Biomedical subjects

C M Giles

Publications and source records attributed to C M Giles.

At least 19 recordsLinked to original sources

PubMed1994

Hereditary complement factor I deficiency.

We describe four cases (from three families) of hereditary factor I deficiency, bringing the total number of cases now reported to 23. In one family there are two affected siblings: one has suffered recurrent pyogenic infections; the other is asymptomatic. In the second family, the patient had recurrent pyogenic infections and a self-limiting vasculitic illness; in the third family, the patient suffered recurrent pyogenic and neisserial infections. All four patients had markedly reduced concentrations of C3 in the serum (family 1 propositus: 28%; family 1 asymptomatic sibling: 15%; family 2: 31%; and family 3: 31% normal human serum) which was in the form of C3b. Low IgG2 levels may occur in primary C3 deficiency, and a reduction in IgG2 concentration to 1.14 g/l (normal: 1.30-5.90 g/l) was found in the patient from family 2. Using radioligand binding assays, we demonstrated increased binding of C3b to erythrocytes in a patient with factor I deficiency. This C3b could not be cleaved by autologous serum but could be cleaved by normal serum or purified factor I. We review and compare the published cases of C3, factor H and factor I deficiency.

Adolescent↗

PubMed1991

C4 Chido 3 and 6 distinguish two diabetogenic haplotypes: HLA-B49, SC01,DR4,DQw8 and B8,SC01,DR3,DQw2.

The combination of the HLA complement allotypes BFS, C2C, C4AQ0 (deleted gene) and C4B1, termed SC01 complotype, usually present in the HLA-B8,DR3,DQw2 diabetogenic haplotype, has also been found in a novel "low frequency" HLA-B49,DR4,DQw8 haplotype associated with Spanish insulin-dependent diabetes mellitus (IDDM). Family studies of C4 antigenic determinants Rodgers/Chido and their specific C4d nucleotide sequences confirm that this novel haplotype bearing Chido -3, -6 is not due to a recent recombination from the common HLA-B8,DR3 haplotype bearing Chido 3,6; moreover, Chido analysis at the serological or DNA level is presently the only way to distinguish both SC01 complotypes, since BF, C2, steroid 21-hydroxylase and C4 genes do not reveal other differences by restriction fragment analysis. On the other hand, HLA-B49,SC01,DR4 is the first DR4-bearing IDDM-susceptible haplotype with a deleted C4 gene described so far and the only DR4-bearing haplotype found in the Spanish population. This report further supports the fact that extended haplotypes with deleted (or "not duplicated") genes in the class III region contain IDDM-susceptibility more often than non-deleted (or "duplicated") haplotypes in the Spanish and other Mediterranean populations.

Base Sequence↗

PubMed1991

Immunoblotting human C4 bound to human erythrocytes in vivo and in vitro.

A study of C4 bound to human erythrocytes in vitro and in vivo has been made by immunoblotting with mouse monoclonal anti-C4c and anti-C4d and human polyclonal anti-C4d (Rodgers and Chido) following SDS-PAGE. Multi-banded patterns differentiated between C4A and C4B isotypes. Treatment of EC4b with trypsin eliminated immunoblotting but not agglutination reactions. Serum inactivation (factor I) of EC4b resulted in banding patterns similar to those obtained from patients' EC4d. Treatment of EC4b membranes with NH2OH affected many of the bands, two were lost, one was markedly reduced and others had altered SDS-PAGE mobility. Interpretation of the bands has been made in terms of C4-acceptor complexes and inactivation fragments of C4. A distinct difference in the banding of C4A and C4B isotypes has been detected.

Ammonium Hydroxide↗

PubMed1991

Three decades of reference serology.

I have tried to show that blood group serology developed rapidly out of necessity and demonstrated a high degree of polymorphism on red cells that was unmatched at that time in man. With new knowledge, these observations have proved to be accurate and informative and correlate well with subsequent biochemical and molecular studies on the antigenic structures, in spite of the fact that they were achieved by relatively simple technology. Serology still has the capacity to focus on points of interest and even to solve problems, albeit in conjunction with other modern and more sophisticated techniques. It provides a good discipline for any scientist to make unbiased and objective studies.

Animals↗

PubMed1991

Quantification of IgG on erythrocytes of patients and normals by a radio-ligand-binding assay.

A monoclonal IgG anti-human IgG, 1B12, was used in a radio-ligand-binding assay to quantify IgG on erythrocytes of patients and normals. The assay detected a range of 10-700 IgG molecules. Good correlation was achieved between the number of molecules and the strength of agglutination in antiglobulin tests performed in capillary tubes. The assay was capable of detecting subagglutinating immune bound IgG on erythrocytes from patients with systemic lupus erythematosus (SLE).

Antibodies, Anti-Idiotypic↗

PubMed1990

Null alleles of human complement C4. Evidence for pseudogenes at the C4A locus and for gene conversion at the C4B locus.

The two genes for the C4A and C4B isotypes of the fourth component of human complement are located in the MHC class III region. Previous studies have demonstrated the unusual expression of C4 genes in the form of aberrant or duplicated haplotypes. Null alleles of C4A or C4B (AQ0 or BQ0) have been defined by the absence of gene products and occur at frequencies of 0.1-0.3. However, only some C4 null alleles are due to gene deletions, the remainder were thought to be nonexpressed genes. We have analyzed the C4 gene structure of 26 individuals lacking either C4A or C4B protein. The DNA of individuals with apparently nonexpressed C4 genes was tested for the presence of C4A- and C4B-specific sequences using restriction fragment analysis and isotype-specific oligonucleotide hybridization of DNA amplified by polymerase chain reaction. All nondeleted AQ0 allels had C4A-specific sequences and may thus be described as pseudogenes, whereas the nondeleted BQ0 alleles had C4A-instead of C4B-specific sequences. Gene conversion is the probable mechanism by which a C4A gene is found at the second C4 locus normally occupied by C4B genes.

Alleles↗

PubMed1990

A study of HLA (Bg) on red cells and platelets by immunoblotting with monoclonal antibodies.

HLA class I antigens (Bg) on red cells (RBCs) are expressed by some normal donors and by many patients with systemic lupus erythematosus (SLE). To identify the membrane components previously detected by hemagglutination with HLA class I-specific monoclonal antibodies (MoAbs), RBC membrane preparations were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotted with the HLA class I MoAbs. Two components were obtained that reacted with the MoAbs: a heavy chain of 45 kDa and a light chain termed beta2-microglobulin (beta2-M) of 11 kDa. The effect of chloroquine and acid elution in stripping HLA antigens is shown to be due to the removal of beta2-M, as only that component was detected in eluates from reactive RBCs. Neither antibody elution method affected the heavy chain expression assessed by immunoblotting. It is concluded that HLA class I antigens on RBCs are integral membrane components of the type normally found and wisely distributed on many nucleated cells. Platelets, which have stronger HLA class I antigen expression, were also studied, and their membrane preparations yielded heavy chain and beta2-M molecules; the effect of chloroquine treatment was harder to assess than that of acid elution, owing to the sensitivity with which both components are detected in immunoblotting. In eluates obtained from acid treatment only beta2-M is detected.

Antibodies, Monoclonal↗

PubMed1990

HLA class I expression on erythrocytes and platelets from patients with systemic lupus erythematosus, rheumatoid arthritis and from normal subjects.

It has previously been shown, by a haemagglutination assay, that patients with systemic lupus erythematosus (SLE) express increased levels of HLA class I on erythrocytes compared with normal subjects and patients with rheumatoid arthritis (RA). A radioligand-binding assay, using monoclonal antibody W6/32, was devised to quantify HLA class I expression on erythrocytes and platelets. An increased number of class I molecules was expressed on erythrocytes from 45 patients with SLE (mean = 354 molecules per cell, median = 255 molecules, range = 30-1270 molecules per cell), compared with cells from 46 normal subjects (mean = 132, median = 78, range = 40-550) and 31 RA patients (mean = 132, median = 89, range = 26-497). The presence of HLA-B7 correlated with increased class I expression on erythrocytes from both normal subjects and patients with SLE. Levels of HLA class I in serum were measured. All subjects with HLA-A9 (A23, 24) showed higher levels of serum class I than their A9-negative counterparts, and there was no difference in levels between SLE patients and normal subjects. There were no correlations between class I levels in serum and on erythrocytes amongst SLE patients or normal subjects. Red cells were fractionated, according to their age in vivo, on Percoll gradients. Class I levels fell with increasing erythrocyte age in all individuals, but were higher in all fractions from SLE patients compared with age-matched fractions from normal subjects. HLA-B7-positive erythrocytes also expressed higher class I levels in each Percoll fraction, compared with their HLA-B7-negative counterparts, suggesting that enhanced B7 expression is not due to greater structural stability of this class I allotype. These data are compatible with the hypothesis that class I is expressed as an intrinsic protein of erythrocyte membranes and that expression is increased amongst patients with SLE.

Arthritis, Rheumatoid↗

PubMed1990

Erythroid HLA class I expression in 300 patients with haematological, renal and rheumatological disorders.

The expression of HLA class I was assessed on erythrocytes by haemagglutination with monoclonal antibodies to monomorphic epitopes on the heavy and light (beta 2-microglobulin) chains. Previously, enhancement of HLA class I expression was observed on erythrocytes of many patients with systemic lupus erythematosus (SLE) and chronic lymphatic leukaemia (CLL), and we have now tested erythrocytes from patients (and 130 normal controls) with other auto-immune diseases and renal and haematological disorders. The striking enhancement in patients with SLE and CLL was confirmed. A significant increase in expression was also observed in aplastic anaemia patients following bone marrow transplantation and in renal patients with primary glomerulonephritis who had received a transplant. No class I was expressed by erythrocytes from many patients with inherited haemoglobinopathies and high reticulocyte counts, which suggests that the enhancement in SLE patients cannot be accounted for by immature or young erythrocyte populations. The distribution of HLA-A and -B types in the patients with enhanced class I expression did not relate to those antigens previously detected more frequently on erythrocytes, B7(Bga), B17(Bgb), A28(Bgc), B8 or A10, and the enhancement was not associated with any particular HLA types.

Antibodies, Monoclonal↗

PubMed1990

C4 reference typing report.

Human C4 is most polymorphic at the protein level, distinction between allotypes of the C4A and C4B proteins resting on electrophoretic migration patterns and difference in hemolytic activity. The aim of the C4 reference typing has been the definition of reference variants, the assignment of rare variants, and the investigation of duplicated, deleted, or non-expressed and hybrid genes. Samples from 136 individuals, predominantly with known segregation, from 16 laboratories were investigated by standard electrophoretic techniques, for their relative hemolytic activity, reactivity with monoclonal antibodies and Rg/Ch reagents, alpha-, and beta-chain types, relative electrophoretic migration distance, as well as the C4/21-OH-TaqI RFLPs. The results were evaluated in three groups; they consisted in the definition of the eight most common C4 alleles, and the ten Rg/Ch standard phenotypes in group I. In group II twelve C4A and fourteen C4B duplications among 96 complotypes, as well as eighteen deleted/non-expressed C4A and twenty-two C4B alleles, and hybrid alleles were seen by correlation of lytic activity, electrophoretic mobility, and monoclonal and/or Rg/Ch reactivity. Group III consisted of the newly defined allotypes A 8, A 7, A 58, A 55, A 45, B 45, B 35, and B 22, furthermore of alleles subdividing the A 1/A 91, and the B 13/B 12/B 11 regions. The reference typing has allowed reclassification of the majority of described C4 allotypes and resulted in a revision of the C4 nomenclature.

Blood Grouping and Crossmatching↗

PubMed1990

C4: Rodgers and Chido typing.

Rodgers (Rg) and Chido (Ch)-typing, by means of haemagglutination inhibition, has been performed on 136 plasma/serum samples selected by or submitted to the 1989 Workshop. All were tested for two Rg and six Ch antigenic determinants and a proportion were also tested for WH. The established interrelationships for the antigenic determinants have been fully supported and previously reported associations with C4 allotypes have been maintained. A second example of the Ch phenotype Ch:-1, 2,-3,4,5-6 was detected in an Italian family with the B3 allotype.

Amino Acid Sequence↗

PubMed1990

C4 nomenclature statement (1990).

A common and revised nomenclature of the allotypes of the fourth component (C4) of human complement has been proposed. It is based on the results of the C4 Reference Typing of the VIth Complement Genetics Workshop and Conference, Mainz, FRG, 1989, the previous C4 nomenclature and the guidelines for human gene nomenclature (ISGN). The designation of allotypes derives from their relative electrophoretic mobility, the distinction between C4A and C4B proteins from their relative hemolytic activity. Common alleles retain their single digit numeric designation, intermediate variants their two- or three-digit designations; newly discovered alleles should not interfere with already described variants. At least 13 C4A alleles, 16 C4B alleles as well as non-expressed genes at each C4 locus are presently known. There are also duplicated loci of each C4 gene; they should be designated by repetition of the locus symbol at the haplotype or genotype level. As a phenotype they will be placed in parenthesis without repetition of the locus symbol. Aberrant allotypes or hybrid genes should be explained by a special suffix. No special nomenclature is recommended for restriction fragment length polymorphisms. Their designation should follow the general rules of the ISGN.

Alleles↗

PubMed1990

Human leukocyte antigens (HLA) class I (Bg) on red cells studied with monoclonal antibodies.

Monoclonal antibodies, capable of detecting monomorphic epitopes on HLA class I polypeptides and beta-microglobulin (Beta2-M), have been used by a variety of techniques to ascertain the type of structure detected on red blood cells (RBCs). Hemgglutination with class I monoclonal antibodies confirmed the reported relationship between Bg blood groups and HLA. It also established that the expression of HLA on RBCs which do not have nuclei is not normally strong, but may be enhanced in patients, notably those with systemic lupus erythematosus (SLE). Estimates of the number of class I molecules on mature RBCs by a radioligand-binding assay have confirmed that all HLA-B7 (Bga) individuals have higher numbers but that SLE patients usually have the most (124/RBC). Class I polypeptides were not elevated in the plasma of SLE patients and all RBCs lost molecules on aging in the circulation. These two facts suggest that HLA on RBCs is not acquired from plasma. when RBCs from SLE patients were immunoblotted with monoclonal antibodies, a complete 45 kDa intrinsic transmembrane heavy chain of HLA class I and a light chain of 11 kDa (Beta2-M) were detected. Chloroquine treatment and acid elution of RBCs did not remove HLA class I but only Beta2-M, As most antibodies recognize epitopes that depend on close association of class I with Beta2-M, the lost reactivity of treated RBCs may be understood.

Journal Article↗

PubMed1989

An epitope on C4 beta light (L) chains detected by human anti-Rg; its relationship with beta chain polymorphism and MHC associations.

Two out of ten Rg-specific antisera tested contain a third antibody specific for the beta chain of C4. Analysis of the beta chains of 66 unrelated individuals by sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed that the epitope detected is located exclusively on the light (L) beta chain. A strong, but incomplete, association between the beta chain epitope and the expression of the Rg:2 determinant on the alpha chain of the same protein was also observed. While H (heavy) and L beta chains were not associated with a particular C4 isotype, previously unrecorded associations of beta chain polymorphism with the DR locus have been established.

Antibodies, Monoclonal↗

PubMed1989

HLA class I (Bg) antigens on red cells of SLE patients: a serological study with polyclonal and monoclonal antibodies.

The enhanced HLA class I (Bg) on red blood cells (RBC) of many patients with systemic lupus erythematosus has allowed a significant correlation to be made between their HLA-B types and haemagglutination reactivity with lymphocytotoxic anti-HLA-B sera stimulated by pregnancy alone. Therefore the class I expression on these RBC relates to classical, rather than non-classical, class I gene products. Studies of class I expression on RBC by means of monoclonal antibodies (MAb) to epitopes on the heavy polypeptide chain and beta 2-microglobulin (beta 2m) have suggested that the complete extracellular structure is present. The specific effect of chloroquine in 'stripping HLA' from RBC had been assumed to support the concept that HLA class I was adsorbed from plasma. However, from our data, we conclude that HLA class I is an intrinsic membrane component. We suggest that the action of chloroquine is to remove beta 2m alone, which prevents normal class I expression and also results in conformational changes to the class I heavy chain, but that it is not capable of removing the membrane-bound heavy chain.

Antibodies↗

PubMed1989

An update on Rodgers and Chido, the antigenic determinants of human C4.

Rodgers (Rg) and Chido (Ch) blood groups are antigenic determinants of the fourth component of human complement (C4). Nine determinants have been defined by means of hemagglutination-inhibition (HAI) with polyspecific human antiserums. The association of C4A isotypes with Rg and of C4B isotypes with Ch is strong hut not complete. Derived amino acid sequences from the C4d region of selected C4 allotypes of known antigenic expression have provided support for the previously reported complex serologic interrelationships. A structural model for antigenic determinants at four polymorphic sites, incorporating sequential and conformational epitopes, was subsequently proposed. Allotype and Rg/Ch data obtained from donors and patients, many with accompanying families, have augmented the model and revealed no exceptions. The antigenic determinants, therefore, make an important contribution to the complex polymorphism of C4.

Journal Article↗

PubMed1988

Antigenic determinants expressed by human C4 allotypes; a study of 325 families provides evidence for the structural antigenic model.

The antigenic determinants of human C4 have been defined by human IgG antisera, Rodgers (Rg) and Chido (Ch), in hemagglutination-inhibition assays (HAI). Eight (2 Rg and 6 Ch) are of high frequency, greater than 90%, and 1, WH, is of low frequency, 15%. The phenotypic combinations are complex; generally, C4A expresses Rg, and C4B has Ch, but reverse antigenicities have been established both by HAI and by sequence data of selected C4 allotypes. A study of 325 families provides data on the antigenic expression of each C4 allotype and demonstrates strong associations. A structural model for the antigenic determinants of C4 proteins has been proposed and is completely supported by the family material. Of the 16 possible antigenic combinations for C4 proteins, only 3 are undetected. A new Ch combination has been recorded in two French families. The reported sequence variation within the C4d region can account for the antigenic determinants but leaves the location of electrophoretic variation in C4 still unclear.

Blood Group Antigens↗

PubMed1988

A new low-frequency antigen BOW (Bowyer).

BOW is a 'new' low-frequency red-cell antigen, detected in 2 unrelated English blood donors, that is sensitive to alpha-chymotrypsin and pronase. Anti-BOW is present in many polyspecific reagents used to define low-frequency antigens. Red-cell groups of the proposita, R.B., and her family show that the BOW blood group segregates independently from the ABO, Rh, MNSs, P1 and Kell blood group systems.

Blood Donors↗