Impaired synthesis of polyclonal (non-paraprotein) immunoglobulins by circulating lymphocytes from patients with multiple myeloma Role of suppressor cells

The nature of cells generating human myeloma colonies in vitro

Freshly explanted human myeloma cells formed colonies of monoclonal plasma cells in soft agar in the presence of medium conditioned by the adherent spleen cells of mineral oil-primed BALB/c mice. The medium showed peak activity at a dilution of 1:4. 2-mercaptoethanol or monothioglycerol was necessary for colony formation. Other thiols tested were ineffective in promoting colony growth. Colony-forming cells adhered to nylon wool, but not glass beads or plastic dishes. The presence of E-rosetting cells was not required for myeloma colony formation. Antibody prepared against a human myeloma cell line, RPMI 8226, reduced colony formation. These studies demonstrate the usefulness of this bioassay for determining functional properties of the myeloma colony-forming cell.

Serum immunoglobulin levels and malaria antibodies in Burkitt's lymphoma

Data are presented to support a relationship between malaria infection and Burkitt's lymphoma in African children. IgG, IgM and IgA levels were measured in sera from Burkitt's lymphoma patients and from sex- and age-matched, nearest-neighbour controls. All three classes of immunoglobulins were present in significantly lower amounts in the sera from Burkitt's lymphoma patients than in the sera from controls. The mechanism of this apparent B-cell suppression is not yet clear. Malaria-specific IgG and IgM antibody titres were determined in the indirect immunofluorescence test. No significant difference in the IgG malaria-specific antibodies was detected between the two groups of sera. Malaria antibody levels measured using IgM specific conjugates were significantly lower in the sera from Burkitt's lymphoma patients in reactions with Plasmodium falciparum antigen. No significant difference was observed when P. malariae was used. Confirmation of this finding would serve as a positive link between Burkitt's lymphoma and P. falciparum infection.

Suppression of the humoral immune response by particulate material extracted from spleen cell subpoulations of MOPC-315 tumor-bearing mice

Particulate extracts were prepared from MOPC-315 plasmacytoma cells, from whole spleen cells or from splenic macrophages of MOPC-315 tumor-bearing mice. These preparations, when injected into normal mice, inhibited their primary humoral immune response to sheep red blood cells (SRBC). At the same time, particulate extracts from whole spleens or splenic macrophages of normal mice and T cell extracts from spleens of MOPC-315 tumor-bearing mice had no effect on the primary immune response to SRBC. The results suggest that phagocytic spleen cells of tumor-bearing mice contain immunosuppressive particles which originate from the tumor cells.

Prostaglandin suppression of mitogen-stimulated lymphocytes in vitro. Changes with mitogen dose and preincubation

In this study we further characterize the properties of the prostaglandin-producing suppressor cell. Overnight preincubation of peripheral blood mononuclear cells results in an increased response of the cells to phytohemagglutinin or Concanavalin A compared to the response of fresh cells. This increase in mitogen response with preincubation was similar in magnitude to the increase in mitogen response of fresh cells after the addition of indomethacin. The two manipulations were not additive; that is, after preincubation, indomethacin caused much less enhancement of mitogen stimulation of peripheral blood mononuclear cells (100 +/- 12% increase before preincubation vs. 12 +/- 6% after preincubation; mean+/-SEM, P < 0.001). Preincubated cells also lose sensitivity to inhibition by exogenous prostaglandin E(2). It requires the addition of 100- to > 1,000-fold more exogenous PGE(2) to produce comparable inhibition of phytohemagglutinin-stimulated preincubated cells than is required for inhibition of phytohemagglutinin-stimulated fresh cells. The enhancing effect of indomethacin increases with decreasing doses of phytohemagglutinin. Indomethacin causes a 1,059+/-134% increase in [(3)H]thymidine incorporation at the lowest dose of phytohemagglutinin (0.2 mug/ml), and a 4+/-3% increase at the highest dose (20 mug/ml). This increase in response to indomethacin with a lower dose of phytohemagglutinin is due to increased sensitivity to inhibition by PGE(2) at lower mitogen doses. The prostaglandin-producing suppressor cell assay and the short-lived suppressor cell assay measure over-lapping phenomena. The increased suppressive effect of the prostaglandin-producing suppressor at suboptimal mitogen dose must be taken into account in the interpretation of any study where the response to a range of mitogen doses is studied.

Studies of immune functions of patients with systemic lupus erythematosus. I. Dysfunction of suppressor T-cell activity related to impaired generation of, rather than response to, suppressor cells

T cell suppressor function in patients with systemic lupus erythematosus (SLE) was evaluated by studying the ability of concanavalin A- (Con A) activated T cells to suppress proliferative responses by responder cells autologous with the Con A-activated T cells. Impaired suppressor T-cell activity in patients with SLE was observed with regard to three effector functions: 1) the allogeneic response of T cells, 2) the Con A response of T cells, and 3) the B cell response to pokeweed mitogen (PWM). No defect was found with regard to suppression of the T-cell response to phytohemagglutinin (PHA). Mixing experiments between SLE and normal cells were carried out to further define the nature of the SLE suppressor defect. When responder cells from SLE patients were cultured with Con A-activated T cells from normal controls, the normal suppressor T cells caused suppression of SLE responder cells. In contrast, Con A-activated T cells from SLE patients were incapable of exerting suppressor effects on normal responder cells. These observations indicate that the impaired suppressor activity in SLE patients resides in the generation of suppressor T cells, rather than in the response to suppressor T cell signals.

Circulating lymphocytes and the spread of myeloma. Review of the evidence

Patients with myeloma harbour circulating lymphocytes which bear the idiotypic determinants (SIg-id+ cells) of their own myeloma protein. Circulating white cells with abnormal karyotypes have been found in other patients with this disease. SIg-id+ lymphocytes have also been identified in the peripheral blood of myeloma-tumour-bearing mice. Murine myelomas have been propagated in vivo from circulating mononuclear cells that possessed myeloma-tumour-associated antigens. This and other evidence reviewed here points strongly to the involvement of circulating lymphocyte-like stem cells in the spread of human myeloma.

Regulation of the mixed leukocyte culture reaction by suppressor cells

Regulation of the mixed leukocyte culture (MLC) reaction by suppressor cells raised and tested in MLC has been evaluated. The experiments described suggest that suppressors are distinct from cytotoxic T lymphocytes (CTL), both in terms of conditions optimal for their activation, as well as through demonstration of efficient suppression in the total absence of cytotoxic activity. Suppressor cells inhibit the activation of the precursors of CTL, and may also prevent the production of the lymphokine blastogenic factor; they do not appear to interfere with the reaction of primed cells. It is suggested that suppressor cells may regulate the MLC reaction by preventing recruitment of fresh competent cells, and by limiting the duration of the reaction of cells already activated.

The effects of single-dose alternate-day prednisone therapy on the immunological status of patients with neuromuscular diseases

Several immunological variables were examined in patients receiving high-single-dose, alternate-day prednisone therapy for neuromuscular diseases. Dose-dependent leukocytosis, lymphopenia, and monocytopenia occurred which were maximal 6 hours after prednisone administration but returned to control levels by the 24-hour point. The lymphopenia involved T-cells, B-cells, and null cells, with the T-cells most affected. Plasma cortisol levels and lymphocyte transformation in response to mitogens were also transiently and reversibly suppressed. There was a persistent decrease in serum IgG. Lymphocyte transformation was also suppressed when normal lymphocytes were incubated with treated patient sera or when treated patient lymphocytes were incubated in autologous pretreatment sera. The suppression factor was not removed from the lymphocytes by extensive washing. Patients whose disease responded to the high-single-dose, alternate-day prednisone regiment were indistinguishable from nonresponders by the immunological responses measured.

Immune suppression of hematopoiesis

Recent evidence suggests that immune mechanisms can injure proliferating hematopoietic precursor cells in the bone marrow. These may involve either humoral antibody or cell-mediated cytotoxic mechanisms. Immune injury can result in a variety of bone marrow failure syndromes. Immunologically induced abnormalities or blood cell production may be restricted to a single series, such as erythrocyte or granulocyte precursors, or may involve several hematopoietic lines; clinical manifestations reflect the cell line or lines that are injured. Immune suppression of hematopoiesis has now been described in pure red cell aplasia, immune panleukopenia, systemic lupus erythematosus, atypical cases of aplastic anemia and miscellaneous other hematologic diseases.

Characterization of a suppressor-cell leukemia. Evidence for the requirement of an interaction of two T cells in the development of human suppressor effector cells

To characterize the suppressor activity of neoplastic T cells from a child with acute lymphoblastic leukemia and hypogammaglobulinemia, we applied an in vitro assay that determines the capacity of pokeweed-mitogen-stimulated lymphocytes to mature into immunoglobulin-secreting cells. The geometric mean synthesis by peripheral blood lymphocytes from 12 normal persons was 3200 ng for IgM, 2447 ng for IgG and 1825 for IgA (2 X 10(6) cells per 12 days in culture). The patient's leukemic cells produced no detectable immunoglobulin and depressed the immunoglobulin production of normal lymphocytes by 85 to 100 per cent in co-culture experiments. However, suppression was observed only when co-operating normal T cells were present. Prior irradiation of either the leukemic T cells or the co-operating normal T cells nullified the suppressor effect. Therefore, an interaction between at least two different T-cell subsets may be required for the generation of suppressor effector T cells in man.

Aplastic anemia associated with bone marrow suppressor T-cell hyperactivity: successful treatment with antithymocyte globulin

In five patients with idiopathic aplastic anemia, the colony-forming unit (CFU-c) assay was used to quantitate stem cells and test the possible presence of suppressor cells inhibiting bone marrow differentiation. All five marrows failed to form CFU-c. In one out of the five cases tested, coculture of the patient's marrow with normal marrow suppressed the latter to form CFU-c. Removal of T-cells from the patient's bone marrow freed the aplastic marrow to produce more colonies and, in the coculture study, abrogated its inhibitory activity on the normal bone marrow. Treatment of the patient with horse antihuman thymocyte globulin (ATG), improved the peripheral blood count and myelopoiesis. Furthermore, the aplastic marrow increased its colony forming capacity from less than 1% pre-ATG to 46% post-ATG of the normal control, and its inhibitory activity on the normal marrow was ablated. In selected cases of aplastic anemia, with evidence of T-suppressor cell hyperactivity, treatment with ATG may offer an alternative approach to bone-marrow transplantation.

Therapeutic leukopheresis of acute myelo-monocytic leukemia in pregnancy

Cytopheresis techniques have proven useful in the provision of platelets and granulocytes for transfusion to the pancytopenic patient. Mechanical cell removal has been applied to the treatment of chronic myelocytic and lymphocytic leukemias and the Sezary syndrome. We have treated a 16-year-old pregnant acute myelomonocytic leukemia (AMML) patient for 12 weeks solely with the use of intensive leukopheresis utilizing batch processing centrifugation and packed red cell transfusions. The patient presented with a white blood cell count of 54,000/mm3 with 64% myelomonoblasts, a platelet count of 45,000/mm3, marked gingival hyperplasia, and splenomegaly. Patient had a normal spontaneous delivery of a 2.5-kg male infant without complications. At the time of delivery, 12 weeks later, the white blood count had fallen to 4,9000/mm3 with 8% blasts and the platelet count had risen to over 100,000/mm3. Gingival hyperplasia decreased and the patient felt well. We have treated an additional small group of patients with acute myelogenous leukemia (AML) with high white counts with short term intensive leukopheresis followed by chemotherapy with promising results.

Impaired immunoglobulin synthesis by peripheral blood lymphocytes in systemic lupus erythematosus

Pokeweed mitogen (PWM)-induced immunoglobulin (Ig) synthesis by peripheral blood mononuclear cells (PBL) from 33 patients with systemic lupus erythematosus (SLE) was compared to that synthesized by PBL from 22 normal individuals. Short-term unstimulated culture of SLE-PBL immediately after separation from PB revealed Ig synthesis 4 times that of normal PBL. However, SLE-PBL had a depressed PWM-induced Ig synthetic response that was partially, but not totally, related to active disease and was not correctable by co-culture with normal lymphocyte populations. In both the short-term-unstimulated and the PWM-stimulated cultures, IgM was the major Ig class synthesized by normal PBL, while IgM synthesis by SLE-PBL was depressed more than the other Ig classes. These results can best be explained by a preactivated PBL population in SLE.

Differentiation of human lymphocytes by pokeweed mitogen in vitro: studies in normal and in immunodeficient subjects

Immunoglobulin (Ig) synthesis and secretion by peripheral blood lymphocytes activated by pokeweed mitogen (PWM), and by phytohemagglutinin (PHA) was measured in normal individuals and in subjects with primary immunodeficiency. Unstimulated cultures demonstrated stable, low Ig synthesis of all major Ig classes; PWM showed a peak of Ig synthesis at day 5; PHA cultures demonstrated a late peak of ig production at day 9. Three cases of common variable immunodeficiency showed different patterns of data when the percentage of B cells in blood and Ig production in vitro were used as parameters. Two persons with immunodeficiency and thymoma showed decreased Ig production in vitro, and had suppressor cells capable of blocking Ig production by normal lymphocytes in co-cultivation experments.

Lymphocyte abnormalities in myeloma

Lymphopenia and monocytosis were found in one third of untreated myeloma patients but there was no correlation between the two. Half of the patients studied had an increase in medium basophilic lymphoid cells, and eight had a raised PAS score. Lymphocytes from the majority of untreated myeloma patients failed to respond to antigenic stimulation in vitro compared with age matched controls. Three patients were immunized but showed no increase in immunoblasts or rise in antibody titre. The findings strongly suggest that abnormal lymphocytes are present in the blood in myeloma. The failure of lymphocytes to respond to antigen provides an explanation for the lack of normal plasma cells and depressed antibody responses in myeloma.

Depressed in vitro peripheral blood lymphocyte response to mitogens in cancer patients: the role of suppressor cells

The reactivity of peripheral blood lymphocytes from patients with advanced malignancy was assessed by mitogen-induced stimulation of protein synthesis as measured by 3H-leucine incorporation. It was confirmed that the lymphocyte response of patients was depressed. Furthermore, the lymphocytes of 15 out of 27 cancer patients, selected because of their low responses, inhibited the reactivity of normal lymphocytes in co-cultures. The lymphocytes from one patient with Hodgkin's disease were also inhibitory. In contrast, lymphocytes from healthy subjects, patients with chronic lymphocytic leukaemia, lymphosarcoma or multiple myeloma caused no suppression. Experiments with purified cell populations from patients with carcinoma indicated that purified T cells responded to mitogens while unseparated lymphocytes failed to respond and that the inhibitory activity was due to adherent cells, presumably monocytes. There was no evidence for B-cell-mediated suppression. However, in two cases inhibition was caused by isolated T cells of the patients and not by adherent cells. These experiments suggested that one mechanism for the depression of cell-mediated immunity seen in patients with advanced cancer may be the nonspecific suppresssion of certain T-cell functions by circulating monocytes.

T-cell regulation of immunoglobulin synthesis and proliferation in pokeweed (Pa-1)-stimulated human lymphocyte cultures

In pokeweed (Pa-1)-stimulated human lymphocyte cultures, T cells are essential for the survival, proliferation, plasma-cell development, and high-rate Ig secretion of B cells. Their effects are T-cell-specific in the sense that B-cell stimulation does not take place in the absence of T cells even when fibroblasts or monocytes are provided. The experimental system is the most effective model for activation of human B lymphocytes so far described. Plasmablast development requires approximately 7 days in culture. In T + B-cell cultures established at 1 X 10(6)/ml (1 X 10(4)/mm2) initial cell density, plasma cells can secrete, on the average, as much as 40-70 pg IgM or IgG per cell per day. When the initial T-cell density is increased well above 1.0 X 10(6)/ml, a T-cell-mediated depression of Ig synthesis becomes predominant. Thus, in the pokeweed model T-cell effects represent a balance of helper and suppressor influences. The study also shows that B cells are heterogeneous. A non-adherent IgG-committed (smIg-?) TONSIL B-cell population seems to be less susceptible to T suppressor effects than normal tonsil B cells. This subset proliferates particularly well and synthesizes large quantities of IgG in the presence of large initial proportions of T cells.

Suppressor function of peripheral blood mononuclear cells in normal individuals and in patients with systemic lupus erythematosus

Normal peripheral blood mononuclear cells demonstrated increased DNA synthesis and secretion of newly synthesized protein when suboptimal concentrations of Concanavalin A (Con A) were added to the cultures after 24-h incubation in vitro. Cells stimulated by Con A, 1 mug/ml, after 24-h incubation demonstrated 3.0 times more tritiated thymidine incorporation, and 4.4 times more 14C-amino acid incorporation into newly synthesized secreted protein, than cells stimulated at 0 h (P less than 0.001). The acquisition of increased responsiveness was not abrogated by washing and resuspending the cells in fresh medium. Since the increased responsiveness could be inhibited by the addition to the cultures of small numbers of cells previously activated by Con A it is suggested that the enhanced reactivity acquired in culture represents the loss of a subpopulation of suppressor cells that modulate the T-lymphocyte response. Cells from nine patients with active, untreated systemic lupus erythematosus demonstrated normal responses to optimal concentrations of Con A added at 0 h, but an impaired response to Con A, 1 mug/ml. When these cells were incubated for 24 h, a significant increased response to Con A was not observed. This observation suggests that patients with active SLE lack circulating suppressor cells. When seven SLE patients were again studied after corticosteroid therapy had led to clinical improvement, the response to Con A, 1 mug/ml, added after 24-h incubation was similar to that observed in normal controls, suggesting that suppressor function in SLE returns as disease activity declines.

The requirement of an adherent cell substratum for the growth of developing plasmacytoma cells in vivo

The intraperitoneal injection of pristane (2,6,10,14-tetramethylpentadecane) produces an environment conductive to primary plasmacytoma growth in as few as 3 days. After pristane injection, the total free peritoneal cell population increases from a normal value of 1.55 X 10(6) to 5.28 X 10(6) and remains at this elevated level for at least 50 days. The adherent peritoneal cell population, composed of both mononuclear cells and polymorphonuclear leukocytes, is the primary source of this increase. In the pristane-conditioned peritoneum, these cells rapidly form a chronic granuloma on the peritoneal connective tissues. Daily subcutaneous treatment of mice with 0.5 mg of hydrocortisone beginning simultaneously with pristane injection prevents the increase in the peritoneal cell population, granuloma formation, d the production of a conditoned environment. In mice treated with hydrocortisone beginning 3 days after pristane injection, however, neither the peritoneal cell increase nor the production of a conditioned environment is prevented. The intraperitoneal injection of thioglycolate medium at 4-day intervals produces an elevation of the free adherent peritoneal cell population similar to pristane, but does not produce a granuloma or a conditioned environment. The intraperitoneal transfer of thioglycolate-induced adherent peritonel cells to mice treated with pristane and hydrocortisone simultaneously restores the production of a conditioned environment. These findings indicate that the adherent peritoneal cell population is responsible for the conditioning effect, and that the establishment of a resident population of these cells is necessary to produce conditioning.

Restoration of defective cellular immunity by levamisole in a patient with immunoblastic lymphadenopathy

A 71-year-old woman presented with acutely developed symptoms of generalized lymphadenopathy, intermittent maculo-papular skin rash, pruritus, weight loss, hepato-splenomegaly, pleural exsudate and alternating breast swellings. The histopathological picture of biopsies from a lymph node and from the skin was diagnostic for immunoblastic lymphadenopathy, and the serum concentrations of IgG and IgA were increased. Delayed cutaneous hypersensitivity reactions to various antigens were totally extinguished and the number of T-lymphocytes in the peripheral blood was consistently very low. The number of both T- and B-lymphocytes further decreased during cytostatic treatment and the patient contracted numerous infections. During intermittent treatment with Levamisole the infectious episodes ceased, the cellular immune response was reestablished and the pathological hyperimmuneglobulinaemia suppressed. It is suggested that the primary immunological defect in this disease could be a failing cellular immunity, and that the hyperplasia and hyper-reactivity of the B-cell system are a secondary phenomenon.