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J A Child

Publications and source records attributed to J A Child.

At least 19 recordsLinked to original sources
PubMed1991

The MHC class I associated beta 2-microglobulin (beta 2m) light chain is expressed in a molar excess over HLA-ABC and CD1 on the membrane of leukaemic B cells but not leukaemic T cells: evidence for further beta 2m-associated molecules.

Beta 2-microglobulin (beta 2m) constitutes the common light chain of both the MHC-encoded HLA-ABC molecules and a group of structurally related glycoproteins recognized by antibodies of the first cluster of differentiation (CD1a, CD1b and CD1c). These CD1 antigens appear similar to murine T1 and Qa molecules in terms of structure and tissue distribution, although the question of inter-species homology is controversial. A further group of alloantigens expressed predominantly on T cells has been reported however, with immunogenetic characteristics more closely analogous to the murine T1/Qa system than the CD1 antigens, although their precise identity remains ill-defined. Having previously shown that malignant B cells may express membrane CD1c, we examined leukaemic B-cells corresponding to early lymphoblastic differentiation (null- and common acute lymphoblastic leukaemia) through to the terminal plasma cell stage for the expression of other non-HLA class I beta 2m-associated molecules. It was found that leukaemic B-cells at intermediate/late stages of differentiation, represented by non-Hodgkin's lymphoma (B-NHL) and 'hairy-cell' leukaemia (HCL), had significantly higher beta 2m:HLA-ABC ratios than did the cells from other types of B-cell malignancy. Although leukaemic B cells with a demonstrable non HLA-ABC-associated beta 2m component expressed detectable levels of CD1c, and insignificant levels of CD1a and CD1b, the antigen density was insufficient to account for the excess beta 2m. In vitro stimulation of leukaemic B cells by phorbol ester substantially increased the expression of HLA-ABC and CD1c, but also accentuated further the difference between the expression of these molecules and that of beta 2m. There was no detectable beta 2m other than that associated with HLA-ABC and CD1 on the surface of malignant T cells by contrast. Our findings strongly support the existence, at certain stages of leukaemic B-cell differentiation, of an additional beta 2m component(s) other than that associated with HLA-ABC and CD1.

Antigens, CD↗
PubMed1990

In vitro beta 2-microglobulin (beta 2m) secretion by normal and leukaemic B-cells: effects of recombinant cytokines and evidence for a differential response to the combined stimulus of phorbol ester and calcium ionophore.

Due to the increasing therapeutic use of immunoregulatory agents and the potential effects on cellular function, we examined the modulation of in vitro beta 2-microglobulin (beta 2m) production rates by 'normal' tonsil and leukaemic B-cells in response to a number of these agents. Tonsil B-cells responded to phorbol ester (TPA) by an increased beta 2m production rate, which was further enhanced by the combined stimuli of TPA plus the calcium ionophore A23187. In marked contrast, however, lymphocytes from a majority (8/11) of B-cell malignancies showed a suppression of the TPA-induced beta 2m production rate in response to the combined TPA/A23187 stimulus. These different responses of 'normal' and malignant B-cells were not apparent when IgM production rates were examined. The recombinant cytokines IL-1, IL-2, IFN-alpha, IFN-gamma and TNF also enhanced beta 2m production rates of both normal and leukaemic B-cells, but to a considerably lesser extent than did TPA. Bryostatin-1 increased beta 2m production to a level intermediate between that obtained by TPA and the cytokines. It is suggested that beta 2m production rates may correspond to the degree of B-cell differentiation, and/or to the degree of cellular 'activation'. The results further indicate that the in vitro measurement of beta 2m production provides a different index of the cellular response than that obtained by the conventional measurement of IgM production.

Adjuvants, Immunologic↗
PubMed1990

Phenotypic switch from CD45RA+ to CD45RA- by normal blood T cells is associated with increased HLA-ABC expression for CD4+ and CD8+ populations but not for the NK-associated CD4-CD8dim+ or CD4-CD8- fractions.

Using the combined techniques of immunomagnetic depletion and multiple colour flow cytometry, the expression of HLA-ABC (W6/32) by normal T-cell subpopulations, defined by 2H4 (CD45RA) expression, was examined. It is thought that a CD45RA+CD45RO- phenotype defines the 'virgin' T-cell fraction, whereas a CD45RA-CD45RO+ phenotype defines the 'primed' or memory T-cell population. In addition, an intermediate phenotype (CD45RA+CD45RO+) appears to correspond to a transitional stage of development. In this study, these three phenotypic stages were represented by distinct levels of 2H4 staining defined as 2H4+, 2H4int and 2H4-, respectively. The results of this current investigation are of importance in two main areas. Firstly, when compared to the 2H4+ component, the HLA-ABC expression of 2H4- cells was significantly higher. This was true for both CD4+CD8- and CD4-CD8+ lymphocytes, but was not the case for CD4-CD8dim+, CD3+CD4-CD8- and CD3-CD4-CD8- fractions. Additionally, when HLA-ABC expression was examined as a function of 2H4 staining intensity, it was found that, for the CD4+ fraction, the greatest increase in HLA-ABC expression occurred between the 2H4int and 2H4- stages. In contrast, the increase in HLA-ABC expression by CD8+ lymphocytes was associated with transition from 2H4+ to 2H4int status, which suggests that increased HLA-ABC expression occurs at an earlier stage in the acquisition of CD45RO in CD8+ cells than for CD4+ cells. Secondly, for each individual blood examined, a close and highly significant correlation (P = 0.002) for membrane HLA-ABC expression was found between (i) CD4+2H4+ and CD8+2H4+ and (ii) CD4+2H4- and CD8+2H4- subpopulations. This suggests that modulation of HLA-ABC expression in CD4+ and CD8+ cells is subject to common control mechanisms and remains proportionate for these lymphocyte fractions in any given individual.

Antigens, CD↗
PubMed1988

MHC class I and class I-like gene product expression by malignant T cells: relationships between CD1a, HLA-ABC and beta 2-microglobulin.

Beta 2-microglobulin (beta 2m) forms the invariant light chain of the MHC-encoded HLA-ABC and the non-MHC-encoded CD1 molecules. While HLA-ABC (MHC Class I) molecules are virtually ubiquitous in tissue distribution, CD1 determinants by contrast are more restricted. We have assessed, by indirect immunoenzymeassay, the relative membrane densities of these molecules on malignant thymic and post-thymic T cells. It was found that the T cells of mature post-thymic proliferations expressed significantly more beta 2m-associated protein, predominantly HLA-ABC in nature, than thymic-ALL blasts. This parallels the situation found in normal peripheral T cells and thymocytes. In contrast to post-thymic T cells, thymic-ALL blasts showed considerable case to case variation with respect to non-HLA-associated beta 2m and, of particular interest, not all of this excess beta 2m could be accounted for by CD1a. We therefore conclude that other beta 2m-containing molecules may be expressed on thymic-ALL blasts and possibly also on post-thymic leukaemic T cells. In addition, it was found that T cells from CD4+ cases of post-thymic proliferations expressed more beta 2m-associated determinants than other T cells, whether of either normal or malignant origin, and that certain post-thymic malignancies express significantly increased levels of beta 2m-associated protein relative to normal peripheral T-cells. This is in direct contrast to the situation seen in many solid malignancies.

Antigens, Differentiation↗
PubMed1979

Abnormal red-cell metabolism of pyridoxine associated with beta-thalassaemia.

Red-cell conversion of pyridoxine to pyridoxal phosphate was studied in control subjects, and patients with heterozygous and homozygous beta-thalassaemia. In 7% of control subjects the rate of pyridoxine conversion was well below the range found in the other control subjects (5.0-8.6%, mean 6.5%/g Hb x 10(-2)) but in heterozygous beta-thalassaemia was below that range in 63% of the patients. The conversion rate was also slow or borderline in the majority of patients with severe transfusion-dependent homozygous beta-thalassaemia, in spite of the presence of some donor cells; but was normal, or fast as in other anaemias, in all but one patient with mild homozygous thalassaemia. There was a much higher incidence of a slow conversion rate in the parents of the severe homozygotes than in parents of the mild homozygotes, illustrating the familial pattern. This supports our view that the red-cell conversion rate of pyridoxine is an inherited characteristic, independent of thalassaemia. The cause of a reduced rate of pyridoxine conversion was investigated. The increase to a normal rate following riboflavin ingestion suggests a defect in the activity of the flavin mononucleotide (FMN)-dependent pyridoxine phosphate oxidase.

Adenosine Triphosphate↗
PubMed1979

Microbicidal function of the neutrophils in hairy-cell leukaemia.

The ability of neutrophils from patients with hairy-cell leukaemia to kill Candida guilliermondii and Staphylococcus aureus in vitro was investigated. Of 10 patients, 8 showed defective candida killing, 5 defective bacteria killing, in comparison with normal controls. Study of those patients who underwent splenectomy suggests that neutrophil function can be improved by splenectomy. The possible causes of defective function in this disease are discussed.

Candida↗
PubMed1979

Family studies of red-cell metabolism of pyridoxine in beta-thalassaemia.

Red-cell conversion of pyridoxine to pyridoxal phosphate was measured in 12 families with thalassaemia and 2 normal families. A strong familial pattern was demonstrated and the evidence suggested that the rate of red-cell conversion of pyridoxine is an independently inherited characteristic.

Erythrocytes↗
PubMed1978

Biochemical markers in Hodgkin's disease and non-Hodgkin's lymphoma.

Vertical studies indicate that, in general, acute phase reactant proteins (APRP) reflect disease activity in both Hodgkin's disease and non-Hodgkin's lymphoma. Longitudinal studies of the selected APRP profile demonstrate the following: 1. The stable profile is characteristic of remission. 2. Considerable elevation of APRPs coincides with relapsed disease. 3. An unstable profile is a feature of relapsing disease and may give early warning of relapse. 4. Patients responding inadequately to treatment frequently have unstable APRP profiles.

Adult↗
PubMed1978

Evaluation of the usefulness of serum gamma-glutamyl transpeptidase levels in the management of haematological neoplasia.

The levels of serum gamma-glutamyl transpeptidase (GGT) and, when appropriate, alkaline phosphatase (AP) and 5'-nucleotidase (NTD) have been measured as a routine in 276 patients with malignant haematological diseases during a 26-month trial period. GGT levels add no prognostic information to the routine haematological surveillance of leukaemia. Polychemotherapy does not appear to be an inducer of liver drug-metabolising microsomal enzymes. Polycythaemia rubra vera, myelofibrosis and chronic lymphocytic leukaemia may cause little change in GGT, AP and NTD levels despite marked hepatomegaly. A raised GGT in Hodgkin's disease and non-Hodgkin lymphoma is generally associated with active and widespread disease, but not necessarily a sign of malignant tissue in the liver. The elevations of GGT in myeloma may be secondary to liver infiltration though this group merits further detailed study.

Hodgkin Disease↗
PubMed1978

Hairy-cell leukemia with T-cell features.

A case of clinically and hematologically typical hairy-cell leukemia has been presented in which, at the various times of testing, 52%-95% of peripheral blood and 73% of splenic mononuclear cells formed spontaneous sheep erythrocyte (E) rosettes. Many of the rosetting cells were shown to be typical morphologic hairy cells by light and electron microscopy. It was found that 70%-75% of peripheral blood mononuclear cells stained with an anti-T antiserum, and this antiserum also abolished E-rosette formation. A variable percentage of peripheral blood mononuclear cells was also shown to bear surface (IgDK) and internal (IgMK and IgGK) immunoglobulins. Additional B-cell features demonstrated included possession of the P29/34 la-like antigen and formation of mouse rosettes. It was demonstrated by a variety of blocking and inhibition studies that the E-rosette formation was not attributable to chance antigen specificity of the surface membrane immunoglobulin. These marker studies suggest that this is a case of true hybrid cell HCL. Despite these unusual marker characteristics, the patient showed no distinctive clinical or hematologic features.

Animals↗
PubMed1978

Defective microbicidal function of neutrophils in haematological malignancies and lymphomas: correction by levamisole in vitro.

The ability of neutrophils to kill Candida guilliermondii was investigated in patients with various haematological malignancies and lymphomas. Twelve of 24 patients showed significant depression of Candida killing in vitro in comparison with normal controls. The addition of levamisole to the test system, in a concentration of 1 X 10(-7)M, resulted in the correction of the Candida killing defect in 7 of 8 patients.

Candida↗
PubMed1978

Serial measurement of beta2 microglobulin, acute phase reactant proteins and the ESR in non-Hodgkin's lymphomas and chronic lymphocytic leukaemia.

Long-term observation of non-Hodgkin's lymphomas indicates they can be sub-divided into two groups with respect to changes in the plasma proteins. The first group has acute phase reactant proteins raised during active disease and sometimes a raised B2m, whilst in remission the protein profile is normal. The second group is typified by a chronic elevation of B2m and ESR but has normal C-RP levels. Chronic lymphocytic leukaemia usually has a raised B2 m level and normal acute phase proteins, a subset with low B2 m is described.

Adult↗