Clinical significance of neutrophil functional activity in HIV infection

Neutrophils Turn Plasma Proteins into Weapons against HIV-1

As a consequence of innate immune activation granulocytes and macrophages produce hypochlorite/hypochlorous acid (HOCl) via secretion of myeloperoxidase (MPO) to the outside of the cells, where HOCl immediately reacts with proteins. Most proteins that become altered by this system do not belong to the invading microorganism but to the host. While there is no doubt that the myeloperoxidase system is capable of directly inactivating HIV-1, we hypothesized that it may have an additional indirect mode of action. We show in this article that HOCl is able to chemically alter proteins and thus turn them into Idea-Ps (Idea-P = immune defence-altered protein), potent amyloid-like and SH-groups capturing antiviral weapons against HIV-1. HOCl-altered plasma proteins (Idea-PP) have the capacity to bind efficiently and with high affinity to the HIV-1 envelope protein gp120, and to its receptor CD4 as well as to the protein disulfide isomerase (PDI). Idea-PP was able to inhibit viral infection and replication in a cell culture system as shown by reduced number of infected cells and of syncytia, resulting in reduction of viral capsid protein p24 in the culture supernatant. The unmodified plasma protein fraction had no effect. HOCl-altered isolated proteins antithrombin III and human serum albumin, taken as representative examples of the whole pool of plasma proteins, were both able to exert the same activity of binding to gp120 and inhibition of viral proliferation. These data offer an opportunity to improve the understanding of the intricacies of host-pathogen interactions and allow the generation of the following hypothetical scheme: natural immune defense mechanisms generate by posttranslational modification of plasma proteins a potent virucidal weapon that immobilizes the virus as well as inhibits viral fusion and thus entry into the host cells. Furthermore simulation of this mechanism in vitro might provide an interesting new therapeutic approach against microorganisms.

Association of T CD4 Lymphocyte Levels and Chronic Periodontitis in HIV-Infected Brazilian Patients Undergoing Highly Active Anti-Retroviral Therapy: Clinical Results

BACKGROUND

Controversial data regarding the association between immunosuppression and prevalence/ severity of periodontal diseases in HIV infection have been reported. Thus, the aim of this study was to test the hypothesis that lower T CD4 lymphocyte levels are not related to a higher prevalence of chronic periodontitis in HIV-infected Brazilians undergoing highly active anti-retroviral therapy (HAART).

METHODS

Sixty-four HIV-infected patients under HAART were classified as having chronic periodontitis; i.e., > or = three sites with probing depth (PD) and/or clinical attachment level (CAL) > or = 5 mm or periodontal healthy (no sites with PD > 3 mm and/or CAL > 4 mm). All subjects received conventional periodontal therapy. Bleeding on probing, plaque accumulation, PD, and CAL were registered at six sites/tooth at baseline and 4 months after therapy. Epidemiological features and levels of T CD4 lymphocytes were obtained from medical records. Significance of differences in periodontal clinical parameters within and between groups were determined using Wilcoxon signed-rank and Mann-Whitney or independent sample t tests. Associations between T CD4 levels and clinical parameters were determined using the chi square test.

RESULTS

Sixty-one percent of the HIV-infected patients represented AIDS cases, although 69% of them were periodontally healthy. The overall T CD4 lymphocyte mean levels was 333 +/- 254 cells/mm3 and viral load was 12,815 +/- 24,607 copies/mm3. Yet the prevalence of chronic periodontitis was relatively low (36%). In addition, patients with periodontitis presented a moderate disease (mean PD = 2.2 +/- 0.10; mean CAL = 2.6 +/- 0.13) and responded successfully to periodontal therapy. These subjects showed higher levels of T CD4 cells, but lower counts of neutrophils than periodontally healthy patients. Among periodontally healthy and chronic periodontitis patients, 41.7% and 22.9%, respectively, had low levels of T CD4 lymphocytes. No significant differences between periodontal status and epidemiological and immunological parameters were observed.

CONCLUSION

Based on these results, the hypothesis that lower T CD4 lymphocyte levels are not associated with higher prevalence of chronic periodontitis in HIV-infected Brazilians under HAART cannot be rejected.

IgG subclass specific antibody response to periodontopathic organisms in HIV-positive patients

BACKGROUND

We previously reported an increased rate of progression of periodontal disease over an 18-month period in human immunodeficiency virus (HIV)-positive subjects compared to controls. The mechanism for disease progression and rapid tissue loss was unknown. Data on the microbiological studies failed to show any significant difference in the microbial characteristics of the periodontal lesions in HIV-positive patients compared to HIV-negative controls. Immunological analysis had identified neutrophils as an important component of the host defense against periodontal infection, especially against rapid tissue loss. Serum IgG reactivities to periodontal pathogens in HIV-positive patients with periodontitis were reduced. Other data provided circumstantial evidence to suggest that IgG subclass (IgG2) specific antibody might assist bacterial clearing in periodontal infection. The aim of the current study was to examine the specific IgG subclass antibody response to a panel of periodontopathic organisms: Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella Intermedia (Pi), Fusobacterium nucleatum (Fn), Campylobacter rectus (Cr), and Bacteroides forsythus (Bf) in HIV-positive patients compared to HIV-negative controls.

METHODS

Sera from 120 HIV-positive patients (40 periodontitis, 69 gingivitis, and 11 no oral diseases) were tested for IgG subclass specific antibody response to the above listed 6 organisms using enzyme-linked immunosorbent assay. Data were compared with those obtained from 40 HIV-negative control subjects (35 periodontitis, 2 gingivitis, and 3 no oral diseases).

RESULTS

In the HIV-positive group, a consistently high response rate was found in IgG1 to all the bacteria tested. In addition, high levels of IgG3 and IgG4 to Pg and IgG1 and IgG2 to Pi were also present. However, no significant difference was detected among the periodontitis, gingivitis, and no oral disease subgroups. When the periodontitis patients from the HIV-positive group were compared to the HIV-negative group, no difference in the antibody levels and response rates was noted.

CONCLUSION

We conclude that in HIV-positive patients, the specific IgG subclass antibody response to periodontopathic organisms was similar to that of HIV-negative subjects.

Risk factors in HIV-1-infected patients developing repetitive bacterial infections: toxicological, clinical, specific antibody class responses, opsonophagocytosis and Fc(gamma) RIIa polymorphism characteristics

The aim of the study was to determine possible factors related to the risk of developing recurrent bacterial respiratory tract infections in HIV-1-infected patients, regardless of the degree of immune cellular impairment. Thirty-three HIV-1 seropositive patients with previous repetitive bacterial respiratory tract infections (case group), 33 HIV-1 seropositive controls (matched by CD4-cell counts) without these antecedents and 27 healthy controls were studied before and after administration of pneumococcal and Haemophilus influenzae type b vaccines. Clinical or toxicological variables, cutaneous tests, complement factors, beta2-microglobulin, serum IgM, IgA, IgG and subclasses, specific antibodies (IgG, IgG2, IgA) against pneumococcal vaccine and polyribosylribitol phosphate (PRP), their avidity, opsonophagocytosis and IgG(2)m and Fc(gamma)RIIa allotypes were determined. A history of drug abuse (P = 0.001), less likelihood of receiving high activity antiretroviral treatment high activity antiretroviral treatment (HAART) (P = 0.01), higher levels of HIV-1 viral load (P < 0.05), serum IgG (P < 0.01) and beta2-microglobulin (P < 0.01) were observed in the case group. Also, a lower increase in specific antibodies to pneumococcal vaccine and PRP was demonstrated in the cases in comparison with the two control groups. No differences were observed in the avidity of antibodies, opsonophagocytic capacity or IgG(2)m and Fc(gamma)RIIa allotypes between the three groups. These data indicate that vaccination strategies against encapsulated bacteria can be unsuccessful in the HIV-1-infected patients presenting repetitive bacterial respiratory tract infections if behavioural aspects or measures to improve adherence to HAART therapies are not considered.

Endocarditis caused by Aspergillus species in injection drug users

Aspergillus endocarditis is a rare event; a very few cases have been reported in injection drug users (IDUs) and patients infected with human immunodeficiency virus (HIV). We report 2 proven cases and 1 highly suggestive case of Aspergillus endocarditis in IDUs, 2 of whom were infected with HIV, and discuss some related clinical and pathogenic aspects.

Interleukin-15 enhances neutrophil functional activity in patients with human immunodeficiency virus infection

Polymorphonuclear leukocyte (PMN) dysfunction has been reported in human immunodeficiency virus (HIV)-infected patients. Interleukin (IL)-15 is a recently discovered cytokine that potentiates antimicrobial functions of normal PMNs. We evaluated the in vitro effect of IL-15 on chemotaxis and fungicidal activity of PMNs from 9 patients with untreated advanced HIV infection, 8 patients with viral suppression after 52 to 130 weeks of highly active antiretroviral therapy (HAART), and 12 patients with treatment failure. We also studied oxidative burst and apoptosis of PMNs in 5 patients with untreated advanced HIV infection. Twelve healthy donors were included as controls. Chemotaxis and fungicidal activity of unprimed PMNs was significantly lower in patients with untreated HIV infection compared with controls. After incubation with IL-15, a significant increase in PMN chemotaxis and fungicidal activity was found; moreover, IL-15 induced a significant reduction in the number of apoptotic HIV+ PMNs. IL-15 did not modulate oxidative burst of HIV+ PMNs as measured by chemiluminescence production. The in vitro priming of PMNs with IL-15 determined a complete reversal of defective chemotaxis and killing in all HAART-treated patients with long-term HIV suppression. IL-15 significantly enhanced chemotaxis and fungicidal activity also in patients with HAART failure. In conclusion, IL-15 is an important cytokine in the activation of the functional properties of HIV+ PMNs, by delaying apoptosis and enhancing chemotaxis and fungicidal activity. The potent stimulant effect of IL-15 on PMN function was observed in antiretroviral naive patients as well as in individuals who were receiving HAART, including those with treatment failure.

Interleukin-15 enhances neutrophil functional activity in patients with human immunodeficiency virus infection

Polymorphonuclear leukocyte (PMN) dysfunction has been reported in human immunodeficiency virus (HIV)-infected patients. Interleukin (IL)-15 is a recently discovered cytokine that potentiates antimicrobial functions of normal PMNs. We evaluated the in vitro effect of IL-15 on chemotaxis and fungicidal activity of PMNs from 9 patients with untreated advanced HIV infection, 8 patients with viral suppression after 52 to 130 weeks of highly active antiretroviral therapy (HAART), and 12 patients with treatment failure. We also studied oxidative burst and apoptosis of PMNs in 5 patients with untreated advanced HIV infection. Twelve healthy donors were included as controls. Chemotaxis and fungicidal activity of unprimed PMNs was significantly lower in patients with untreated HIV infection compared with controls. After incubation with IL-15, a significant increase in PMN chemotaxis and fungicidal activity was found; moreover, IL-15 induced a significant reduction in the number of apoptotic HIV+ PMNs. IL-15 did not modulate oxidative burst of HIV+ PMNs as measured by chemiluminescence production. The in vitro priming of PMNs with IL-15 determined a complete reversal of defective chemotaxis and killing in all HAART-treated patients with long-term HIV suppression. IL-15 significantly enhanced chemotaxis and fungicidal activity also in patients with HAART failure. In conclusion, IL-15 is an important cytokine in the activation of the functional properties of HIV+ PMNs, by delaying apoptosis and enhancing chemotaxis and fungicidal activity. The potent stimulant effect of IL-15 on PMN function was observed in antiretroviral naive patients as well as in individuals who were receiving HAART, including those with treatment failure.

Dysregulation in IL-12 secretion by neutrophils from HIV-infected patients

It is generally believed that neutrophils from HIV-infected patients are functionally competent, but several studies have shown impairment in neutrophil fungal killing and cytokine production. In this study we evaluated the ability of neutrophils from healthy donors and HIV-infected patients to produce IL-12 in response to stimulation with Candida albicans, lipopolysaccharide (LPS) and Cryptococcus neoformans (acapsular and encapsulated), with and without MoAb opsonization. Neutrophils from healthy donors secreted IL-12 in response to LPS or C. albicans but not in response to encapsulated or acapsular C. neoformans, regardless of MoAb opsonization. Surprisingly, neutrophils from HIV-infected patients demonstrated constitutive IL-12 production, although these cells were not responsive to LPS stimulation. The inability of MoAb to C. neoformans capsular polysaccharide to promote IL-12 production by neutrophils excludes phagocytosis and/or CD16 cross-linking in this process, and distinguishes neutrophils from monocytes. Our results provide additional evidence for cytokine dysregulation in neutrophils from HIV-infected patients. Furthermore, the IL-12 response of neutrophils and monocytes to CD16 stimulation appears to be different, suggesting differences in the role of these phagocytic cells during the inflammatory response.

Improvement in neutrophil and monocyte function during highly active antiretroviral treatment of HIV-1-infected patients

OBJECTIVE

To investigate the effect of highly active antiretroviral treatment (HAART) on neutrophil and monocyte function in patients with moderately advanced HIV-1 infection.

DESIGN

Eighteen HIV-1-infected patients with CD4 T cell counts below 350/microl, no concomitant active infection, and no previous use of protease inhibitors were treated with indinavir or ritonavir and two reverse-transcriptase inhibitors and were followed up for 9 months. Ten age- and sex-matched healthy subjects were included as controls.

METHODS

The functional activity of neutrophils and monocytes was measured by assessing chemotaxis towards a bacterial peptide, killing activity against Candida albicans, and oxidative burst as measured by chemiluminescence production.

RESULTS

Neutrophils and monocytes from the treatment group exhibited a significantly diminished baseline chemotactic and fungicidal activity compared with healthy controls (P < 0.001). After starting HAART, there was a significant improvement in chemotaxis and fungicidal activity of phagocytic cells (P < 0.001). Values of chemotaxis reached normal ranges in 13 out of 18 patients (72%) for neutrophils and eight out of 18 (44%) for monocytes, whereas phagocyte killing was rarely restored to normal values (3/18 cases for monocytes and 0/18 for neutrophils). The administration of HAART was also associated with significantly increased phagocyte chemiluminescence production in response to phorbol-12-myristate 13-acetate or opsonized C. albicans (P < 0.01).

CONCLUSION

The functional improvement of two critical components of innate antimicrobial immunity, such as neutrophils and monocytes, may contribute to the improved cell-mediated immune responses against opportunistic infections in HAART-treated patients.

New concepts regarding the pathogenesis of periodontal disease in HIV infection

Periodontal manifestations of human immunodeficiency virus (HIV) infection were first described in 1987. Initially, the lesions receiving attention were HIV-associated gingivitis (now known as linear gingival erythema [LGE]) and HIV-associated periodontitis (now known as necrotizing ulcerative periodontitis [NUP]). The true prevalence of LGE was difficult to determine due to variable diagnostic criteria. Recently, LGE has been associated with intraoral Candida infection. The prevalence of NUP is low (< or = 5%), and this lesion is associated with pronounced immunosuppression. Current focus on the periodontal manifestations of HIV infection centers on rapid progression of chronic adult periodontitis in HIV+ patients. Attempts to identify the pathogenesis of the increased progression of periodontitis have not proven successful. For example, analysis of subgingival plaque for the presence of bacterial pathogens has failed to detect differences between HIV+ and HIV- patients. Recently our laboratory has identified alterations in the host response in the gingival crevice of HIV+ patients. Comparing HIV+ and HIV- injecting drug users (IDU), levels of the proinflammatory cytokine interleukin-1 beta (IL-1 beta) in gingival crevicular fluid (GCF) were slightly elevated at sites with a probing depth of 1 to 3 mm. At deeper sites (> or = 4 mm), total IL-1 beta in GCF was significantly greater in HIV+ individuals. Using the lysosomal acid glycohydrolase beta-glucuronidase (beta G) as a measure of the influx of polymorphonuclear leukocytes (PMN) into the gingival crevice, our data indicated a significant correlation of total beta G in GCF and probing depth in the HIV-IDU (r = 76; P = .02). This result was similar to what we have observed in other studies. In contrast, for HIV+ subjects, total beta G was not associated with probing depth (r = .20; NS). These data suggest that HIV+ patients have altered regulation of PMN recruitment into the gingival crevice. We have begun to investigate the conditions under which subgingival Candida may contribute total periodontal lesions in HIV+ individuals. Candida from subgingival sites has been cultured in HIV+ individuals. Subgingival Candida was distinct from Candida isolated from tongue and buccal mucosal surfaces (as indicated by genomic fingerprinting). We hypothesize the absence of adequate priming of PMN by HIV+ patients. This may be due to a reduced Th1 lymphocyte response. The inability of HIV+ individuals to adequately prime PMN may allow Candida to colonize the subgingival environment. In that milieu, it may act directly or in concert with subgingival bacterial pathogens, or as a cofactor (by inducing production of proinflammatory cytokines) to increase the occurrence of periodontal attachment loss.

Impaired cytokine production by neutrophils isolated from patients with AIDS

OBJECTIVES

To determine the ability of neutrophils isolated from HIV-seropositive patients to produce proinflammatory cytokines.

DESIGN

The in vitro responsiveness of polymorphonuclear neutrophils (PMN) and peripheral blood mononuclear cells (PBMC) to lipopolysaccharide (LPS), used in the presence or absence of interferon (IFN)gamma, was determined in 47 HIV-positive patients with advanced stages of virus infection.

METHODS

Cytokines in cell-free supernatants were measured by enzyme-linked immunosorbent assay or radioimmunoassay.

RESULTS

Cell-free supernatants from PMN isolated from the peripheral blood of HIV-positive patients and stimulated with LPS contained increased amounts of tumour necrosis factor (TNF)-alpha and interleukin (IL)-8 with respect to supernatants obtained from PMN of normal donors. In contrast, release of IL-1beta and IL-1ra (IL-1 receptor antagonist) in response to LPS, or LPS plus IFNgamma, was found to be lower in PMN from HIV-positive patients than in PMN from controls, but was significant only in the case of IL-1ra. Furthermore, the release of IL-12 induced by LPS or LPS plus IFNgamma did not significantly differ between PMN from HIV-positive patients and healthy donors. Concerning PBMC, the production of TNF-alpha and IL-12 in response to LPS, or LPS plus IFNgamma, was found to be significantly higher in cells isolated from HIV-positive patients, whereas the release of IL-1beta was significantly lower. In the case of IL-8, no statistically significant difference was found between PBMC isolated from HIV-positive patients and healthy donors.

CONCLUSIONS

Collectively, the data suggest that in HIV-positive patients with advanced stages of disease, the ability of PMN to produce specific cytokines in response to LPS is significantly altered. Alterations in this ability might contribute to the evolution of HIV disease.

Bacterial infections

Non-opportunistic bacterial infections are an important cause of morbidity and mortality for HIV-infected adults and children. Factors associated with increased risk of these include altered B- and T-cell function; altered phagocytic cell function; skin and mucous membrane defects; and use of indwelling vascular catheters, antibiotics, or cytotoxic agents. The pathogens encountered most frequently are S. aureus, S. pneumoniae, H. influenzae, Salmonella sp., and Pseudomonas aeruginosa. Less commonly encountered organisms include Rhodococcus equi, Listeria monocytogenes, Shigella sp., and Nocardia asteroides, Strategies for prevention as well as diagnosis and treatment of these are discussed.

Inflammatory and immune mediators in crevicular fluid from HIV-infected injecting drug users

Gingival crevicular fluid (GCF) levels of the polymorphonuclear leukocyte (PMN) lysosomal enzyme beta-glucuronidase (beta G), the pro-inflammatory cytokine interleukin 1 beta (IL-1 beta), and immunoglobulins (IgA, IgG, and IgM) were examined in 16 HIV seropositive (HIV+) and 10 HIV seronegative (HIV-) injecting drug users (IDU). Each subject received a periodontal examination including assessment of probing depth, attachment level, bleeding on probing, and plaque and calculus accumulation. GCF was collected from the mesial surfaces of premolar and molar teeth using filter paper strips. Although HIV+ subjects had a significantly lower number of peripheral blood CD4+ T cells/mm3 compared to HIV- subjects, there were no significant differences in mean probing depth, percentage of sites exhibiting bleeding on probing, or plaque and calculus accumulation between HIV- and HIV+ subjects. When the GCF components were analyzed, we found no significant differences between HIV- and HIV+ subjects in GCF levels of beta G, IL-1 beta, IgA or IgM, but GCF levels of IgG were significantly increased in HIV+ subjects. When sites were categorized by probing depth, no differences in the levels of beta G, IgA, IgG, and IgM existed between sites with probing depth < or = 3 mm compared to sites with probing depth > or = 4 mm in both HIV- and HIV+ IDU. However, levels of IL-1 beta in GCF were increased in the deeper sites (> or = 4 mm) in HIV+ IDU when compared to sites with PD < or = 3 mm. Analyzing GCF constituents in relation to the CD4 cell number, no differences were found between subjects with < or = 400 or > 400 CD4 cells/mm3 with respect to the levels of IL-1 beta, IgG, and IgM. However, the level beta G was significantly decreased in the HIV+ IDU with < or = 400 CD4 cells when compared to those with > 400 CD4 cells/mm3, while levels of IgA were significantly higher in HIV+ subjects with < or = 400 CD4 cells/mm3. Our results suggest that levels of IgG, and in immunodeficient subjects IgA were increased in GCF of HIV+ IDU while decreased levels of beta G were found in immunodeficient HIV+ IDU. These findings may be local manifestations of systemic alterations and suggest that analysis of GCF may provide insight into the immune and inflammatory responses of HIV-infected individuals to periodontal microorganisms.

Hematologic disorders and growth factor support in HIV infection

During the course of HIV disease a broad spectrum of hematologic disorders develop including abnormalities in blood cell generation, survival, and function Alterations in coagulation parameters may evolve associated with disruption of immunoglobulin or factor production. This article reviews the manifestations and pathophysiology of these abnormalities and discusses the role for growth factor support.

Phagocytosis and oxidative burst of blood phagocytes in chronic obstructive airway disease

Acute diseases and chronic conditions might be associated with altered blood neutrophil functions. The aim of this study was to investigate teh effects of stable chronic obstructive pulmonary disease (COPD) and superimposed acute bacterial bronchopneumonia (ABP) on the phagocytosis and oxidative metabolism of blood phagocytes. The 129 participants were assigned to 6 groups: group 1, healthy controls; group 2, previously healthy controls with ABP; group 3, patients with stable COPD on inhaled corticosteroids (IC); group 4, individuals with stable COPD on IC and ABP; group 5, patients with stable COPD requiring oral corticosteroids (OC); group 6, individuals with COPD on OC and ABP. Phagocytosis and oxidative burst was measured. Both tests showed a significant difference between the groups without acute infection when compared to the patients with ABP. No differences were observed between patients with stable COPD without ABP (groups 3 and 5) and group 1. The number of phagocytized E. coli/cell was 9.1 +/- 0.37, 7.9 +/- 0.27 and 8 .2 +/- 0.28 (groups 2, 4, and 6, respectively) reversed the observed changes. We conclude, that acute bacterial bronchopneumonia is associated with an impairment of phagocytosis and oxidative metabolism in blood. We suggest, that stable COPD has no influence on phagocytosis and oxidative burst.