Idiopathic paraproteinaemia V. Expression of Igh1 and Igh5 allotypes within the homogeneous immunoglobulins of ageing (C57BL/LiARij X CBA/BrARij)F1 mouse

The role of genetic factors linked to the immunoglobulin loci and the development of idiopathic paraproteinaemia (IP)--a benign B-cell proliferative disorder--was investigated in F1 hybrid mice of low (CBA/BrARij) and high (C57BL/LiARij) IP frequency strains. Igh1 and Igh5 allotypes were used as markers for the (parental type) origin of homogeneous immunoglobulins (H-Ig) which appeared in the sera of the F1 mice with ageing. The frequencies of H-Ig in the F1 mice were intermediate with those of the parental strains. The isotype distribution of the H-Ig was 27%, 24%, 12%, 12%, 11%, 10%, 3% and 1% for IgG2a, IgM, IgG1, IgG3, IgG2b, IgD, IgA and IgE, respectively. H-Ig of the IgG2 subclass carried the Igh1b (C57BL) allotype in 98% and the Igh1a (CBA) allotype in 2% cases. Of the IgD H-Ig, 70% carried the Igh5b and 30% the Igh5a determinant. The Igh1 allotype distribution in the bone marrow and spleen plasma cells showed a large variation in the Igh1a/Igh1b ratio among old individual mice and often also between bone marrow and spleen within a single animal with or without a H-Ig component. The categorization of the paraproteinaemias on the basis of their origin showed that 10% of the H-Ig were the result of a transient monoclonal B-cell proliferation; multiple myeloma or lymphoma was found to be responsible for about 1% of the paraproteinaemias; H-Ig fulfilling the criteria for IP were detected in about 42% of cases. The origin of the remaining old age paraproteinaemias could not be determined. These data indicate that the F1 mice develop monoclonal proliferative disorders in a manner more similar to the C57BL than to the CBA parental strain. The allotype associated genetic material from the parental C57BL strain was shown to be mainly responsible for the development of IP in ageing F1 mice.

Molecular forms of tear IgA and distribution of IgA subclasses in human lacrimal glands

Tears and sera from 14 subjects were analyzed for IgA levels by radioimmunoassay by use of secretory IgA standards for tear samples and monomeric IgA standards for serum samples. [corrected] Tears from subjects without conjunctival inflammation contained 93% polymeric IgA (pIgA) and 7% monomeric IgA; tears from subjects with conjunctival inflammation had less pIgA (79%). Biopsy specimens of 11 lacrimal glands and one accessory lacrimal gland were obtained from 12 additional subjects. Tissues were stained with polyclonal antisera for immunoglobulins, J chain, and secretory component. In addition, tissues were stained for IgA subclasses with monoclonal reagents specific for IgA1 and IgA2. IgA plasma cells predominated over other types of plasma cells, and most were J chain positive. Secretory component, although absent from the interstitium of the gland, was found in most acinar and ductal cells. The average proportion of IgA1 to IgA2 cells was 56% to 44%. We concluded that the lacrimal system of the human resembles other exocrine systems in the production of predominantly pIgA and the nearly equal occurrence of IgA1 and IgA2 plasma cells.

Monoclonal gammapathies in patients undergoing immunosuppressive treatment after renal transplantation

The frequency of monoclonal gammapathies (MG) and their possible origin were investigated in renal graft recipients undergoing immunosuppressive treatment. In a cross-sectional study, homogeneous immunoglobulins were found in 30% of the patients investigated. This incidence was 10-times higher than that in a control group of patients with chronic renal failure on dialysis treatment. The increase in the frequency of homogeneous immunoglobulins in the renal transplant recipients was related to the age of the patients but not to the duration of the immunosuppressive treatment. A longitudinal study in 55 patients demonstrated that most of the MG reflected transient B-cell monoclonal proliferations, probably due to an immunodeficiency; however, the incidence of benign and malignant B-cell neoplasias seemed also to be unusually high. These findings indicate that the immunosuppressive treatment enhances and accelerates an immunodeficiency which develops spontaneously with aging of the immune system; it also may contribute to the development of other age-related, both benign and malignant monoclonal B-cell proliferative disorders.

Subclass distribution and molecular form of immunoglobulin A hemagglutinin antibodies in sera and nasal secretions after experimental secondary infection with influenza A virus in humans

Serum and nasal wash specimens from 13 human volunteers undergoing experimental secondary infection with influenza A/Peking/2/79 (H3N2) wild-type virus were examined for the molecular form and subclass distribution of immunoglobulin A (IgA) antibodies to the viral hemagglutinin (HA). Nasal IgA antibodies were polymeric and did not bind radiolabeled secretory component, indicating that they were secretory IgA antibodies. Both IgA1 and IgA2 antibodies were detected; however, IgA1 accounted for most of the rise in IgA anti-HA levels seen after infection. In serum virtually all of the IgA HA antibodies were of the IgA1 subclass. Furthermore, the serum antibodies were predominantly polymeric and were capable of binding radiolabeled secretory component. These results suggested that the serum IgA antibodies to HA were of mucosal origin and that influenza A virus HA preferentially stimulates an IgA1 response.

Light chain types of IgD in human bone marrow and serum

One of the unexplained features of human IgD is its preferential expression with either kappa or lambda light chains in different situations. While the membrane IgD on B lymphocytes shows a predominance of the kappa type, about 90% of all known IgD myeloma proteins and 87% of normal IgD producing plasma cells in spleens of healthy individuals were shown to belong to the lambda type. Very little is known of the kappa/lambda light chain distribution of normal polyclonal IgD in the serum and in the bone marrow plasma cells. In this study, the kappa/lambda representation of IgD in bone marrow plasma cells and in the serum of 25 adult persons (two healthy and 23 suffering from various nonmalignant diseases) was investigated. The kappa/lambda ratio of IgD+ bone marrow plasma cells showed a large variation among the individuals of this group, in 84% of the cases being below 1.0. While about 1/3 of the investigated subjects had 80% or more of IgD of the lambda type (kappa/lambda ratio below 0.2), most showed a kappa/lambda ratio of IgD higher than that, with four persons exhibiting a clear cut predominance of IgD of the kappa type. A positive correlation (Spearman's correlation co-efficient, P = 0.005) between the percentages of IgD+ plasma cells and their kappa/lambda ratio was found. Semiquantitative evaluation of the kappa/lambda composition within the serum IgD by immunoselection was in agreement with the kappa/lambda ratio of IgD+ plasma cells in all individual cases.

Influence of treatment with APD-bisphosphonate on the bone lesions in the mouse 5T2 multiple myeloma

The effects of the treatment of multiple myeloma (MM) with APD-bisphosphonate on bone destruction, the dissemination pattern of the MM, and toxicity for normal and malignant cells were investigated in an animal model, the 5T2 MM. This mouse MM very closely resembles the human disease, including the typical bone lesions. It was demonstrated by radiography, microradiography, and histologic investigation that the treatment of the 5T2 MM with APD-bisphosphonate protected the mice against a loss of bone to a significant extent. It seemed that the treatment with APD not only diminished the bone destruction by the MM but also led to the formation of new bone in already-affected bone tissue. The growth pattern of the MM was not substantially influenced by the treatment, even though there was an indication that APD exerts some cytotoxic effect on the MM cells.

Occurrence of IgA subclasses (IgA1 and IgA2) in the human nervous system. Correlation with disease

The occurrence of IgA subclasses in pathological conditions of the nervous system was studied by means of monoclonal antibodies and an indirect immunofluorescence technique. IgA1- and/or IgA2-positive lymphoid (plasma) cells were found in demyelinating diseases comprising multiple sclerosis, Guillain-Barré syndrome, and adrenoleukodystrophy, in various inflammatory diseases, and in tumors, some of which exhibited labeling of tumor cells. Demyelinating and inflammatory diseases with chronic course displayed some prevalence of IgA2-, and tumors some prevalence of IgA1-positive cells. This is the first demonstration of IgA1 and IgA2 in the nervous system.

Differences among the three major categories of paraproteinaemias in aging man and the mouse. A minireview

The frequency of homogeneous immunoglobulins markedly increases with aging. These homogeneous Ig, paraproteins, reflect three different major categories of disorders within the immune system: B-cell malignancies; B-cell benign proliferative disorders; and Secondary immunodeficiency, a T-B immune system imbalance due to aging. A correct differential diagnosis among these conditions is crucial for the prognosis and potential treatment. Recent studies in animal models offer some clues which are helpful for our better understanding of the mechanism of the development of the paraproteinemias and for their differential diagnosis.

Circulating and mesangial secretory component-binding IgA-1 in primary IgA nephropathy

In a prospective study of 38 patients who presented with hematuria of renal origin, 15 patients were found to have primary IgA nephropathy and 23 had other renal disorders. Sera and renal biopsy specimens of these patients were studied for the presence of macromolecular IgA1 and IgA2 using monoclonal antibodies, and the presence of J-chain as demonstrated either by immunofluorescence or its capacity to bind free secretory component. Circulating macromolecular IgA was found exclusively in the sera of patients (80%) with primary IgA nephropathy. In these sera the polymer/monomer ratio for IgA1 (0.64 +/- 0.13) was significantly higher than for normal human serum (0.39 +/- 0.01) (P less than 0.001), while no differences were found for IgA2. The polymeric IgA1 was isolated from serum by gel chromatography and was shown to have the capacity to bind free secretory component. Direct two-color immunofluorescence studies revealed the presence of only IgA1 in the mesangial deposits and also its capacity to bind free secretory component. We conclude (1) that demonstration of circulating macromolecular IgA in patients with renal hematuria is of diagnostic value and (2) that antigenetic similarities between the circulating and the mesangial macromolecular IgA suggest that dimeric IgA1 is deposited in the mesangium of patients with primary IgA nephropathy.

Idiopathic paraproteinaemia. IV. The role of genetic factors in the development of monoclonal B cell proliferative disorders--a study in the ageing C57BL/KaLwRij and CBA/BrARij mouse radiation chimeras

Mouse radiation chimeras, employing strains with a low (CBA/BrARij) and a high (C57BL/KaLwRij) frequency of idiopathic paraproteinaemia (IP), were used in a study on genetic influences in the development of IP, a benign B cell monoclonal proliferative disorder. Taking advantage of the different Igh1 allotypic markers between the two strains, the development of IP with increasing age was investigated by agar electrophoresis, immunoelectrophoresis and immunofixation. Four of 18 CBA recipients transplanted with C57BL bone marrow cells were shown to develop IP of the IgG2a isotype and the Igh1b (donor) allotype during their life. In contrast, none of the 23 C57BL recipients of CBA bone marrow developed an IgG2a paraprotein of the Igh1a allotype. However, in three of these 23 chimeras, an IgG2a and Igh1b (recipient) allotype paraprotein appeared with age; two of these mice proved to be reversals at 12 months and one at 15 months of age. The frequencies of homogeneous immunoglobulins of the donor type in the chimeras corresponded roughly to those of normal mice of the donor strain. Histopathological examination excluded a malignant origin of these monoclonal proliferations. These findings support the view that intrinsic cellular genetic factors are of major importance in the development of IP, a benign B cell neoplasia.

Autoantibodies in highly aged humans

The presence of 14 different autoantibodies was determined in 65 persons, aged 95 years and older, without overt disease. The prevalence of positive anti-immunoglobulin latex tests, of autoantibodies against nuclear components and against thyroid microsomes was significantly increased. This selective increase of autoantibodies of low titre and without cluster formation is considered to be the result of a loss of control within the immune system due to ageing, rather than as a sign of latent disease.

Hyperimmunoglobulinaemia D and periodic fever: a new syndrome

Six patients of Dutch ancestry with a long history of recurrent attacks of fever of unknown cause were found to have a high serum IgD level and a large number of plasma cells with cytoplasmic IgD in the bone marrow. Because the clinical picture in some ways resembled that of familial Mediterranean fever (FMF), sera of patients with FMF were also investigated; only one of eight such patients had a raised serum IgD.

Increased incidence of transient homogeneous immunoglobulins in irradiated and reconstituted C57BL/KaLwRij mice treated with 2'-deoxyguanosine

Prolonged administration of micromolar amounts of 2'-deoxyguanosine (dGuo) to lethally irradiated and reconstituted mice led to an increased incidence of transient homogeneous immunoglobulins (H-Ig) in their sera. Analysis of the heavy and light chain isotype distribution among the H-Ig revealed more of the IgG2b and IgG3 isotypes and less of the IgM isotype and the lambda light chain containing H-Ig in the dGuo-treated group as compared to the control group. The increased incidence of H-Ig was preceded by a decreased suppressor T cell generation and activation in the dGuo treated group. These data indicate that deficient suppressor T cell activity plays an important role in the development of transient H-Ig.

Instability of the human immunoglobulin heavy chain constant region locus indicated by different inherited chromosomal deletions

Previously we reported a gross genetic polymorphism of the human immunoglobulin heavy chain locus manifest by a large internal deletion within the constant region gene segment. We now describe a detailed serological and molecular genetic study of a Tunisian family in which members appear to carry two chromosomes 14 with different DNA deletions. The first is similar to that previously described encompassing three gamma subclass genes, a pseudo-epsilon gene and the alpha 1 subclass gene; the second deletion is less complex involving only the pseudo-epsilon gene and the alpha 1 gene.

Low molecular weight IgM in sera of children following bone marrow transplantation for severe aplastic anaemia and acute leukaemia

Serum samples of 16 children, treated with allogeneic bone marrow grafts for either aplastic anaemia or leukaemia, were investigated longitudinally for the presence of pentameric (19S) and low molecular weight (LMW) (7S) IgM. From 2 months following grafting, serum IgM increased in all patients, gradually in seven cases and with a transient overshoot in the other nine. In eight patients, LMW-IgM was detected transiently in the serum within the period when total IgM was increasing, either with (five patients) or without (three patients) overshoot. These data indicate that, at a certain stage of the immunological reconstitution after transplantation as in normal ontogeny, rather immature cells of the B cell lineage are able to produce and secrete LMW-IgM.

Increased levels of IgG4 subclass in 5 patients with acquired respiratory disease

5 sera from a series of more than 1,000 serum samples from hospitalized patients tested by immunoelectrophoresis were selected for further examination because of a disproportional increase in the anodic part of IgG. A marked polyclonal increase in IgG4 subclass level was detected in each of these sera. While the patients suffered from a variety of diseases (e.g. Loeffler's syndrome, leiomyosarcoma, periarteritis nodosa, chronic bronchitis, and mycosis fungoides, respectively), they all had an acquired respiratory disease as the only common clinical denominator.

Serum immunoglobulins in nude mice and their heterozygous littermates during ageing

Serum immunoglobulin (Ig) levels were investigated in 6, 40 and 110 week old congenitally athymic (nude) mice and their heterozygous littermates. Concentrations of IgM, IgG1, IgG2a, IgG2b, IgG3 and IgA were determined by rocket electrophoresis. At 6 weeks of age, IgM was the most prominent serum Ig in both nude and heterozygous mice. Except for IgM and IgG3, some nude mice displayed unquantifiable levels of some of the other Ig classes or subclasses. At this age, the average levels of the various Ig classes and/or subclasses did not differ significantly between the two groups of mice. At the ages of 40 and 110 weeks, most nude mice showed serum Ig spectra in which all classes and subclasses were present. Young (6 week) and middle-aged (40 week) nude mice generally showed a wider variation in Ig levels than did their heterozygous littermates. The most striking differences between aged nude mice and aged heterozygous mice were: (a) the generally decreased levels of IgG2a, IgG2b and IgA; (b) the frequent occurrence of increased serum levels of IgG1; and (c) the increased incidence of homogeneous Ig components ('paraproteins') in the sera of nude mice.

Idiopathic paraproteinemia. III. Increased frequency of paraproteinemia in thymectomized aging C57BL/KaLwRij and CBA/BrARij mice

The influence of thymectomy on the appearance of idiopathic paraproteinemia (IP) during aging was investigated in mice of the C57BL/KaLwRij and the CBA/BrARij strains, which under normal conditions develop IP in high and low frequency, respectively. Compared with sham-thymectomized mice, C57BL mice thymectomized at a young adult age showed a markedly increased frequency and an earlier onset of IP during aging; this was even more pronounced in neonatally thymectomized mice. A similar effect of thymectomy was also observed in mice of the CBA strain. Restriction in the heterogeneity of the serum immunoglobulins and the appearance of transient homogeneous Ig components was another frequent finding and this often preceded the appearance of IP in mice of both strains. Thymectomy did not substantially influence either the incidence of paraproteinemias due to a B cell malignancy or the isotype distribution among the paraproteins produced. The results are compatible with the hypothesis that IP develops in three stages as a consequence of an age-related immunnodeficiency that primarily affects the T immune system.