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Forty-nine patients with severe aplastic anemia, 33 due to unknown cause, 11 drug or chemical related, 2 associated with hepatitis, 1 with paroxysmal nocturnal hemoglobinuria, and 2 possibly associated with Fanconi syndrome did not show recovery after 0.5–96 (median 2) mo of conventional therapy. Twenty-two were infected and 21 were refractory to random platelet transfusions at the time of admission. All were given marrow grafts from HLA-identical siblings. Forty-five were conditioned for grafting by cyclophosphamide (CY), 50 mg/kg on each of 4 successive days, and four by 1000 rad total body irradiation. All were given intermittent methotrexate therapy within the first 100 days of grafting to modify graft-versus-host disease (GVHD). Three patients died from infection too early to evaluate (days 1–8). Forty-six had marrow engraftment. Of these, 20 are surviving with good peripheral blood counts between 186 and 999 days, and 18 have returned to normal activities. Chronic GCHD is a problem in five. Twelve patients died of infection following rejection of the marrow graft. Twelve patients died with bacterial or fungal infections or interstitial pneumonia and active GVHD or soon following resolution of GVHD. Two patients died with marrow engraftment and no GVHD, one with an interstitial, and the other with a bacterial pneumonia. Thirty-six patients who had received random donor blood transfusions were randomly assigned to receive either CY or procarbazine-antithymocyte globulin-CY as conditioning regimens to test whether the incidence of graft rejection could be decreased. There was no difference in the incidence of graft rejection between the two regimens. In 13 patients with rejection, second transplants were attempted either with the original marrow donor (9 patients) or another HLA-identical sibling (4 patients). Three of these transplants were not evaluable, seven were unsuccessful and three were successful with only one of the three surviving for more than 468 days. In conclusion, the long-term survival of 41% of the patients in the present study is similar to that achieved in our first 24 patients, and confirms the importance of marrow transplantation for the treatment of severe aplastic anemia. Marrow graft rejection, GVHD, and infections continue to be the major causes of failure.

Ablation of the bursa of Fabricius in the chicken at different times and by different techniques was carried out to assess the relative effects on production of antibodies to SRBC and of IgM and IgG. In confirmation of previous work, IgG and IgG antibody production were readily inhibited by bursectomy. In contrast, IgM production was increased by the methods used unless irradiation was added. Dipping eggs in testosterone propionate at 3 days of incubation, which completely prevented development of the bursa, resulted in IgM levels at 14 wk that were 4 × those of controls but not accompanied by any increase in the level of IgM anti-SRBC. The results indicate that: 1) the bursa has a major role in the maturation from IgM to IgG synthesis, and 2) the bursa is not essential for antibody and immunoglobulin production.

Human marrow transplantation has resulted in observations of fundamental significance in understanding both aplastic anemia and acute leukemia. For example, the observation that transplanted marrow can grow successfully in patients with aplastic anemia indicates that the disease is due to a defect in the marrow precursor cells and not in the marrow microenvironment. Similarly, the observation of recurrent leukemia in donor cells has important implications. Nonetheless, marrow transplantation is sufficiently established therapeutically to be considered the treatment of choice for patients with severe aplastic anemia, and a realistic alternative for patients with recurrent acute leukemia. We suggest that patients be managed with regard to marrow transplantation according to the general approach outlined in Table 3. Marrow transplantation and histocompatibility typing are available at increasing numbers of institutions throughout the world. More and more patients with either severe aplastic anemia or recurrent acute leukemia should have marrow transplantation available to them when it is indicated as part of optimal management of these no longer hopeless diseases.

Twenty-five dogs with malignant lymphoma (L) and 18 dogs with solid, nonhematologic tumors (ST) were treated with 1200 R total body irradiation (TBI). Rescue from the otherwise lethal hemopoietic toxicity by infusion of autologous marrow aspirated before TBI was attempted, and survival, response to TBI, and immune reactivity post-grafting were determined. Eight L dogs survived more than 14 days post TBI and marrow grafting, and 12 out of 19 evaluable dogs showed a decrease of 75 per cent or more in clinically detectable tumor. There was no evident relationship between clinical status or marrow status before TBI and survival of more than 14 days or tumor response to TBI. Seven of the 8 survivors ultimately developed recurrent tumor. Eight ST dogs survived more than 14 days. Only 4 of 14 evaluable ST dogs showed significant clinical response of their tumor to TBI. Humoral and cellular immune reactivity were significantly impaired during the 10-week period following TBI and marrow grafting in all dogs studied. These results indicate that therapy in addition to lethal doses of TBI is necessary to cure spontaneous L or to significantly affect ST in dogs. They also provide baseline data which are necessary to assess the immunotherapeutic effectiveness of allogeneic marrow grafts.

Canine radiation chimeras were used to investigate further mechanism(s) responsible for maintaining the stable chimeric state. Chimeras were studied 7 to 46 months after 1200 R total body irradiation and transplantation of marrow from a littermate donor matched at the major histocompatibility complex. An attempt was made to perturb the stable chimeric state by infusion of large numbers (0.6 to 13.7 x 10(8)/kg) of donor peripheral blood lymphocytes into each respective chimera. Two groups were studied: donors in Group A were normal; donors in Group B had been specifically sensitized against minor histocompatibility antigens of the chimera by repeated skin grafts. None of the nine chimeras in Group A developed significant clinical or histologic evidence of graft-vs-host disease (GVHD) after donor lymphocyte infusion. Eight of the 12 chimeras in Group B, however, developed GVHD which was transient in three and fatal in five. The results in Group A are not consistent with classical theories of tolerance, i.e., elimination or inactivation of potentially reactive cell clones, but suggest the presence of an active mechanism suppressing recognition of host antigens by the infused donor lymphocytes and development of GVHD. The results in Group B indicate that this mechanism can be overcome by infusion of sensitized donor cells. In an attempt to elucidate the nature of this postulated active mechanism, the cytotoxicity of donor lymphocytes for fibroblasts of the chimera and the presence or absence of serum-blocking factors were assessed in vitro by using a cellular inhibition (CI) assay. The presence of serum-blocking factors did not protect against the development of significant GVHD in two chimeras (fatal in one). GVHD did not occur in four other chimeras after infusion of cytotoxic donor lymphocytes despite the absence of serum-blocking factors. These and previous results suggest that serum-blocking factors are not the mechanisms suppressing the development of GVHD in canine radiation chimeras, and raise the possibility that a suppressor cell population may be responsible for preventing GVHD.

This clinicopathologic study of patients with chronic graft-versus-host disease (GVHD) after allogeneic marrow transplantation emphasizes the most prominent feature of the syndrome, the cutaneous aspects, and describes the ophthalmic-oral sicca syndrome with sialoadenitis and the neurologic findings. Chronic cutaneous GVHD affected 19 of 92 recipients surviving 150 days or more. In 6 patients chronic GVHD presented as a continuation of acute GVHD; in 8 it occurred after the resolution of acute GVHD; and in 5 it arose without preceding acute GVHD, ie, de novo late onset. Two cutaneous types were distinguished. The generalized type affected 16 patients and ran a progressive course resulting in late complications of poikiloderma, diffuse dermal and subcutaneous fibrosis, and contractures. Microscopically, it resembled generalized morphea and lupus erythermatosus hypertrophicus et profundus. The local type affected 3 patients with a more variable picture of poikiloderma, dermal sclerosis, and contractures. Microscopically, it resembled lupus of erythematosus profundus and scleroderma. Guidelines for defining and subclassifying chronic cutaneous GVHD are proposed.

The morphology of graft-versus-host disease (GVHD) in canine radiation chimeras was studied by examination of autopsy tissue from 95 dogs including: 1) 13 healthy, untreated dogs; 2) 9 dogs given 1200 R total body irradiation and no marrow infusion; 3) 17 dogs given 1200 R and autologous marrow infusion; 4) 25 dogs given 1200 R and hemopoietic cells from dog-leukocyte-antigen (DLA)--identical littermates; and 5) 31 dogs given 1200 R and nonidentical DLA hemopoietic cells. Some of the dogs in Groups 3--5 received a postgrafting methotrexate (MTX) regimen of 0.25--0.5 mg/kg body weight on Days 1, 3, 6, and 11 and once weekly until Day 102. Prominent lesions were found in the small and large intestines, skin, and liver of dogs with allogeneic grafts. Skin lesions consisted of lymphocytic infiltrates of epidermis with necrosis of basal epidermal cells progressing to denudation. Gut lesions consisted of mucosal destruction progressing from crypt abscess formation to denudation. Liver lesions consisted of portal triaditis, plasmacytic and lymphocytic infiltrates, necorsis and atypia of small bile ducts, and scattered individual hepatocyte necrosis. These lesions were differentiated from changes caused by irradiation and MTX and were deemed characteristic of GVHD. The overall severity of GVHD lesions was less in the identical DLA group than in the nonidentical DLA group, and also less in dogs treated with MTX than in those not given MTX. The degree of lymphoid depletion in the lymph nodes, spleen, and intestinal lymphoid tissue was very similar in dogs with autologous and allogeneic grafts at comparable survival times. No specific evidence of pancreatic or renal involvement in GVHD was discovered.

A case of multiple small well-differentiated hepatomas with early peliosis hepatis, multiple pancreatic islet cell tumors, and a renal medullary interstitial cell tumor following five years of androgen and prednisone therapy for idiopathic aplastic anemia is reported in a patient who died shortly after allogeneic bone marrow transplantation. The hepatic tumors were well differentiated, and the pancreatic tumors were of mixed ribbon and islet cell pattern. Therapeutic and experimental implications and the relevant literature are briefly summarized.