H. Permin

Quantitative and Qualitative Estimations of IgE Bound to Basophil Leukocytes from Hay Fever Patients

IgE was removed from human basophils of 4 nonatopic persons and 10 hay fever patients allergic to timothy grass pollen by treating the cells with buffer to adjusted pH 4. IgE could be removed and refixed to the same cells. Refixation was demonstrated by immunofluorescence and by the ability of basophils to release histamine on exposure to timothy pollen. Removed total IgE and specific IgE directed against timothy pollen were estimated, and a linear correlation to the level of total IgE and specific IgE in serum was found. The total number of IgE molecules per basophil was calculated to be in the range of 30,000 to 300,000, and timothy‐specific IgE constituted 4%‐15% of the total IgE molecules on the cells. It was furthermore established that specific cell‐bound IgE was linearly correlated to the pollen concentration releasing 20% of the histamine contents of the basophils. Separated IgE from sensitized and nonsensitized basophils could be bound to basophils from other patients, resulting in a change in cell sensitivity. This could be ascribed to additional binding to free cell receptors as well as to a partial replacement of bound IgE. Basophils from nonatopic persons could not be sensitized by incubation with surface IgE from atopic persons. The results indicate that acid treatment is a simple method suitable for removing IgE from basophils. This IgE is intact and can be quantitated.

Bacterial Histamine Release by Immunological and Non-Immunological Lectin-Mediated Reactions

The mechanisms of bacteria‐induced histamine release were examined in vitro in human leukocytes and rat mast cells. Three types of bacterial responders were found. In persons with IgE‐bearing basophilocytes bacterial histamine release could be triggered by two different mechanisms, an IgE‐dependent mechanism where removal of IgE abolished the release and a non‐immunological mechanism where this was not the case. In responders with no IgE‐bearing cells bacterial histamine release was caused by a non‐immunological mechanism. The non‐immunological mechanism was further substantiated by release in isolated mast cells from germ‐free rats. These experiments suggest a direct interaction between bacteria and target cell, and experiments with multi‐washed bacteria and bacteria cell wall preparations indicate the possibility of the bacteria wall interacting with the target cell. It is probable that the non‐immunological mechanism depends on lectin‐mediated reactions, since bacteria‐induced histamine release was inhibited by lectin‐binding sugars as is release caused by plant lectins.

Influence of bacterial endotoxins on basophil histamine release: potentiation of antigen- and bacteria-induced histamine release

The histamine‐releasing capability of lipopolysaccharides (LPS) was examined in human leukocyte suspensions. LPS alone did not release histamine, but was found to enhance the histamine release caused by anti‐IgE. Also the IgE‐mediated histamine release caused by specific antigens (allergens or bacteria) in sensitized individuals was enhanced by LPS. The potentiating effect of LPS was observed in grass pollen and dog dander allergic patients as well as in patients sensitized to E. coli or Staph, aureus bacteria. No potentiation was obtained by exposure to unspecific allergens or bacteria to which the persons were not sensitized. Bacteria can release histamine by immunological or nonimmunological mechanisms, and only the immunological histamine release was found to be potentiated by LPS. It is speculated that endotoxins reinforce release of histamine caused by allergens in allergic patients or by bacteria in persons sensitized to these microorganisms.

Inhibitory Effect of Cyclosporin A on Histamine Release from Human Leukocytes and Rat Mast Cells

The influence of cyclosporin A (CyA) on human basophil histamine release induced in vitro by specific antigen, anti‐IgE, calcium ionophore A23187, or concanavalin A (Con A) was studied. CyA inhibited the release induced by these four stimulators. It is suggested that the drug acts directly on the target cell, since similar effect was obtained with isolated peritoneal rat mast cells. The basophil histamine release was not changed by a non‐immunosuppressive cyclosporin derivate.

Basophil‐bound IgE and serum IgE directed against Haemophilus influenzae and Streptococcus pneumoniae in patients with chronic bronchitis during acute exacerbations

The investigation includes 12 patients hospitalized with acute exacerbations of chronic bronchitis (CB) and infected in the lower respiratory tract with Haemophilus influenzae (HI) or Streptococcus pneumoniae (SP). Eight patients were infected with HI, three with SP, and one patient with both species. Basophil‐bound IgE and serum IgE directed against these species were examined using the patients own bacterial isolates. All patients showed IgE‐mediated histamine release when their peripheral leukocytes were incubated in vitro with the infecting species, indicating basophil‐bound IgE directed against their own bacterium. No IgE‐mediated response was obtained in the control group of 12 healthy individuals. Bacteria‐specific IgE in serum was demonstrated by immunofluorescence assay and further verified by passive sensitization. There was a positive serum titre in seven of nine patients housing HI and in all SP‐infected patients but not in the control group. No synchronism was found between a positive response in the histamine release test and the immunofluorescence assay by parallel testing during the test period. This may be due to a time delay between production of serum IgE and its fixation to the cell surface. The results indicate a potential for a bacteria‐specific IgE‐mediated immune response in CB. Thus, by triggering mediator release, bacteria may be involved in the pathogenesis of exacerbations in CB.

Histamine release from basophil leukocytes induced by microbial antigen preparations in patients with AIDS.

Type I allergy against some common microorganisms was investigated in 14 patients with AIDS and 11 human immunodeficiency virus (HIV) antibody‐positive homosexual men, and in a control group consisting of 13 heterosexual men without HIV antibodies. Basophil histamine release technique was used as a sensitive method to detect type I allergy against Candida albicans (CA), Herpes simplex virus type I (HSV‐I) and cytomegalovirus (CMV). Of the 14 AIDS patients 11 (78%) showed significant histamine release when stimulated with CA, and HSV‐I caused release in 10 (71 %), whereas no response was obtained by CMV. In the group of HIV antibody‐positive men only one released histamine when stimulated with CA and HSV‐I and this patient also had lymphadenopathia. In contrast to these results, no release of histamine was obtained in the control group consisting of 13 heterosexual men. The histamine release caused by CA and HSV‐I is mediated by an immunological reaction, since the release was abolished and regained by removal from and refixation to the cell surface of the cell‐bound immunoglobulins. These results suggest an involvement of type I allergy as a pathogenetic co‐factor in some infections in AIDS, and allergic type I reactions to CA and HSV‐I might be an indicator for the presence of manifest AIDS.

Bacteria and endotoxin enhance basophil histamine release and potentiation is abolished by carbohydrates

Histamine release caused by anti‐IgE, specific antigens and calcium ionophore A23187 was examined in leukocyte suspensions from healthy individuals and patients allergic to house dust mite and birch pollen. Staphylococcus aureus and LPS from Salmonella typhimurium were found to cause a synergistic enhancement of the release. The potentiation of mediator release by the bacteria and the endotoxin depends on a binding to the basophilocyte, followed by a non‐transient event, since the potentiating effect persists after preincubation of the cells with the LPS followed by washout and leaving the cells for 30 min at 37°C before stimulation with anti‐IgE. The potentiation was abolished or reduced by galactose (10−7 and 10−6 M) and N‐acetylglucosamine (10−6 and 10−5 M), acting by a binding to the basophil cell membrane, demonstrated by the persistence of effect after preincubation and washout of unbound sugar.

Endotoxins release histamine by complement activation and potentiate bacteria-induced histamine release

The histamine-releasing capability of bacterial lipopolysaccharides (LPS) was examined in human leukocyte suspensions. LPS alone did not release histamine, but it was found to enhance the histamine release caused by bacteria in basophils from persons sensitized to these bacteria. In the presence of serum, LPS was able to release histamine through complement activation. It is speculated that endotoxins reinforce release of histamine caused by bacteria in persons sensitized to these microorganisms, and a direct mediator release via complement activation might play a role in septic conditions.

Intrinsic asthma and bacterial histamine release via lectin effect

Bacteria-induced histamine release from basophil leukocytes was observedin vitro in both children with intrinsic asthma (IA) as well as in normal individuals.In vivo the release is suggested to take place only in the lung of IA patients, where a defective pulmonary barrier would permit the bacteria to enter, but not in healthy individuals. The study indicates that two different mechanisms of bacterial histamine release might exist, an IgE-mediated reaction and a non-immunological mechanism consisting of a direct interaction with the basophil cell surface. The non-allergic mechanism might depend on a lectin effect where bacterial surface lectins interact with the basophil cell surface leading to release of histamine. Inhibition studies with carbohydrates suggest a multi-lectin reaction in the bacterial histamine release involving several types of lectins on the bacterial membrane reacting with different carbohydrate moieties on the cell surface of basophil leukocytes.

Antibodies against nuclear components in schistosomiasis: results compared to values in patients with rheumatoid arthritis, systemic lupus erythematosus, and osteoarthrosis

Occurrence of autoantibodies against nuclear material was compared in groups of patients with rheumatoid arthritis (RA n= 22), systemic lupus erythematosus (SLE. n= 24), osteoarthrosis (OA n= 25), and chronic schistosomiasis mansoni (CSM n= 28). Anti‐ds DNA antibody was detected by an ammonium sulphate precipitation radioimmunoassay, antibodies against ex tractable nuclear antigen (ENA) were detected and differentiated in RNAse‐resistant and RNAse‐sensitive components (Sm and RNP antigens with an ELISA technique. IgG organ‐non‐specific and granulocyte‐specific antinuclear antibodies (ANA) were detected by immunofluorescence technique with quantitative titration of positive reactions and determination of complement‐fixing properties, The results in groups of patients with SLE, RA and OA were of confirmative nature and supported that the different methods detect different systems of autoantibodies and nuclear autoantigens. In CSM it was demonstrated that 23 of 28 cases had positive reactions to the RNAse‐resistant part of ENA (the Sm‐antigen), a significant difference from the three other groups of patients (P < 0.001). The antibody was in all cases of IgM class, in seven cases also of IgA class. Antibodies against nuclear material in CSM arc probably a consequence of heavy disturbance of the immune system in this chronic infection with great permanent antigen load. It is a matter of discussion, whether production of these antibodies is induced by nuclear material from the host or from the parasite.