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.

P-170 glycoprotein (P-170) is involved in the impairment of natural killer cell-mediated cytotoxicity in HIV+ patients

In the present study we analyze peripheral blood lymphocytes (PBL) from patients with human immunodeficiency virus (HIV) infection for both phenotypic expression and function of P-glycoprotein (P-170). This transmembrane efflux pump is known to be one of the mechanisms responsible for the multidrug resistance (MDR) in cancer therapy and it is also constitutively expressed in normal PBL. P-170 function, evaluated as Rhodamine 123 (Rh123) efflux in flow cytometry, was found to be significantly reduced in CD16+ natural killer (NK) cells from patients with HIV infection. Interestingly, this reduced efflux significantly correlates with the decreased NK cytotoxicity observed in HIV+ patients, as evaluated against the NK-specific K562 target cell line. These results support a possible role of the P-170-related pump in specific immunological lymphocyte function such as NK cell-mediated cytotoxicity.

Clostridium difficile-associated diarrhoea in patients with human immunodeficiency virus infection: a case-control study

OBJECTIVE

To evaluate the prevalence of, risk factors for, treatment and outcome of Clostridium difficile-associated diarrhoea (CDAD) in patients with human immunodeficiency virus (HIV) infection.

DESIGN

A prospective case-control study, conducted between January 1992 and April 1994.

SETTING

Department of Infectious Diseases in a large university hospital with HIV in- and out-patient units.

PATIENTS AND METHODS

The study included 124 patients grouped as follows: 31 HIV-infected patients with CDAD (group A); 31 HIV-seronegative patients with CDAD (group B) and 62 HIV-infected patients without CDAD (group C). The patients in group B and C were selected randomly during the study period.

RESULTS

The prevalence of CDAD in HIV-infected patients was 3.1% compared with 1.6% in HIV-seronegative patients (P = 0.02). On univariate analysis, the predisposing factors in group A were antibiotic use in the 4 weeks prior to the onset of CDAD (P = 0.03 versus group C), prolonged hospitalization (over 20 days; P = 0.04), low levels of circulating CD4+ cells (P = 0.03) and use of antacids (P = 0.04). The antibiotics significantly associated with CDAD were trimethoprim-sulfamethoxazole (P = 0.02 versus group C), third generation cephalosporins (P = 0.03) and clindamycin (P = 0.03). On multivariate analysis of the risk factors, the use of antibiotics was the sole independent risk factor for CDAD (P = 0.03). The clinical symptoms of CDAD were more severe in HIV-infected patients than in controls. Three patients in group A (9.7%) had one relapse and one patient (3.2%) experienced chronic diarrhoea. The outcome of CDAD was not influenced by the number of circulating polymorphonuclear cells and CD4+ cells. No difference in the survival curves of AIDS patients with or without CDAD, stratified according to age, sex and CD4+ cell count was observed.

CONCLUSIONS

Our data suggest that CDAD is more common in HIV-infected patients, particularly those receiving antibiotic therapy, than in HIV-seronegative patients. Since C. difficile can cause severe and recurrent or chronic infections in HIV-infected patients, CDAD must be always considered in the differential diagnosis of diarrhoea in patients with AIDS and AIDS-related conditions.

Analysis of natural killer (NK) cell subsets defined by the expression of two novel surface antigens (EB6 and GL183) in AIDS and AIDS-related conditions

In this study we analyzed the expression of EB6 and GL183, which are part of P58 molecular family that represents the putative NK receptor for MHC class I molecules, in peripheral blood lymphocytes of 60 patients with HIV infection (20 asymptomatic HIV-seropositive individuals, 20 patients with constitutional symptoms, and 20 AIDS patients) and correlated it with the level of CD4+, CD56+ cells, and the NK cell activity in order to determine a possible relation with disease progression. The absolute number (but not the percentage) of CD56+, EB6+, and GL183+ cells was significantly reduced only in AIDS patients but not in the other AIDS-related clinical conditions. On the contrary, NK cell activity was reduced in all HIV-infected patients. In a 6-month follow-up, patients with constant clinical conditions and stable CD4+ cells level showed no significant difference, either in the percentage or absolute number of EB6+ and GL183+ cells. Interestingly, dual-color fluorescence indicates that GL183 and EB6 molecules (that in normal individuals are virtually absent on CD3- NK cells) are expressed in HIV-infected individuals not only in CD56+ cells but also in CD3+ cells. This may reflect a depletion of other T cell subsets or alternatively (less likely) a specific immune response. Our data indicate that the expression of EB6 and GL183 in T and NK cells from HIV-infected patients might be relevant in the course of the disease and for the disease-associated functional defect of NK cell activity.

An emerging opportunistic infection in HIV patients: a retrospective analysis of 11 cases of pulmonary aspergillosis

Invasive pulmonary aspergillosis usually occurs in patients with severe granulocytopenia or defects of cell-mediated immunity secondary to cytotoxic chemotherapy or high-dose corticosteroids, but it is an unusual opportunistic infection in patients with AIDS. Eleven cases of Aspergillus pulmonary disease were diagnosed in HIV-infected patients from January 1985 to December 1992, in the Department of Infectious Diseases of the Catholic University. Four patients had invasive pulmonary aspergillosis, six probable pulmonary invasive aspergillosis and one allergic bronchopulmonary aspergillosis. Fiberoptic bronchoscopy with bronchoalveolar lavage was confirmed to be an useful tool for the diagnosis of pulmonary aspergillosis in AIDS patients. The response of aspergillosis to therapy, either amphotericin B or itraconazole, has usually been poor. It is possible to speculate that the longer survival of AIDS patients and the latter development of other functional immunological abnormalities related to HIV infection may allow the appearance of opportunistic infection, such as pulmonary aspergillosis, different from those more often observed.

Meningococcal meningitis in Italy: 1887-1986

In Italy three epidemic peaks of meningococcal meningitis have occurred reflecting pandemic recrudescence of the disease. The seasonal distribution of the disease is similar in the epidemic or non-epidemic periods. There is no significant difference in the regional distribution of the disease. The disease is more prevalent among young males. The prevalent serogroup of Neisseria meningitidis is C. There has been a decrease in resistance to sulphonamides and an increase to rifampin among the isolated strains.

Synthetic peptides corresponding to sequences in HIV envelope gp41 and gp120 enhance in vitro production of interleukin-1 and tumor necrosis factor but depress production of interferon-alpha, interferon-gamma and interleukin-2

Patients with human immunodeficiency virus (HIV) infections have aberrant production of a number of lymphokines and monokines. Envelope glycoproteins are believed to be important in HIV pathogenesis and may influence the production of these cytokines. Therefore, synthetic peptides corresponding to amino acid sequences 735-752 and 846-860 of glycoprotein gp41 and to amino acid sequence 304-328 of gp120 were investigated for their abilities to affect the production of the following cytokines by normal peripheral blood mononuclear cells in the presence of appropriate inducers: interferon (IFN)-alpha, IFN-gamma, interleukin (IL)-1, IL-2, and tumor necrosis factor (TNF). In contrast to cells and inducers alone (or in the presence of a control peptide), gp41 or gp120 synthetic peptides were able to depress the production of IFN-alpha, IFN-gamma and IL-2. In contrast, these peptides produced an elevation of the production of IL-1 and TNF. The effect of the gp41 peptides was more marked than that of gp120 peptides in most cases. These studies indicate that these HIV envelope glycoproteins may be directly responsible for aberrant lymphokine and monokine production in patients infected with this virus and therefore may be at least partially responsible for the pathogenesis of AIDS.

[Meningococcal meningitis in Italy: 1887-1986]

We report the epidemiological data relative to meningococcal meningitis observed through a century, 1887-1986, in Italy. It is evident both from mortality and morbidity data that in Italy three epidemic peaks have occurred in 1915-1918, in 1939-1943 and in 1968-1972 respectively. The first two epidemic episodes are likely to be connected with the World Wars, the third one, recorded in other european and non european countries, probably reflects a pandemic recrudescence of the disease. The case fatality rate has shown periodic fluctuations connected with the epidemics and an average value of 10% until the sixties. Since then, the case fatality rate has stably decreased below that value. The seasonal distribution of the disease is similar both in the epidemic or non-epidemic period, with the higher incidence of cases between December and April and the lowest in August. There are no substantial differences in the regional distribution of the disease among the various regions of Italy. The distribution of cases, according to the different age-groups (0-14, 14-25, greater than 25 years old), indicates that the disease is more prevalent among the first group. However, in the last decade it is evident a trend of reduction among this group and a relative increase in other groups, in particular in subjects older than 25 years. In addition, meningococcal meningitis is prevalent among the males in the first two decades of life (less than 25 years old) while, afterward, there is an equal incidence both in males and females. The higher prevalence suggests a role of various close environmental contacts, such as the military service.(ABSTRACT TRUNCATED AT 250 WORDS)

A national voice for information about HIV infections: the Italian state AIDS hot-line

Because of the variety of problems connected with the AIDS epidemic, there is an urgent need for qualified information and counselling. In June 1987, The Italian Ministry of Health established a hot-line, acting within the National AIDS Operational Centre. Through the analysis of more than 39,000 calls received during the first year of activity, a clear outline has been obtained of the emotional impact of the disease on Italian public opinion, and of the problems raised. 67% of callers belong to 20-39 age group; the male/female ratio is 2:1. Interesting correlations have been found between the content of the questions and the sex, age, and type of caller. The vast majority of questions concerning basic concepts and notions about HIV infections are asked by no-risk-related subjects. During the first year, the percentage of questions asked by subjects actually at risk increased, and the questions themselves have become more specific.

Immunological alterations associated with recurrent herpes simplex genitalis

Immunological studies on 12 patients with culture-proven frequently recurrent herpes simplex genitalis were performed. All the patients were evaluated at three time intervals, initially without lesions and/or within 24 hr of lesion onset (acute illness); Days 5-7 from onset and after healing (convalescence); and between recurrences (quiescence). During the first 24 hr of lesions there was a decreased number of helper (CD4+) and an increased number of suppressor/cytotoxic (CD8+) cells with a resultant decrease in the CD4/CD8 ratio. An increased proportion of CD8+ cells coexpressing the CD11 marker (suppressor cells) was noted and correlated with a low proliferative response to HSV-2 antigens. Both the NK cells (CD16+) and the NK cell activity versus HSV-2-infected targets and the K562 cell line were decreased. Five to seven days after onset the number of CD8+ cells remained increased, although the expression of CD11 marker was decreased, indicating that the majority of CD8+ cells were cytotoxic (i.e., CD8+CD11-). At this time, the lymphoproliferative response to HSV-2 antigens and NK cell activity increased, correlating both with the number of CD16+ cells and with the expression of HLA-DR on this subset. In the interval between two recurrences, no significant alteration in any of the above immunological parameters was observed.

[Clinical picture of the onset of AIDS in 2911 adults in Italy]

Since 1982, 2911 adult AIDS cases have been officially reported in Italy up to December 31, 1988. The clinical presentation of all cases, reported to the Istituto Superiore di Sanità, Rome, and contained into the National AIDS Register, has been analyzed, with particular attention to opportunistic infections. 168 cases (mainly homosexual men) were found exclusively affected at diagnosis by Kaposi's Sarcoma (KS), while the other 2743 patients were affected by opportunistic infections and/or other pathologies. At diagnosis, 23.5% of patients had Pneumocystis carinii pneumonia (PCP), 32% esophageal or pulmonary candidiasis, and 7% cerebral toxoplasmosis. A decrease in frequency of Cytomegalovirus (CMV) diseases has been observed, as well as an increase of HIV encephalopathy from 1982 to 1988. The clinical picture of full-blown AIDS showed stability during the whole period of observation, with slight geographical variations.

The Italian AIDS 'hot-line': providing information to the people

The Italian AIDS hot-line has recently completed its first two operational years. Established as an emergency service, it was initially overloaded with calls, under the emotional impact of a new disease. As the average number of calls settled to around a hundred per day, a wider approach aimed at the concerns raised by callers has been possible. A particular effort has been made to handle psychological and social aspects of HIV infections. A large proportion of the questions analyzed (62,500) deal with doubts about transmission (30%), reliability of diagnostic tests (15%), and handling individual situations. Some categories of callers, such as drug users, parents or relatives of HIV-infected people, and seropositives often require experienced telephone counselling. HIV-positive callers follow the proportional distribution of AIDS cases in Italy: intravenous drug users forming the majority, followed by homosexuals and finally heterosexual subjects (reaching 10%, a value in accordance with trend projections). The demand for advice has increased over time, together with an evident refinement of question content.

Ten years of brucellosis in Italy (1977-1986)

In the decade 1977-1986 the total number of cases of brucellosis recorded in Italy was 25,165. The reported cases probably reflect only a minority of the total number of the effective cases due to lack of reporting. The epidemiological and clinical features of 62 cases of brucellosis, observed by the authors are reported as a sample of the total number of cases.

Inhibition of normal human natural killer cell activity by human immunodeficiency virus synthetic transmembrane peptides

The inhibitory effect on normal natural killer (NK) cell activity of two synthetic peptides corresponding to amino acid sequences 735-752 and 846-860, respectively, as deduced from the amino acid sequences of HTLV-IIIB gp160, was assessed. Sequences 735-752 and 846-860 correspond to regions located within the HIV transmembrane gp41, the carboxy terminus of HIV gp160. These two synthetic peptides have been shown previously to suppress the mitogen- and alloantigen-induced normal human lymphocyte blastogenic responses. Peptides 735-752 and 846-860 conjugated to protein carriers exerted a significant inhibition on the normal NK cell activity assayed against K562 tumor target cells in an in vitro 51Cr-release cytoltoxicity assay. At variance, control peptides similarly conjugated had no effect on NK activity. Addition of exogenous recombinant human interleukin-2 (IL-2) resulted in a partial restoration of the suppression of NK cell activity exerted by both peptides. Binding experiments indicated that peptides 735-752 and 846-860 did not affect the formation of effector cell-target cell conjugates, suggesting inhibitory effect(s) subsequent to the formation of the lytic complex as one potential mechanism of the observed NK suppression. These results suggest that peptides 735-752 and 846-860 homologous to sequences within the HIV transmembrane gp41 may play an important role in the pathogenesis of the defective NK cell activity observed in patients with acquired immunodeficiency syndrome (AIDS).