Diagnostic accuracy of plasma glial fibrillary acidic protein for differentiating intracerebral hemorrhage and cerebral ischemia in patients with symptoms of acute stroke.

BACKGROUND: Glial fibrillary acidic protein (GFAP) is a biomarker candidate indicative of intracerebral hemorrhage (ICH) in patients with symptoms of acute stroke. GFAP is released rapidly in the presence of expanding intracerebral bleeding, whereas a more gradual release occurs in ischemic stroke. In this study the diagnostic accuracy of plasma GFAP was determined in a prospective multicenter approach. METHODS: Within a 1-year recruitment period, patients suspected of having acute (symptom onset<4.5 h before admission) hemispheric stroke were prospectively included into the study in 14 stroke centers in Germany and Switzerland. A blood sample was collected at admission, and plasma GFAP was measured by use of an electrochemiluminometric immunoassay. The final diagnosis, established at hospital discharge, was classified as ICH, ischemic stroke, or stroke mimic. RESULTS: The study included 205 patients (39 ICH, 163 ischemic stroke, 3 stroke mimic). GFAP concentrations were increased in patients with ICH compared with patients with ischemic stroke [median (interquartile range) 1.91 µg/L (0.41-17.66) vs 0.08 µg/L (0.02-0.14), P<0.001]. Diagnostic accuracy of GFAP for differentiating ICH from ischemic stroke and stroke mimic was high [area under the curve 0.915 (95% CI 0.847-0.982), P<0.001]. A GFAP cutoff of 0.29 µg/L provided diagnostic sensitivity of 84.2% and diagnostic specificity of 96.3% for differentiating ICH from ischemic stroke and stroke mimic. CONCLUSIONS: Plasma GFAP analysis performed within 4.5 h of symptom onset can differentiate ICH and ischemic stroke. Studies are needed to evaluate a GFAP point-of-care system that may help optimize the prehospital triage and management of patients with symptoms of acute stroke.

Aplastic crisis as primary manifestation of systemic lupus erythematosus.

Aplastic crisis is an unusual feature of systemic lupus erythematosus (SLE). We report the case of a 54-year-old woman presenting with both (extravascular) Coombs-positive hemolytic anemia and laboratory findings of bone marrow hyporegeneration with concomitant severe neutropenia. A bone marrow biopsy confirmed aplastic crisis. Diagnostic work-up revealed soaring titers of autoantibodies (anti-nuclear, anti-double-stranded DNA, anti-cardiolipin-IgM, and anti-ß2-glykoprotein-IgM antibodies), indicating a connective tissue disease as the most plausible reason for bone marrow insufficiency. As the criteria for SLE were fulfilled, we initiated an immunosuppressive therapy by steroids, which led to a rapid complete hematologic and clinical remission in our patient. In this case, we could report on one of the rare cases of SLE-induced aplastic crisis showing that this condition can be entirely reversed by immunosuppressive treatment and that SLE-induced aplastic crisis yields a good prognosis. In conclusion, in a case of aplastic crisis, physicians should be aware that SLE can be a rare cause that is accessible to specific treatment.

Periarticular bone structure in rheumatoid arthritis patients and healthy individuals assessed by high-resolution computed tomography.

OBJECTIVE: To define the nature of structural bone changes in patients with rheumatoid arthritis (RA) compared with those in healthy individuals by using the novel technique of high-resolution microfocal computed tomography (micro-CT). METHODS: Fifty-eight RA patients and 30 healthy individuals underwent a micro-CT scan of the proximal wrist and metacarpophalangeal joints. Bone lesions such as cortical breaks, osteophytes, and surface changes were quantified on 2-dimensional (2-D) slices as well as by using 3-D reconstruction images, and exact localization of lesions was recorded. RESULTS: Micro-CT scans could detect bone lesions <0.5 mm in width or depth. Small erosions could be observed in healthy individuals and RA patients, whereas lesions >1.9 mm in diameter were highly specific for RA. Cortical breaks were mostly found along the radial sites of the metacarpal heads. No significant difference in the presence of osteophytes between healthy individuals and RA patients was found. Cortical surface changes, presumably cortical thinning and fenestration, became evident from 3-D reconstructions and were more pronounced in RA patients. CONCLUSION: Micro-CT allows exact detection of morphologic changes of juxtaarticular bone in healthy individuals and RA patients. Even healthy individuals occasionally show bone changes, but the severity of these lesions, with the exception of osteophytes, is greater in RA patients. Thus, micro-CT allows accurate differentiation among physiologic bone changes in joints and among types of pathologic bone damage resulting from RA.

Dual selection pressure by drugs and HLA class I-restricted immune responses on human immunodeficiency virus type 1 protease.

To determine the influence of human immunodeficiency virus type 1 (HIV-1)-specific CD8+ T cells on the development of drug resistance mutations in the HIV-1 protease, we analyzed protease sequences from viruses from a human leukocyte antigen class I (HLA class I)-typed cohort of 94 HIV-1-positive individuals. In univariate statistical analyses (Fisher's exact test), minor and major drug resistance mutations as well as drug-associated polymorphisms showed associations with HLA class I alleles. All correlations with P values of 0.05 or less were considered to be relevant without corrections for multiple tests. A subset of these observed correlations was experimentally validated by enzyme-linked immunospot assays, allowing the definition of 10 new epitopes recognized by CD8+ T cells from patients with the appropriate HLA class I type. Several drug resistance-associated mutations in the protease acted as escape mutations; however, cells from many patients were still able to generate CD8+ T cells targeting the escape mutants. This result presumably indicates the usage of different T-cell receptors by CD8+ T cells targeting these epitopes in these patients. Our results support a fundamental role for HLA class I-restricted immune responses in shaping the sequence of the HIV-1 protease in vivo. This role may have important clinical implications both for the understanding of drug resistance pathways and for the design of therapeutic vaccines targeting drug-resistant HIV-1.

Analysis of the Candida albicans - specific T-cell response and oropharyngeal Candida colonization in a cohort of HIV-1-infected patients.

To investigate Candida epidemiology and immunologic correlates of protection in HIV-1 infected patients, we analyzed oral Candida colonization in correlation to the Candida-specific T-cell response measured by g-IFN ELISPOT using different Candida (C.) albicans strains. In 16/46 patients (13 asymptomatic, 3 with oral thrush), but in 0/28 controls, Candida (13 C. albicans, 1 C. lusitaniae, 1 C. krusei, 1 C. parapsilosis) was isolated. Candida specific T-cells were detected more frequently in controls (20/28) than in HIV-1+ subjects (16/46, p= 0.03). We observed a significant association of higher CD4 cell numbers with both detection of Candida specific T-cells and lack of oral Candida colonization, but there was no significant correlation of oral Candida colonization to the detection of Candida specific T-cells, viral load or antiretroviral therapy. Thus, local mucosal immunity seems to be more important in the pathogenesis of Candida colonization than circulating Candida specific T-cells. The pathogenic C. albicans strain K24122 was less frequently recognized by patients (6/46) than the laboratory adapted strain SC5314 (14/46, p= 0.03), whereas a similar recognition of both strains was observed in healthy controls. This indicates an impaired Candida-specific T-cell repertoire in HIV+ patients that could increase the risk of immune evasion by C. albicans.

Recognition patterns of HLA-A2-restricted human immunodeficiency virus-1-specific cytotoxic T-lymphocytes in a cohort of HIV-1-infected individuals.

The cytotoxic T-lymphocytes (CTL) response to three histocompatibility leukocyte antigen (HLA)-A2-restricted CTL epitopes was investigated in a cohort of 51 HLA-A2-positive human immunodeficiency-1 (HIV-1)-infected subjects. CTL activity was evaluated by testing peptide stimulated peripheral blood mononuclear cells (PBMC) in chromium release assays. The most prevalent CTL response was directed to the RT-peptide ILKEPVHGV (IV9) recognized by 37.3%. The p17-peptide SLYNTVATL (SL9), reported to be the immunodominant epitope in chronically infected untreated patients, was recognized only by 13.7%. Only 9.8% recognized both IV9 and SL9, and none recognized the RT-peptide VIYQYMDDL (VL9). CTL activity correlated significantly with absolute CD8 T-cell counts but not with CD4 counts, viral load, or antiviral therapy. Analysis of the recognition patterns of amino acid substitutions in the IV9 epitope revealed the presence of at least four functionally different T-cell receptors (TCR) in this cohort. All analyzed mutations within the TCR recognition site of this epitope could abrogate CTL recognition by individual CTL clones, but all were fully immunogenic for other CTL clones with peptide-sensitizing capacities similar to that of IV9. Further studies should be performed to evaluate whether a convergent epitope vaccination strategy using immunogenic variants of CTL epitopes is a feasible approach to broaden the TCR repertoire and to inhibit CTL escape.

Therapeutic vaccination of HIV-1-infected patients on HAART with a recombinant HIV-1 nef-expressing MVA: safety, immunogenicity and influence on viral load during treatment interruption.

The safety and immunogenicity of an HIV-1 nef-expressing modified vaccinia virus Ankara (MVA) was investigated in 14 HIV-1-positive patients (CD4 >400/microl) on highly active antiretroviral therapy (HAART). Patients were vaccinated at weeks 0, 4 and 16, followed by interruption of HAART at week 18. MVA-nef was well-tolerated except for local reactions, with only mild systemic side effects reported in a few patients. Vaccination with MVA-nef was associated with recognition of new HIV-1 T-cell epitopes (cytotoxic T-lymphocyte epitopes in 9/14 patients, CD4 epitope/recombinant Nef protein in 2/14) and an increase in CD4+ and CD8+ T cells. All patients had been vaccinated against smallpox and a strong T-cell and antibody response to MVA was induced in all patients. After interruption of HAART, viral load rebounded in all patients, but after a median time of 36 (4-76) weeks in 9/14 patients, viraemia remained below the pre-HAART viral load and CD4 counts stayed above the pre-HAART levels. While six patients have remained off therapy for a median time of 64 (57-76) weeks, HAART was resumed in 8/14 patients after a median treatment interruption time of 15 (4-38) weeks. This study has demonstrated that MVA-nef is safe and immunogenic in HIV-1-infected subjects and has provided encouraging data on the potential of therapeutic vaccinations.