Paroxysmal nocturnal hemoglobinuria associated with in vitro inhibition of erythropoiesis by bone marrow T lymphocytes.

BACKGROUND: The etiology of bone marrow failure, a prominent feature of paroxysmal nocturnal hemoglobulinuria, is presently unknown. OBJECTIVES: To evaluate the possible influence of cellular immune mechanisms in the bone marrow failure of PNH. METHODS: We studied marrow erythroid colony formation in a patient with paroxysmal nocturnal hemoglobinuria without hypoplastic/aplastic marrow complications. RESULTS: In vitro assays revealed a pronounced inhibition of primitive erythroid (BFU-E) progenitor cell growth by marrow T lymphocytes. Removal of T cells prior to culture resulted in a 4.5-fold enhancement of BFU-E numbers. Reevaluation of in vitro erythropoiesis during steroid administration indicated a persistent, albeit less prominent, T cell inhibitory effect. CONCLUSION: Our findings provide the first direct evidence for a cellular immune inhibitory phenomenon accompanying PNH.

Middle ear laser office ventilation (LOV) with a CO2 laser flashscanner.

BACKGROUND: Laser assisted ventilation of the middle ear with a defocused laser beam has been performed on adults in an office setting without anesthesia. OBJECTIVE: The purpose of this study was to evaluate the efficacy and safety of a highly controlled, char-free CO2 flashscanner technology for the ventilation of the middle ear in young children, at this stage under general anesthesia, and later without anesthesia. METHODS: A CO2 flashscanning laser, in conjunction with a micromanipulator, was used on 21 SOM patients ages 3-7 years old, with followup at 2 months. Operating time is approximately 5 minutes. RESULTS: Postoperative results show average patency of 2-3 weeks without adverse effects. Of the treated patients, 53% did not require a second treatment, whereas 47% still suffered from otitis media and needed a second treatment. CONCLUSION: The CO2 flashscanner laser technology is effective and safe for middle ear ventilation and provides excellent control of the perforation diameter. It is already being performed in an office setting with sedation on a limited basis with very promising preliminary results. Based on the current study and on 70 additional cases with longer interval followup, we anticipate the office technique to become widely used in the future.

[Neonatal alloimmune thrombocytopenia].

Neonatal alloimmune thrombocytopenia (NAIT) was first described in the 1950s. The disease results from maternal antiplatelet antibodies against surface antigens on fetal platelets due to feto-maternal platelet incompatibility. Although NAIT is transient, during its active phase thrombocytopenia can cause intracranial hemorrhage with grave neurological sequelae or death. We characterized the alloimmune antibodies in 29 mothers and found anti-HPA-1a (in 11 cases), anti-HPA1b (1), anti-HPA-5a (1) and anti-HPA-5b (5). In 11 women no specific antibodies were identified despite characteristic disease in the newborns. 3 neonates in the anti-HPA-1a, and 1 in the anti-HPA-1b groups were born with intracranial hemorrhage and are severely disabled. We described a case of successful prenatal treatment by a combination of steroids, high-dose immunoglobulins and intraumbilical platelet transfusion in a mother known to have anti-HPA-1, whose previous child was severely affected. It is important to examine antibodies in any woman whose neonate has thrombocytopenia of unknown etiology.

[Post-transfusion purpura].

Post-transfusion purpura (PTP) is a rare syndrome that may develop a week after blood transfusion. In this syndrome, which occurs mainly in women, blood transfusion is followed by severe thrombocytopenia a week later. A 72-year-old woman with this syndrome is presented. High-dose intravenous gamma-globulin resulted in prompt resolution of her thrombocytopenia. The basic pathophysiologic mechanism of PTP is the development of an alloantibody to a human platelet antigen. The mystery of PTP is why the patients' own, as well as transfused PLA1-negative platelets, are destroyed.

Involvement of a protein kinase C and protein phosphatases in adhesion of CD4+ T cells to and detachment from extracellular matrix proteins.

For immune surveillance and function to be effective, T lymphocytes constantly recirculate via lymph and blood between lymphoid organs and body tissues. To enable efficient cell movement and migration, cell adhesion to components of the basement membrane and the extracellular matrix (ECM) must be a rapid and transitory process. Whether phosphorylation and dephosphorylation of cellular proteins are involved in this phenomena was explored by monitoring the adhesion of T cells to immobilized ECM proteins. A short exposure of 51Cr-labeled human CD4+ T cells to phorbol esters in vitro induced a rapid beta 1-integrin-mediated adhesion to both fibronectin and laminin, as determined by inhibition with anti-integrin antibodies. Adhesion was reversible; detachment from the immobilized ECM ligands occurred between 20 and 120 min without further intervention. This T cell adhesion was regulated by the activation of protein kinase C because (a) staurosporine and H-7 inhibitors of protein kinase C suppressed T cell adhesion, and (b) PMA-induced down-regulation of intracellular levels of protein kinase C was associated with the abrogation of the T cell adhesiveness to fibronectin and laminin. Furthermore, inhibition of protein phosphatases activity by okadaic acid delayed the detachment of the T cells from fibronectin or laminin. Thus, we suggest that T cell-ECM interactions such as adhesion and detachment are regulated, respectively, by protein kinase C and protein phosphatases.

The determination of intracellular sodium concentration in human red blood cells: nuclear magnetic resonance measurements.

The intracellular sodium concentration and intracellular volume of human red blood cells were determined from 23Na and 1H NMR spectra. It is shown that sodium dissolved in the intracellular water has a concentration higher than that previously published. The intracellular sodium concentration measured was 11.4 +/- 3.1 mM. A comparison of different NMR methods used to determine sodium concentration is given.

[Treatment of pemphigus with plasmapheresis].

Therapeutic plasmapheresis was successfully used in a 29-year-old man with corticosteroid-resistant pemphigus vulgaris who had severe side-effects from the medication. 4 plasmaphereses were performed over a period of 3 weeks with removal of a total of 7900 ml of plasma. Concurrently he received large doses of adrenal steroids and Imuran. There was clinical improvement soon after the first plasmapheresis and 8 weeks after the treatment was started he was free of lesions. IC-Ab titers markedly decreased during the course of treatment and continued to decrease after it was completed. Side-effects were few and relatively mild. Plasmapheresis may be a useful adjunct in the treatment of pemphigus vulgaris resistant to conventional therapy. It may be used initially together with corticosteroids, giving more rapid improvement, as well as a corticosteroid-sparing effect.

Characterization of a neuraminidase from Corynebacterium aquaticum responsible for Th polyagglutination.

Th polyagglutinability is characterized by the agglutination of the red blood cells (RBC) by Arachis hypogaea, Medicago disciformis, Vicia cretica but, in contrast to the T phenomenon, not by Glycine max (Glycine soja). Because Th transformation of RBC has been obtained in vitro, the mechanism of Th polyagglutinability expression has been studied and reproduced experimentally. An enzyme with neuraminidase specificity has been isolated from the culture supernatant of Corynebacterium aquaticum, and further characterized (MW = 55,600 kDa, pH = 5.5, Km = 0.138 microM, Kcat = 0.22 micrograms). Reversely, Th transformation of RBC could be obtained by using other neuraminidases but in very mild conditions of hydrolysis. From our results, it can be concluded that by the release of less than 20 micrograms of sialic acid per 10(10) RBC, Th reactivity can be induced whereas hydrolysis of greater amounts of sialic acid (greater than 20 micrograms/10(10) RBC) give the classical T polyagglutinability.

Immunological studies of pancytopenia in visceral leishmaniasis.

We report three cases of combined anemia, neutropenia and thrombocytopenia in patients with visceral leishmaniasis (kala-azar). Using immunofluorescence techniques and the common antiglobulin (Coombs') test, we showed membrane-associated antiplatelet, antineutrophil and antierythrocytic IgG antibodies in all three cases. Treatment with sodium stibogluconate raised the patients' platelet, neutrophil and erythrocyte count. At that time no antibodies were detected on peripheral blood cells. Immunological studies performed on these patients did not show marked abnormalities except for reduced T-helper cells and elevated OKM1-positive cells, which normalized after recovery. As bone marrow suppression was not found, it is suggested that pancytopenia resulted from rapid destruction of antibody-coated blood cells. Whether these antibodies are specific is not clear.

Human alloantibodies detecting a red cell antigen apparently identical to MER2.

Three examples of an antibody were found to be detecting a red cell polymorphism probably identical to MER2. The antibodies were made by Jews originating from India and living in Israel. Two of them were sibs and the third was unrelated. All 3 had kidney disease requiring renal dialysis and regular blood transfusion. In 2 cases the antibodies were detected before dialysis was started and before the patients had been transfused. The human antibodies reacted with red cells of 90% of Israeli blood donors tested. In tests on selected blood donors, 82 English and 56 Israeli, one of the human antibodies gave almost identical reactions to those given by monoclonal anti-MER2. Anomalous reactions were probably due to anti-Bga. Two of the human antibodies completely blocked, and one partially blocked, the reaction of monoclonal anti-MER2 with MER2+ red cells.

Antibodies to insulin receptor followed by anti-idiotype. Antibodies to insulin in child with hypoglycemia.

A child presenting severe hypoglycemia despite low or normal secretion of insulin was found to have IgM antibodies to the insulin receptor. These antibodies stimulated lipogenesis in fat cells in vitro and competed with insulin for binding to insulin receptors. After treatment with glucocorticoids, the anti-receptor antibodies and the hypoglycemia both disappeared, and antibodies to insulin appeared in the patient's serum. The anti-insulin antibodies were isolated by affinity chromatography and were found to inhibit the anti-insulin-receptor antibodies that were present earlier. The interaction between the patient's anti-insulin antibodies and his anti-receptor antibodies suggests that these two species of antibodies are related as idiotypes and anti-idiotypes. We also studied the interaction of the hypoglycemic patient's anti-receptor antibodies with anti-insulin antibodies of a diabetic patient and with anti-insulin antibodies of mice immunized to insulin. The hypoglycemic patient's anti-receptor antibodies were neutralized by the diabetic patient's anti-insulin antibodies, indicating that anti-insulin antibodies with a common idiotype may arise in both diabetes and hypoglycemia. Moreover, mouse anti-insulin antibodies that interacted with mouse anti-receptor antibodies neutralized the hypoglycemic patient's anti-receptor antibodies. In contrast, mouse anti-insulin antibodies that did not interact with the mouse anti-receptor antibodies did not neutralize the hypoglycemic patient's anti-receptor antibodies. Thus, the human anti-insulin antibodies share an idiotype with a specific class of mouse anti-insulin antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)

Mouse antibodies to the insulin receptor developing spontaneously as anti-idiotypes. II. Effects on glucose homeostasis and the insulin receptor.

Mice immunized to bovine insulin were observed to develop anti-idiotypic antibodies which behaved in in vitro assays as antibodies to the insulin receptor. The studies described here were undertaken to investigate the effects of these antibodies in vivo on the physiology of glucose homeostasis and the state of insulin receptors. Mice developing anti-idiotypic receptor antibodies manifested abnormal fasting blood glucose concentrations: a period of hypoglycemia followed by a period of hyperglycemia. Moreover, the mice were deficient in their ability to respond to a glucose load. Changes in the number and activity of insulin receptors were associated with these physiological aberrations. In an insulin binding assay, adipocytes obtained from immunized mice had only 40% of the number of insulin receptors demonstrable on the adipocytes of control mice. The lipogenic response of the affected adipocytes was also relatively insensitive to insulin, and in addition, they manifested only 70% of the maximal response to high concentrations of insulin. Thus, development of anti-idiotypic receptor antibodies appeared to be associated with insulin resistance of adipocytes and abnormal glucose homeostasis.

Local aggregation of hormone-receptor complexes is required for activation by epidermal growth factor.

An analogue of epidermal growth factor (EGF) which is virtually devoid of biological activity retains receptor binding activity but cannot form cell surface clusters or patches. Bivalent anti-EGF antibodies restore both bioactivity and patch formation. The sensitivity of fibroblasts to native EGF can also be enhanced greatly by these antibodies, especially in hormone-resistant cell lines.

Antagonism by propranolol of the ganglion stimulant action of 5-hydroxytryptamine.

The effects of racemic propranolol and its constituent isomers were studied on ganglionic stimulation produced in situ by close arterial injection of 5-HT and DMPP to the superior cervical ganglion. Ganglion stimulation was recorded in terms of the resultant contraction of the nictitating membrane. d,l-Propranolol caused a biphasic antagonism of the ganglion stimulant effect of 5-HT. At low doses, 0.5-10 mug, the antagonism was surmountable by increasing the amount of 5-HT. The l-isomer (0.2-4 mug) but not d-propranolol also caused antagonism. At higher doses, 0.1-5 mg, both d,l- and d-propranolol caused a second type of blockade of 5-HT which was not surmountable and resembled that seen with procaine. The ganglion stimulant effects of DMPP and acetylcholine were only antagonised by the higher doses of d- and d,l-propranolol. d,l-Propranolol did not reduce the direct stimulation by 5-HT on the muscle of the nictitating membrane.

Beta-adrenoceptor blocking agents and responses to adrenaline and 5-hydroxytryptamine in rat isolated stomach and uterus.

1 Four beta-adrenoceptor blocking agents, (+/-)- and (+)-propranolol, practolol and oxprenolol, were found to antagonize, apparently competitively, the responses of both the rat isolated stomach and uterus to 5-hydroxytryptamine (5-HT).2 The pA(2) values for each of these agents as antagonists of the contractile action of 5-HT on the rat stomach were found to be: (+/-)-propranolol, 6.08; (+)-propranolol, 4.94; practolol, 3.43; and oxprenolol, 5.99. These values were very similar to the corresponding figures for antagonism of 5-HT-induced contractions of the uterus.3 pA(2) values for antagonism of adrenaline-induced relaxations by the four blocking agents on the rat stomach and uterus did not differ from the values for 5-HT blockade.4 To antagonize contractile responses to acetylcholine of the rat stomach it was necessary to give 100 times more (+/-)-propranolol than was needed to antagonize responses to 5-HT.