Infecção respiratória aguda por adenovirus: comparação dos métodos de PCR e imunofluorescência indireta para o seu diagnóstico e dados clínicos dos pacientes infectados

Infecções respiratórias por Adenovírus (ADV) são geralmente descritas associadas com alta mortalidade. O diagnóstico laboratorial é essencial para o estabelecimento da terapêutica adequada e para orientar a implantação de medidas preventivas evitando a propagação da infecção. Com o objetivo de analisar a sensibilidade e a especificidade dos métodos de avaliação de diagnóstico laboratorial, foi comparada a detecção de antígeno por imunofluorescência indireta (IF) com a reação em cadeia da polimerase específica (PCR) para detectar AdV em amostras respiratórias coletadas de pacientes internados com doença respiratória aguda. As amostras com resultados positivos foram inoculadas em cultura celular. Foram analisadas 381 amostras da secreção nasofaríngea coletadas durante o ano de 2008, das quais 2,6% foram positivas pela IF e 10% pela PCR, isolamento positivo foi obtido em 40% e 26% dos casos positivos pelos testes anteriores, respectivamente. A maioria dos pacientes infectados eram crianças com menos de seis meses de idade, e apesar do fato de que um número significativo de pacientes necessitou de cuidados intensivos, a taxa de mortalidade foi baixa (5%). Em conclusão, os métodos moleculares são úteis para o diagnóstico rápido de infecções por adenovírus com maior sensibilidade do que a detecção do antígeno, a sua introdução na rotina permitiu um aumento significativo no diagnóstico de infecções por adenovírus.Adenovirus (AdV) respiratory infections are usually described as being associated with high mortality rates. Laboratory diagnosis is essential for the establishment of the appropriate therapy, and for guiding the implementation of preventive measures in order to prevent the spread of the infection. Aiming to analyze the sensitivity and specificity of the laboratorial diagnosis methods available, we compared antigen detection by indirect immunofluorescence assay (IF), and a specific nested polymerase chain reaction (PCR), to detect AdV in respiratory samples collected from patients admitted to hospital with acute respiratory disease. Positive samples were inoculated into a cell culture to confirm the results. We analyzed 381 samples from the nasopharyngeal aspirates collected during the year 2008; of these, 2.6% tested were positive for adenovirus through IF and 10% through PCR; positive isolation was obtained in 40% and 26% of these cases, respectively. Most infected patients were children under six months of age, and despite of the fact that a significant number of patients required intensive care, the mortality rate was low (5%). In conclusion, molecular methods were found to be useful for rapid diagnosis of adenovirus infections with higher sensitivity than antigen detection; their introduction permitted a significant increase in diagnoses of adenovirus infections

Blood-CSF barrier and compartmentalization of CNS cellular immune response in HIV infection

HIV infection is persistent in the CNS, to evaluate the compartmentalization of the CNS immune response to HIV, we compared soluble markers of cellular immunity in the blood and CSF among HIV- (n=19) and HIV+ (n=68), as well as among HIV participants with or without CSF pleocytosis. Dysfunction of the blood cerebrospinal fluid barrier (BCSFB) was common in HIV participants. CSF levels of TNFα, IFNγ, IL-2, IL-6, IL-7, IL-10, IP-10, MIP-1α, MIP-1β, and RANTES were significantly higher in participants with CSF pleocytosis (p<0.05); serum levels of these biomarkers were comparable. The CNS immune response is compartmentalized, and remains so despite the BCSFB dysfunction during HIV infection; it is markedly reduced by virology suppression, although BCSFB dysfunction persists on this subgroup

Genotypical diversity of HIV clades and central nervous system impairment

The central nervous system (CNS) and the immune system are considered major target organs for HIV infection. The neurological manifestations directly related to HIV are acute viral meningitis, chronic meningitis, HIV associated dementia, vacuolar myelopathy and involvement of the peripheral nervous system. Changes in diagnosis and clinical management have changed the aspect of HIV infection so that it is no longer a fatal disease, and has become a chronic disease requiring sustained medical management. After HAART the incidence of most opportunistic infections, including those affecting the CNS, has dropped markedly. Some studies suggest that neurological involvement of infected patient occur with different frequency, depending on HIV subtype involved in the infection. Subtype C may have reduced neuroinvasive capacity, possibly due to its different primary conformation of HIV transactivating regulatory protein (Tat), involved in monocyte chemotaxis. This review focus on physiopathologic aspects of HIV infection in CNS and its correlation with HIV clades

IgG intrathecal synthesis in HIV-associated neurocognitive disorder (HAND) according to the HIV-1 subtypes and pattern of HIV RNA in CNS and plasma compartments

We hypothesized that humoral immunity stimulation in the CNS in HIV-1C patients would be lower than that in HIV-1B due to a defective Tat chemokine dimotif (C30C31) that might influence cellular trafficking and CNS inflammation. Sixty-eight paired CSF and blood samples from people with HIV (PWH), free of CNS opportunistic infections, were included, HIV-1B (n&nbsp;=&nbsp;27), HIV-1C (n&nbsp;=&nbsp;26), and HIV negative (n&nbsp;=&nbsp;25). IgG intrathecal synthesis was assayed using quantitative and qualitative methods. IgG oligoclonal bands (OCB) in CSF were observed in 51% of PWH, comparable between HIV-1B and HIV-1C, as well as the medians of IgG intrathecal synthesis formulas. The group with HIV infection aviremic in CSF and blood showed 75% of OCB. There was a poor positive correlation between the IgG quotient and GDS. The impact of HIV-1 on IgG intrathecal production was not subtype dependent. Low-grade CNS intrathecal IgG production persists in HIV CNS infection even in PWH with CSF and blood HIV RNA controlled

Cerebrospinal fluid CD14++CD16+ monocytes in HIV-1 subtype C compared with subtype B

CD14++CD16+ monocytes are susceptible to HIV-1 infection, and cross the blood-brain barrier. HIV-1 subtype C (HIV-1C) shows reduced Tat protein chemoattractant activity compared to HIV-1B, which might influence monocyte trafficking into the CNS. We hypothesized that the proportion of monocytes in CSF in HIV-1C is lower than HIV-1B group. We sought to assess differences in monocyte proportions in cerebrospinal fluid (CSF) and peripheral blood (PB) between people with HIV (PWH) and without HIV (PWoH), and by HIV-1B and -C subtypes. Immunophenotyping was performed by flow cytometry, monocytes were analyzed within CD45 + and CD64 + gated regions and classified in classical (CD14++CD16-), intermediate (CD14++CD16+), and non-classical (CD14lowCD16+). Among PWH, the median [IQR] CD4 nadir was 219 [32-531] cell/mm3; plasma HIV RNA (log10) was 1.60 [1.60-3.21], and 68% were on antiretroviral therapy (ART). Participants with HIV-1C and -B were comparable in terms of age, duration of infection, CD4 nadir, plasma HIV RNA, and ART. The proportion of CSF CD14++CD16+ monocytes was higher in participants with HIV-1C than those with HIV-1B [2.00(0.00-2.80) vs. 0.00(0.00-0.60) respectively, p = 0.03 after BH correction p = 0.10]. Despite viral suppression, the proportion of total monocytes in PB increased in PWH, due to the increase in CD14++CD16+ and CD14lowCD16+ monocytes. The HIV-1C Tat substitution (C30S31) did not interfere with the migration of CD14++CD16+ monocytes to the CNS. This is the first study to evaluate these monocytes in the CSF and PB and compare their proportions according to HIV subtype