Predictive value of cross-matching for transfusion of platelet concentrates to alloimmunized recipients

Compatibility tests in which donor platelets were tested with recipient sera were performed retroactively after 64 transfusions of platelets from 59 unrelated donors to 10 alloimmunized patients. Techniques used were serotonin release, aggregometry, platelet factor 3 release, and lymphocytotoxicity, each of which has been advocated as a means of testing donor-recipient platelet compatibility. Although "false positive" reactions were few (positive crossmatch but satisfactory transfusion response), "false negative" reactions (negative crossmatch but poor transfusion response) were unacceptably high (43% by lymphocytotoxicity, 60% by serotonin release, 76% by platelet factor 3 release, and 83% by aggregometry). We conclude that current methods of detecting isosensitization to platelet alloantigens are less satisfactory than HLA phenotyping in selecting unrelated platelet donors for an alloimmunized patient population.

Changes in lymphoid cyclic adenosine 3':5'-monophosphate metabolism during murine leukemogenesis

Cyclic adenosine 3':5'-monophosphate (cyclic AMP) levels were slightly increased in preleukemic AKR mouse thymus cells, compared with nonleukemic thymus cells, but were markedly reduced in leukemic cells. Adenylate cyclase activity rose during the preleukemic and leukemic phases of leukemogenesis. Although the drop of epinephrine-induced stimulation of thymus adenylate cyclase in the preleukemic phase was probably age related, there was an additional decrease of adenylate cyclase activation by epinephrine in leukemic cells. Cyclic AMP phosphodiesterase activity was slightly higher in preleukemic cells and more than fourfold AKR thymus. These observations suggest that cyclic AMP phosphodiesterase is largely responsible for the low levels of cyclic AMP in leukemic cells. Significant changes in cyclic AMP metabolism are already detectable before neoplastic cells may be found in the thymus.

Platelet migration inhibition: a new method for detection of platelet antibodies

A test for platelet antibodies based on the inhibition of migration of platelets from a capillary tube is described. The technique is simple and is capable of detecting antibodies directed against HL-A antigens and the platelet-specific antigen, Pl-A1. Inhibitory activity was detected in sera from two of seven patients with idiopathic thrombocytopenic purpura. The platelet migration inhibition test was as sensitive as platelet lysis and more sensitive than complement fixation, aggregometry, and platelet factor-3 release for detection of the antibodies studied.

Lymphoid cell adenylate cyclase activity after x-irradiation and cortisone treatment

Cortisone injection and x-irradiation of normal mice lead to extensive destruction of thymus and spleen lymphocytes. The lymphocytes resistant to these treatments have basal adenylate cyclase activities that are the same as or slightly lower than the cells of untreated animals. On the other hand, the ability of the cyclase of the cortisone-resistant and radioresistant lymphocytes to respond to stimulation by epinephrine is greatly diminished. The results provide an explanation for the previously observed lack of epinephrine sensitivity of the cyclase of lymphoid cells of immunodeficient pituitary dwarf mice and suggest that the depressed lymphoid cell population of the dwarf is the result of an inability to recover from stress-related lymphoid involution. It is also suggested that the more mature population of lymphoid cells of normal mice is less responsive to hormonal influences.

Thymus adenylate cyclase activity during murine leukemogenesis

Activity of thymus adenylate cyclase was more than three times higher in leukemic AKR mice than in nonleukemic AKR mice and CBA mice. Preleukemic AKR mice that had no evidence of leukemia but were expected to soon develop the disease exhibited similarly elevated activities of thymus adenylate cyclase.

Endocrinological studies in ataxiatelangiectasia and other immunological deficiency diseases

Endocrinological and immunological studies were performed in five patients with ataxia-telangiectasia, two patients with sex-linked non-lymphopenic hypogammaglobulinaemia, one patient with sex-linked lymphopenic hypogammaglobulinaemia, and two patients with hypopituitary dwarfism. One of five patients with ataxia-telangiectasia had deficient growth hormone responses to insulin-induced hypoglycaemia but normal responses to arginine infusion. One pubertal ataxia-telangiectasia patient had increased gonadotropin secretion. Patients with hypopituitary dwarfism failed to respond to insulin-induced hypoglycaemia and arginine infusion with increased growth hormone secretion. The patients with sex-linked lymphopenic and non-lymphopenic hypogammaglobulinaemia had normal endocrine function. Immunological studies indicated defects in humoral and cellular immunity in the patients with ataxia-telangiectasia and sex-linked lymphopenic and non-lymphopenic hypogammaglobulinaemia, whereas normal immunological function was demonstrated in the patients with hypopituitary dwarfism. No relationship between endocrinological and immunological function could be demonstrated in these patients.