Role of polymorphonuclear leukocytes in infection by retroviruses with emphasis on the human immunodeficiency virus

Neutrophils may be a vehicle for viral replication and dissemination in human H5N1 avian influenza

The mechanism of systemic spread of H5N1 virus in patients with avian influenza is unknown. Here, H5N1 nucleoprotein and hemagglutinin were identified by immunohistochemistry in the nucleus and cytoplasm of neutrophils in the placental blood of a pregnant woman. Viral RNA was detected in neutrophils by in situ hybridization and enhanced real-time polymerase chain reaction. Therefore, neutrophils may serve as a vehicle for viral replication and transportation in avian influenza.

Mucormicosis cutánea primaria en un paciente con virus de la inmunodeficiencia humana

Primary cutaneous mucormycosis is an unusual mycotic infection associated to immunosupression. We present a 34 year-old woman with HIV infection with a necrotic primary mucormycosis of the skin associated to a venous catheter. She was treated with amphotericin B and surgical debridement.

Impact of highly active antiretroviral therapy (HAART) on the incidence of bacterial infections in HIV-infected subjects

The aim of this study was to evaluate the effect of highly active antiretroviral therapy (HAART) on the incidence of bacterial infections in HIV-infected patients. Two time periods were compared: (A) January 1992-December 1995 (before HAART) and (B) January 1997-December 2000 (after HAART). During the study periods, we observed 931 patients with bacterial infections, i.e. 322 with bacteremia, 369 with bacterial pneumonia and 240 with urinary tract infections, out of 4,242 HIV-infected subjects admitted to the Department of Infectious Diseases of a large university hospital. By comparing the overall incidence of bacterial infections during periods A and B, a statistically significant difference, from 32% to 18% (p<0.01), was observed. Analysis of risk factors of community- and hospital-acquired bacterial infections did not significantly differ in the two study periods. This study establishes that a significant reduction in bacterial infection incidence occurred in HIV-infected subjects when HAART became the standard therapy for HIV infection.

Expression of Fc(gamma)r1 (CD64) on polymorphonuclear leucocytes during progression to acquired immunodeficiency syndrome in perinatally human immunodeficiency virus-infected children

CD64, the high-affinity receptor in the family of FCgamma receptors, is not expressed constitutively in polymorphonuclear leucocytes (PMN). CD64 is expressed by PMNs in the late stages of human immunodeficiency virus (HIV) infection in adults. We followed the expression of CD64 on PMNs in perinatally HIV-infected children during disease progression. Peripheral blood leucocytes (PBL) from 45 perinatally HIV-infected paediatric patients and 13 healthy age-matched controls were analysed using cytofluorimetry after reaction with a fluorophore-labelled monoclonal antibody (MoAb) to CD64. In parallel, we examined the expression of CD32, CD16, CD11b and the human neutrophil-specific BH2-Ag using fluorophore-labelled MoAbs. We found that up to 79.5% of the PMNs in children in class C3 express CD64. Most importantly, we observed a continuous and significant increase in the appearance of CD64+ PMNs as a function of CDC classification (P < 0.001) but no changes in the expression of CD32, CD16, CD11b and BH2-Ag. This suggests that following the expression of CD64 on PMNs can be useful in evaluating the progression of HIV infection in perinatally HIV-infected children.

Nosocomial bloodstream infections in HIV-infected patients: attributable mortality and extension of hospital stay

A 3-year prospective matched case-control study was performed to investigate the potential risk factors, prognostic indicators, extension of hospital stay, and attributable mortality of nosocomial bloodstream infections in HIV-infected patients. Matching variables were: age, gender, number of circulating CD4+ T lymphocytes, cause of hospital admission, hospitalization in the same ward within the 6 weeks of diagnosis of the case, and length of stay before the day of infection in the case. Eighty-four cases and 168 matched controls were studied. Nosocomial bloodstream infections complicated about 3 of 1000 hospital days per patient in the study period. With step-wise logistic regression analysis, the most important predictors for developing nosocomial bloodstream infections were: increasing value of Acute Physiology and Chronic Health Evaluation (APACHE II) score (p = .001) and use of central venous catheter (CVC) (p = .002). The excess of hospital stay attributable to nosocomial bloodstream infections was 17 days. The crude mortality rate was 43%. The attributable mortality rate was estimated to be 27% (95% confidence interval [CI] = 13%-48%). The estimated risk ratio for death was 3.91 (95% CI = 2.06-7.44). Multivariate analysis identified two prognostic indicators that were significantly associated with unfavorable outcome of bloodstream infections: number of circulating CD4+ T cells <100/mm3 (p = .002) and APACHE II score >15 (p = .01). Nosocomial bloodstream infections are more common in patients with advanced HIV disease. Important cofactors are high APACHE II score and use of CVC. These infections can cause an excess mortality and significantly prolong the hospital stay of HIV-infected patients.

Bacterial pneumonia in HIV-infected patients: analysis of risk factors and prognostic indicators

This case control study assessed risk factors and prognostic indicators of 350 episodes of bacterial pneumonia in 285 HIV-infected patients. On univariate analysis, intravenous drug abuse (i.v.DA; p < .001 versus controls), regular cigarette smoking (p < .001), cirrhosis (p = .04), and history of a previous episode of pneumonia (p = .04) were risk factors for community-acquired episodes of bacterial pneumonia, whereas length of hospitalization (p = .01) was a risk factor only for nosocomial bacterial pneumonia. The small amount of circulating T CD4+ cells (<100/ mm3) was a risk factor in both groups of pneumonia (p < .05). Stepwise logistic regression analysis revealed that i.v.DA in community-acquired episodes and low levels of circulating T CD4+ cells, both in community-acquired and hospital-acquired episodes, were independent risk factors for the development of bacterial pneumonia. The case-fatality rate observed in our study was 27%. On stepwise logistic regression analysis, T CD4+ cell counts < or = 100/mm3 (p = .02), neutropenia (p = .04), PO2 arterial level < or = 70 mm Hg (p = .01), and Karnofsky score < or = 50 (p = .04) were independent indicators of mortality. According to a personally developed prognostic score, 211 episodes of pneumonia (60%) were classified as mild, 63 (18%) as moderate, and 76 (22%) as severe. Clinicians must carefully evaluate those variables that can influence the prognosis of bacterial pneumonia to make early identification of affected patients and to promptly establish the most appropriate therapeutic strategy in each case.

Predictors of Staphylococcus aureus pneumonia associated with human immunodeficiency virus infection

This study is based on a retrospective logistic regression analysis of all human immunodeficiency virus (HIV)-infected patients with Staphylococcus aureus pneumonia (SAP) admitted to the Department of Infectious Diseases, Catholic University, Rome, Italy between January 1986 and December 1994. Nineteen patients with 24 episodes of SAP were enrolled in the study. A control group of 38 HIV-infected patients without pneumonia was included. The attack rate of SAP was 8.31/1000 HIV-related hospital admissions and the frequency, out of the total number of bacterial pneumonia observed in the study period, was 16% (24 of 154 patients). The large majority of SAP was community acquired. On the univariate analysis, intravenous drug abuse (IVDA) (P = 0.02), history of previous Pneumocystis carinii pneumonia (PCP) (P = 0.03) and cirrhosis (P = 0.03) were significant risk factors for SAP. In addition, IVDA and previous PCP were independent risk factors on multivariate analysis. All patients presented with fever associated with cough (74%), chest pain (26%) or shortness of breath (37%). Chest X-ray documented lobar pneumonia (78%), predominantly in the lower lobes, consolidation with cavitation (11%), and interstitial-nodular infiltrates (11%). Pleural effusion was present in 31% of patients. The response to therapy was favourable in 79% of patients. Recurrence occurred in 26% and death occurred in 21% of patients. Death was significantly associated with the low level (< 50 mm-3) of circulating T CD4+ cells (P = 0.03) and the recurrence of pneumonia (P = 0.03). In conclusion, the present study indicates that S. aureus is an important aetiologic agent of bacterial pneumonia in HIV-infected patients, especially if they are drug abusers with previous PCP.

Quantitative analyses of plasma opsonizing activity and polymorphonuclear cell response during phagocytosis: standardisation of a chemiluminescent method

Although measurement of chemiluminescence has become a widespread tool in the study of phagocytosis of peripheral neutrophils, several problems linked to spontaneous fluctuation in chemiluminescence and the number of variables involved have occasionally either limited its usefulness for clinical and experimental purposes or compelled operators to take particular care when using the technique. In the present paper, sources of variability are investigated and most of the parameters involved are thoroughly analysed and step-by-step normalised. A stochastic calibration procedure for validation of the method is applied and a monofunctional test protocol for quantitative evaluation of plasma opsonizing activity in whole blood chemiluminescence is suggested. With regard to the goal of proposing a reverse monofunctional test, we discuss the reasons why further studies aimed at standardised evaluation of the cellular components are needed.

The impact of bacteraemia on HIV infection. Nine years experience in a large Italian university hospital

The object of this case control study was to evaluate the frequency, the risk factors, the microbiological spectrum and the outcome of 249 cases of bacteraemia observed in 209 HIV-infected patients, most them affected by AIDS. The rate of bacteraemia in the total yearly HIV-related admissions increased from 4% in 1985 to 13% in 1993. The more common aetiological agents of bacteraemia were: Staphylococcus aureus (29.7%), non-typhoidal species of Salmonella (14.1%), Staphylococcus epidermidis (10.9%), Streptococcus pneumoniae (8.4%) and Pseudomonas aeruginosa (7.6%). A mixed flora was found in 14% of the episodes. Multivariate analysis of predisposing factors indicated that a low CD4+T-cell count (<0.2 x 10(9)/l) (P=0.01), use of central venous catheters (CVC) (P=0.01) and neutropenia (polymorphonuclear neutrophils <1.0 x 10(9)/l) (P=0.04) were independent risk factors for the development of bacteraemia. Logistic regression did not reveal any association of bacteraemia with intravenous drug abuse (on univariate analysis P=0.04). The response (31.8%). Recurrences to specific therapy was favourable in 170 episodes (68.2%); death occurred in 79 (31.8%). Recurrences arose in 40 patients, 17 (42.5%) of them died. The outcome of bacteraemia was influenced by a low number of CD4+T-cells (P<0.001) but not of polymorphonuclear cells. Our findings suggest that bacteraemia is a relatively common event in HIV-infected patients, especially under particular conditions (e.g. intravenous drug abuse, use of CVC, neutropenia and a low CD4-T-cell count). It requires special attention from physicians who must recognise and treat the condition promptly at an early stage.

Zygomycosis and HIV infection

The severe immunosuppression associated with HIV infection increases susceptibility to opportunistic fungi. We describe a primary gangrenous cutaneous infection caused by Rhizopus arrhizus in an HIV-infected intravenous narcotic user. In addition, we review nine reported cases of zygomycosis in HIV-infected patients and discuss the frequency and outcome of zygomycosis in HIV infection. Eight of 10 patients were intravenous drug users. Cutaneous infection occurred in four patients. Another case was associated with drug-induced neutropenia. With treatment, 60% of the patients recovered. HIV-induced immunosuppression rarely predisposes to zygomycosis except in intravenous drug users or persons with other risk factors for this fungal infection.

Candidal infection of the gingiva in HIV-infected persons

Gingival biopsies were taken from 27 HIV (human immunodeficiency virus)-seropositive persons with gingivitis or periodontitis and 16 HIV-seronegative persons with periodontitis. Sections were stained with hematoxylin and eosin or periodic acid-Schiff. Candidal hyphae and pseudohyphae were found in the parakeratinized oral epithelium in 7 specimens from the HIV-infected patient group such specimen. No fungal invasion was found in any of the biopsies from the HIV-seronegative persons. Candidal invasion was significantly more frequent (P < 0.05) in patients with a confirmed history of necrotizing periodontal diseases (5/9) than in patients without known episodes of such diseases (3/18). The most prominent histopathologic changes observed in connection with candidal invasion comprised polymorphonuclear leucocyte infiltration of the oral gingival epithelium and numerous mitoses, some of which were located suprabasally. It is suggested that Candida albicans may contribute to the development of necrotizing periodontal diseases in HIV-infected persons.