Reduced expression of interleukin-2 receptors in hypogammaglobulinaemia: a possible cause of higher cancer incidence

Membrane-bound/soluble IL-2 receptor (IL-2R) and levels of IL-1 alpha, IL-2, and IL-6 in the serum and in the PBMC culture supernatants from 17 patients with hematological malignancies

The present study investigated the peripheral blood mononuclear cells (PBMC) blastic responses to PHA, PHA plus recombinant IL-2 (rIL-2) and rIL-2 alone; the expression of membrane-bound IL-2R on PHA-stimulated PBMC; and the levels of IL-1 alpha, IL-2, IL-6, and sIL-2R in serum and in culture supernatants from PHA-stimulated PBMC in 17 patients with with non-Hodgkin's lymphoma (NHL), 4 with Hodgkin's lymphoma (HL), 5 with Hairy cell leukemia, 1 with chronic myelogenous leukemia, and 1 with chronic lymphocytic leukemia. The patients with HL and NHL with active disease (AD) were separated from those in clinical remission. The patients with AD were studied at diagnosis (obviously before therapy) and the patients in clinical remission were out of therapy since at least 6 mo. The lymphocyte blastogenic response to PHA was significantly lower in patients with HL and NHL with AD than in the control group. The response to rIL-2 alone was in the same range in the control group and in HL and NHL AD patients. By adding rIL-2 to PHA there was an increase of the blastogenic response of the same patients. The percentage of CD25 expressed on PHA-stimulated lymphocytes from patients with HL and NHL AD and from normal subjects is in the same range. Serum levels of IL-2, IL-6, and sIL-2R were significantly higher in HL and NHL AD patients than in controls as well as in all other hematological malignancies. Supernatants derived from PHA-stimulated PBMC were assessed for the presence of cytokines and sIL-2R by ELISA. The levels of IL-2, IL-6, and sIL-2R were significantly lower in HL and NHL AD patients than in controls as well as in all other hematological malignancies.

Increased IL-6 gene expression and production in patients with common variable immunodeficiency

We have studied IL-6 gene expression and production by in vitro stimulated peripheral blood mononuclear cells (PBMC) isolated from common variable immunodeficiency (CVI) patients. A strong hybridization signal for the IL-6 probe was observed in mRNA extracted from phytohaemagglutinin (PHA)- and PHA/phorbol myristate acetate (PMA)-stimulated PBMC from most of 12 CVI patients analysed. IL-6 production by PHA-stimulated PBMC from 28 CVI patients was evaluated in ELISA and found to be significantly (P < 0.0001) higher than in normal controls. IL-6 production, however, did not correlate with the lymphocyte populations examined, nor with the absolute number of monocytes. We have also showed that IL-6 was able to increase IgM secretion by several Epstein-Barr virus (EBV)-transformed cell lines derived from both normal donors and CVI patients, but it failed to modify substantially the amounts of IgM and IgG produced in vitro by PBMC derived from CVI patients and activated with pokeweed mitogen (PWM) or anti-IgM. Our data indicate that IL-6 gene expression and production is increased in CVI, but CVI cells do not respond to IL-6 with increased production of immunoglobulin.

Membrane-bound and soluble IL-2 receptors (p55 and p75 chains) on peripheral blood mononuclear cells from patients with solid malignancies

The aim of the investigation was to study directly the IL-2 receptor (IL-2R) and its subunits, p55 and p75 chains, either membrane-bound or soluble, on PBMC of patients with solid malignancies and, indirectly, the same patients' PBMC ability to produce IL-2. Fifty-eight cancer patients, 29 men and 29 women, were studied: their mean age was 57.3 yr, range 35-79. Twenty-two healthy age-sex-matched subjects served as controls. The tumors were the most common and the most representative among human cancers, i.e., breast, lung, head and neck, digestive tract and liver, prostate and gynecologic cancers: they were generally in advanced stages and in 23 cases metastatic. The PBMC proliferative response to PHA, PHA plus IL-2, and IL-2 was evaluated along with the response to PHA in the presence of anti-p55, anti-p75 monoclonal antibodies, or both. Moreover, membrane-bound IL-2R (p55 and p75 chains) on PHA-stimulated PBMC was detected, along with soluble IL-2R in the serum and in the culture supernatants. The conclusions suggest that in solid malignancies: the membrane-bound IL-2Rs, both p55 and p75 chains, are expressed normally, there is an high serum level of soluble IL-2R, there is a normal release of soluble IL-2R in culture, and there is an indirect evidence of a lack of IL-2 production. Therefore, no primary impairment of IL-2R was found in solid tumors. Moreover, in our study we have found no difference in any parameter studied between patients with and patients without metastases.

Immunophenotypical alterations in a subset of patients with common variable immunodeficiency (CVID)

We investigated the expression of surface molecules on lymphocytes from 20 patients with CVID and 40 healthy subjects. Lymphocytes were analysed by dual colour flow cytometry. We identified a subset of patients (8 of 20) characterized by low CD4/CD8 ratio (less than 1.1), expansion of T cells co-expressing the activation marker HLA-DR and significant increase in CD8+ T cells co-expressing CD57. Expression of the adhesion molecules LFA-3 (CD58) and ICAM-1 (CD54) was significantly increased in this subgroup. In addition, within the CD4+ T cells the percentage of CD29+ (memory) cells was increased, while the CD45RA and LAM-1 (Leu-8) antigens were depressed. These results indicate that in a subgroup of CVID patients T cells are activated in vivo and the CD57+CD8+ lymphocyte subpopulation, supposed to comprise functional suppressor T cells, is expanded. We suggest a chronic viral infection in these patients, but it is not clear whether this is primary or secondary to the underlying defect.

The role of lymphokines in common variable hypogammaglobulinemia

Common variable (acquired) hypogammaglobulinemia (CVH) is a rare primary immunodeficiency disease of great interest as an immunological model of defects in antibody production. In this article, Gavin Spickett and John Farrant discuss evidence of abnormalities in lymphokine production and responses in the generation of the functional failure. It is not yet clear whether the B cell is intrinsically abnormal or lacks appropriate signals, but the block appears to occur in the differentiation phase of B cells, since membrane (but not secreted) IgG is made. Some T-cell defects also occur in this disease. The cause of CVH is unknown, although a viral aetiology has been suggested. Better understanding of lymphokine networks may allow the provision of specific signals to overcome the block in antibody production.

B cell function in acquired "common-variable" hypogammaglobulinemia: proliferative responses to lymphokines

We have compared the proliferative responses of an enriched population of B lymphocytes from patients with acquired (common variable) hypogammaglobulinemia (CVH) with the responses of cells from normal individuals. The uptake of [3H]thymidine into DNA was measured on stimulation with a range of interleukins (IL-2, IL-4, and IL-6) and solid-phase anti-IgM. Flow cytometry using CD19 and surface IgM showed that the "non-T" preparations from the peripheral blood of CVH patients either contained B cells within the normal range (30-40% of the cells) or in a minority group no B cells (less than 3% of the cells). Overall, there were no significant differences between the proliferative responses of patients' cells (in the group where normal numbers of B cells were present) and normal cells with any combination of stimulus used. No IgG was produced by cells from any patient and in only one patient was IgM production observed. This suggests that the primary B lymphocyte defect in CVH is in the differentiation phase in B cell function rather than in the growth phase. However, the presence or absence of B cells suggests that different defects exist in subgroups of patients with this disease.

Natural killer and interleukin-2 induced cytotoxicity in asthmatics. I. Effect of acute antigen-specific challenge

Natural killer (NK) cell activity and interleukin-2 (IL-2) induced cytotoxicity to NK-resistant targets T24 in a group of patients with grass pollen seasonal asthma were investigated. Acute bronchial provocation with this antigen was also performed and blood samples were taken before and 15 min after the maximal clinical response. NK activity was elevated in this group but there was a significant decrease after acute challenge. IL-2 induced cytotoxicity was also increased and declined after antigen challenge. Limiting dilution analysis for minimal frequencies of precursors of the IL-2 induced killer cells was introduced and showed increased numbers of lymphokine-activated killing precursors in this group of patients. These data might indicate the aberrations of the IL-2 system in immediate type allergy but the clinical significance of these findings remains to be determined.

Interleukin 2 and its receptor: structure, function and therapeutic potential

In this review, salient molecular, biochemical and functional features of human interleukin 2 (IL-2), its membrane receptor, and its clinical relevance are outlined. We also describe experimental systems, where observed biological or pharmacological effects of IL-2 could be applied to corresponding clinical situations. In particular, IL-2 has been intensively studied in the context of cancer therapy. We discuss the rationale for the use of IL-2 in cancer treatment and our experience in this area. A better understanding of the IL-2 system and, specifically, the nature of signals transduced through it will allow us to manipulate the immune response in a variety of different ways, resulting in new approaches to investigation of immune responsiveness in general. This may have a profound impact on clinical medicine.

Effect of human recombinant interleukin (IL-2) on peripheral blood mononuclear cells of burned patients

Interleukin-2 (IL-2) has been suggested to play a key role in the immune response. To investigate the effect of human recombinant IL-2 on proliferative and cytotoxic responses in burn patients, peripheral blood mononuclear cells from 20 severely burned patients (body surface area (BSA) greater than 20 per cent) were studied in this way. Proliferative response measured by tritiated thymidine uptake was impaired from week 2 following injury. IL-2-activated cytotoxicity to NK-resistant target T24 was significantly impaired from week 2. To clarify if the defect in cytotoxic response is due to a decreased number of cell precursors or due to reduced responsiveness to IL-2, a limiting dilution assay was introduced. However, there was no reduction in precursor cell numbers. These data suggest that, in addition to impaired IL-2 production, there is an endogenous defect in IL-2 responsiveness. This may be of clinical importance since it is not possible to reverse this defect, at least in vitro.