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Biomedical subjects

M E Conley

Publications and source records attributed to M E Conley.

At least 91 records · Page 5Linked to original sources
PubMed1989

Clonal diversity in the B cell repertoire of patients with X-linked agammaglobulinemia.

Ig protein and mRNA expression was examined in a collection of 18 monoclonal EBV-transformed B cell lines derived from five patients with X-linked agammaglobulinemia (XLA). A diversity of H and L chain isotypes were synthesized by these lines: the majority (12 lines) expressed mu kappa chains, while mu lambda (two lines), gamma kappa (one), gamma lambda (one), delta lambda (one), and alpha kappa (one) isotype expression was also observed. For all the mu kappa-producing XLA B cell lines, the mu and kappa mRNA transcripts were of native size, and sequence analysis across the regions of VHDJH and V kappa J kappa gene joining showed that Ig gene rearrangements occurred in a typical manner. A variety of VHDJH and V kappa J kappa gene rearrangements were observed, not only within the set of mu kappa+ XLA B cells as a whole, but also among the cell lines derived from single patients. Southern blot analysis for genomic Ig H chain gene rearrangements was done to fully assess the extent of clonal heterogeneity among multiple mu kappa+ XLA B cell lines derived from two patients; all the B cell lines possessed distinct gene rearrangement patterns demonstrating their clonal unrelatedness. Our findings indicate that the B cell repertoire in individual XLA patients is clonally diverse and that it is unlikely that the defect in B cell differentiation in XLA is the result of inefficient or ineffective rearrangement of Ig H or L chain genes. Rather, this study provides support for the idea that the XLA defect relates to a more generalized cellular function, such as regulating the proliferation and/or clonal expansion of cells of the B lymphoid lineage.

Adolescent↗
PubMed1989

X-linked severe combined immunodeficiency: localization within the region Xq13.1-q21.1 by linkage and deletion analysis.

X-linked severe combined immunodeficiency (SCID) (McKusick 30040; IMD4) is a disease of unknown pathogenesis characterized by severe and persistent infections from early in life that are due to absence of both cellular and humoral immune function. Although the disease has been provisionally mapped to proximal Xq, high lethality and lack of a carrier test have limited the number of scorable meioses. We performed linkage analysis in six new kindreds with X-linked SCID, using a random pattern of T-cell X inactivation to rule out the carrier state in at-risk women. Our linkage results, combined with analysis of Xq interstitial deletions, confirmed the regional assignment of X-linked SCID, narrowed the boundaries within which this locus lies to Xq13.1-q21.1, and established the locus order DXS159-(PGK1, SCID)-DXS72-DXS3, defining flanking markers for prenatal diagnosis and carrier testing.

Female↗
PubMed1988

Carrier detection in typical and atypical X-linked agammaglobulinemia.

We have recently demonstrated that B cells from obligate carriers of typical X-linked agammaglobulinemia (XLA) exhibit nonrandom X chromosome inactivation. The active X is always the X that does not carry the gene defect. To determine if this were also true in carriers of atypical XLA and to provide carrier detection for all women at risk of being carriers of XLA, we developed a technique that permits analysis of X chromosome inactivation in cells from any woman. This technique combines the production of somatic cell hybrids that selectively retain the active X chromosome with the use of X-linked restriction fragment length polymorphisms that permit the distinction of the two X chromosomes. Three obligate carriers of typical XLA and four women whose sons might be considered to have atypical or sporadic XLA were studied. B cell hybrids from all seven women demonstrated exclusive use a single X as the active X. In addition, B cell hybrids from four of eight women at 25% or 50% risk of being carriers exhibited nonrandom X chromosome inactivation, indicating that these women were also carriers of X-linked forms of hypogammaglobulinemia. These results illustrate a technique that can be used both to help define XLA and to provide carrier detection for all women at risk of being carriers of this disorder.

Agammaglobulinemia↗
PubMed1988

Nonrandom X chromosome inactivation in B cells from carriers of X chromosome-linked severe combined immunodeficiency.

X chromosome-linked severe combined immunodeficiency (XSCID) is characterized by markedly reduced numbers of T cells, the absence of proliferative responses to mitogens, and hypogammaglobulinemia but normal or elevated numbers of B cells. To determine if the failure of the B cells to produce immunoglobulin might be due to expression of the XSCID gene defect in B-lineage cells as well as T cells, we analyzed patterns of X chromosome inactivation in B cells from nine obligate carriers of this disorder. A series of somatic cell hybrids that selectively retained the active X chromosome was produced from Epstein-Barr virus-stimulated B cells from each woman. To distinguish between the two X chromosomes, the hybrids from each woman were analyzed using an X-linked restriction fragment length polymorphism for which the woman in question was heterozygous. In all obligate carriers of XSCID, the B-cell hybrids demonstrated preferential use of a single X chromosome, the nonmutant X, as the active X. To determine if the small number of B-cell hybrids that contained the mutant X were derived from an immature subset of B cells, lymphocytes from three carriers were separated into surface IgM positive and surface IgM negative B cells prior to exposure to Epstein-Barr virus and production of B-cell hybrids. The results demonstrated normal random X chromosome inactivation in B-cell hybrids derived from the less mature surface IgM positive B cells. In contrast, the pattern of X chromosome inactivation in the surface IgM negative B cells, which had undergone further replication and differentiation, was significantly nonrandom in all three experiments [logarithm of odds (lod) score greater than 3.0]. These results suggest that the XSCID gene product has a direct effect on B cells as well as T cells and is required during B-cell maturation.

Alleles↗
PubMed1987

In vitro regulation of IgA subclass production. III. Selective transformation of IgA1 producing cells by Epstein-Barr virus.

In past experiments, using limited dilution analysis, we have demonstrated that a high percentage of immunoglobulin-secreting clones derived from Epstein-Barr virus- (EBV) stimulated lymphocytes secrete IgA. To further characterize the IgA produced by these clones, the IgA subclass of supernatants from clones stimulated 4 to 6 wk previously with EBV was determined by radioimmunoassay. All of 17 IgA-producing clones secreted IgA1; none secreted IgA2. Because we have shown that surface IgM+ (sIgM+) B cells are an enriched source of IgA2 plasma cell precursors, panning techniques were used to purify sIgM+ B cells from tonsils. Of 103 clones derived from these sIgM+ B cells, 102 secreted IgA1 and only one secreted IgA2. The relative absence of IgA2-producing clones could not be attributed to an absence of EBV receptors on IgA2 cells. A mean of 84 +/- 4% of freshly isolated IgA2 B cells and 78 +/- 6% of IgA1 B cells could be stained with a monoclonal antibody binding the EBV receptor; and there was no failure of EBV to infect IgA2 plasma cells precursors. Of IgA2 plasma cells derived from peripheral blood lymphocytes stimulated 7 days previously with EBV, 54 +/- 7% were positive for the EBV nuclear antigen, compared with 54 +/- 18% of IgA1 plasma cells from the same cultures. Seven days after EBV stimulation, a mean of 25% of the total IgA plasma cells were positive for cytoplasmic IgA2, whereas by 21 days after stimulation only 7% were positive for IgA2. This shift in the proportions of IgA1 and IgA2 plasma cells could be attributed to a failure of the IgA2 plasma cell number to increase after 10 days in culture. There was no evidence for selective suppression of IgA2 production by T cells or selective lysis of IgA2 plasma cells by infectious EBV particles. These results demonstrate that although precursors for both IgA1- and IgA2-producing cells can be stimulated to differentiate in response to EBV, there is preferential transformation of IgA1-producing cells.

Antibody-Producing Cells↗
PubMed1987

IgG subclass potential of surface IgM-negative and surface IgM-positive human peripheral blood B cells.

To examine the IgG subclass potential of B cells at various stages of maturation, human peripheral blood B cells were separated into surface IgM-positive (sIgM+) and surface IgM-negative (sIgM-) cells by panning techniques and cultured with pokeweed mitogen, LPS, or Epstein-Barr virus. At the end of 7 days, cells were harvested, counted, spun onto slides, fixed, and stained with subclass-specific monoclonal antibodies. In all experiments with all mitogens, there was an enrichment of IgG2 plasma cells in sIgM+ cultures compared to the sIgM- cultures (P less than 0.0001). In the Epstein-Barr virus-stimulated cultures there was also a statistically significant enrichment for IgG3 in the sIgM+ cultures (P less than 0.01). In contrast, sIgM- cultures were always enriched for IgG1 plasma cells (P less than 0.0001). In the pokeweed mitogen-stimulated cultures, the sIgM- cultures also contained a higher proportion of IgG4 plasma cells than did the sIgM+ cultures (P less than 0.01). These results demonstrate that the IgG subclass potential of immature, surface IgM-positive precursors of IgG plasma cells differs from that of more mature surface IgM-negative precursors.

B-Lymphocytes↗
PubMed1987

Recurrent infections and staphylococcal liver abscess in a child with C1r deficiency.

Complete absence of the C1r portion of the first component of complement was found in a 2 1/2-year-old boy of Puerto Rican origin who presented with a staphylococcal liver abscess. His medical history also included two episodes of pneumonia complicated by a pneumatocele and empyema, purulent staphylococcal lymphadenitis, recurrent otitis media, and pneumococcal bacteremia. The C1s component of complement was 50% of normal, and C4 was elevated. Other immunologic tests, including nitroblue tetrazolium test, and IgE were normal. This is the tenth patient reported with C1r deficiency. The patient differs from other reported patients with C1r deficiency in that he presented with a liver abscess, an infection that has not been reported in patients with complement deficiencies, and in that he has an apparent susceptibility to staphylococcal infection.

Child, Preschool↗
PubMed1987

Relationship of the genes for Chediak-Higashi syndrome (beige) and the T-cell receptor gamma chain in mouse and man.

The genetic linkage of Chediak-Higashi syndrome and its murine analog, beige (bg), to the T-cell receptor (TCR-gamma) gamma chain gene is further defined. Previous studies using recombinant inbred strains of mice demonstrated that the murine bg gene is genetically linked to a murine TCR-gamma gene. We report that in the mouse the frequency of recombination between these two markers is 0.025. Further, we tested the hypothesis that these two genes are linked in the human genome by analyzing restriction fragment length polymorphisms (RFLPs) in five families with children afflicted with Chediak-Higashi syndrome. In three families, RFLPs in TCR-gamma genes were inherited discordantly from Chediak-Higashi syndrome, demonstrating nonlinkage. We postulate that there is an evolutionary chromosomal breakpoint between the bg gene and the TCR-gamma gene.

Animals↗
PubMed1987

Carrier detection in X-linked severe combined immunodeficiency based on patterns of X chromosome inactivation.

The X-linked form of severe combined immunodeficiency (XSCID) is underdiagnosed because no methods have been available for detecting carriers. Although boys with XSCID are deficient in T cells, female carriers are immunologically normal. Carriers' normal immune function would be expected if all their T cells were derived from precursors whose X chromosome bearing the XSCID mutation was inactivated early in embryogenesis. Using somatic cell hybridization to separate the active and inactive X chromosomes and restriction fragment length polymorphisms to distinguish them, we have determined the lymphocyte X inactivation pattern in XSCID carriers and their female relatives. In the T cells of three carriers, the X chromosome bearing the XSCID mutation was consistently inactive. Nonrandom X inactivation was also found in the T cells of one at-risk female, while two others had normal, random X inactivation. This method constitutes a generally applicable carrier test for XSCID.

Alleles↗
PubMed1987

Intravascular and mucosal immunoglobulin A: two separate but related systems of immune defense?

Immunoglobulin A has long been referred to as the antibody of mucosal secretions. However, in the last few years there has been increased interest in serum IgA, in factors that regulate the various forms of IgA produced, and in the relationship between serum and mucosal IgA. Recent data indicate that in humans, the mucosal surfaces are neither the source nor the destination of serum IgA. By estimating the amounts of IgA produced at various sites throughout the body, we have shown that in humans more IgA is synthesized and secreted each day than IgG and IgM combined; about one third of this IgA is secreted directly into the vascular compartment and never reaches the mucosal surfaces. We also consider a possible role for serum IgA as the "discreet housekeeper," the relationship between cells that produce IgA in the serum and IgA in secretions, and factors that influence the various forms of IgA produced.

Animals↗
PubMed1987

A polymeric IgA response in serum can be produced by parenteral immunization.

The magnitude and the kinetics of the serum-specific polymeric (p-) and monomeric (m-) IgA antibody responses were analysed following parenteral stimulation with tetanus toxoid (TT) vaccine in 10 volunteers, 5-20 years after a previous boost. A rapid marked serum IgA antibody response involving both the monomeric and polymeric components of IgA was observed: m-IgA and p-IgA antibodies reached a peak of serum activity at about 11 days, around 6 days before the peak of IgG antibody activity. At the peak of the IgA response, p-IgA accounted for approximately half of the anti-TT activity (median 54%, 25-79%). However, p-IgA antibodies rapidly disappeared from serum over a few weeks, whereas the serum m-IgA antibody response was maintained over a prolonged period of time. For one subject out of five, anti-TT IgA were also detected in saliva with a peak of activity earlier than in serum. Calculation of the albumin relative coefficient of excretion for anti-TT IgA in this saliva suggested a local synthesis of these antibodies. The present study indicates that a polymeric IgA antibody response in serum can be produced by parenteral immunization in primed individuals, and it raises the question of the mechanisms that control polymeric versus monomeric IgA production.

Adult↗
PubMed1986

Monoclonal antibodies against isotypic and isoallotypic determinants of human IgA1 and IgA2: fine specificities and binding properties.

We have analysed and compared the fine specificity and behavior in various immunoassays of 10 mouse monoclonal antibodies, from three independent laboratories, directed against IgA1, IgA2 or non-IgA2m(2). The following observations were made. (1) Although all of the monoclonal antibodies were specific for a particular IgA subclass or isoallotype in a radioimmunoassay, three of them were not specific when tested in indirect immunofluorescence on plasma cells derived from pokeweed-activated peripheral blood lymphocytes. In this highly sensitive system, contrary to direct immunofluorescence previously performed using formalin-fixed lymphoid tissue, the anti-IgA1 69.114 reacted with some of the IgA2 plasma cells, the anti-IgA2 DLDB7 reacted with some of the IgA1 plasma cells and the anti-IgA2 16.512 dimly reacted with all IgM plasma cells. (2) Among the eight anti-IgA subclass antibodies, seven were directed against the CH2 domain of IgA whereas the anti-IgA1 1-155-1 recognised an epitope destroyed by Streptococcus sanguis IgA1 protease and localised in the hinge region of IgA1. The two anti-isoallotype antibodies were directed against epitope(s) probably localised in the 65 C-terminal amino acid residues of the alpha-CH3 domain. All of the 10 antibodies were able to react with endogeneously produced surface IgA on B-cells. (3) Using monoclonal anti-IgA subclass antibodies in radioimmunoassay may be hazardous in the absence of knowledge of their affinity constants and of careful control experiments: some of the antibodies were not sensitive in radioimmunoassays designed to measure the serum titer of specific IgA1 and IgA2 antibodies. Moreover, major differences were observed between the different monoclonal reagents with respect to the influence of the size of IgA on a solid-phase sandwich radioimmunoassay. While three of the anti-IgA1 underestimated dimeric IgA relative to monomeric IgA, the fourth anti-IgA1 and all the anti-IgA2 overestimated dimeric IgA relative to monomeric IgA, by a factor sometimes close to 7.

Animals↗
PubMed1986

Childhood common variable immunodeficiency with autoimmune disease.

Clinical and laboratory findings in eight patients with childhood common variable immunodeficiency and autoimmune disease are described. Six of the eight patients had initial signs of the disease, persistent secretory diarrhea, recurrent upper respiratory tract infections, or both, in the first year of life. Autoimmune manifestations included idiopathic thrombocytopenia (4/8), hemolytic anemia (3/8), secretory diarrhea (4/8), arthritis (2/8), chronic active hepatitis (2/8), parotitis (2/8), and Guillain-Barré syndrome (2/8). In addition to the expected sinusitis, otitis, and pneumonia caused by encapsulated bacteria, these patients also had severe infections with viruses of the herpes group. Most of these patients had lymphadenopathy, splenomegaly, growth failure, and failure to develop secondary sexual characteristics. Laboratory studies demonstrated a significant increase in the ratio of T cells expressing the T helper phenotype (OKT4) to T cells expressing the T suppressor-cytotoxic phenotype (OKT8) (T4/T8). This increase could be attributed to a decrease in the absolute number of T8 cells. Additional findings included fluctuating levels of serum immunoglobulins and markedly diminished in vitro antibody production by B cells. The clinical course was relapsing and remitting, and dominated by the autoimmune manifestations of the disease. This group of patients constitutes a distinct subset of children with hypogammaglobulinemia, a subset with a complex, multisystemic disorder associated with significant morbidity and mortality.

Adolescent↗
PubMed1986

The pathology and treatment of interstitial pneumonitis in two infants with AIDS.

Two infants with AIDS who presented with interstitial pneumonitis, failure to thrive, lymphadenopathy, and hypergammaglobulinemia have been studied. Antibody to human T-lymphotropic retrovirus (HTLV-III) was identified by ELISA and Western blot analysis in serum samples from both patients. The T4/T8 ratios of peripheral blood T-lymphocytes in both patients were mildly decreased, with normal absolute numbers of lymphocytes and positive T4 cells. Lung biopsies from both patients demonstrated similar histopathologic features with features of lymphocytic interstitial infiltrates and accumulation of macrophages in the air spaces. Immunoperoxidase studies of the lung biopsy from 1 patient revealed that the lymphocytic infiltrate was composed predominantly of T cells of the T8 subset. Each patient was treated with prednisone, with improvement or resolution of pulmonary symptoms, hepatosplenomegaly, lymphadenopathy, and growth failure. Neither patient has had any opportunistic infections. One patient has been followed for more than 4 years and the other for 8 months.

Acquired Immunodeficiency Syndrome↗