In this study, we have evaluated the levels of blood histamine, serum interleukin-1 beta (IL-1 beta), and plasma tumor necrosis factor-alpha (TNF-alpha) in 20 patients with mild to moderate Alzheimer disease (AD; 13 early onset and 7 late-onset AD subjects) and in 20 age-matched control subjects (C). AD patients showed higher concentrations of histamine (AD = 452.9 +/- 237.9 pmol/mL; C = 275.3 +/- 151.5 pmol/mL; p < 0.05) and IL-1 beta (AD = 211.2 +/- 31.1 pg/mL; C = 183.4 +/- 24.4 pg/mL; p < 0.01), and lower values of TNF-alpha (AD = 3.59 +/- 2.02 pg/mL; C = 9.47 +/- 2.64 pg/mL; p < 0.001) than elderly controls. Increased levels of histamine and decreased levels of TNF-alpha were observed in both early onset AD (EOAD) and late-onset AD (LOAD) patients, but only EOAD subjects had elevated serum IL-1 beta values compared with age-matched controls. Age negatively correlated with histamine (r = -0.57; p < 0.05) and positively with IL-1 beta levels (r = 0.48; p < 0.05) in healthy subjects, but not in AD, whereas a positive correlation between TNF-alpha scores and age was only found in AD patients (r = 0.46; p < 0.05). Furthermore, histamine and TNF-alpha values correlated negatively in AD (r = -0.50, p < 0.05). In addition, cognitive impairment increased in patients with lower TNF-alpha and higher histamine and IL-1 beta levels, as indicated by the correlations between mental performance scores and histamine (r = -0.37, ns), IL-1 beta (r = -0.33, ns) and TNF-alpha levels (r = 0.42, p < 0.05). Finally, histamine concentrations decreased as depression scores increased in AD (r = -0.63, p < 0.01). These data suggest a dysfunction in cytokine and histamine regulation in AD, probably indicating changes associated with inflammatory processes.

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The detection of antibodies to Taenia solium metacestodes is very important in the differential diagnosis of neurocysticercosis (NCC). In this study, an electroimmunotransfer blot (EITB) assay that uses an elaborate protocol with metacestode glycoproteins as antigens was compared with two other Western blots that use glycoproteins obtained using simpler methods, including an eluate from a lectin column, or the vesicular fluid (VF) of the parasite. The concordance between the three assays was 91% in patients with active NCC and 100% in patients with suspected NCC and previous documentation of negative serology. The specificities for the Western blots and the EITB assay were 98% and 100%, respectively (98% concordance). These data suggest that the simplest of these immunoassays, the one that uses the VF of T. solium metacestodes in a Western blot format, can be reliably used for the serologic diagnosis of NCC in developing countries where access to the EITB assay is difficult.

Summaryobjective Microbiological identification of Mycobacterium tuberculosis is insensitive and slow, and clinical distinction of tuberculous meningitis (TBM) from other subacute or chronic meningoenchephalitides (SACM) is difficult. Successful use of highly specific M. tuberculosis serological assays on cerebrospinal fluid has been reported, but their performance for diagnosis in a tuberculosis endemic country where they would be of most value is unclear. We sought to determine the biological basis for the uncertainty in interpretation of antibody detection in the CSF of TBM patients.methods We identified prospectively 46 adults with SACM and explored the concordance between TBM diagnosis and detection of highly specific M. tuberculosis antibodies in CSF. The source of antibodies in CSF was explored by evaluating the correlation between antibody titres in CSF with those in serum, or with the albumin quotient. Intrathecal IgG synthesis was assessed by the IgG index.results Positive antibody titres were more frequent among TBM patients (76%), but were also present in individuals with other SACM (59%). A positive correlation between antibody titres in CSF with those in serum, or with the albumin quotient, supported the leakage of antibodies from plasma to CSF through an increased blood-brain barrier permeability. Intrathecal IgG synthesis was only detected in 35% of the TBM cases.conclusion Plasma antibodies likely synthesized in response to previous tuberculosis infections were a major source of mycobacterial antibodies in CSF due to leakage through an impaired blood-brain barrier. Interpretation of mycobacterial antibodies in CSF of adults for TBM, however specific, must take into account the contribution of antibodies from plasma, and hence, has questionable use for diagnosis.