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New requirements regarding the exclusion of virus transmissions have led to new production methods of commercial IgG preparations. Nevertheless, the protein and antibody composition necessary for safe and efficacious preparations must be guaranteed. Minimal requirements have been defined by European Pharmakopeia and DAB 10 and are usually met by commercial IgG preparations. However, significant differences, depending on production methods and origin of donors, have been observed regarding the content of stabilizers, polymers and aggregates, IgA, IgG subclasses and also antibody titers and activities. Most of these quality criteria can be monitored by well standardized electrophoretic, immunological or chromatographic methods. A safe and universally applicable IgG preparation should be characterized by a low content of polymers and IgA, a physiological IgG subclass distribution and high antibody activities against relevant infectious agents. These requirements are more easily met by preparations not chemically or enzymatically modified.

ZusammenfassungDie Diagnose und Lokalisation einer Liquorfistel erworbener Ursache stellt weiterhin eine Herausforderung für viele Fachdisziplinen (u.a. Unfallchirurgie, HNO, Neurochirurgie, Kieferchirurgie) dar. Durch die Untersuchung liquorspezifischer Markerproteine kann der Nachweis einer Liquorfistel zuverlässig gelingen. Etabliert haben sich hierfür qualitative und quantitative Nachweismethoden, wie z.B. Beta-2 Transferrin oder Beta-Trace Protein (Prostaglandin-D-Synthase).Für die operative Fistelobliteration ist eine genaue topografische Diagnostik erforderlich. Hierfür kommen bildgebende Verfahren zum Einsatz, die eine Anwendung von intrathekal applizierten Tracersubstanzen erfordern.

Intravenous immunoglobulin (IVIg) preparations are increasingly used for therapy of several neuroimmunologic diseases. IVIg therapy is considered safe, although serious side effects like aseptic meningitis, cerebral vasospasm, or ischemic encephalopathy have been reported. These side effects are frequently associated with neutrophilic pleocytosis in the cerebrospinal fluid (CSF), suggesting a neutrophil-mediated mechanism. To elucidate the potential role of neutrophil activation, we analyzed IVIg preparations from 5 different commercial sources for the presence of antineutrophil cytoplasmic antibody (ANCA)–like immunoglobulins against ethanol-fixed peripheral-blood neutrophils, purified human antigens, and a panel of human and nonhuman tissues. All IVIg batches tested (n = 13) contained atypical ANCAs (IgG titer up to 1:2048, IgA up to 1:512). Moreover, all preparations were capable of inducing hydrogen peroxide production in TNFα-primed human neutrophils, with a significant correlation (P< .005) between atypical ANCA titers in IVIg preparations and neutrophil activation. Fc-mediated binding and activation was ruled out by the use of IVIg-F(ab′)2fragments. Our findings strongly suggest that in vivo activation of TNFα-primed neutrophils by atypical ANCAs of IVIg may contribute to the side effects of IVIg therapy and for the first time demonstrate that the activation of neutrophil granulocytes by IVIg occurs in an Fc receptor (FcR)–independent, hence antigen-dependent, way.

Intravenous immunoglobulin (IVIg) preparations are increasingly used for therapy of several neuroimmunologic diseases. IVIg therapy is considered safe, although serious side effects like aseptic meningitis, cerebral vasospasm, or ischemic encephalopathy have been reported. These side effects are frequently associated with neutrophilic pleocytosis in the cerebrospinal fluid (CSF), suggesting a neutrophil-mediated mechanism. To elucidate the potential role of neutrophil activation, we analyzed IVIg preparations from 5 different commercial sources for the presence of antineutrophil cytoplasmic antibody (ANCA)–like immunoglobulins against ethanol-fixed peripheral-blood neutrophils, purified human antigens, and a panel of human and nonhuman tissues. All IVIg batches tested (n = 13) contained atypical ANCAs (IgG titer up to 1:2048, IgA up to 1:512). Moreover, all preparations were capable of inducing hydrogen peroxide production in TNFα-primed human neutrophils, with a significant correlation (P < .005) between atypical ANCA titers in IVIg preparations and neutrophil activation. Fc-mediated binding and activation was ruled out by the use of IVIg-F(ab′)2 fragments. Our findings strongly suggest that in vivo activation of TNFα-primed neutrophils by atypical ANCAs of IVIg may contribute to the side effects of IVIg therapy and for the first time demonstrate that the activation of neutrophil granulocytes by IVIg occurs in an Fc receptor (FcR)–independent, hence antigen-dependent, way.

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An isoelectric focusing procedure for the detection of oligoclonal IgA in cerebrospinal fluid (CSF) samples is presented. CSF IgA bands were found in 69% of patients with various inflammatory neurological diseases, in 22% of patients with other neurological diseases, but in none of the patients with non-neurological diseases. In patients with inflammatory neurological diseases we examined the relationship between an intrathecal synthesis of oligoclonal IgA and an intrathecal IgA synthesis as proved by a formula recently described by Reiber and Felgenhauer: 83% of patients with an intrathecal IgA synthesis according to the formula of Reiber and Felgenhauer also showed CSF IgA bands whereas 59% of patients without an intrathecal IgA synthesis displayed an intrathecal synthesis of oligoclonal IgA. Seventeen percent of patients with inflammatory neurological diseases were characterized by an intrathecal synthesis of oligoclonal IgA but did not show either an intrathecal IgA synthesis or an intrathecal synthesis of oligoclonal IgG, the detection of oligoclonal IgA therefore being the only evidence of an intrathecal humoral immune response in these patients.

The mechanism of block of nicotinic acetylcholine receptor (nAChR) channels by purified antibodies from patients with myasthenia gravis (MG) was investigated by using an ultrafast system for solution exchange at outside‐out patches. IgG of MG patients and controls was purified by using protein A–Sepharose columns. Probes from 9 seropositive MG patients and 3 seronegative MG patients were tested. As a preparation, cultured mouse myotubes expressing the embryonic‐type nAChR channels were used. Twenty‐millisecond pulses of 1.0 mM ACh were applied repetitively to outside‐out patches. Outside‐out patches were preexposed with IgG in concentrations between 0.1 and 200 mg/L during application of ACh pulses. The peak current amplitude was reduced to values between 6% and 71% of control for the 9 seropositive and 3 seronegative MG patients. The block was concentration dependent and fully reversible after washout of antibodies. Incubation with IgG from different control patients did not reduce the peak current amplitude. In addition, our findings with purified IgG from seronegative MG patients support the idea of the immunopathogenesis of this disorder and may allow the development of a diagnostic test for seronegative MG patients.

To determine whether matrix metalloproteinase (MMP)-9 is a potential mediator involved in the frequently detected blood-brain barrier leakage in human immunodeficiency virus (HIV)-infected patients, zymography was used to detect MMP-9 activity in cerebrospinal fluid (CSF) samples of 80 HIV-infected patients and of 10 control patients. CSF MMP-9 activity was detected in 40% of HIV-infected patients (but not in controls) and was significantly more frequent in HIV-infected patients than in those without neurologic deficits (50% vs. 13.6%). The frequency of CSF MMP-9 activity did not significantly differ between neurologically symptomatic HIV-infected patients with or without opportunistic central nervous system disease (51.6% vs. 48.1%). Additionally, the presence of CSF MMP-9 activity in HIV-infected patients was associated with an increased CSF white blood cell count and an elevated CSF-to-serum albumin ratio, suggesting that it may play a role in blood-brain/CSF barrier leakage in HIV-infected patients.