HL-A-matched platelet concentrates.

Matching donor-recipient pairs for HL-A antigens provides a logical starting point for selecting donors for recipients with extensive prior transfusion histories. However, during the course of continued exposure to even HL-A-matched platelet concentrates, further sensitization occurs, as indicated by progressively poorer post-transfusion increments and transfusion reactions. There is evidence that such sensitization may be due to non-HL-A antigens. Finally, it is postulated that the poor post-transfusion platelet increments obtained when standard platelet concentrates are used result from the leukoagglutinin antigen-antibody reaction involving the platelet as an "innocent bystander." The standard platelet concentrate can be purified by a simple method of centrifugation (178 g times 3 min), removing about 96% of the contaminating white blood cells with concomitant loss of about 21% of the platelets. The use of these leukocyte-poor platelet concentrates can restore compatible transfusion increments in highly alloimmunized thrombocytopenic recipients. The luekocyte-poor concentrates can diminish undesirable transfusion reactions following imcompatible platelet transfusions.