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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The number of immunocompromised patients is steadily increasing due to HIV infection, solid organ and stem cell transplantation, intensified chemotherapy, immunosuppression for autoimmune diseases, and a marked increase in the use of monoclonal antibodies. Prevention strategies for pulmonary infections and diagnostic methods have evolved and patient outcome has improved. However, therapies affecting the immune system are also given to older patients and patients with comorbidities. While the rate of pulmonary complications in HIV patients has dramatically decreased under antiretroviral therapy, we are seeing more patients with pulmonary problems after chemotherapy. Neutropenia is still the most important risk factor for bacterial and fungal infection. Flexible bronchoscopy with BAL remains an important diagnostic method with a low morbidity and high diagnostic yield in patients with pulmonary infiltrates following cancer chemotherapy.
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PMID:Breakdown of pulmonary host defense in the immunocompromised host: cancer chemotherapy. 1632 98

Retrocyclin (RC)-101 is a cationic theta-defensin that inhibits HIV-1 entry. Passaging HIV-1(BAL) under selective pressure by this cyclic minidefensin resulted in only a 5- to 10-fold decrease in viral susceptibility to RC-101. Emergent viral isolates had three amino acid substitutions in their envelope glycoprotein. One was in a CD4-binding region of gp120, and the others were in the heptad repeat (HR) domains of gp41 (HR1 and HR2). Each mutation replaced an electroneutral or electronegative residue with one that was positively charged. These mutations were evaluated either alone or in combination in a single-round viral entry assay. Although the mutation in gp120 did not affect viral entry, the mutation in HR1 of gp41 conferred relative resistance to RC-101. Interestingly, the envelope with the HR2 mutation was less efficient and became codependent on the presence of RC-101 for entry. The adaptive response of HIV-1 to this cationic host defense peptide resembles the responses of bacteria that modulate their surface or membrane charge to evade analogous host defense peptides. These findings also suggest that interactions between theta-defensins and gp41 may contribute to the ability of these cyclic minidefensins to prevent HIV-1 entry into target cells.
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PMID:HIV-1 adapts to a retrocyclin with cationic amino acid substitutions that reduce fusion efficiency of gp41. 1670 50

Forty-seven HIV-infected adults had broncho-alveolar lavage stimulated with purified protein derivate of Mycobacterium tuberculosis. Eighteen of 19 (95%) with tuberculosis co-infection had interferon-gamma synthetic CD4 lymphocyte responses > 1% versus three of 28 (11%) without (P < 0.0001). Lung response was unrelated to blood CD4 cell count. BAL HIV tuberculosis responses were similar in 25 HIV-uninfected tuberculosis patients. Responses in matched blood samples were often undetectable. Therefore, immunological tuberculosis assays seem less affected by HIV co-infection when lung-based.
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PMID:Detection of mycobacterial antigen responses in lung but not blood in HIV-tuberculosis co-infected subjects. 1681 64

gp120 is a subunit of the envelope glycoprotein of HIV-1. The third variable loop region of gp120 (V3 loop) contains multiple immunodominant epitopes and is also functionally important for deciding cell-tropism of the virus. 447-52D is a monoclonal antibody that recognizes the conserved tip of the V3 loop in a beta-turn conformation. This antibody has previously been shown to neutralize diverse strains of the virus. In an attempt to generate an immunogen competent to generate 447-52D-like antibodies, the known epitope of 447-52D was inserted at three different surface loop locations in the small, stable protein Escherichia coli Trx (thioredoxin). At one of the three locations (between residues 74 and 75), the insertion was tolerated, the resulting protein was stable and soluble, and bound 447-52D with an affinity similar to that of intact gp120. Upon immunization, the V3 peptide-inserted Trx scaffold was able to generate anti-V3 antibodies that could compete out 447-52D binding to gp120. Epitope mapping studies demonstrated that these anti-V3 antibodies recognized the same epitope as 447-52D. Although the 447-52D-type antibodies were estimated to be present at concentrations of 50-400 microg/ml of serum, these were not able to effect neutralization of strains like JRFL and BAL but could neutralize the sensitive MN strain. The data suggest that because of the low accessibility of the V3 loop on primary isolates such as JRFL, it will be difficult to elicit a V3-specific, 447-52D-like antibody response to effectively neutralize such isolates.
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PMID:Design of immunogens that present the crown of the HIV-1 V3 loop in a conformation competent to generate 447-52D-like antibodies. 1682 63

The frequency of Pneumocystis carinii occurrence in BAL of 38 HIV-infected patients was determined with three different method. BAL sediments were stained with Giemsa method, silvered according to Gomori-Grocott method and studied with indirect immunofluorescence assay. Using Giemsa method staining Pneumocystis carinii was diagnosed in 81.6% of patients, in Gomori-Grocott method--in 31.6% of patients, but results of indirect immunofluorescence assay were positive only in 23.,7%. In our study staining BAL sediments with Giemsa method allowed to detect Pneumocystis carinii in the highest percentage of examined patients.
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PMID:[The estimation of Pneumocystis carinii in HIV-infected patients occurrence based on three different methods]. 1689 72

Repetitive exposure of macrophages to microbial antigen is known to tolerize them to further stimulation and to inhibit proinflammatory cytokine release. Using transgenic (Tg) mice that incorporate the entire HIV-1 genome we have previously shown that toll like receptor (TLR)-2, -4, and -9 ligands induced tolerance as assessed by decreased proinflammatory cytokine secretion and nuclear factor-kappa beta activation. Yet, despite cytokine modulation, HIV-1 p24 production was enhanced in tolerized cells in vitro and in vivo. Since mice are not natural hosts for HIV infection, in the following report we examined whether TLR2 and TLR4 ligands induced tolerance in human monocytic cell lines stably expressing the HIV-long terminal repeat (LTR) luciferase construct (THP-LTR-Luc) as well as in primary macrophages that had been infected with HIV(BAL)in vitro. In THP-LTR-luc, TLR2 and TLR4 tolerization suppressed tumor necrosis factor (TNF)-alpha release and HIV-LTR transactivation. In HIV(BAL) infected macrophages, repeated LPS exposure inhibited HIV replication as assessed by decreased genetic expression and protein production of HIV-1 p24, although TNF-alpha release was not inhibited. These observations may have important clinical implications in understanding the role of macrophages as HIV reservoirs at anatomical sites where there is repeated exposure to microbial antigens.
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PMID:Repeated lipopolysaccharide (LPS) exposure inhibits HIV replication in primary human macrophages. 1691 50

Macrophage migration inhibitory factor (MIF) activates macrophages, promotes delayed-type hypersensitivity reaction, and regulates Th1/Th2 balance in inflammatory response. Serum MIF concentration is high in patients with pulmonary tuberculosis (PTB). Higher MIF levels are associated with high mortality. No study has addressed MIF levels and its role in PTB/HIV-co infection. We determined serum and BAL MIF levels in Tanzanian HIV-infected patients with and without PTB, and correlated the levels with 1-month outcome. We compared with serum MIF levels of HIV seronegative patients with PTB and of healthy controls. All HIV-infected patients irrespective of PTB infection had significantly higher serum MIF levels than HIV-seronegative patients with PTB, and than healthy controls. In HIV seropositive patients low serum MIF levels were associated with high 1-month mortality. In conclusion, HIV infection was associated with elevated serum MIF levels regardless of PTB. Low serum MIF levels were associated with high mortality.
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PMID:Serum and BAL macrophage migration inhibitory factor levels in HIV infected Tanzanians with pulmonary tuberculosis or other lung diseases. 1727 14

The chemokine receptor CCR5 plays an important role as an entry gate for the human immunodeficiency virus-1 (HIV-1) and for viral postentry events. Among signal transducers used by chemoattractant receptors, the phosphatidylcholine-specific phospholipase D (PLD) produces large amounts of second messengers in most cell types. However, the relevance of PLD isoforms to CCR5 signaling and HIV-1 infection process remains unexplored. We show here that CCR5 activation by MIP-1beta in HeLa-MAGI cells triggered a rapid and substantial PLD activity, as assessed by mass choline production. This activity required the activation of ERK1/2-MAP kinases and involved both PLD1 and PLD2. MIP-1beta also promoted the activation of an HIV-1 long terminal repeat (LTR) by the transactivator Tat in HeLa P4.2 cells through a process involving ERK1/2. Expression of wild-type and catalytically inactive PLDs dramatically boosted and inhibited the LTR activation, respectively, without altering Tat expression. Wild-type and inactive PLDs also respectively potentiated and inhibited HIV-1(BAL) replication in MAGI cells. Finally, in monocytic THP-1 cells, antisense oligonucleotides to both PLDs dramatically inhibited the HIV-1 replication. Thus, PLD is activated downstream of ERK1/2 upon CCR5 activation and plays a major role in promoting HIV-1 LTR transactivation and virus replication, which may open novel perspectives to anti-HIV-1 strategies.
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PMID:CCR5 signaling through phospholipase D involves p44/42 MAP-kinases and promotes HIV-1 LTR-directed gene expression. 1762 30

A method of collecting pharyngeal and oral swabs from humans and laboratory rats, to be examined later for Pneumocystis infection with simple and nested PCR, was developed. The swabs were obtained from 15 HIV-infected patients, including 5 suffering from PCP, and from 10 immunocompetent children aged 2 to 6 years. Furthermore, the swabs were taken from 30 healthy laboratory rats and 23 animals subjected to immunosuppressive treatment. DNA of Pneumocystis was detected in all the examined rats with nPCR method, but only in 47% of healthy animals when simple PCR was used. Nested PCR examination of swabs collected from human subjects revealed the infection with Pneumocystis in all HIV-infected patients with PCP, and in 8 out of 10 symptomless carriers of Pneumocystis; moreover, the examination was positive in 2 out of 10 immunocompetent children. It was concluded, that noninvasive method of collecting pharyngeal and oral swabs in conjunction with very sensitive method of amplification DNA by nPCR is suitable for measuring the prevalence of Pneumocystis infection in the populations of humans and laboratory animals. The developed method offers a possibility of safe diagnosis of pneumocystosis in patients whose clinical status precludes collection of BAL through bronchoscopy.
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PMID:[An evaluation of the occurrence of pneumocystis infection through examination of pharyngeal and oral swabs using the nested PCR method]. 1764 15

The human infection by Rhodococcus equi, even in the presence of HIV infection, remains a rare disease. The authors present a case report of pneumonia, occurring in a HIV+ man. After identifying Pneumocystis jiroveci in the BAL, despite proper medication, the patient didn't improve. Another BAL was performed and a Rhodococcus equi isolated. The therapeutic regimen was changed according to this finding and the patient improved. The authors make a review of the literature, focusing on the rarity of this association and the high survival observed.
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PMID:[Rhodococcus equi pneumonia in an HIV+ patient: An uncommon association]. 1796 88


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