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Abstract Background Testing for cerebrospinal fluid (CSF)-restricted oligoclonal bands (OCB) by isoelectric focusing is used to detect intrathecally produced total IgG. By contrast, antibody indices (AI) are assessed to test for intrathecally produced antigen-specific IgG. A number of previous cases reports have suggested that AI testing might be more sensitive than OCB testing in detecting intrathecal IgG synthesis. Findings Here we report on 21 patients with positive AI for either herpes simplex virus, varicella zoster virus, cytomegalovirus, measles virus, rubella virus, or Borrelia burgdorferi in the absence of total-IgG OCB and, accordingly, in the presence of a normal total-IgG CSF/serum ratio. Conclusion Our findings indicate that AI testing should not generally be omitted in OCB-negative patients and provide a rationale for systematic and prospective studies on the comparative sensitivity and specificity of AI and total-IgG OCB testing in infectious and other diseases of the CNS.

The analysis of cells in the cerebrospinal fluid (CSF) is a routine procedure that is usually performed manually using the Fuchs–Rosenthal chamber and cell microscopy for cell counting and differentiation. In order to reduce the requirement for manual assessment, automated analyses by devices mainly used for blood cell analysis have been also used for CSF samples. Here, we summarize the current state of investigations using these automated devices and critically review their limitations. Despite technical improvements, the lower limit for reliable leukocyte counts in the CSF is still at approximately 20 cells/µL, to be validated depending on the device. Since the critical range for clinical decisions is in the range of 5–30 cells/µL this implies that cell numbers < 30/µL require a manual confirmation. Moreover, the lower limit of reliable erythrocyte detection by automated devices is at approximately 1000/µL. However, even low erythrocyte numbers may be of clinical importance. In contrast, heavily hemorrhagic samples from neurosurgery may be counted automatically at an acceptable precision more quickly. Finally, cell differentiation by automated devices provides only a rough orientation for lymphocytes, granulocytes and monocytes. Other diagnostically important cell types such as tumor cells, siderophages, blasts and others are not reliably detected. Thus, although the automation may give a gross estimate sufficient for the emergency room situation, each CSF requires a manual microscopy for cytological evaluation for the final report. In conclusion, although automated analysis of CSF cells may provide a first orientation of the cell profile in an individual sample, an additional manual cell count and a microscopic cytology are still required and represent the gold standard. [ABSTRACT FROM AUTHOR]

Abstract: BAFF (B-cell activating factor of the TNF family) plays a crucial role in B-cell survival. Elevated BAFF serum levels have been linked to several autoimmune diseases in humans, and therapies targeting BAFF were successful in animal models of rheumatoid arthritis and systemic lupus erythematosus. Wagener''s granulomatosis (WG), a chronic systemic vasculitis, is characterized by circulating autoantibodies (cANCA) targeting neutrophils, which can produce BAFF. To investigate whether BAFF is involved in WG pathology, BAFF serum levels were measured by ELISA in 46 WG patients and 62 healthy donors. We report the novel finding that in WG patients serum levels of BAFF were significantly increased (median 3.95ng/ml, p =0.009) compared to healthy controls (median 2.38ng/ml). The difference was even more pronounced when comparing controls with untreated WG patients (median 4.61ng/ml, p =0.001). Treatment of WG patients with glucocorticoids was associated with lower BAFF levels. The serum BAFF level in treated WG patients was about the same as in the control group. We propose that BAFF might be a pathogenic factor in WG and that targeting BAFF may represent a new therapeutic strategy in a subset of chronically relapsing WG patients with elevated BAFF levels. [Copyright &y& Elsevier]

Background: Recently, subclass-specific antisera have been introduced for application in a nephelometric assay. The aim of this study was to establish age-dependent reference values for serum concentrations of the two IgA subclasses in children and adults. Methods: Serum levels of IgA1 and IgA2 were measured by automated immunonephelometry in samples from 235 clinically healthy children between 6 months and 18 years of age and 36 healthy adults. Results: Both IgA1 and IgA2 were detectable in all samples, and both IgA1 and IgA2 increased with increasing age. In adults, the mean value for IgA1 is 1.46 g/l for IgA2 0.21 g/l and for total IgA 1.94 g/l. Individual IgA2 values correlate significantly (p<0.0001) with IgA1 values (r2=0.5433). In addition, there was a highly significant (p<0.0001) correlation (r2=0.9530) between the measured total IgA and the sum of the two IgA subclasses indicating that immunonephelometry using highly specific polyclonal antisera might be superior to other methods. Conclusions: These results and the availability of age-dependent reference values make it worthwhile to reassess the role of IgA subclasses in immunodeficiency and autoimmune diseases where conventional methods have led to conflicting results. [Copyright &y& Elsevier]