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Objective: The effect of serotonin (5-hydroxytryptamine; 5HT) on the in vitro proliferation of mitogen-stimulated lymphocytes was studied in primary cultures of rat spleen cells., Methods: 5HT was added to the cultures 1 h prior to the mitogen, at final concentrations from 10(-13) up to 10(-2) M. T and B cell mitogens (concanavalin A, pokeweed mitogen and lipopolysaccharide) were used at suboptimal and optimal concentrations. The cell proliferation was measured 24-72 h after the addition of mitogen. The effect of each 5HT concentration was studied on a group of 6-12 animals and was expressed as a percentage of the control values obtained with mitogen alone., Results: No significant effect of 5HT at concentrations from 10(-13) to 10(-5) M was found. At concentrations of > or =10(-4) M, a regular dose-dependent inhibition of the lymphocyte proliferation appeared, the concentration producing the half-maximal effect being 6 x 10(-4) M. The observed suppression was not due to 5HT cytotoxicity toward spleen cells., Conclusion: With the experimental system used, we failed to confirm an immunostimulatory effect of 5HT in the range of concentrations of its receptor sensitivities or lower, but found a clear-cut immunoinhibitory effect at higher concentrations., (Copyright 2001 S. Karger AG, Basel)

Background: Previously, it could be demonstrated that human patients with malignant diseases of various tissues exhibited characteristic and highly significant changes in the serum patterns of immunoglobulin (Ig)G subclasses, consisting of a decrease in IgG1 and an increase in IgG2 relative to total IgG. The aim of the current study was to determine whether this phenomenon was detectable at the level of IgG-producing B lymphocytes., Methods: Using a competitive reverse transcriptase polymerase chain reaction specific to IgG1 and IgG2, the gene expression of these 2 IgG subclasses in peripheral B cells from 10 patients with carcinomas of various sites within the female reproductive tract and 10 healthy controls was quantitatively determined, in parallel with the concentrations of the respective serum proteins., Results: Absolute levels of IgG subclass messenger ribonucleic acid (mRNA) showed a slight but not significant decrease in IgG1 and an increase in IgG2 in patients with gynecologic malignancies. However, the ratio of IgG1 to IgG2 expression showed a highly significant (P < 0.001) decrease in tumor patients compared with healthy controls, and corresponded to the change in the ratio of IgG1 to IgG2 serum proteins., Conclusions: These data suggest that the shifts in the serum patterns of IgG1 and IgG2 observed in patients with gynecologic malignancies are due to irregular biosynthesis of these IgG subclasses at the B-cell level., (Copyright 2000 American Cancer Society.)

Prior investigations showed that acutely diseased patients with an aspergillus sinusitis manifested immune dysfunctions in respect of both T and B lymphocytes. In contrast to patients with nonmycotic sinusitis reduced in vitro and in vivo responsiveness was observed. The aim of this study, carried out after removal of the fungus ball and endoscopic surgery in clinically healthy patients, was to ascertain whether this reduced responsiveness was to be regarded as the effect or cause of an Aspergillus fumigatus infection. Two years later, the in vivo response to recall antigens was normal in both groups of patients, whereas the response to mitogens (ConA, PHA and PWM) was still decreased in the aspergillus sinusitis groups. The data suggest that the reduced immune response is a consequence of the Aspergillus fumigatus infection. Depressed skin reactivity is only present during acute infection, while proliferative capacity, as measured in the "whole blood stimulation" assay is depressed for a long time after healing the acute infection.

In about 10% of patients operated on a chronic sinusitis, an aspergilloma is found in the paranasal sinus. To detect possible underlying immunodeficiencies, patients with aspergilloma were subjected to an immunological screening programme. The data were compared with those of patients suffering from non-mycotic chronic sinusitis and healthy controls. Totale lymphocyte counts and immunological levels were normal in both groups of sinusitis. Leukocyte subset analyses by membrane fluorescence revealed a significant decrease of CD11+ cells, i.e. macrophages/monocytes and NK cells, in both types of sinusitis. Furthermore, a markedly enhanced frequency of CD25+-cells, i.e. IL 2-receptor bearing cells, was observed in patients with aspergilloma. Peripheral blood lymphocytes of both groups of patients showed a significant reduction in the proliferative response to both T and B-cell mitogens, the values for the mitogens ConA and PWM being significantly lower in aspergilloma patients than in those with non-mycotic sinusitis. This lack of lymphocyte stimulation in the aspergilloma group was also manifest in skin tests to recall antigens. These first data suggest an immunodeficiency in association with chronic sinusitis caused by Aspergillus fumigatus. Further studies are needed to clarify if this defect is cause or result of the mycotic infection.