Development of a taxonomy for pharmaceutical interventions in HIV+ patients based on the CMO model.

OBJECTIVE: To agree on a proposal for pharmaceutical interventions and establish their classification taxonomy according to the CMO-Pharmaceutical Care Model (Capacity-Motivation- Opportunity). METHOD: A study conducted between March and May, 2016. Two phases of development were defined. A literature review was initially conducted. Then, the DELPHI-Rand-UCLA methodology was used in order to reach a consensus about those interventions selected, and to define the taxonomy. Fifteen (15) experts, specialists in Pharmaceutical Care for HIV+ patients, were selected. This selection was explicitly conducted, following a protocol in order to avoid any bias. An initial proposal was developed according to the interventions extracted from Phase 1. These were tentatively classified according to the CMO Model, in a category based on their design and utility. Three issues were raised from the initial question: Do you agree with the proposed classification? If not, there was an option to re-categorize. Additionally, they were asked about the importance, priority and impact to achieve pharmacotherapeutic objectives that they would assign to it. Interventions were classified according to the degree of agreement. Once a consensus was reached, the final taxonomy was established. RESULTS: Eighteen (18) articles were finally considered. The initial proposal included 20 pharmaceutical interventions with the following classification: seven in Capacity, eight in Motivation, and five in Opportunity. Those interventions considered to have greater importance and priority were: Review and Validation, Safety, and Adherence. The interventions with the greatest impact were: Review and Validation, Coordination, Adherence, and Motivation. On the other hand, the lowest scores for importance were for: Planning and Social Coordination; and in terms of impact: Social Coordination. CONCLUSIONS: The taxonomy reached by consensus will allow to classify pharmaceutical interventions with the new model, and therefore to conduct an improved research and patient care.

Objetivo: Consensuar una propuesta de intervenciones farmacéuticas y llevar a cabo su taxonomía de clasificación según el modelo de Atención Farmacéutica-CMO (Capacidad-Motivación- Oportunidad). Método: Estudio realizado entre marzo-mayo de 2016. Se definieron dos fases de desarrollo. Inicialmente, se realizó una revisión bibliográfica. A continuación, para consensuar las intervenciones seleccionadas y definir la taxonomía se utilizó metodología DELPHI-Rand-UCLA. Se seleccionaron 15 expertos, especialistas en Atención Farmacéutica al paciente VIH+. La selección se realizó explícitamente, siguiendo un protocolo para evitar sesgos. Se elaboró, inicialmente, una propuesta a partir de las intervenciones extraídas de la fase-1. Se clasificaron tentativamente según el Modelo-CMO en una categoría según su diseño y utilidad. Se plantearon tres preguntas a partir de la cuestión inicial: ¿Está de acuerdo con la clasificación propuesta? En caso negativo, se daba opción de recategorizar. Adicionalmente, se planteó qué importancia, prioridad e impacto en la consecución de objetivos farmacoterapéuticos le daría. Las intervenciones se clasificaron en función del grado de acuerdo. Una vez consensuadas, se realizó la taxonomía definitiva. Resultados: Se consideraron finalmente 18 artículos. La propuesta inicial incluyó 20 intervenciones farmacéuticas clasificadas siete en Capacidad, ocho en Motivación y cinco en Oportunidad. Las intervenciones consideradas de mayor importancia y prioridad fueron: revisión y validación, seguridad y adherencia. Las de mayor impacto fueron: revisión y validación, coordinación, adherencia y motivación. Por contra, las de menor puntuación en importancia fueron: planificación y coordinación social y, en impacto, coordinación social. Conclusiones: La taxonomía consensuada permitirá clasificar las intervenciones farmacéuticas realizadas con el nuevo modelo y, así, profundizar en la investigación y la mejora asistencial.

The natural history of HIV-1 infection: staging classifications of disease.

We evaluated and compared four staging classification systems for HIV infection in a population-based cohort: (1) a staging based on prodromal clinical criteria; (2) the Walter Reed Staging Classification (WRSC); (3) the immunologic staging system (ISS), and (4) a simple staging based on oral disease and CD4+ T-cell depletion. The staging systems were applied to 386 HIV-infected men in the San Francisco Men's Health Study cohort who did not have AIDS at the baseline examination. After 48-56 months of follow-up the cumulative incidence of AIDS and the cumulative mortality by stage was determined for each staging. Unlike the other systems, the WRSC could not classify a substantial proportion of HIV-infected men (51.9%). The WRSC and ISS include one or more stages which did not appear to be associated with a prognosis substantially different from that of adjacent stages. The simplified staging system based on CD4+ T-cell depletion and oral disease may be the most effective of the systems studied. A more complete understanding of the pathophysiology during the evolution of HIV infection will be required to define a more detailed staging of this disease.

Urinary excretion of porphyrins is increased in patients with HIV-1 infection.

Urine concentrations of total porphyrins and of porphyrin precursors, delta-aminolaevulinic acid and porphobilinogen, were analysed in the first-morning urine samples of 36 people with established HIV-1 infection. For comparison, we also analysed the urine samples of 26 healthy HIV-seronegative people. In patients with HIV-1 infection concentrations of total porphyrins were found to be significantly higher than in healthy controls. Furthermore, there was a close correlation between concentrations of total porphyrins and porphobilinogen and urine neopterin concentrations in patients. Our data indicate an association between chronic immune activation and altered porphyrin metabolism. The data may provide a rationale for the observation of acute porphyria in patients with HIV-1 infection.

T lymphocyte subset changes in human immunodeficiency virus infection.

The absolute number of CD4+ and CD8+ T cells was determined by an immunomagnetic technique directly in the blood of 75 healthy controls and 223 HIV-infected individuals. The HIV-seropositive individuals were also classified clinically according to the system recommended by the Centers for Disease Control (CDC), and the CDC classification was correlated with the patients' T cell subset counts. Compared to the control group, the HIV-infected individuals demonstrated an early and sustained increase in the number of CD8+ T cells with median values of CDC groups II, III, and IV C2 twice that observed in the control group. Patients with AIDS had CD8+ T cell counts comparable to those of the control group. The HIV-infected individuals showed a decrease in the number of CD4+ T cells correlating with clinical deterioration of the disease. T cell subset counts significantly distinguished the group of healthy seropositive individuals from those with HIV-related disease, and the group of patients with AIDS from those with other HIV-related opportunistic infections.

Prognostic usefulness of the Walter Reed staging classification for HIV infection.

We evaluated the usefulness of both the Walter Reed (WR) staging classification and the component criteria used in the system in predicting progression to AIDS. The WR classification was applied to a cohort of 431 men who were seropositive for the human immunodeficiency virus on entry into a prospective study. The WR classification was of limited usefulness, as only 133 men (31%) could be assigned to a WR stage. Among men who could be WR classified, only individuals in WR stage 5 were found to have a significantly more rapid progression to AIDS. The seropositive cohort was also classified based on initial CD4 cell number. Low CD4 counts (less than 400 cells/mm3) were significantly associated with progression to AIDS, and grouping seropositive men by CD4 number alone provided as much prognostic information as the WR classification. Skin test anergy was also a significant predictor for progression to AIDS, but only in individuals with low CD4 counts.

Specific western blot bands are associated with initial CD4+ lymphocyte counts in human immunodeficiency virus seroconverters. The Navy HIV Working Group.

The Western blot is the most widely used confirmatory test for determining human immunodeficiency virus (HIV) seropositivity. Specific bands in the Western blot indicate antibody responses to various portions of HIV or its precursors, and each is assigned a score from 0 to 3+. While the precise role of humoral antibody responses has not been fully established, specific antibody responses might influence the course of HIV infection. This study investigated the association between antibody reactivity to nine principal Western blot bands and initial CD4+ counts among 877 Navy and Marine Corps personnel during 1988 to 1991. Multiple regression was used to evaluate the strength and significance of the associations and to adjust for age and estimated duration of infection. Strong antibody responses to the p24 core (P < 0.05), p53 reverse transcriptase (P < 0.005), and p55 core precursor (P < 0.0001) antigens were associated with higher initial CD4+ counts, with 33 to 48 additional cells/mm3 associated with each unit increase in the Western blot score, according to a multiple regression analysis which controlled for age and duration of infection (maximum 24 months). By contrast, antibodies to the gp41 transmembrane antigen (P < 0.0001) were associated with lower initial CD4+ counts. Each unit increase in the gp41 band was associated with 76 fewer CD4+ cells/mm3. A negative association was also observed for the gp160 envelope precursor antigen, with each unit increase in reactivity associated with 51 fewer CD4+ cells, although this association was not statistically significant (P = 0.09).(ABSTRACT TRUNCATED AT 250 WORDS)

Nutrition in the management of HIV antibody positive patients: a longitudinal study of dietetic out-patient advice.

The efficacy of a dietetic service was evaluated in an AIDS clinic; 17 asymptomatic (CDC II) and 17 symptomatic (CDC IV) patients participated in a 12 week evaluation of out-patient dietetic advice. The symptomatic group, classified as CDC stage IV according to the Centre for Disease Control classification, were significantly lighter (P less than 0.05) and had significantly lower values for usual weight, current body mass index, mid-upper arm and mid-arm muscle circumferences and triceps and subscapular skinfold thicknesses (P less than 0.05) at the outset of the study. There were no significant differences in nutrient intakes between the two groups. After 12 weeks of dietetic intervention which included personalised advice, prescription of food supplements and the provision of a special food allowance as social welfare payments for the unemployed, there were significant increases in the intakes of most nutrients, the effect being greater with the symptomatic CDC IV group. It is concluded that dietetic intervention has a significant role to play in the management of HIV antibody positive patients.

Autonomic dysfunction in patients with human immunodeficiency virus infection.

Autonomic function tests have been recorded in 40 male homosexual patients with serum antibodies to human immunodeficiency virus (HIV) and 12 male homosexuals without such antibodies. Abnormalities of autonomic function were found in 15 of 31 patients without other recognized reasons for autonomic dysfunction. Four patients had two or more test abnormalities. The profile of these abnormalities was found to be different from that of autonomic neuropathy associated with diabetes and other disorders and was consistent with the presence of sympathetic overactivity. Abnormalities in autonomic function were particularly associated with clinically identifiable neurological complications of HIV infection.

Periodontal disease in HIV-positive individuals: association of periodontal indices with stages of HIV disease.

BACKGROUND: Periodontal disease has been previously associated with human immunodeficiency virus (HIV) infection, and HIV infection has been considered a modifier of periodontal disease. The aim of this study was to report the prevalence and severity of periodontal disease in a population of HIV-positive individuals and to investigate the association between clinical periodontal indices and the stage of HIV disease, as expressed by CD4 cell counts. METHODS: Thirty-nine male HIV-positive patients were recruited and a medical history was taken. To evaluate periodontal disease, probing depth (PD), attachment level loss (AL), bleeding index (BI), and modified gingival index (MGI) were recorded. Associations between the above indices and CD4 counts were examined. RESULTS: Immunocompromised patients (with CD4 cell counts < 200 cells/microl) showed significantly lower BI and fewer sites with PD and AL > 4 mm compared to patients with CD4 cell counts > 200 cells/microl. When patients with CD4 counts < 500 cells/microl were considered alone, a correlation was observed between CD4 cell counts and BI (r2 = 0.1617, P = 0.0463), MGI (r2 = 0.2123, P = 0.0204), and number of sites with AL > 4 mm (r2 = 0.1469, P = 0.056). CONCLUSIONS: Severely immunocompromised HIV-positive patients showed less severe gingival inflammation than expected. Patients with CD4 cell counts > 500 cells/microl showed no association between CD4 cell count and periodontal indices.

Loss of periodontal attachment in HIV-seropositive military personnel.

The cross-sectional relationship between severe loss of periodontal attachment (LPA) and worsening immune status due to HIV infection was evaluated in 474 HIV-infected subjects (416 men, 58 women) aged 18 to 49 years who had been classified at stages 1 through 6 of the Walter Reed Army Institute of Research (WR) Staging Classification System. LPA was measured at four sites per tooth using a manual probe; severe LPA was defined as > or = 1 site/subject exhibiting > or = 5 mm LPA. Severe LPA was found in 94 (20%) of the subjects. Modeling with multiple logistic regression analysis revealed that WR stage and peripheral CD4+ lymphocyte cell counts were not significant independent predictors of severe LPA. Severe LPA was more common in subjects at WR stage 5 or 6 who exhibited oral candidiasis (OC), a marker of immune system damage, than in persons at those WR stages without OC (odds ratio = 7.85; 95% confidence interval (CI) = 1.94-31.81). After the analysis controlled for WR stage, younger subjects receiving AZT had greater odds of severe LPA than same-age subjects not taking the drug (e.g., odds ratio for subjects aged 30 years = 2.59; 95% CI = 1.22, 5.49). Other significant predictors in the model included male sex; retired military status; cigarette smoking; and presence of cratered, ulcerated, or necrotic interdental papillae. HIV-associated immune deficiency may be associated with localized severe LPA, but this may be an indirect association due to medication use, opportunistic infection, or other factors not captured by the WR staging system or peripheral CD4+ cell counts.(ABSTRACT TRUNCATED AT 250 WORDS)

Human immunodeficiency virus, fever, dyspnoea and a dry cough. Expect the unexpected?

This report describes an HIV-seropositive patient with symptoms suggestive of Pneumocystis carinii pneumonia. The final diagnosis of pulmonary embolism was delayed because initially only HIV-specific complications were considered. The relation between AIDS and pulmonary embolism is discussed briefly.

Patient classification and cost analysis of AIDS and HIV: the case of Belgium.

The study calculates inpatient costs generated at the University Hospital in Antwerp (Belgium) and outpatient costs generated at the Institute of Tropical Medicine or at the University Hospital of 213 seropositive patients without AIDS and of 48 AIDS patients, for the year 1991. Outpatient drug use other than Zidovudine was excluded. An HIV + patient has an average annual total billing cost of 2062 ECU, 43% of which is spent in hospital, 29% on Zidovudine and 28% for follow-up at the Institute of Tropical Medicine. The average cost of care for an AIDS patient is 5.5 times higher and amounts to 11,277 ECU--hospitalisation costs (8349 ECU) and costs of Zidovudine (2031 ECU) are much higher. Costs vary with the severity of illness. In comparison to 1987, costs decreased due to lower drug prices and reduced hospitalisations. Life time costs of a seropositive patient are estimated at about 35,000 ECU, based on cost calculations per CD4-class for a follow-up period from 1991 to 1993.

Electrophysiological study (VEP, BAEP) in HIV-1 seropositive patients with and without AIDS.

One hundred-twenty nine HIV-1 seropositive patients (39 females, 90 males) were studied by means of pattern visual evoked potential (VEP) and brainstem auditory evoked potential (BAEP) recording. Utilizing the criteria of the Centers for Disease Control the patients were clinically defined and then subdivided into four groups: group A included patients of category II (n:11); group B patients of category III (n:29); group C patients of category IVa and IVc2 (n:55) and group D patients belonging to the other subgroups of category IV (n:34). EP were altered in 26.35% of the entire group with a marked prevalence of BAEP alterations (21.7%) rather than of VEP (4.65%). A considerable amount of BAEP abnormalities (24.13%) were found in patients with persistent generalized lymphadenopathy (group B). A significant increase of BAEP mean interpeak latencies were observed in group B, C, D patients when compared with those of the control group. On the whole, EP were altered in 20.65% of the neurologically asymptomatic patients. EP alterations may precede any clinical manifestation and can be found during the earlier phases of HIV-1 infection.

Correlation of the ratio of CD4+/CD8+ cells in lymph node fine needle aspiration biopsies with HIV clinical status. A preliminary study.

OBJECTIVE: To test the hypothesis that lymph node (LN) fine needle aspiration biopsy (FNAB) may provide reliable measures of human immunodeficiency virus (HIV) disease status. STUDY DESIGN: HIV+ participants in this study had persistent generalized lymphadenopathy without clinical evidence of lymphoma or nodal infections due to organisms other than HIV. Seven males and five females ranging in age from 23 to 55 and at HIV Centers for Disease Control (CDC) stages A2-C3 were enrolled in this study. From each participant, LN and blood samples were submitted for cytologic examination and flow cytometric analysis of lymphocyte subsets. Flow cytometry measures included T, B, CD4+, CD8+ and natural killer (NK) cells. The percentages of T, B and NK cells in LN and blood samples were different and reflected the expected distribution of these cell types in the respective tissues. RESULTS: The percentages of CD4+ and CD8+ cells in blood and LN were different, but this variation was not statistically significant. In contrast, the ratio of CD4+/CD8+ cells in LN and blood was different and statistically significant (P < .001) for patients in CDC categories A2-B2 but not different for categories B3-C3. More important, there was a significant (r = .76) correlation between the ratio of CD4+/CD8+ cells in LN with CDC stage. CONCLUSION: FNAB, in combination with flow cytometry, may prove to be an important tool in HIV clinical staging. However, further assessment, including clinical follow-up and participation of additional patients, is necessary and currently under way.

Use of HIV postexposure prophylaxis by dental health care personnel: an overview and updated recommendations.

BACKGROUND: The authors conducted a study on the use of postexposure prophylaxis, or PEP, for exposure to human immunodeficiency virus, or HIV, among dental health care personnel, or DHCP, enrolled in a surveillance system established by the Centers for Disease Control and Prevention, or CDC. They also discuss updated U.S. Public Health Service, or USPHS, recommendations for managing occupational exposures to HIV, as well as considerations for dentistry. METHODS: The authors analyzed occupational exposures reported by DHCP to the CDC to describe characteristics of the exposure (for example, type and severity), the source patient's HIV status and use of PEP. RESULTS: From June 1995 through August 2001, DHCP reported 208 exposures--199 percutaneous injuries, six mucous membrane exposures and three skin exposures--to the CDC. One-third of these percutaneous injuries were caused by small-bore hollow syringe needles, and most (66 percent) were moderate in depth. Nearly half the devices involved (46 percent) were visibly bloody at the time of injury. Per the criteria described in USPHS guidelines, one-half of the injuries were categorized as "less severe." Twenty-four (13 percent) known source patients were HIV-positive; 14 had symptomatic HIV infection or a high viral load. In this study, three in four DHCP exposed to an HIV-positive source warranted a three-drug PEP regimen. Twenty-nine (24 percent) DHCP exposed to a source patient who subsequently was found to be HIV-negative took PEP; six took PEP for five to 29 days. No exposures resulted in HIV infection. CONCLUSIONS: Findings of this study are consistent with earlier reports indicating that the risk of HIV transmission in dental settings is low. Strategies such as rapid HIV testing of source patients and follow-up counseling may reduce unnecessary use of PEP. CLINICAL IMPLICATIONS: Dental practices should develop comprehensive, written programs for preventing and managing occupational exposures to blood.

Tooth extraction in HIV sero-positive patients.

Tooth extraction is the dental treatment most commonly carried out among HIV positive patients. In this paper we propose a simple protocol for dental extractions in patients of this type, based on a review of the literature and on our own experience in this field. The factors to be considered when planning a dental extraction for HIV positive patients are: diagnosis of the lesion justifying the need for tooth extraction and medical assessment of the patient including the infection pathway, the stage of the disease, laboratory tests and drug therapy. The most frequent post extraction complications are a delay in the wound healing process, alveolitis and surgical wound infection. Fortunately, these complications tend to be rather uncommon and not too severe; they can be managed on an out-patient basis and their prevalence will probably tend to decrease with the introduction of the new anti-retroviral drugs for HIV-1.

Isolation of HIV-1 from Filipino commercial sex workers (CSWs).

Peripheral blood mononuclear cells (PBMC) from 36 HIV-1 antibody positive Filipino female commercial sex workers (CSWs) were co-cultivated at a 1:1 ratio with phytohemagglutinin-P activated PBMC from healthy, HIV-1 antibody negative donors. After 3-18 (mean 7.2) days of incubation at 37 degrees C in 5% CO2, 29 cultures showed evidence of replication of HIV-1: increasing concentrations of p24 antigen in the growth medium and the appearance of multinucleated giant cells. Although the length of incubation required for the appearance of cytopathogenic effect for each particular isolate was essentially the same when either 6 microwell plates were seeded with 3.0 x 10(6) cells/well or 24 well plates were seeded with 1.5 x 10(6) cells/well, the 24 well format was more sensitive. The ability to isolate HIV-1 from PBMC did not appear to be associated with the progression of disease or the presence or absence of any specific clinical findings. However, if the PBMC were from individuals with a concomitant p24 antigenemia, the incubation time required for isolation was significantly shorter (mean 3.8 days). The absolute CD4+ lymphocyte count was also slightly reduced in the culture positive, p24 antigenemic patients (range 302-813 cells/mm3, mean 502 cells/mm3) compared to the culture positive, p24 serum negative cases (range 311-1,511 cells/mm3, mean 830 cells/mm3). The p24 serum negative cases with CD4+ counts of < 500 cells/mm3 had positive PBMC cultures by 6 days of incubation.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical predictors of HIV-1 infection among preschool children in Dar es Salaam, Tanzania.

Seroprevalence of HIV-1 infection was determined in children aged between eighteen months and five years, attending maternal and child health (MCH) clinics in Dar es Salaam, Tanzania. A total of 889 children were eligible for the study, however seven children could not be enrolled because their mothers/guardians absconded and blood could not be drawn from 21 children due to refusal of mothers/guardians and from another 12 children due to technical reasons. Therefore, the participation rate was 95.5%. Of the 849 children screened, 14 (1.65%) were found to have IgG anti HIV-1 antibodies in their sera. The main clinical features found in children with symptomatic HIV-1 disease were weight loss, generalized lymphadenopathy, recurrent fevers, and prolonged diarrhoea. The utility of clinical features suggestive of HIV-1 infection (according to CDC classification) in identifying HIV-1 infection in children was evaluated and found to have high sensitivity (100%), specificity (96.9%) and negative predictive value (100%), but a low positive predictive value (35%). Marked variations in progression to symptomatic phase were noted, whereby some relatively young children had progressed to symptomatic phase (CDC class P-2A), while some older children were still in the asymptomatic stage (CDC class P-1 C). None of the symptomatic HIV-1 infected children presented with neurological disease, severe opportunistic infections, or malignancies. Although reduced mid-upper arm circumference and weight-for-age were associated with HIV seropositivity, these clinical parameters had low positive predictive values compared to the CDC classification.

PIP: Serologic testing of 849 children 18 months-5 years of age attending the Lugalo and Mwananyamala maternal-child health clinics in Dar es Salaam, Tanzania, during May-August 1994 identified 14 cases (1.65%) of HIV infection. The sample represented 95.5% of children making mandatory monthly clinic visits during the 3-month study period. The main clinical symptoms in HIV-infected children were weight loss, generalized lymphadenopathy, recurrent fever, and prolonged diarrhea, all included in the Centers for Disease Control and Prevention (CDC) classification scheme. Children with symptomatic HIV infection were younger than those with asymptomatic infection. None of the children with symptomatic HIV infection presented with neurologic impairment, severe opportunistic infections, or cancers. The clinical features included in the CDC classification for HIV had a 100% sensitivity, a 96.9% specificity, and a 100% negative predictive value, but the positive predictive value was only 35%. Although the model with the best fit included mid-upper arm circumference less than 14 cm and a reduced weight-for-age (odds ratios, 3.8 and 1.9, respectively), the positive predictive values for these two factors were only 4.3% and 4.1%, respectively. The 1.65% HIV seroprevalence rate recorded in this community-based study is lower than the 2.4% rate estimated among newborns in Dar es Salaam, presumably because of high infant mortality and hospitalization among HIV-infected newborns. Use of a simplified version of the CDC classification of HIV infection in children is recommended for routine clinical use in Tanzania.

Multifunctional immunological monitoring of HIV positive patients: a novel staging system.

A tri-functional in vitro evaluation has been utilized to analyze peripheral blood mononuclear cells (BMNC) from HIV-infected patients, which allows for the classification of these individuals into convenient stages, according to the number of in vitro parameters affected. The classifying functional parameters are: the mitochondrial metabolic activity of freshly isolated BMNC, measured by an MTT reduction assay, the detection of apoptosis in 72 hour cultures of these cells assessed by propidium iodide staining and dual parametric flow cytometric analysis, and their proliferative response to pokeweed mitogen. Our results indicate that HIV-infected patients at different stages of their clinical disease, can present dysfunctions in one, two or three of the above-mentioned parameters. Based on these results, patients can be classified into four newly-described stages which are Stage 0, including uninfected controls and all patients with unaffected parameters, and Stages 1, 2 and 3, including patients having one, two or all three parameters affected, respectively. This type of immunological evaluation and classification of HIV-infected patients has the potential of becoming a predictive tool in the longitudinal follow-up of their HIV infection.

HIV: epidemiology, immunopathogenesis, and clinical consequences.

HIV infection is a global problem, with the largest number of cases occurring in the United States. HIV affects men, women, and children with varying frequency in different parts of the world. The spectrum of HIV infection and its consequences is broad. HIV, a retrovirus, is responsible for gradual and progressive damage to the human immune system. Over the course of years (more than 7 in many), the resultant deficiency in cell-mediated immunity leaves the host susceptible to infections, malignancies, and possible neuropsychiatric abnormalities. Current efforts to better understand this virus, its interaction with the human immune system, its clinical consequences, and its detection will continue to bring us closer to finding effective means of preventing and treating HIV infection. In addition, an understanding of the epidemiology, immunopathogenesis, and clinical consequences of HIV infection will contribute to a more knowledgeable approach to caring for HIV-infected individuals and anticipating their many needs.