IgG allotypes and subclasses in Norwegian patients with multiple sclerosis.

Multiple sclerosis (MS) is a multifactorial disease in which genetic and environmental factors apparently have a major influence on the susceptibility and course of the disease. In the present study we have investigated the genetic basis and subclass levels of IgG in MS. Hundred and thirty-six Norwegian patients with MS and 92 controls were genotyped for IgG allotypes of the GM and KM systems. IgG and IgG subclasses were quantified in sera from 115 MS patients and 20 controls. Neither GM nor KM allo-, haplo- or genotypes were significantly correlated with susceptibility, severity or course of the disease. The G1M (3) (3), G2M (23) (23) and G3M (5) (5) allotypes were significantly correlated with high serum levels of IgG3, whereas high IgG2 levels were correlated with G1M (3) (3) and G2M (23) (23) in both patients and controls. Serum levels of IgG subclasses were not significantly correlated with course or severity of the disease. The results indicate no major role for IgG allotypes or IgG subclass levels in the pathogenesis of MS.

GM and KM immunoglobulin allotypes in a Spanish Pyrenean population: Val d'Aran.

Four hundred and thirteen unrelated individuals (202 autochthonous and 211 non-autochthonous) of Val d'Aran (Catalan Pyrenees) have been analysed for the GM and KM immunoglobulin genetic system using the inhibition haemagglutination method. This population was defined by eight GM haplotypes (GM*3 23 5*, GM*3 5*, GM*1,17 21,28, GM*1,2,17 21,28, GM*1,17 5*, GM*1,17 5,6,11,24, GM*1,17 10,11,13,15 and GM*1,17 10,11,13,15,16) inferred from the 17 observed phenotypes. The Val d'Aran population frequencies conform to Hardy-Weinberg expectations. The frequencies of phenotypes and haplotypes show a definite homogeneity between the autochthonous and non-autochthonous people of Val d'Aran and 11 other Pyrenean populations (Mauléon, Macaye, St. Jean Pied de Port, Vallée de L'Ouzom, Gavarnie, Barèges, Luz St. Sauveur, Esparros, Camurac, Capcir and Pays de Sault) that have already been studied for the same allotypes. A factorial correspondence analysis was performed for the 12 autochthonous Pyrenean populations, showing a high frequency of the GM*3 23 5* haplotype in the three Pyrenean regions (Western, Central and Eastern), while the GM*1,17 21,28 haplotype is mainly found in the Central region, GM*3 5* in the Eastern and Western zones, and the GM*1,2,17 21,28 is mainly present in the Central and Eastern populations. The results show a relative regional homogeneity, so there is no evidence of a frequency gradient in the Pyrenean populations for the GM and KM genetic systems. It may, however, be noticed that the Central Pyrenean populations form a group, with one population (Vallée de l'Ouzom) isolated from the rest, probably because of its particular model of inheritance by which the heritage is passed to the first born without sex consideration. It has been possible to point out some differences in the genetic structure of the autochthonous and non-autochthonous Val d'Aran population and to place the autochthonous Aranese group among its Pyrenean neighbours.

GM and KM allotypes in eight tribal populations of Madyha Pradesh and Orissa, India.

Serum samples from eight endogamous Indian tribal populations of Madhya Pradesh (Dhurwa, Halba, Bhatra, Muria, Maria) and Orissa (Deshia Khond, Binjhal, Kisan) with a total of n = 731 unrelated individuals were typed for G1M (1,2,3,17), G3M (5,10,11,13,14,15,16,21, 26), and KM (1). In seven of these populations five different GM haplotypes were found: GM* 1,17;21,26; GM* 1,17;10,11,13,15,16; GM* 1,2, 17;21,26; GM* 1,3;5,10,11,13,14,26; and GM* 3;5,10,11,13,14,26. In the Kisan sample the haplotype GM* 1,2,17;21,26 is absent. The intergroup variability in the distribution of these haplotypes is considerable and statistically highly significant. The reasons for that can be attributed to the ethnohistory and to the genetic isolation of these eight endogamous tribal populations. The GM haplotype distribution pattern of all these groups is quite different from that of the non-tribal populations of India, whereas it is in good agreement with that of the so far tested other tribal populations from India. This can be explained by different origin and history of the Indian tribal and non-tribal populations. In the KM system, too, remarkable variability is seen in the distribution of phenotype and allele frequencies among the eight tribal populations under study.

Gm and Km allotypes in autoimmune diseases.

The associations or linkages between the polymorphisms of the Gm and Km immunoglobulin allotypes and the susceptibility to autoimmune diseases, including diseases with immuno-pathological pathogenesis are reported in this review. These diseases include multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, insulin-dependent diabetes mellitus, Crohn's disease, coeliac disease, Graves' disease, atrophic thyroiditis, Hashimoto's thyroiditis, myasthenia gravis, chronic active hepatitis, alopecia areata, uveitis, vitiligo, Turner's syndrome, glomerular nephritis, Berger's disease and idiopathic dilated cardiomyopathy. Immunoglobulin allotypes are described as well as the statistical methods used to analyse the data.

Polymorphisms of human immunoglobulins: Gm, Am, Em and Km allotypes.

A brief review of the polymorphisms of human immunoglobulins (Ig) is presented here as the introductory paper of this special issue on Ig allotypes. The different allelic forms of the Ig genes for the heavy chains of IgG1, IgG2, IgG3, IgA2 and IgE and for the kappa light chains, which give rise to the G1m, G2m, G3m, A2m, Em and Km allotypes, respectively, are discussed. Until now, 24 allotypes have been described and confirmed by other investigators: 4 G1m, 1 G2m, 13 G3m, 2 A2m, 1 Em and 3 Km allotypes. The alleles of the heavy chain genes are inherited in haplotypes because these genes are located close to each other on chromosome 14. The variations in haplotype frequencies in different populations and the occurrence of isoallotypes in IgG and IgA subclasses are discussed. Applications of Ig allotyping and new developments in this field are mentioned with reference to the other papers in this issue.

HLA and immunoglobulin allotypes in mixed connective tissue disease.

A group of patients with mixed connective tissue disease (MCTD) were HLA and immunoglobulin allotyped. We found that the incidence of DR4 in the patient group was increased compared with that in the normal controls, but the increase was restricted to the subgroup of patients with arthritis. The age at onset of MCTD was lower in patients with DR4 and higher in patients with DR2 compared with patients who did not have these antigens. A1, B8, and DR3 were more frequent, but not significantly so, in the MCTD patient group. We also found that there was a significant perturbation of the Gm allotype frequencies in patients with MCTD.

Immunoglobulin allotypes in head and neck cancer patients with multiple primary cancers.

Immunoglobulin allotypes G1m, G2m, G3m, A2m and Km were determined in patients with a single head and neck cancer and in head and neck cancer patients with multiple primary tumours. Frequencies were compared with those of healthy controls. In all 39 patients with multiple primary tumours studied, Km(1) was absent vs. 82% and 75% absence in healthy controls and patients with a single head and neck cancer, respectively. This difference is highly significant. We conclude that head and neck cancer patients lacking the Km(1) are susceptible to the development of new cancers, and therefore should be screened thoroughly for more tumours.

Three Chido determinants detected on the B5Rg+ allotype of human C4: their expression in Ch-typed donors and families.

A study was made of polyspecific human allo-anti-C4, anti-Chido (Ch), which reacts with determinants usually located on C4B protein. Some anti-Ch reagents are capable of reacting with Ch- red cells coated with C4 from Ch:-1,-2,-3 donors. A complex serologic pattern demonstrated three more Ch determinants, Ch4, Ch5, and Ch6, which were detected by haemagglutination-inhibition tests. All Ch:1,2,3 samples were Ch:4,5,6 but samples lacking one or more of the Ch1,Ch2,Ch3 series of determinants also lacked some of the new determinants. MHC typed families demonstrated the inheritance of the new determinants as part of the Ch haplotype, and associations with C4 allotypes and haplotypes have been established. Ch4 always associates with C4B protein. Ch5 and Ch6, normally detected on C4B protein, were detected in several individuals who lacked C4B (BQO allotypes) and were therefore presumed in these instances to be located on the accompanying C4A protein.

Influence of immunoglobulin-dependent T cells on antibody class switching.

Normal and B cell-deficient, carrier-primed mice were irradiated and were adoptively transferred with B cells to evaluate the role of putative Ig- and B cell-dependent T cells in anti-hapten antibody responses. The response was analyzed by using the splenic focus assay, which allowed us to examine the frequency of responding B cells and the production of multiple isotypes by single precursor B cells. This analysis revealed that both primary and secondary B cells were activated at higher frequency in the spleens of normal recipients, and production of isotypes other than IgM and IgG1 was enhanced in normal recipients as compared with anti-mu-treated recipients. Both changes could be restored to control levels by co-transfer of T cells from normal donors primed with an unrelated carrier, provided the free carrier was added to the assay culture. These results are consistent with a role for Ig or B cell-dependent helper T cells in the optimal activation and the resulting isotype expression of both primary and secondary B cells.

Idiotypic analysis of a B cell clone with anti-intermediate filament specificity in a patient with Sjögren's syndrome: involvement of five subpopulations producing different immunoglobulin isotypes.

An IgM paraprotein from patient LP with Sjögren's syndrome exhibited an antibody activity to intermediate filaments (IMF) of cells from all vertebrates examined, and appeared to recognize several classes of IMF (i.e., vimentin, desmin, and keratin). A mouse monoclonal anti-idiotype (Id) antibody, K4A, was prepared against the IgMk (LP) and used as a specific probe in two-color immunofluorescence to examine the extent of clonal involvement in the patient's blood and bone marrow mononuclear cells (MNC). Twenty to 30% of MNC in her blood samples were IgMk+ plasmablasts with morphologic similarity to Waldenström's macroglobulinemia cells. IgG+ and IgA+ plasmablasts were demonstrated in lower frequencies (approximately 2%). Almost all of the IgM+ cells and approximately 80% of the IgG+ cells and IgA+ cells in the blood were reactive with the K4A anti-Id antibody. Immunoglobulin (Ig) subclass analysis revealed that the K4A Id was expressed by IgG1+, IgG3+, IgA1+ and IgA2+ plasmablasts. Similar observations were obtained with bone marrow samples, although the proportion of Id+ cells among IgG+ or IgA+ cells was lower in marrow than in blood. IgG and IgA fractions isolated from the patient's serum were also shown to contain anti-IMF activity. Ig biosynthetic analysis of blood MNC revealed that the K4A anti-Id antibody precipitated not only IgM but also IgG and IgA. Because cells simultaneously producing two different Ig isotypes were not detected, these results indicate the presence of five separate subpopulations of the K4A Id+ neoplastic clone. The data thus suggest the occurrence of a neoplastic or pre-neoplastic transformation event before the switching of Ig heavy chain isotypes, and imply a role for the IMF antigen in the exaggerated proliferation and differentiation along five of the nine potential intraclonal pathways.

Class-switching from mu to gamma 3 or gamma 2b production at pre-B cell stage.

An Abelson virus-transformed murine pre-B cell line class-switched from mu to gamma 3 or gamma 2b at the pre-B stage during culture. A class-switch was mediated by the deletion mechanism of the intervening CH genes on the active chromosome. This study showed for the first time that class-switching at the pre-B cell stage was not always confined to gamma 2b production.

Lymphocyte function in human bone marrow. III. Isotype commitment, metabolic and secretory characteristics of immunoglobulin producing cells.

We have examined the functional and metabolic properties of immunoglobulin (Ig)-secreting cells in adult (rib) bone marrow, the tissue which provides the major proportion of serum Igs. In the absence of polyclonal activators, high rate Ig production (1-2 micrograms/day/10(6) marrow mononuclear cells) was sustained from the beginning of culture throughout 2 weeks and then declined. Ten percent of the Ig secreted was of the IgM isotype and IgG/A made up the remainder at equal proportions. Infection of marrow cells with Epstein-Barr virus (EBV) induced the production of large amounts of IgM, but virtually all IgG/A-committed cells were refractory to stimulation with EBV. Both EBV-induced and the "spontaneous" Ig production was inhibited by cycloheximide, but only EBV-induced IgM production was blocked by hydroxyurea and gamma-irradiation. The polyclonal activators PHA and PWM induce suppressor-T-cell activity in marrow cultures. This suppressor function involves nonproliferating cells which acquire suppressive activity 3-4 days after mitogenic activation. Prednisolone and cyclosporine A modulate Ig production in cultures of peripheral lymphocytes but had no effect on Ig secretion in marrow cell cultures. This observation was reminiscent of the absent or at best marginal short-term effects on in vivo serum Ig levels which is typical for these drugs. Our observations suggest that the marrow Ig-producing B-lymphoid cell compartment shows major differences to other tissue sites with respect to properties of the Ig-secreting cells the immunoregulatory activities able to control their function, and the response of these cells to clinically important drugs.

Importance of antibody isotype in monoclonal anti-idiotype therapy of a murine B cell lymphoma. A study of hybridoma class switch variants.

An initial panel of four syngeneic monoclonal antibodies directed against the idiotype of a murine B cell lymphoma was used to treat this tumor in vivo. The antibody in the panel of the IgG2a isotype was more effective in treatment than the other antibodies, which were of the IgG1 and IgG2b isotypes. To independently assess the role of antibody isotype in mediating antitumor effects, switch variant hybridoma families were isolated from the hybridomas secreting the less effective IgG1 and IgG2b antibodies. A family isolated from an IgG1-secreting parent consisted of IgG1-, IgG2b-, and IgG2a-secreting members, and an IgG2a variant was isolated from an IgG2b-secreting parent for another family. Antibody members of each family differed only in heavy chain composition and were the same with respect to their light chains and their affinity and specificity for idiotype. The IgG2a members of both families were superior to the other members in inhibiting tumor growth with an order of effectiveness of IgG2a greater than IgG1 greater than IgG2b. These in vivo results paralleled the abilities of these different isotype antibodies to mediate antibody-dependent cellular cytolysis in vitro. For the IgG2b----IgG2a family, in vivo treatment with the IgG2a member given i.p. after i.p. tumor challenge at one-tenth the dose of the IgG2b member was still superior to the latter. At one-hundredth the dose of the IgG2b, the IgG2a was still superior to the latter when the antibodies were given i.p. and tumors subcutaneously. These data and those showing that the clearance of these antibodies from the serum differed in only a relatively minor way indicate that the IgG2a antibodies in this system had greater antitumor effects primarily by virtue of their greater capacity for host effector interaction.

Relation of age, race, and allotype to immunoglobulin subclass concentrations.

Concentrations of IgG1, IgG2, and total IgG were measured by a solid phase radioimmunoassay in sera from 36 healthy adults and 114 healthy children. As expected, IgG2 and total IgG had a positive correlation with age in children. In addition to age, several other factors were associated with significant differences in serum subclass concentrations. Female children had higher concentrations of IgG1 than males, and black subjects had significantly higher concentrations of IgG1, IgG2, and total IgG than whites. Although Km(1) and Gm(23) immunoglobulin allotypes had no relation to subclass concentrations when tested as single factors, the Km(1) allotype interacted significantly with race so that Km(1)-positive black children had higher IgG2 concentrations than other subjects. Our findings may explain, in part, recent observations of an association of the Km(1) allotype with altered immune responses of blacks to certain vaccines containing bacterial polysaccharides. In addition, our data indicate the need to control factors such as sex, race, and allotype in studies of subclass concentrations or immune responses.

Immunoglobulin allotypes in Jewish populations living in Israel and the United States.

The ongoing interest in the interrelationships of Jewish populations justifies inclusion of the immunoglobulin allotypes in an ethnohistorical analysis. A total of 2,184 serum specimens obtained from unrelated Israeli Jewish and self-identified Milwaukee, WI, Jewish blood donors were classified as Ashkenazi, Sephardi, Asiatic, or North African and tested for G1m (a, x, z, and f), G3m (b0, b1, b3, b5, g), A2m (1 and 2), and Km (1). Selected sera were also tested for G3m (s, t, c3, c5). The estimated maximum likelihood Gm-Am haplotype frequencies were used in a heterogeneity chi-square analysis. The results indicate that there is less heterogeneity within Jewish populations from Europe, Middle East, and North Africa than in corresponding non-Jewish populations representing the same geographical areas. In order to avoid the hazards of a univariate focus, previously published data were incorporated into two additional analyses: 15 populations with information on 16 genetic loci and 24 populations with information on five genetic loci. Both sets of data were analyzed using principal-components and cluster analysis. In both sets of analyses, with the exception of the Yemenite Jews, Jewish populations grouped together. These analyses support the belief that Jewish populations appear to be derived from a common gene pool, and there has been some genetic drift and minimal gene flow with surrounding populations.

Distribution of Ig classes and IgG subclasses among human B cells activated by Nocardia opaca-delipidated cell mitogen or by pokeweed mitogen.

The relative proportions of cells synthesizing the three major Ig classes or one of the four IgG subclasses in cultures stimulated with pokeweed mitogen (PWM) or Nocardia-delipidated cell mitogen (NDCM) were investigated. In cultures of human peripheral blood mononuclear cells (PB MNC) stimulated with PWM, the number of IgG-containing cells (CC) was higher than the number of IgM-CC, and a substantial number of IgA-CC was found. Conversely, in NDCM-stimulated PB MNC cultures IgM-CC outnumbered IgG-CC and only few IgA-CC were detected. In those cultures, the removal of T cells resulted in an increase in the number of IgM-CC concomitant with a decrease in the number of IgG-CC. A substantial number of cells containing simultaneously IgG or IgA in addition to IgM could be found in PWM-stimulated cultures. These cells were virtually absent in NDCM-stimulated cultures. The relative proportions of IgG subclass-CC were IgG1-CC greater than IgG2-CC greater than IgG3-CC greater than or equal to IgG4-CC in PWM-stimulated and IgG2-CC greater than IgG1-CC greater than IgG3-CC greater than or equal to IgG4-CC in NDCM-stimulated cultures. The removal of T cells from NDCM-stimulated cultures did not result in major alteration of this distribution. The role of T cells and of the genomic order of the Igh-C genes in their phenotypic expression triggered in vitro by PBA is discussed.

Germline VH genes in an a3 rabbit not typical of any one VHa allotype.

We have undertaken investigations in the rabbit of VH genes that may be responsible for the observations of VHa allotypes unexpected from an animal's pedigree (latent allotypes). A short cDNA probe was prepared and shown to be specific for VHa2 mRNA. Southern analyses with short and large probes were unrevealing but screening of a lambda phage library from a VHa3-expressing animal identified a number of unusual genes. These VH genes are remarkable in that they are far closer to one another in the genome (in one case 3085 bps) than VH genes reported in mouse or man, they are highly homologous over long stretches of sequence, and they encode proteins not typical of any one VHa allotype. Proteins similar to the sort encoded by these genomic V-regions may explain some of the observations of latent allotype. Our data suggest that the allelic behavior of VHa allotypes is not due to allelism of a regulatory mechanism that acts upon identical VH genes in rabbits of different VHa phenotypes.