Tadashi Kagimoto

Characteristic mode of action of gangliosides in selective modulation of CD4 on human T lymphocytes

We have explored the possible mechanisms for selective modulation by gangliosides of CD4 on human T lymphocytes and subsequent re-expression of CD4. Indirect immunofluorescence staining with anti-CD4 antibodies revealed newly internalized CD4 in ganglioside-treated cells after membrane permeabilization with 0.1% saponin. Cycloheximide and other metabolic inhibitors did not alter the modulation but inhibited significantly the re-expression of CD4. These results suggest both selective modulation of CD4 by a process of endocytosis and re-expression of CD4 through de novo protein synthesis.

Paroxysmal nocturnal haemoglobinuria with coexisting deficiency of the ninth component of complement: lack of massive haemolytic attack

A 47‐year‐old woman with paroxysmal nocturnal haemoglobinuria (PNH) was found to have an inherited deficiency in the ninth complement component (C9). In complement‐sensitivity lysis tests, 80% of her erythrocytes were markedly complement‐sensitive (PNH‐III). Laser cytofluorimetry with a monoclonal antibody against decay‐accelerating factor (DAF) revealed that 95% of her erythrocytes were DAF‐negative. Surprisingly, she has suffered only mild haemolysis and has never experienced massive spontaneous haemolysis. Gross haemoglobinuria and jaundice occurred only after receiving postoperative transfusions of whole blood. In her serum, C9 was not detectable either by immunological or by functional assays. Both the Ham test and the sugar water test using normal human serum or plasma yielded marked haemolysis of the patients erythrocytes. When the patients serum or plasma was used, only a trace of lysis was detected. Addition of purified human C9 to her plasma fully restored haemolysis. These observations indicated that C9 may play a critical role in haemolytic attacks in patients with PNH and that characteristic haemolysis in PNH may be tempered by coexisting C9 deficiency.

Monoclonal gammopathies in adult T-cell leukemia.

Age and sex distributions of monoclonal gammopathy were studied for 12,196 healthy controls and 2056 patients with various malignancies. The frequency of monoclonal component in adult T‐cell leukemia (ATL) patients was found to be much higher than that in patients with other malignancies and in healthy controls. This suggested that the occurrence of ATL and monoclonal gammopathy is not coincidental. Three cases of ATL with monoclonal gammopathy are also reported.

Assignment of proximal histidyl imidazole exchangeable proton NMR resonances to individual subunits in hemoglobins A, Boston, Iwate and Milwaukee☆

Abstract The proton nmr spectra of the synthetic valency hybrids, α 2 (β + CN) 2 , (α + CN) 2 β 2 of hemoglobin A and the natural valency hybrids of the mutant hemoglobins Boston, Iwate and Milwaukee have led to the unambiguous assignment of the two proximal histidyl imidazole exchangeable proton signals at 64 and 76 ppm to individual α and β subunits, respectively. New single non-exchangeable proton resonances detected in the extreme downfield region of the spectra of Hbs Boston and Iwate are tentatively assigned to the coordinated tyrosine of the mutated α chains.

Ectopic production of salivary‐type amylase by a lga‐λ‐type multiple myeloma

A patient with IgA‐λ‐type multiple myeloma who appeared to be secreting salivary‐type amylase ectopically is reported. Both the patients serum and urine contained high levels of amylase. Amylase activity in the supernatant of cultured myeloma cells, obtained from the patients pleural effusion while he had malignant pleuritis, increased almost linearly from the time of cell seeding. The presence of IgA and S‐type amylase in the myeloma cells was demonstrated cytochemically and by immunoelectron microscopy. These observations showed that amylase was produced by these human myeloma cells.

Expression of cryptantigen Th on paroxysmal nocturnal hemoglobinuria erythrocytes in association with a hemolytic exacerbation.

Paroxysmal nocturnal hemoglobinuria (PNH) erythrocytes lack complement regulatory membrane proteins and are susceptible to complement. Although the critical role of complement in intravascular hemolysis in PNH is accepted, the precise mechanism of complement activation in vivo is unknown. Accordingly, in a PNH patient who was suffering from a hemolytic precipitation soon after a common cold-like upper respiratory infection, we analyzed the erythrocytes with lectins and by flow cytometry to detect membrane alteration that lead to complement activation. The lectin reactivity of erythrocytes showed the expression of cryptantigen Th. The patient serum at the time of the hemolysis induced the expression of Th on erythrocytes from PNH patients and from healthy volunteers in vitro, whereas neither the patient serum after recovery from the hemolysis nor blood type-matched control serum from healthy donor showed this activity. Moreover, autologous serum selectively hemolyzed Th+ PNH erythrocytes, but not Th- PNH erythrocytes, or Th+ control erythrocytes. Hemolysis was not observed either in complement-inactivated serum or in blood type-matched cord blood serum, which lacks natural antibodies to cryptantigens. These findings indicate that the immunoreaction of infection-induced Th with natural antibody on PNH erythrocytes is a trigger of the complement activation, leading to intravascular hemolysis.

A new hemoglobin variant: HB yatsushiro α2Aβ260Val→Leu

Abstract This study was performed to establish the structural abnormality of a new hemoglobin variant discovered in a Japanese patient with angina pectoris. The hybridization of the separated hemoglobin with canine hemoglobin revealed a β-chain anomaly. Peptide βTp-6 was found to be abnormally located on the peptide map of tryptic digests of the S-carboxymethylated β-chain from the variant hemoglobin. A structural study on the abnormal βTp-6 revealed that the variant hemoglobin differs from hemoglobin A by substitution of leucine for valine at residue 60 of the β-chain. This new variant hemoglobin is designated as hemoglobin Yatsushiro after the name of the city where the propositus lived. The patient is hematologically healthy and his clinical history has nothing to do with this abnormal hemoglobin.

Altered Expression of Gangliosides in Erythrocytes of Paroxysmal Nocturnal Hemoglobinuria

In paroxysmal nocturnal hemoglobinuria (PNH), impaired glycosyl-phosphatidylinositol (PI)-anchoring of membrane proteins such as decay-accelerating factor has been known to lead to increased susceptibility to complement. Moreover, abnormal expression of non-PI-anchoring glycoproteins such as C3b/C4b receptor (CR1) or glycophorin-alpha also has been shown in PNH. Therefore, we biochemically analyzed glycosphingolipids (GSL) as one of the membrane glycoconjugates of PNH erythrocytes. Erythrocytes of all seven PNH patients showed altered expression of sialosyl GSL (gangliosides) as compared with the control erythrocytes of healthy donors. Both a sialosylparagloboside (IV6NeuAc-nLc4Cer) among four major gangliosides and some minor gangliosides in normal erythrocytes variably disappeared in erythrocytes from the peripheral blood of PNH patients. As one of the possible mechanisms of altered expression of gangliosides in PNH erythrocytes, structural analysis suggested impaired sialylation of GSL. These results suggest not only the altered metabolism of gangliosides in PNH erythrocytes, but also a metabolic disorder of membrane glycoconjugates as a new feature of PNH.

Differential glycosylation of Bence Jones protein and kidney impairment in patients with plasma cell dyscrasia

Although Bence Jones protein (BJP) is generally accepted to be critically involved in the pathogenic process of kidney impairment in patients with myeloma, patients with BJP do not always have kidney dysfunction. As proteins often undergo glycosylation and alter their molecular nature, it is expected that the heterogeneity in kidney dysfunction can be explained at least partly by the differential affinity to the kidneys of BJP dependent on its glycosylation. Accordingly, we analyzed the structures of carbohydrates of urine BJP biochemically to correlate the structure with kidney function. BJP was obtained from 16 patients with myeloma, 2 patients with light chain amyloidosis, a patient with plasma cell leukemia, and a patient with Waldenstroms macroglobulinemia. All BJP had five forms of oligosaccharides: three forms of biantennary oligosaccharides and two forms of triantennaries. The three biantennaries correspond to previously reported oligosaccharides on only lambda-type BJP, whereas the triantennaries are novel oligosaccharides found on BJP. Among the five oligosaccharides, the triantennary oligosaccharide Gal(beta)1-4GlcNAc(beta)1-2Man(alpha)1-6 [Gal(beta)1-GlcNA(beta)1-4(Gal(beta)1-4GlcNAc(beta) 1-2)Man(alpha)1-3]Man(beta)1-4GlcNAc(beta)1-4GlcNAc showed a significant negative correlation with the serum creatinine level (p = 0.015 by Spearmans correlation test, R = 0.744). Thus determination of BJP glycosylation may be useful for the evaluation of kidney impairment in patients with BJP.

31P-NMR study on nucleotides and intracellular pH of hereditary spherocytes.

As determined by31p-NMR spectroscopy, intracellarar pH of hereditary spherocytes was lower (pH 6.7–6.9) than that of normal red cells. The level of adenosine diphosphate in hereditary spherocytes was found to be persistently high. The metabolism of nucleotides and other phosphoryl compounds in human red blood cells have been studied in detail by31p-NMR spectroscopy1–3. However, to our knowledge, there seems to be no report describing the result of31p-NMR spectroscopy on red blood cells from hereditary spherocytosis.