Biomedical subjects

T O Landaas

Publications and source records attributed to T O Landaas.

7 recordsLinked to original sources

PubMed1981

Immunological subsets in human B-cell lymphomas.

Fifty human B-cell lymphomas have been studied with regard to surface markers (surface immunoglobulins (sIg) and complement receptors (CR)), capping of sIg, and relative amounts of sIg by single-cell flow cytometry. The results show that these lymphomas can be subdivided into distinct immunological subsets. Whereas one histological subgroup (lymphocytic) consisted of only one immunological subtype, others were heterogeneous with regard to immunological subtypes. This was most striking in nodular lymphomas of germinal centre cell origin (centroblastic/centrocytic). Our studies provide further evidence for the existence of a large number of subsets in the B-cell compartment of the immune system, sIgD was only found in association with sIgM. The relative amounts of sIgD varied, especially in nodular lymphomas. A discrepancy between capping of sIgM and sIgD was also found in some lymphomas belonging to this group. These findings together with other observations suggest that sIgD plays a role in B-cell maturation and differentiation events taking place in germinal centres and becomes lost during this process. A close association was found between the presence of CR and capping of sIgM but not capping of sIgD or sIgG. Nodular lymphomas expressing sIgG only, lacked CR. These findings suggest that CR may become lost during maturation and differentiation processes also taking place in germinal centres. Lymphoplasmacytoid lymphomas, which show morphological evidence of differentiation towards plasma cells, could be subdivided into three immunological subsets, indicating that plasma cell maturation may take place from different subsets of B cells.

B-Lymphocytes↗

PubMed1981

Cell-associated immunoglobulin in human non-Hodgkin lymphomas. A comparative study of surface immunoglobulin on cells in suspension and cytoplasmic immunoglobulin by immunohistochemistry.

Eighty-three non-Hodgkin lymphomas classified according to the Kiel classification have been studied with regard to surface immunoglobulin (sIg) on cells in suspension and cytoplasmic immunoglobulin (cIg) by the peroxidase anti-peroxidase method (PAP) on formaline-fixed tissue sections. Fifty-six out of 66 examined (i.e. 85%) revealed a monoclonal staining pattern for sIg, whereas 37/70 (53%) gave a monoclonal staining pattern for cIg by PAP. The methods combined gave a monoclonal staining pattern in 73/83, i.e. in 88%, of the biopsies tested. The discrepancies between the two methods were largest in centroblastic/centrocytic and lymphocytic lymphomas. With regard to the light chain staining patterns, complete agreement between the two methods was obtained in the 20 cases that allowed such analysis to be made. This suggests that the specificity of PAP, as carried out in this study with reagents purified by immunoabsorbent techniques, is satisfactory. On a basis of heavy chain isotypes centroblastic/centrocytic, lymphoplasmacytoid, and immunoblastic lymphomas could be divided into distinct immunological subgroups. In four biopsies the sIg heavy chains were mu + delta, whereas mu + gamma chains were detected by PAP. This finding may be relevant to the mu leads to gamma switch known to occur during normal B-cell differentiation. Immunoglobulin inclusions were found in 8 cases--3 belonging to the immunoblastic group, and 5 to the lymphoplasmacytoid group.

Adult↗

PubMed1980

Mitogenic effect on human lymphocytes of insolubilized anti-immunoglobulins. I. Specificity of the stimulating agent.

The mitogenic response of peripheral blood lymphocytes to various anti-immunoglobulin reagents has been studied by measuring incorporation of a radioactive thymidine into macromolecules. Coupling of anti-F(ab')2 or anti-light chain antibodies to Sepharose beads leads to a 5-fold increase in their mitogenic capacity with 50-fold less antibodies per culture. Pepsin-digested F(ab')2 fragments had a mitogenic capacity similar to intact antibody molecules. Anti-F(ab')2 antibodies purified by immunoabsorbent columns were found to be more effective as mitogen than unpurified antibody fractions. Antibodies to kappa- or lambda-light chains were found to be mitogenic, whereas antibodies specific to various heavy chain classes failed to induce a significant response. Isolated light chains were much more effective in inhibiting the reaction than isolated mu-chains. It is concluded that insolubilized anti-light chain antibodies are mitogenic to human peripheral blood lymphocytes.

Animals↗

PubMed1979

Circulating immune complexes and prognosis in human malignant lymphoma, a prospective study.

Sera from 53 patients with Hodgkin's disease (HD) and 56 patients with non-Hodgkin malignant lymphoma (NH) were investigated, prior to treatment, for the presence of circulating immune complexes (CIC) by the 125I-C1q-binding radioassay. The patients were then followed for 14-31 months. No significant association was found between the presence of CIC and achievement of complete remission in any of the groups. In none of the groups could a difference be found between the survival rates of patients with and without CIC in their sera prior to treatment. About half of the patients were retested for the presence of CIC after completion of initial therapy. No significant association was found between the presence of post-treatment CIC and lack of complete remission in any of the patient groups. In the HD group, both pre- and post-treatment CIC appeared to be most frequent among patients over 50 years. No such association was found in the NH group.

Adolescent↗

PubMed1979

Increased serum IgE in Hodgkin's disease is of polyclonal origin.

The light chain of serum IgE from 4 untreated patients with Hodgkin's disease with elevated IgE levels was studied by an immunoadsorbent technique. Serum IgE was found to contain both kappa and lambda light chains in all cases studied. In addition an association between serum levels of IgE and that of IgA, IgG, and IgM was demonstrated. These findings make it unlikely that increased serum IgE in Hodgkin's disease is of monoclonal origin and support the view that serum IgE in such patients reflects a general disturbance in the regulation of their humoral immune response.

Adult↗

PubMed1978

Altered membrane-associated functions in chronic lymphocytic leukemia cells.

Peripheral blood lymphocytes consisting mainly of neoplastic B cells from patients with chronic lymphocytic leukemia (CLL cells) showed a markedly reduced response to the human B-cell mitogens anti-beta2 microglobulin, Sepharose-bound protein A and Sepharose-bound anti-human immunoglobulin (anti F(ab')2) in all of nine patients studied. On the other hand, CLL cells from three out of eight patients tested responded well to the calcium ionophore A23187. Sepharose-bound protein A and anti-beta2 microglobulin also failed to induce increased uptake of 86Rubidium (potassium analogue) in CLL cells as compared to B-cell-enriched preparations of normal peripheral blood lymphocytes. The capacity of CLL cells to cap various surface markers including beta2 microglobulin was reduced. On the other hand, surface concentrations of beta2 microglobulin were not reduced as measured by fluorescein-labelled anti-beta2-microglobulin in single-cell cytofluorometry. It is concluded that various membrane-associated events elicited by ligand-receptor interactions are altered or blocked in CLL cells.

Aged↗

PubMed1977

Characterization of immunoglobulins in Hodgkin cells.

Fifteen of 42 formalin-fixed lymph-node biopsies with Hodgkin lesions of different histological types and stages gave positive staining for immuno-globulins by the peroxidase/antiperoxidase method. The immunoglobulins in all the positively stained Hodgkin cells were of IgG type, but staining for IgA, D and E was negative. One of the 15 biopsies was positive for IgM. Thirteen of the 15 positive biopsies were positive for both kappa and lambda. Sequential double staining using two different substrates for peroxidase showed that most of the Hodgkin cells simultaneously contained light chains of both kappa and lambda type. It is concluded that Hodgkin cells do not contain a "monoclonal" immunoglobulin product.

Hodgkin Disease↗