Seventeen patients with antibody immunodeficiency (9 subclass
IgG immunodeficiencies, 8
common variable immunodeficiencies) and clinically unambiguous immunodeficiency symptomatology participated in the study with 14 healthy donors. The patients were given regular
intravenous immunoglobulin (
IVIG) infusions with
Endobulin. Blood was collected before and 7 days after infusion of the usual
IVIG dose. Mononuclear cells were isolated from peripheral blood (PBMC) of the patients by
Ficoll-Paque gradient centrifugation. In order to monitor the ability to inhibit or activate polyclonal production of
immunoglobulins in vitro, we stimulated PBMC with
pokeweed mitogen (PWM) and with a mixture of
pokeweed mitogen +
concanavalin A (PWM+ConA). We found that an immunomodulatory effect of
IVIG persists in vitro even one week after infusion. Polyclonally stimulated
IgA and
IgM production was suppressed by
IVIG infusion mainly in patients with
IgG subclass deficiency. The positive stimulatory effect of
IVIG infusion on
IgG production was confirmed. The
IgG production increased in vitro after infusion in both groups of patients and was significantly higher than in healthy donors. Co-stimulation of PWM-stimulated cells with ConA caused an inhibition of
immunoglobulin release in normal healthy donors. The infusion supported the capability of ConA to inhibit
IgG production in vitro in patients with
IgG subclass deficiency, whereas an increase in
IgG production with PWM+ConA stimulation after infusion was found in CVID patients. We assume that lymphocytes activated by ConA produce suppressive factors, which can be affected by the
IVIG infusion and which can have both an immunostimulatory and an immunosuppressive effect.