Intrathecal production of HIV antibodies in suspected AIDS encephalopathy

Cerebrospinal fluid oligoclonal bands in Neuroborreliosis are specific for Borrelia burgdorferi

Background

Cerebrospinal fluid (CSF) oligoclonal bands (OCB) occur in chronic or post-acute phase of inflammatory diseases of the central nervous system.

Objective

To determine whether CSF OCB in patients with neuroborreliosis (NB) are specific for borrelia burgdorferi senso lato.

Methods

We performed isoelectric focusing followed by immunoblotting in CSF of 10 NB patients and 11 controls (7 patients with multiple sclerosis, 2 patients with neuromyelitis optica spectrum disease, 1 patient with dementia and 1 patient with monoclonal gammopathy). Immunoblotting was performed using an uncoated as well as a borrelia antigen pre-coated nitrocellulose membrane (NCM). OCB were counted by visual inspection and photometric analysis. OCB were compared between uncoated und pre-coated NCM both in the NB and control group. For validation purposes inter-assay precision was determined by calculating the coefficient of variation (CV)

Results

Borrelia-specific OCB were found in the CSF of 9 NB patients and in none of the control subjects resulting in a sensitivity of 90% and a specificity of 100%. Number of NB specific OCB were 11±7 bands by photometric analyses compared to 9±5 bands by visual inspection. Validation experiments revealed an inconsistent inter-assay precision between visual and photometric analyses (NB uncoated: visual 28% versus photometric 14%, control subject uncoated: visual 16% versus photometric 24%).

Conclusions

In CSF samples with positive OCB, Borrelia-specific bands were detected in almost all NB patients and in none of the control subjects. Inconsistent inter-assay precision may be explained by a poor comparability of visual and photometric approach.

High levels of anti-HIV-1 envelope antibodies in cerebrospinal fluid as compared to serum from patients with AIDS dementia complex

The antibody response to the HIV-1 envelope protein has not been well characterized in patients with AIDS dementia complex (ADC). We evaluated the frequency of antibodies against the HIV-1 envelope in cerebrospinal fluid (CSF) and serum from 21 persons with ADC and 10 symptom-free HIV-1-positive subjects using Western immunoblot with reducing and nonreducing buffer and radioimmunoprecipitation (RIP) analysis. RIP analysis revealed anti-envelope antibodies in all sera tested. Higher anti-envelope levels were observed in CSF than in serum of 12 of 21 ADC patients and only 1 of 10 symptom-free subjects (two-sided Fisher exact test, p < 0.05). All persons with moderate to severe ADC had higher anti-envelope levels in CSF than in sera (p < 0.005). CSF anti-gp120 antibodies were not as readily detected by Western blot analysis even under nonreduced conditions, suggesting that they are directed to conformational epitopes. Higher CSF anti-envelope antibodies appear to be more common in patients with ADC than in symptom-free HIV-1-positive subjects. This antibody pattern may serve as a marker for ADC and its progression.

Quantitation of intrathecal measles virus IgG antibody synthesis rate: subacute sclerosing panencephalitis and multiple sclerosis

A method for quantitating specific anti-viral antibodies in serum and cerebrospinal fluid (CSF) is established using enzyme-linked immunosorbent assay (ELISA). Quantitated antibody levels are used to determine intrathecal specific IgG synthesis rate for the particular antibody. Measles virus was used as a model for validating this quantitative technique: a mutated form of measles virus is a cause of subacute sclerosing panencephalitis (SSPE) and there is a possibility that measles virus is related to the cause of multiple sclerosis (MS). Matched serum and CSF samples were assayed. Concentration of anti-measles IgG was determined and intrathecal measles-specific IgG synthesis rate was calculated. For the SSPE samples, measles-specific IgG synthesis rate was elevated and comprised > 20% of the total intrathecal IgG synthesis rate; these results are consistent with the literature. The ELISA method can be performed routinely, providing a quick, simple, reproducible means of quantitating specific antibody concentrations, with sensitivity greater than 1 nanogram per milliliter. With this method, quantitation of IgG antibodies to any other viral antigen can be reliably and precisely determined.

Intrathecal synthesis of specific antibodies in neuroborreliosis. Comparison of different ELISA techniques and calculation methods

The sensitivity of six different ELISA techniques and calculation methods for the determination of intrathecal synthesis of IgG antibodies specific to Borrelia burgdorferi was investigated in paired CSF and serum specimens from 33 patients with neuroborreliosis. The diagnostic value of the Antibody Index (AI) was compared with the meaningfulness of serum antibodies to B. burgdorferi (Bb), established by immunofluorescence assay (IFA). The AI, as a standard for intrathecal antibody synthesis was determined from specific antibody ratios (QBb) in the CSF and serum and the CSF/serum ratio of IgG (QIgG) or albumin (QAlb). Using Western blotting with identical concentrations of IgG in the CSF and serum all patients displayed intrathecal synthesis of specific antibodies to at least two B. burgdorferi proteins. The different ELISA methods and calculation procedures were almost equivalent in demonstrating intrathecal synthesis of specific antibodies (32 and 33/33). Calculation of AI from IFA titers was somewhat less sensitive (30/33). In 5 patients titers of serum IgG- and IgM-antibodies to B. burgdorferi determined by IFA were within the normal range or borderline, while elevated AIBb values indicated an autochthonous immune response to B. burgdorferi in the CSF. In uncertain cases of neuroborreliosis calculation of AI from ELISA titers will be useful in clarifying the diagnosis.

Cerebrospinal fluid (CSF) analyses in HIV-1 primary neurological disease

This paper will focus on CSF findings in HIV-1 Neurological Disease (ND). Why use CSF as exploration window of the HIV-CNS involvement? Traditionally, CSF analysis has been an effective diagnostic method as well as a means of monitoring treatment in several infectious and immune pathologies of the CNS. Consequently there is an abundance of mature background information [113, 145, 147] particularly in terms of detecting infectious agents, using IgG findings as immunological indexes, and utilizing CSF findings to map the evolution of ND. We will explore the papers that utilize CSF variables as dependent measures to explore the effects of HIV disease, particularly HIV ND, cited in Index Medicus and MEDLINE data base, and published in Spanish, Italian and English, between 1985 to 1991. We will restrict our review to those studies that exclude HIV cases with CNS opportunistic infections or neoplasms, and thus focus on what the CSF can tell us about the primary effects of HIV on the brain as defined above. The primary long-term goal is to find some elements of the CSF that would lead to an understanding of the etiopathogenesis of HIV ND. However, an almost equally important aim is to determine which CSF variables may be clinically predictive of HIV ND occurrence and progression. The latter variables can also be expected to provide the best measures of HIV ND treatment efficacy. This is particularly important since it is our contention that treatment of HIV ND will eventually be initiated and monitored on the basis of laboratory markers of HIV ND, most likely from the CSF. Finally, this summarized information would be useful in drafting a CSF profile in order to have a reference pattern for cases with complications. The data of this review will be broken down, when the information permits, according to clinical stage and presence or absence of clinical manifestations of ND.

Subacute AIDS-related lumbosacral radiculopathy: a bacterial infection?

A case of lumbosacral polyradiculitis in an HIV-1-positive man (CDC IIB) leading to a flaccid paraplegia below the level of L4 is reported. A detailed analysis of several cerebrospinal fluid samples led to the suspicion of a bacterial infection. After treatment with antibiotics and tuberculostatic agents the neuropathy improved and the patient has survived for 2 years. In contrast to similar cases that were probably caused by cytomegalovirus in terminal stages of AIDS, it is argued that an unidentified bacterial infection was the cause of the polyradiculitis in the present case.

Antibody specificity for human immunodeficiency virus type 1 in serum and cerebrospinal fluid from patients with AIDS and AIDS-related complex

Since little information has been reported about the specificity of antibodies to human immunodeficiency virus type 1 (HIV-1) found in the cerebrospinal fluid (CSF), 21 CSF and serum specimens were examined from 19 patients with clinical AIDS, AIDS-related complex, or asymptomatic HIV-1 infection. The predominant specificity of antibodies using Western blot analysis in both serum (100%) and CSF (100%) was directed toward env gene products. The next most common antibody specificities were to the pol gene products (serum 95%; CSF 62%). Less commonly found was antibody to the gag-encoded proteins (serum 71%; CSF 38%). The level of antibody to HIV-1 in CSF could not be predicted from the level found in serum. Also, the spectrum of antibodies seen did not correlate with disease stage or with the quantity of antibody present. The serum/CSF pairs were also examined for the presence of HIV-1 antigen by commercial enzyme immunoassay. HIV-1 antigen was present in eight of 19 (43%) of the serum samples and five of 20 (25%) of the CSF samples tested.

Human immunodeficiency virus infection: affinity-mediated immunoblot detects intrathecal synthesis of oligoclonal IgG specific for individual viral proteins

An affinity-mediated immunoblot (AMI) is introduced, able to identify virus-specific, oligoclonal IgG in unconcentrated cerebrospinal fluid (CSF) of patients infected by HIV. CSF specimens are isoelectrically focused in agarose gels and blotted to nitrocellulose (NC) strips coated with E. coli recombinant HIV-specific proteins. Virus-specific antibody clones transferred to the filter are detected by solid-phase enzyme immunoassay (EIA). Only 0.5 micrograms IgG is sufficient to demonstrate the clonal distribution of antibodies specific for an individual HIV protein. Intrathecal synthesis of oligoclonal antibodies is seen by AMI, comparing equal quantities of serum- and CSF-derived IgG. Because of its excellent sensitivity and specificity, AMI detects autochthonous HIV-specific IgG synthesis even when comparative EIA fails. Because multiple specimens can be processed within a few hours by AMI, this technique is recommendable for routine diagnosis.

Human immunodeficiency virus antibodies in cerebrospinal fluid

The relative concentrations of human immunodeficiency virus (HIV) antibodies in relation to equal IgG contents of 46 serum cerebrospinal fluid (CSF) samples from 32 patients were determined by serial dilution in an anti-HIV enzyme-linked immunosorbent assay (ELISA). The ratio of CSF and the serum HIV antibody concentration was expressed as QHIV = CSF dilution/serum dilution. QHIV is regarded as a parameter for specific intrathecal HIV antibody production. The QHIV ranged from 0.7 to 16. Six of seven patients with clinical signs of acquired immunodeficiency syndrome (AIDS)-related dementia (ARD), but only seven of 25 patients without clinical diagnosis of ARD showed a QHIV greater than 2.