Graft-vs-leukemia and moderation of graft-vs-host reaction in transplantation therapy of viral leukemia.

In transplantation studies of Rauscher leukemic SJL/J mice longer median survival times (MST) were obtained with spleen cells from syngeneic donors than with marrow. These could be further extended by immunization of the donors to Rauscher virus (RLV) and Rauscher leukemia cells. This suggests that spleen cells exert a greater graft-vs-leukemia effect than marrow. Nevertheless, with syngeneic cells all recipients eventually died of leukemia relapse. In contrast, the use of RLV-resistant C57BL/10J allogeneic marrow cells resulted in a substantial number of long-term survivors and a low incidence of GvH disease, while the use of pure allogeneic spleen cells resulted in early and fatal GvH response in all recipients. To determine if allogeneic spleen cells might have any demonstrably beneficial effect on survival of leukemic mice various small quantities of C57BL/10J spleen cells were mixed with marrow from the same donors and engrafted into normal and leukemic SJL/J recipients. Among the normal mice MST decreased as a function of spleen cell concentration. However, with the leukemics the use of 2.5 or 5% spleen cells resulted in later deaths than that found when leukemic mice were given only marrow. Also, for all allogeneic spleen/marrow mixtures tested, survival of leukemic recipients exceeded that of normal recipients given the same cell mixtures. These data suggest a possible beneficial effect of small amounts of allogeneic spleen cells in transplantation therapy for leukemia, and a possible competitive interaction of anti-host and anti-leukemic activities of the transplanted cells leading to a moderation of the GvH response.

Fatal response suggestive of graft-versus-host reaction following transplantation of spleen cells from allogeneic athymic (nude) donors.

Normal female SJL/J mice were exposed to 950 R of total body irradiation (TBI) and transplanted with allogeneic spleen or marrow cells from normal or nude (athymic) C57BL/10 donors. With nude mouse donor marrow, no evidence of graft-versus-host (GVH) response was seen and all SJL/J recipients survived for more than 75 days. In contrast, when spleen cells taken from the same nude C57BL/10 donors were engrafted into SJL/J mice the incidence of fatalities among the recipients was 70% by 60 days. Furthermore, all of the recipients of nude mouse spleen cells showed signs strongly suggestive of GVH response. Comparative fatalities among the recipients of cells from normal donors were 27% for marrow at 60 days and 100% for spleen at 11 days, and these were accompanied by the characteristic signs of GVH response usually seen after transplantation of cells from normal allogeneic donors. Transplantation of normal C57BL/10 marrow mixed with small numbers at normal spleen cells resulted in an increase in the number of fatalities among the SJL/J recipients, and an increase in the severity of the signs of GVH response as compared to that seen following engraftment of normal C57BL/10 marrow alone. However, no such increases in fatalities or severity were observed when similar amounts of nude C57BL/10 spleen cells were engrafted along with normal marrow cells into SJL/J recipients. The results suggest that a factor may exist in nude mouse spleen which in allogeneic transplantation can lead to a fatal response suggestive of GVH reaction, but that nude mouse spleen lacks the T cell-related ability to enhance GVH response that has been previously demonstrated following allogeneic transplantation using normal spleen and marrow donors.

Histocompatibility influence in allogeneic marrow transplantation therapy of murine viral leukemia. I.--Studies of the relative influence of major versus minor histocompatibility determinants.

The anti-leukemic effectiveness (GvL activity) and anti-host response (GvH response) of several allogeneic donor marrows were compared in lethally irradiated normal and Rauscher leukemia SJL/J recipients. Although both types of effects could be demonstrated, the degree of GvL activity did not parallel the severity of GvH response. The level of GvL activity of the donor marrow also appeared to be independent of sensitivity of the donors to the leukemia inducing Rauscher virus (RLV), as a high level of leukemia recurrence was found using marrow from RLV-resistant RF/J donors, while a lesser degree of recurrence occurred with the use of RLV-sensitive DBA-2J marrow. Analysis of the possible influence of major (MHC) and Minor (MiHL) histocompatibility loci suggested that GvL activity may be independent of the H-2 locus, and that the "a" alleles of the H-4 and H-13 loci may not be contributing to GvL effect. Likewise the "a" alleles of the H-7 and H-12 loci did not appear to affect the severity of GvH response. The possibly that GvL activity may be independent of th MHC, but governed by MiHL possibility different from those regulating GvH response might explain why in this and previous studies GvL activity could only be demonstrated following allogeneic marrow transplantation but did not appear to correlate with severity of GvH response.

Potentiating effect of benzo[a]pyrene and caffeine on Friend viral leukemogenesis.

The effect of exposing mice to both a chemical carcinogen and leukemia virus with and without an inhibitor of DNA repair were compared. The data indicated that benzo[a]pyrene (BP) could exert a potentiating effect of Friend viral leukemogenesis in mice, which was dependent on the relative times of administration of the chemical and virus. The addition of caffeine as an inhibitor of DNA repair further enhanced the potentiating effect of BP on the leukemia, but in the absence of BP, caffeine showed no carcinogenic effect either when given alone or in conjunction with Friend leukemia virus.

Methyl methane sulfonate induced enhancement of Friend viral leukemogenesis.

Exposure to the chemical carcinogen, methyl methane sulfonate, enhanced leukemogenesis in mice given threshold doses of Friend leukemia virus, as shown by peripheral white blood cell counts, splenomegaly and survival.

Effect of Rauscher leukemia development on DNA synthesis by hematopoietic CFU-S.

The effect of Rauscher viral leukemia on the number of colony forming cells (CFU-S) in the spleen has been measured as a function of time after virus administration. These were increased substantially after the first week, reaching a maximum at 2 weeks, after which they decreased in number. Determination of the proportion of these CFU-S which were in DNA synthesis was carried out using the in vitro 3HTdR suicide technique. Within 4 hours of injection of the virus the number of spleen CFU-S which could be inactivated by in vitro 3HTdR exposure increased to 20.9% from a normal mean value of 10.2%. For the next 2 weeks the proportion of CFU-S responding to tritiated thymidine exposure remained at the same value of approximately 20%; the change in number of surviving CFU-S roughly paralleled the change in total colony forming cells. In the third week after virus injection, the proportion of CFU-S which was inactivated by 3HTdR decreased to the point where it could no longer be detected, even though the total number of CFU-S was elevated several fold over the normal. These findings indicate that infection with moderate dose levels of Rauscher virus does result in a measurable early increase in the proportion of cells in DNA synthesis. However, the failure to detect further substantial increases as the disease develops suggests that the virus of itself is not an initiator of all the steps of DNA synthesis. Rather, it would appear that it is to some degree dependent upon other aspects of normal DNA synthesis which remain under control of the cell.

Effect of antiserum on transplantable hematopoietic colony-forming units during Rauscher leukemia development.

Studies have been carried out to determine the sensitivity of hematopoietic CFU-S from Rauscher leukemic mice to an antiserum against the disease prepared in syngeneic mice. Test of this antiserum against Rauscher virus prior to injection showed it to be effective both in vitro and in vivo. At the same time, normal serum was shown to be without effect either against the CFU-S or against the virus. Spleen CFU-S were obtained from control and leukemic mice over a sequence of days following Rauscher virus injection and assayed by transplantation technique. Prior to transplantation these were incubated in vitro in either normal syngeneic serum or syngeneic antiserum. Incubation with antiserum had no effect on CFU-S obtained from the spleens of normal mice. However, incubation in this antiserum of spleen CFU-S from Rauscher leukemic mice resulted in a reduction of up to 50% in their colony-forming ability. Additional tests with guinea pig complement suggested that the levels of inactivation seen are not complement limited. This antiserum-induced reduction in colony formation was first evident in the second week after the injection of virus, coincident with the onset of splenomegaly in the leukemic mice. Thereafter, sensitivity of CFU-S to the antiserlm could be detected up to the terminal point of the leukemia (44 days).

Iron metabolism in patients undergoing regular dialysis therapy.

Thirteen patients with chronic renal failure maintained on regular renal dialysis were studied. Seven proved to have iron deficiency on the basis of marrow iron studies, reticulocyte iron uptake, and saturation of the serum iron-binding capacity. They absorbed iron when given it by mouth and were able to utilize it for haemoglobin formation. Iron-deficient patients given 600 mg of ferrous sulphate daily for three months showed an increase in haemoglobin, but the failure to replace stores of iron is probably related to their relatively limited ability to absorb iron and the variable but sometimes considerable blood loss occurring with each dialysis.The loss may be occult, and prolonged iron therapy may be required. This is most safely achieved by giving iron by mouth.

Semi-automated micromethod for estimating the unsaturated iron-binding capacity of serum using radioactive iron.

A semi-automated micromethod for the determination of the unsaturated iron-binding capacity (UIBC) of serum using radioactive iron and magnesium carbonate as an adsorbing substance is presented. The method has the advantage of simplicity and speed. The determination of UIBC is carried out on 0.1 ml of serum in duplicate, using autodiluters, at the rate of up to 200 sera per day. The reproducibility of the presented method is comparable to the reproducibility of other methods for the determination of iron-binding capacity. As the method is a simple one it can easily be introduced into laboratories with facilities for radioactive counting.