Influence of HIV antigens on functional activity of neutrophilic granulocytes in

CD8+ T cells but not polymorphonuclear leukocytes are required to limit chronic oral carriage of Candida albicans in transgenic mice expressing human immunodeficiency virus type 1

Candida albicans causes oropharyngeal candidiasis (OPC) but rarely disseminates to deep organs in human immunodeficiency virus (HIV) infection. Here, we used a model of OPC in CD4C/HIV(Mut) transgenic (Tg) mice to investigate the role of polymorphonuclear leukocytes (PMNs) and CD8+ T cells in limiting candidiasis to the mucosa. Numbers of circulating PMNs and their oxidative burst were both augmented in CD4C/HIV(MutA) Tg mice expressing rev, env, and nef of HIV type 1 (HIV-1), while phagocytosis and killing of C. albicans were largely unimpaired compared to those in non-Tg mice. Depletion of PMNs in these Tg mice did not alter oral or gastrointestinal burdens of C. albicans or cause systemic dissemination. However, oral burdens of C. albicans were increased in CD4C/HIV(MutG) Tg mice expressing only the nef gene of HIV-1 and bred on a CD8 gene-deficient background (CD8-/-), compared to control or heterozygous CD8+/- CD4C/HIV(MutG) Tg mice. Thus, CD8+ T cells contribute to the host defense against oral candidiasis in vivo, specifically in the context of nef expression in a subset of immune cells.

Immunopathogenesis of oropharyngeal candidiasis in human immunodeficiency virus infection

Oropharyngeal and esophageal candidiases remain significant causes of morbidity in human immunodeficiency virus (HIV)-infected patients, despite the dramatic ability of antiretroviral therapy to reconstitute immunity. Notable advances have been achieved in understanding, at the molecular level, the relationships between the progression of HIV infection, the acquisition, maintenance, and clonality of oral candidal populations, and the emergence of antifungal resistance. However, the critical immunological defects which are responsible for the onset and maintenance of mucosal candidiasis in patients with HIV infection have not been elucidated. The devastating impact of HIV infection on mucosal Langerhans' cell and CD4(+) cell populations is most probably central to the pathogenesis of mucosal candidiasis in HIV-infected patients. However, these defects may be partly compensated by preserved host defense mechanisms (calprotectin, keratinocytes, CD8(+) T cells, and phagocytes) which, individually or together, may limit Candida albicans proliferation to the superficial mucosa. The availability of CD4C/HIV transgenic mice expressing HIV-1 in immune cells has provided the opportunity to devise a novel model of mucosal candidiasis that closely mimics the clinical and pathological features of candidal infection in human HIV infection. These transgenic mice allow, for the first time, a precise cause-and-effect analysis of the immunopathogenesis of mucosal candidiasis in HIV infection under controlled conditions in a small laboratory animal.

Changing prevalence of oral manifestations of human immuno-deficiency virus in the era of protease inhibitor therapy

OBJECTIVE

The purpose of this study was to determine temporal trends in the prevalence of oral manifestations of human immunodeficiency virus (HIV).

STUDY DESIGN

Five hundred seventy HIV-infected adults recruited consecutively were examined by using established presumptive clinical criteria for HIV-associated oral lesions. Prevalence of oral lesions before the widespread use of HIV protease inhibitors (February 1995 through August 1996, 8% of the early sample, n = 271) was compared with lesion prevalence in a more recent period of greater protease inhibitor use (December 1996 through February 1999, 42% of the late sample, n = 299).

RESULTS

Overall prevalence of oral lesions significantly decreased from early to late periods, 47.6% to 37.5%, respectively (P =.01), with some variation by lesion type. Prevalence of hairy leukoplakia (25. 8% to 11.4%; P <.01) and necrotizing periodontal diseases (4.8% to 1. 7%; P =.03) decreased, whereas HIV salivary gland disease increased (1.8% to 5.0%; P =.04). Changes in prevalence of oral candidiasis (20.3% to 16.7%), aphthous ulcers (3.7% to 3.0%), oral warts (2.2% to 4.0%), herpes simplex virus lesions (1.8% to 2.0%), and Kaposi's sarcoma (1.1% to 0.3%) were not statistically significant (P >.20 for all comparisons).

CONCLUSION

The pattern of oral opportunistic infections is changing in the era of protease inhibitor use.

Frequency of oropharyngeal candidiasis in HIV-infected patients on protease inhibitor therapy

OBJECTIVE

The purpose of this study was to investigate the effect of HIV-1 protease inhibitors on the frequency of oropharyngeal candidiasis in HIV-infected patients.

STUDY DESIGN

A clinical and analytic follow-up was carried out to determine the number of episodes of oropharyngeal candidiasis during HIV-1 protease inhibitor therapy and the relation of this incidence to the CD4 lymphocyte count and circulating neutrophils level. Seventy-five HIV-positive patients were selected, and HIV-1 protease inhibitor therapy was administered to each patient over a minimum of 6 months. These patients did not receive long-term preventive antifungal therapy for oral candidiasis, even as secondary prophylaxis against cryptococcosis. Results were compared with those obtained during the previous 6 months, during which patients had been treated only with reverse transcriptase inhibitors.

RESULTS

At least one episode of oropharyngeal candidiasis was seen in 56% (42/75) of patients during reverse transcriptase inhibitor therapy and in only 9.3% (7/75) of patients after the initiation of protease inhibitor therapy. The number of relapses decreased significantly when the 2 follow-up periods were compared (P<.0001). The CD4 and CD8 lymphocyte counts increased significantly with protease inhibitor therapy (P<.001 and P<.05, respectively). During reverse transcriptase inhibitor treatment, the probability of the presentation of oropharyngeal candidiasis correlated with falling CD4 counts (P<.0001). The HIV-1 protease inhibitor therapy was associated with a significant increase in the neutrophil count (P<.01). The probability of the occurrence of some episode of candidiasis correlated inversely with the circulating neutrophil level (P<.05).

CONCLUSIONS

Protease inhibitor therapy decreases the frequency of HIV-related oropharyngeal candidiasis. The mechanism involved is unknown, but it can be speculated that a reduction of the viral load increases the number of intact T helper cells, which in turn enhances the number of circulating polymorphonuclear neutrophils and regulates their function by means of colony-stimulating factors.

Modification of lymphocyte and monocyte functional activity by polymorphonuclear neutrophils in HIV infection

The aim of this study was to determine whether polymorphonuclear neutrophils (PMN) can modify the immune response in HIV cases. Supernatants of PMN (PMNS) from 33 HIV-infected patients (16 with lymphoadenopathy syndrome, 17 with AIDS-related complex) were tested for their influence on the functional activity of lymphocytes and monocytes from 6 healthy donors. PMNS from another 6 healthy donors comprised a control group. It was found that PMNS from HIV-infected patients, but not from healthy donors, induced suppression of lymphocyte proliferative response and down-regulation of CD8 receptor expression on lymphocytes. Decrease of NK-cell cytotoxicity in the presence of PMNS from HIV-infected patients was the same as that from healthy donors. PMNS did not influence the production of anti-HIV antibody by lymphocytes from HIV-infected patients, as well as non-specific IgG by lymphocytes from healthy donors. PMNS effect on functional activity of lymphocytes was blocked completely after treatment of PMN by catalase and superoxide dismutase. At the same time PMNS from HIV-infected patients but not from healthy donors induced increased production of TNF-alpha by monocytes and up-regulation of monocyte phagocytosis. These effects were independent of catalase and superoxide dismutase and were not abrogated by antibody against IL-1, IL-8, TNF-alpha, IFN-gamma or IFN-alpha.

Membrane expression and function of complement receptors CR1 and CR3 on neutrophils from HIV-infected subjects: modulation by rTNF-alpha and rGM-CSF

We evaluated membrane expression and function of complement receptors CR1 and CR3 on neutrophils from 27 HIV-positive (HIV+) subjects (14 in the CDC class III and 13 class IV) as well as their modulation in vitro by recombinant tumour necrosis factor-alpha (rTNF-alpha) and granulocyte-macrophage colony stimulating factor (rGM-CSF). While CR1 was expressed at similar levels on neutrophils from controls and HIV+ subjects, CR3 expression was significantly higher in CDC class IV subjects than in healthy controls. CR1 and CR3 expression was significantly increased after treatment of neutrophils with both cytokines, without differences between controls and HIV+ subjects. Similarly, the superoxide anion (O2-) production in response to C3-coated zymosan (C3zy) was significantly enhanced on neutrophils from CDC class IV subjects when compared with controls. rGM-CSF and rTNF-alpha treatment significantly enhanced the spontaneous as well as C3zy-stimulated O2- production by neutrophils from controls and CDC class III subjects, and induced an upward trend in the CDC class IV group. These results indicate that the neutrophils of HIV+ patients are preactivated in vivo but they also indicate that these cells may correctly respond to a subsequent particulate stimulus as well as to activating cytokines. Our findings suggest that desensitization or functional exhaustion of complement receptors are not implicated in the abnormalities observed on neutrophils from HIV+ patients.

Mononuclear cells from HIV-infected patients produce factors which enhance functional activity of polymorphonuclear neutrophils from healthy subjects

The influence of mononuclear cell supernatants (MNCS) from nine healthy donors and 35 HIV-infected patients (17 with lymphoadenopathy syndrome (LAS), 15 with ARC and three with AIDS) on functional activity of polymorphonuclear neutrophils (PMN) from healthy donors was investigated. MNC after short-term cultivation (24 h) produced factors which enhanced chemiluminescence (CL) and chemotaxis of PMN. This augmentation did not depend on stimulation of MNC by mitogens (lipopolysaccharide Escherichia coli (LPS) and concanavalin A (Con A)) or on activation of PMN by FMLP. After 48 h of cultivation only MNC stimulated by LPS produced these factors. MNCS from HIV-infected patients provoked a more pronounced augmentation of PMN CL compared with MNCS from healthy subjects. This enhancement was observed in patients at all stages of infection, but was more pronounced in patients with LAS. MNCS impact on PMN CL was not connected with proliferative activity of MNC but was correlated with the level of CD4 cells. It was shown that removal of adherent cells from MNC fraction resulted in decreased MNCS impact. Treatment of MNCS by antibody to IL-1 beta, IL-8, interferon-alpha (IFN-alpha) and tumour necrosis factor-alpha (TNF-alpha) did not decrease MNCS impact on PMN CL.

The direct binding of an HIV fragment with granulocytes from healthy subjects and infected patients

The binding of the synthetic fragment from the CD4 binding site of HIV (gp 120) with polymorphonuclear neutrophils (PMN) in 13 healthy donors and 31 HIV-infected patients was studied using a biotin-streptavidin-texas-red complex. The largest percentage of PMN-bound peptide was reached at a final peptide concentration of 10 micrograms/ml. The increase of peptide concentration did not raise the per cent of positive PMN. Preliminary incubation of PMN or mononuclear cells with non-biotinylated peptide abolished subsequent binding of these cells with biotinylated peptide, while preliminary treatment of the cells by anti-CD4 monoclonal antibody did not lead to such abrogation. It was revealed that about 14% of PMN but no lymphocytes from healthy donors were able to bind peptide. The number of such PMN in HIV-infected patients was significantly less (6.3 +/- 8.9%, P less than 0.05). A connection between peptide-bound PMN and their functional activity was found. The percentage of such cells was 13.0 +/- 11.5% in patients with normal values in a stimulated nitroblue tetrazolium reduction test and only 2.6 +/- 2.8% in patients with low values in this test (P less than 0.05).