Risk factors for primary Pneumocystis carinii pneumonia in human immunodeficiency virus-infected adolescents and adults in the United States: reassessment of indications for chemoprophylaxis

Pneumocystis jirovecii pneumonia in people living with HIV: a review

Pneumocystis jirovecii is a ubiquitous opportunistic fungus that can cause life-threatening pneumonia. People with HIV (PWH) who have low CD4 counts are one of the populations at the greatest risk of Pneumocystis jirovecii pneumonia (PCP). While guidelines have approached the diagnosis, prophylaxis, and management of PCP, the numerous studies of PCP in PWH are dominated by the 1980s and 1990s. As such, most studies have included younger male populations, despite PCP affecting both sexes and a broad age range. Many studies have been small and observational in nature, with an overall lack of randomized controlled trials. In many jurisdictions, and especially in low- and middle-income countries, the diagnosis can be challenging due to lack of access to advanced and/or invasive diagnostics. Worldwide, most patients will be treated with 21 days of high-dose trimethoprim sulfamethoxazole, although both the dose and the duration are primarily based on historical practice. Whether treatment with a lower dose is as effective and less toxic is gaining interest based on observational studies. Similarly, a 21-day tapering regimen of prednisone is used for patients with more severe disease, yet other doses, other steroids, or shorter durations of treatment with corticosteroids have not been evaluated. Now with the widespread availability of antiretroviral therapy, improved and less invasive PCP diagnostic techniques, and interest in novel treatment strategies, this review consolidates the scientific body of literature on the diagnosis and management of PCP in PWH, as well as identifies areas in need of more study and thoughtfully designed clinical trials.

HIV-associated lung disease

Lung disease encompasses acute, infectious processes and chronic, non-infectious processes such as chronic obstructive pulmonary disease, asthma and lung cancer. People living with HIV are at increased risk of both acute and chronic lung diseases. Although the use of effective antiretroviral therapy has diminished the burden of infectious lung disease, people living with HIV experience growing morbidity and mortality from chronic lung diseases. A key risk factor for HIV-associated lung disease is cigarette smoking, which is more prevalent in people living with HIV than in uninfected people. Other risk factors include older age, history of bacterial pneumonia, Pneumocystis pneumonia, pulmonary tuberculosis and immunosuppression. Mechanistic investigations support roles for aberrant innate and adaptive immunity, local and systemic inflammation, oxidative stress, altered lung and gut microbiota, and environmental exposures such as biomass fuel burning in the development of HIV-associated lung disease. Assessment, prevention and treatment strategies are largely extrapolated from data from HIV-uninfected people. Smoking cessation is essential. Data on the long-term consequences of HIV-associated lung disease are limited. Efforts to continue quantifying the effects of HIV infection on the lung, especially in low-income and middle-income countries, are essential to advance our knowledge and optimize respiratory care in people living with HIV.

Rising incidence of Pneumocystis pneumonia: A population-level descriptive ecological study in England

OBJECTIVES

Pneumocystis pneumonia (PCP) is an opportunistic infection that causes significant morbidity and mortality in the immunocompromised population. This population is growing and diversifying, yet contemporary epidemiology is lacking. We investigated the population-level incidence of PCP over the past decade.

METHODS

We conducted a descriptive study of all hospital admissions in England from April 2012 to March 2022. PCP episodes, age, median length of stay, gender and episodes of other respiratory fungal infections were collected. Consumption of Trimethoprim-Sulfamethoxazole was obtained between January 2019 and May 2022.

RESULTS

The incidence of PCP increased from 2·2-4·5/100,000 population between 2012/2013 and 2019/2020 (p < 0·0001). There was a drop in 2020/2021 to 2·7/100,000 before returning to 3.9/100,000 in 2021/2022. PCP episodes rose as a proportion of all-cause admissions as well as a proportion of episodes due to other fungal infections. The proportion of PCP patients aged 75+ increased from 14% to 26%. The median length of stay was 13.5 days. Consumption of intravenous Trimethoprim-Sulfamethoxazole increased from 0.24 × 100,000 to 0.30 × 100,000 defined daily doses.

CONCLUSIONS

The incidence of PCP is rising rapidly and represents a significant burden to the healthcare system. Further study into who is at risk of PCP is needed to better determine who should be given prophylaxis.

Prophylaxis for Pneumocystis jirovecii pneumonia in patients with inflammatory bowel disease: A systematic review

Patients with inflammatory bowel disease (IBD) are at increased risk of developing Pneumocystis jirovecii pneumonia (PJP) than the general population. Many medications utilized for the treatment of IBD affect the immune system, potentially further increasing the risk of PJP. Recommendations for prophylaxis against PJP in this patient population are based upon limited evidence, and risk factors for PJP development are not well-agreed upon. The purpose of this systematic review was to consolidate and evaluate the evidence for PJP prophylaxis in patients with IBD. An electronic literature search was performed, and 29 studies were included in the review, of which 24 were case reports or case series. Combined data from five cohort studies showed an absolute risk of developing PJP to be 0.07%. The majority of patients who developed PJP were receiving corticosteroids at the time of diagnosis (76%). The number of concomitant immunosuppressants received at time of PJP diagnosis varied from one to four. All studies reporting treatment of PJP utilized sulfamethoxazole-trimethoprim. Of the 27 studies reporting mortality data, 19% of patients died. Given the lack of conclusive data regarding risk factors for PJP development and the overall low incidence of PJP in patients with IBD, it is recommended to assess the patient's risk on a case-by-case basis to determine whether PJP prophylaxis is warranted.

Trends in the Epidemiology and Outcomes of Pneumocystis Pneumonia among Human Immunodeficiency Virus (HIV) Hospitalizations

Introduction: Pneumocystis Pneumonia (PCP) is a common opportunistic infection among people living with the human immunodeficiency virus (HIV). This study’s objective was to assess temporal trends in PCP epidemiology among hospitalized patients with HIV/AIDS in the US and to compare data for hospitalizations with HIV with PCP to those without PCP. Methods: The national inpatient sample (NIS) data were analyzed from 2002−2014. The discharge coding identified hospitalized patients with HIV or AIDS and with or without PCP. Results: We identified 3,011,725 hospitalizations with HIV/AIDS during the study period; PCP was present in 5% of the patients with a diagnosis of HIV. The rates of PCP progressively declined from 6.7% in 2002 to 3.5 % in 2014 (p < 0.001). Overall mortality in patients with HIV was 3.3% and was significantly higher in those with PCP than without PCP (9.9% vs. 2.9%; p < 0.001). After adjusting for demographics and other comorbidities, PCP had higher odds of hospital mortality 3.082 (OR 3.082; 95% CI, 3.007 to 3.159; p < 0.001). Conclusion: From 2002 to 2014, the rate of PCP in HIV patients has decreased significantly in the United States but is associated with substantially higher mortality.

No need for secondary Pneumocystis jirovecii pneumonia prophylaxis in adult people living with HIV from Europe on ART with suppressed viraemia and a CD4 cell count greater than 100 cells/µL

INTRODUCTION

Since the beginning of the HIV epidemic in resource-rich countries, Pneumocystis jirovecii pneumonia (PjP) is one of the most frequent opportunistic AIDS-defining infections. The Collaboration of Observational HIV Epidemiological Research Europe (COHERE) has shown that primary Pneumocystis jirovecii Pneumonia (PjP) prophylaxis can be safely withdrawn in patients with CD4 counts of 100 to 200 cells/µL if plasma HIV-RNA is suppressed on combination antiretroviral therapy. Whether this holds true for secondary prophylaxis is not known, and this has proved difficult to determine due to the much lower population at risk.

METHODS

We estimated the incidence of secondary PjP by including patient data collected from 1998 to 2015 from the COHERE cohort collaboration according to time-updated CD4 counts, HIV-RNA and use of PjP prophylaxis in persons >16 years of age. We fitted a Poisson generalized additive model in which the smoothed effect of CD4 was modelled by a restricted cubic spline, and HIV-RNA was stratified as low (<400), medium (400 to 10,000) or high (>10,000copies/mL).

RESULTS

There were 373 recurrences of PjP during 74,295 person-years (py) in 10,476 patients. The PjP incidence in the different plasma HIV-RNA strata differed significantly and was lowest in the low stratum. For patients off prophylaxis with CD4 counts between 100 and 200 cells/µL and HIV-RNA below 400 copies/mL, the incidence of recurrent PjP was 3.9 (95% CI: 2.0 to 5.8) per 1000 py, not significantly different from patients on prophylaxis in the same stratum (1.9, 95% CI: 0.1 to 3.7).

CONCLUSIONS

HIV viraemia importantly affects the risk of recurrent PjP. In virologically suppressed patients on ART with CD4 counts of 100 to 200/µL, the incidence of PjP off prophylaxis is below 10/1000 py. Secondary PjP prophylaxis may be safely withheld in such patients. While European guidelines recommend discontinuing secondary PjP prophylaxis only if CD4 counts rise above 200 cells/mL, the latest US Guidelines consider secondary prophylaxis discontinuation even in patients with a CD4 count above 100 cells/µL and suppressed viral load. Our results strengthen and support this US recommendation.

Risk factors for post-tooth extraction complications in HIV-infected patients: A retrospective study

To assess the rate and risk factors of postoperative complications following tooth extraction in HIV-infected patients by CD4 count. The study subjects were 231 HIV-infected patients who underwent tooth extraction at our institution between January 2007 and December 2011. Results of blood test, underlying diseases, surgical site, extraction method, and postoperative complications were obtained from the medical records. The risk factors potentially involved in postoperative complications were analyzed by multivariate logistic regression. Patients were divided into two groups, 61 (26%) patients with CD4 count of <200 /μL, and 170 (74%) patients with ≥200 /μL. Of the 231 patients, 12 (5.2%) developed postoperative complications (alveolar osteitis, n=10; surgical site infection, n=2). The rate of complications was not different between the CD4<200 /μL group (1.6%), and the CD4≥200 /μL group (6.5%) (adjusted odds ratio (aOR): 9.328, 95% confidence interval (CI): (0.470, 185.229), p=0.1431). Surgical extraction method with bone excavation, but not CD4 count, were identified as risk factors for post-extraction complications (aOR: 22.037, 95%CI: (1.519, 319.617), p=0.0234). A low CD4 count is not a risk factor for post-extraction complications in HIV-infected patients. We advise that tooth extraction should be performed based on dental/oral condition, rather than delayed until improvement of CD4 count.

High incidence of Pneumocystis jirovecii pneumonia in allogeneic hematopoietic cell transplant recipients in the modern era

BACKGROUND

International guidelines for Pneumocystis jirovecii pneumonia (PJP) prevention recommend prophylaxis for ≥6 months following allogeneic hematopoietic cell transplantation, and longer in patients with graft-versus-host disease (GVHD) or on immunosuppressive therapy (IST). These recommendations are based on cohorts of patients who did not routinely receive anti-thymocyte globulin (ATG) for GVHD prophylaxis.

METHODS

We performed a retrospective chart review of 649 patients, all of whom received ATG as part of GVHD prophylaxis.

RESULTS

The cumulative incidence of definite PJP was 3.52% at both 3 and 5 years (median follow up, 1648 days for survivors). PJP occurred in 13 non-GVHD patients between days 207 and 508, due in part to low CD4 T-cell counts (<200 CD4 T cells/µL). PJP occurred in eight GVHD patients between days 389 and 792, due in part to non-adherence to PJP prophylaxis guidelines (discontinuation of PJP prophylaxis at <3 months after discontinuation of IST). Breakthrough PJP infection was not observed in patients receiving prophylaxis with cotrimoxazole, dapsone or atovaquone, whereas three cases were observed with inhaled pentamidine.

DISCUSSION

In conclusion, for non-GVHD patients receiving ATG-containing GVHD prophylaxis, 6 months of PJP prophylaxis is inadequate, particularly if the CD4 T-cell count is <200 cells/µL or if there is a high incidence of PJP in the community. For patients with GVHD receiving ATG-containing GVHD prophylaxis, continuing PJP prophylaxis until ≥3 months post-discontinuation of IST is important. Cotrimoxazole, dapsone and atovaquone are preferred over inhaled pentamidine.

The Impact of Absolute CD4 Count and Percentage Discordance on Pneumocystis Jirovecii Pneumonia Prophylaxis in HIV-Infected Patients

Current guidelines suggest that HIV-infected patients should receive chemoprophylaxis against Pneumocystis jirovecii pneumonia (PJP) if they have a cluster determinant 4 (CD4) count <200 cells/mm³ or oropharyngeal candidiasis. Persons with CD4 percentage (CD4%) below 14% should also be considered for prophylaxis. Discordance between CD4 count and CD4% occurs in 16% to 25% of HIV-infected patients. Provider compliance with current PJP prophylaxis guidelines when such discordance is present was assessed. Electronic medical records of 429 HIV-infected individuals who had CD4 count and CD4% measured at our clinic were reviewed. CD4 count and percentage discordance was seen in 57 (13%) of 429. Patients with CD4 count >200 but CD4% <14 were significantly less likely to be prescribed PJP prophylaxis compared with those who had CD4 count <200 and CD4% >14 (29% versus 86%; odds ratio = 0.064, 95% confidence interval: 0.0168-0.2436; P < .0001). We emphasize monitoring both the absolute CD4 count and percentage to appropriately guide PJP primary and secondary prophylaxis.

IL-4 polymorphism influences susceptibility to Pneumocystis jirovecii pneumonia in HIV-positive patients

OBJECTIVES

Pneumocystis jirovecii pneumonia (PJP) is an important cause of morbidity and mortality in HIV-positive patients. Polymorphisms in immune genes are increasingly reported to influence susceptibility to fungal infections. We analysed the role of 21 single nucleotide polymorphisms from 19 candidate genes on PJP development in patients from the Swiss HIV Cohort Study.

DESIGN AND METHODS

The analysis included patients with a nadir CD4 T-cell count less than 200 cells/μl, divided into a discovery (N = 1645) and a replication (N = 1861) cohort. The associations were analysed by using cumulative incidence curves as well as competing risk regression over 18 years, starting from the estimated date of HIV infection, considering death a competing risk, with censoring at lost follow-up, and assuming the dominant mode of inheritance.

RESULTS

The minor allele of rs2243250 in IL-4 was associated with the risk of PJP in the discovery cohort (cumulative incidence 0.18 versus 0.12, P = 0.002). This association was replicated in the validation cohort (0.16 versus 0.12, P = 0.02). It was still significant in multivariate models, adjusted for HIV transmission mode, viral load, CD4 T cells slope, age, antiretroviral therapy, tobacco smoking, hepatitis C virus coinfection, year of cohort entry and PJP prophylaxis (global subhazard ratio 1.42, 95% confidence interval 1.17-1.73, P = 0.0004).

CONCLUSION

Our data suggest rs2243250, a single nucleotide polymorphism known to influence IL-4 production, is associated with susceptibility to PJP in HIV-positive patients.

Treatment of Pneumocystis jirovecii pneumonia in HIV-infected patients: a review

INTRODUCTION

Pneumocystis pneumonia is a potentially life-threatening pulmonary infection that occurs in immunocompromised individuals and HIV-infected patients with a low CD4 cell count. Trimethoprim-sulfamethoxazole has been used as the first-line agent for treatment, but mutations within dihydropteroate synthase gene render potential resistance to sulfamide. Despite advances of combination antiretroviral therapy (cART), Pneumocystis pneumonia continues to occur in HIV-infected patients with late presentation for cART or virological and immunological failure after receiving cART. Areas covered: This review summarizes the diagnosis and first-line and alternative treatment and prophylaxis for Pneumocystis pneumonia in HIV-infected patients. Articles for this review were identified through searching PubMed. Search terms included: 'Pneumocystis pneumonia', 'Pneumocystis jirovecii pneumonia', 'Pneumocystis carinii pneumonia', 'trimethoprim-sulfamethoxazole', 'primaquine', 'trimetrexate', 'dapsone', 'pentamidine', 'atovaquone', 'echinocandins', 'human immunodeficiency virus infection', 'acquired immunodeficiency syndrome', 'resistance to sulfamide' and combinations of these terms. We limited the search to English language papers that were published between 1981 and March 2017. We screened all identified articles and cross-referenced studies from retrieved articles. Expert commentary: Trimethoprim-sulfamethoxazole will continue to be the first-line agent for Pneumocystis pneumonia given its cost, availability of both oral and parenteral formulations, and effectiveness or efficacy in both treatment and prophylaxis. Whether resistance due to mutations within dihydropteroate synthase gene compromises treatment effectiveness remains controversial. Continued search for effective alternatives with better safety profiles for Pneumocystis pneumonia is warranted.

Approach to Fungal Infections in Human Immunodeficiency Virus-Infected Individuals: Pneumocystis and Beyond

Many fungi cause pulmonary disease in patients with human immunodeficiency virus (HIV) infection. Pathogens include Pneumocystis jirovecii, Cryptococcus neoformans, Aspergillus spp, Histoplasma capsulatum, Coccidioides spp, Blastomyces dermatitidis, Paracoccidioides brasiliensis, Talaromyces marneffei, and Emmonsia spp. Because symptoms are frequently nonspecific, a high index of suspicion for fungal infection is required for diagnosis. Clinical manifestations of fungal infection in HIV-infected patients frequently depend on the degree of immunosuppression and the CD4⁺ helper T cell count. Establishing definitive diagnosis is important because treatments differ. Primary and secondary prophylaxes depend on CD4⁺ helper T cell counts, geographic location, and local prevalence of disease.

Pneumocystis jirovecii pneumonia in systemic autoimmune rheumatic disease: A case-control study

INTRODUCTION AND OBJECTIVES

Pneumocystis jirovecii pneumonia (PJP) is an opportunistic fungal infection that affects the immunocompromised. Patients with systemic autoimmune rheumatic disease are increasingly recognised as an at-risk clinical population with a high mortality. This case-control study examined differences in the characteristics and peripheral blood parameters between patients with systemic autoimmune rheumatic disease who developed PJP and gender, age and disease-matched controls.

METHODS

Historical data collected between 2002 and 2013 at the Royal Melbourne Hospital, Australia were reviewed. Cases were defined by having a systemic autoimmune rheumatic disease and a diagnosis of PJP (either a positive toluidine blue O stain or P. jirovecii PCR, with a concurrent respiratory illness that was clinically consistent with PJP). Controls were matched for age, gender and disease in a 4:1 ratio. Peripheral blood results were retrieved from an in-house pathology database. Clinical information including glucocorticoid exposure, PJP prophylaxis, comorbidities and month of admission were retrieved from medical notes.

RESULTS

After adjustment for corticosteroid exposure and C-reactive protein, lymphocyte count on admission (0.4 vs. 1.3; p = 0.04) and at nadir (0.2 vs. 0.8 × 10⁹/L; p = 0.05) was significantly lower in cases than in controls. Cases (n = 11) were more frequently Caucasian rather than non-Caucasian (81.8% vs. 65.9%; p = 0.04). In addition, cases more commonly presented in autumn (March to May) than in other seasons (OR = 7.3; 95% CI: 1.4-38.7; p = 0.02).

CONCLUSION

These data demonstrate that patients with systemic autoimmune rheumatic disease who develop PJP have significantly greater lymphopenia than age, gender and disease-matched controls, independent of corticosteroid exposure, as well as a potential ethnicity and seasonal predilection to PJP. This may help to inform prophylactic guidelines for PJP in these patients.

Pneumocystis Pneumonia in Human Immunodeficiency Virus-infected Adults and Adolescents: Current Concepts and Future Directions

Pneumocystis jirovecii pneumonia (PCP) is one of the most common opportunistic infections in human immunodeficiency virus–infected adults. Colonization of Pneumocystis is highly prevalent among the general population and could be associated with the transmission and development of PCP in immunocompromised individuals. Although the microscopic demonstration of the organisms in respiratory specimens is still the golden standard of its diagnosis, polymerase chain reaction has been shown to have a high sensitivity, detecting Pneumocystis DNA in induced sputum or oropharyngeal wash. Serum β-D-glucan is useful as an adjunctive tool for the diagnosis of PCP. High-resolution computed tomography, which typically shows diffuse ground-glass opacities, is informative for the evaluation of immunocompromised patients with suspected PCP and normal chest radiography. Trimethoprim–sulfamethoxazole (TMP-SMX) is the first-line agent for the treatment of mild to severe PCP, although it is often complicated with various side effects. Since TMP-SMX is widely used for the prophylaxis, the putative drug resistance is an emerging concern.

Update on opportunistic infections in the era of effective antiretroviral therapy

Despite enormous improvements in effectiveness of treatment for HIV infection, opportunistic infections continue to occur in those who have not yet been diagnosed with HIV and in those who are not receiving antiretroviral therapy. This review focuses on tuberculosis and cryptococcal infections, the most common opportunistic infections (OIs) in patients living with human immunodeficiency virus infection around the world, as well as on new developments in progressive multifocal leukoencephalopathy and pneumocystis pneumonia. In the sections on these conditions, updates on diagnosis, treatment, and complications, as well as information on when to start antiretroviral therapy is provided. The article concludes with a discussion of new data on 2 vaccine-preventable OIs, human papillomavirus and varicella-zoster virus.

Lower incidence of Pneumocystis jirovecii pneumonia among Africans in the Netherlands host or environmental factors?

BACKGROUND AND OBJECTIVE

HIV-associated Pneumocystis jirovecii pneumonia (PJP) remains one of the commonest opportunistic infections in Western countries. Although it has been suggested that racial differences in PJP incidence exist, early studies report conflicting results. This study aimed to investigate differences in PJP incidence in a developed country among patients originating from sub-Saharan Africa compared with other regions of origin.

DESIGN AND METHODS

A retrospective observational cohort study was performed among 13,844 HIV-infected patients from the Dutch ATHENA cohort. The main outcome measure was occurrence of PJP.

RESULTS

A total number of 1055 PJP infections were diagnosed. Patients originating from sub-Saharan Africa had a significantly lower risk of having PJP at the time of HIV diagnosis after adjustment of confounders compared with patients from Western origin [Western Europe, Australia and New Zealand; adjusted odds ratio (aOR) 0.21 (95% confidence interval (CI) 0.15-0.29)]. Other factors associated with higher PJP risk were increasing age [aOR 1.01 per year (95% CI 1.00-1.02)], a low CD4 count at HIV diagnosis [CD4 <50 versus >350 cells/μl aOR 123.3 (95% CI 77.8-195.5)] and a high plasma HIV-RNA (>100,000 copies/ml) at HIV diagnosis [aOR 1.41 (95% CI 1.19-1.66)]. Moreover, a clearly lower risk for PJP acquisition later during follow-up was observed among sub-Saharan Africans versus Western patients [adjusted hazard ratio 0.60 (95% CI 0.39-0.90)].

CONCLUSION

Among HIV-infected patients living in the Netherlands, PJP occurrence is substantially lower in patients originating from sub-Saharan Africa, as compared to Western patients. Differences in genetic susceptibility may partially explain the lower PJP incidence in these patients.

Pneumocystis pneumonia associated with human immunodeficiency virus

Pneumocystis pneumonia (PCP) is caused by the yeastlike fungus Pneumocystis. Despite the widespread availability of specific anti-Pneumocystis prophylaxis and of combination antiretroviral therapy (ART), PCP remains a common AIDS-defining presentation. PCP is increasingly recognized among persons living in Africa. Pneumocystis cannot be cultured and bronchoalveolar lavage is the gold standard diagnostic test to diagnose PCP. Use of adjunctive biomarkers for diagnosis requires further evaluation. Trimethoprim-sulfamethoxazole remains the preferred first-line treatment regimen. In the era of ART, mortality from PCP is approximately 10% to 12%. The optimal time to start ART in a patient with PCP remains uncertain.

Point prevalence of Pneumocystis pneumonia in patients with non-Hodgkin lymphoma according to the number of cycles of R-CHOP chemotherapy

R-CHOP chemotherapy composed of rituximab, cyclophosphamide, adriamycin, vincristine, and prednisolone which might increase the risk of Pneumocystis pneumonia in patients with non-Hodgkin lymphoma. We estimated the point prevalence of Pneumocystis pneumonia in non-Hodgkin lymphoma patients according to the number of R-CHOP cycles and investigated whether cytoreduction by chemotherapy is associated with Pneumocystis pneumonia development. We retrospectively established a cohort of patients who received R-CHOP for non-Hodgkin lymphoma in our institution. Using this cohort, we estimated the incidence rate and point prevalence of definite and probable Pneumocystis pneumonia. To assess factors associated with Pneumocystis pneumonia development several clinical variables, including absolute neutrophil and lymphocyte count at the time of non-Hodgkin lymphoma diagnosis and when the last R-CHOP cycle was administered, were compared between patients with and without Pneumocystis pneumonia. Of 713 patients in the cohort, 14 and 18 patients were diagnosed with definite and probable Pneumocystis pneumonia, respectively. The overall incidence of definite and definite plus probable PCP in NHL patients receiving R-CHOP were 2.0 % (14/713; 95 % CI, 1.1–3.3 %) and 4.5 % (32/713; 95 % CI, 3.2–6.4 %), respectively. This corresponded to 3.8 (95 % CI, 2.2–6.4) and 8.4 (95 % CI, 5.9–11.9) per 1000 persons. Many cases of Pneumocystis pneumonia (22/32, 68.7 %) developed after administration of the fourth R-CHOP cycle. However, there was no statistical difference in Pneumocystis pneumonia prevalence between patients receiving four or more cycles of R-CHOP and fewer than. Higher absolute neutrophil count (4,742/mm³ vs. 2,627/mm³; p < 0.01) was associated with Pneumocystis pneumonia development at the last R-CHOP cycle, while absolute lymphocyte count at the time of NHL diagnosis was not. Contrary to expectations, Pneumocystis pneumonia is not a frequent complication of R-CHOP treatment for non-Hodgkin lymphoma. Cytoreduction of R-CHOP might not be a risk factor of Pneumocystis pneumonia development. Universal prophylaxis against Pneumocystis pneumonia during R-CHOP treatment could not be strongly recommended.

Serologic responses to pneumocystis proteins in HIV patients with and without Pneumocystis jirovecii pneumonia

BACKGROUND

Immune responses to Pneumocystis jirovecii are not well understood in HIV infection, but antibody responses to proteins may be useful as a marker of Pneumocystis risk or presence of Pneumocystis pneumonia (PcP).

DESIGN

Retrospective analysis of a prospective cohort.

METHODS

Enzyme-linked immunosorbent assays of antibodies to recombinant Pneumocystis proteins of major surface glycoprotein fragments (MsgC1, C3, C8, and C9) and of antibody titers to recombinant kexin protein (KEX1) were performed on 3 sequential serum samples up to 18 months before and 3 samples after first AIDS-defining illness from Multicenter AIDS Cohort Study participants and compared between those who had PcP or a non-PcP AIDS-defining illness.

RESULTS

Fifty-four participants had PcP and 47 had a non-PcP AIDS-defining illness. IgG levels to MsgC fragments were similar between groups before first AIDS-defining illness, but the PcP group had higher levels of IgG to MsgC9 (median units/mL 50.2 vs. 22.2, P = 0.047) post-illness. Participants with PcP were more likely to have an increase in MsgC3 [odds ratio (OR): 3.9, P = 0.02], MsgC8 (OR: 5.5, P = 0.001), and MsgC9 (OR: 4.0, P = 0.007). The PcP group was more likely to have low KEX1 IgG before development of PcP (OR: 3.6, P = 0.048) independent of CD4 cell count and to have an increase in high IgG titers to KEX1 after PcP.

CONCLUSIONS

HIV-infected individuals develop immune responses to both Msg and kexin proteins after PcP. Low KEX1 IgG titers may be a novel marker of future PcP risk before CD4 cell count has declined below 200 cells per microliter.

Serum antibody levels to the Pneumocystis jirovecii major surface glycoprotein in the diagnosis of P. jirovecii pneumonia in HIV+ patients

Background

Pneumocystis jirovecii remains an important cause of fatal pneumonia (Pneumocystis pneumonia or PcP) in HIV+ patients and other immunocompromised hosts. Despite many previous attempts, a clinically useful serologic test for P. jirovecii infection has never been developed.

Methods/Principal Findings

We analyzed serum antibody responses to the P. jirovecii major surface glycoprotein recombinant fragment C1 (MsgC1) in 110 HIV+ patients with active PcP (cases) and 63 HIV+ patients with pneumonia due to other causes (controls) by an enzyme-linked immunosorbent assay (ELISA). The cases had significantly higher IgG and IgM antibody levels to MsgC1 than the controls at hospital admission (week 0) and intervals up to at least 1 month thereafter. The sensitivity, specificity and positive predictive value (PPV) of IgG antibody levels increased from 57.2%, 61.7% and 71.5% at week 0 to 63.4%, 100%, and 100%, respectively, at weeks 3–4. The sensitivity, specificity and PPV of IgM antibody levels rose from 59.7%, 61.3%, and 79.3% at week 0 to 74.6%, 73.7%, and 89.8%, respectively, at weeks 3–4. Multivariate analysis revealed that a diagnosis of PcP was the only independent predictor of high IgG and IgM antibody levels to MsgC1. A high LDH level, a nonspecific marker of lung damage, was an independent predictor of low IgG antibody levels to MsgC1.

Conclusions/Significance

The results suggest that the ELISA shows promise as an aid to the diagnosis of PCP in situations where diagnostic procedures cannot be performed. Further studies in other patient populations are needed to better define the usefulness of this serologic test.

Pneumocystis carinii expresses an active Rtt109 histone acetyltransferase

Species in the genus Pneumocystis can cause severe pneumonia in immune-compromised hosts. The identification of specific targets present in Pneumocystis species, but lacking in mammalian hosts, is paramount to developing new means to treat this infection. One such potential protein is Rtt109, which is a type of histone acetyltransferase (HAT) required for DNA replication in fungi, but not found in mammals. Sequence orthologues of Rtt109 are present in other fungi, but are absent in mammals, making it a potential pan-specific target against medically relevant fungi. Accordingly, we sought to identify the presence of an Rtt109 in P. carinii. A Pneumocystis carinii (Pc) Rtt109 165-bp partial sequence was initially identified from the incomplete P. carinii genome database. Subsequently, a full-length, 1,128-bp cDNA with homology to Saccharomyces cerevisiae Rtt109 (39% Basic Local Alignment Search Tool (BLASTP)) was cloned and characterized. Sequence analysis of PcRtt109 indicated that the P. carinii molecule contains the putative catalytic aspartate present in yeast. We further demonstrated that the PcRtt109 expressed in rtt109Δ S. cerevisiae cells restored H3-K56 acetylation and the sensitivity toward DNA-damaging agents of rtt109Δ mutant cells. Purified PcRtt109 had the ability to acetylate lysine-56 of histone H3, similar to the ability of Schizosaccharomyces pombe Rtt109 protein. The site-directed mutagenesis of PcRtt109 D84A, a potential regulatory site in the Rtt109 HAT family, abolished H3 acetylation, whereas a DD218/219AA mutation that compromised the activity of ScRtt109 had little effect, demonstrating similarities and differences in Pneumocystis PcRtt109 compared with yeast Saccharomyces cerevisiae Rtt109. These results indicate that P. carinii contains an Rtt109 HAT molecule, and represent the complete identification and characterization of a HAT molecule from this important opportunistic fungal pathogen.

Characterization of a novel ADAM protease expressed by Pneumocystis carinii

Pneumocystis species are opportunistic fungal pathogens that cause severe pneumonia in immunocompromised hosts. Recent evidence has suggested that unidentified proteases are involved in Pneumocystis life cycle regulation. Proteolytically active ADAM (named for "a disintegrin and metalloprotease") family molecules have been identified in some fungal organisms, such as Aspergillus fumigatus and Schizosaccharomyces pombe, and some have been shown to participate in life cycle regulation. Accordingly, we sought to characterize ADAM-like molecules in the fungal opportunistic pathogen, Pneumocystis carinii (PcADAM). After an in silico search of the P. carinii genomic sequencing project identified a 329-bp partial sequence with homology to known ADAM proteins, the full-length PcADAM sequence was obtained by PCR extension cloning, yielding a final coding sequence of 1,650 bp. Sequence analysis detected the presence of a typical ADAM catalytic active site (HEXXHXXGXXHD). Expression of PcADAM over the Pneumocystis life cycle was analyzed by Northern blot. Southern and contour-clamped homogenous electronic field blot analysis demonstrated its presence in the P. carinii genome. Expression of PcADAM was observed to be increased in Pneumocystis cysts compared to trophic forms. The full-length gene was subsequently cloned and heterologously expressed in Saccharomyces cerevisiae. Purified PcADAMp protein was proteolytically active in casein zymography, requiring divalent zinc. Furthermore, native PcADAMp extracted directly from freshly isolated Pneumocystis organisms also exhibited protease activity. This is the first report of protease activity attributable to a specific, characterized protein in the clinically important opportunistic fungal pathogen Pneumocystis.

Fungal infection as a risk factor for HIV disease progression among patients with a CD4 count above 200/microl in the era of cART

The identification of clinical risk factors for AIDS in patients with preserved immune function is of significant interest. We examined whether patients with fungal infection (FI) and CD4 cell count >or=200/microl were at higher risk of disease progression in the era of cART. 11,009 EuroSIDA patients were followed from their first CD4 cell count >or=200/microl after 1 January 1997 until progression to any non-azoles/amphotericin B susceptible (AAS) AIDS disease, last visit or death. Initiation of antimycotic therapy (AMT) was used as a marker of FI and was modelled as a time-updated covariate using Poisson regression. After adjustment for current CD4 cell count, HIV-RNA, starting cART and diagnosis of AAS-AIDS, AMT was significantly associated with an increased incidence of non-AAS-AIDS (IRR=1.55, 95% CI 1.17-2.06, p=0.0024). Despite low incidence of AIDS in the cART era, FI in patients with a CD4 cell count >or=200/microl is associated with a 55% higher risk of non-AAS-AIDS (95% confidence interval 1.17-2.06, p=0.0024). These data suggest that patients with FI are more immune compromized than would be expected from their CD4 cell count alone. FI can be used as a clinical marker for disease progression and indirect indicator for initiation/changing cART in settings where laboratory facilities are limited.

Pneumocystis jiroveci pneumonia prophylaxis is not required with a CD4+ T-cell count < 200 cells/microl when viral replication is suppressed

OBJECTIVE

To determine the safety of discontinuing Pneumocystis jiroveci pneumonia (PCP) prophylaxis, in patients on effective antiretroviral therapy with CD4+ T-cell counts that have plateaued at < 200 cells/microl.

METHODS

We prospectively evaluated a cohort of HIV infected patients at a multidisciplinary HIV clinic with sustained HIV RNA levels < 50 copies/ml and CD4+ T-cell counts that have plateaued at < 200 cells/microl and who have discontinued PCP prophylaxis.

RESULTS

Nineteen patients fulfilled the above criteria. Eleven had been taking daily trimethoprim-sulfamethoxazole, seven were receiving monthly aerosolized pentamidine, and one patient never received any prophylaxis. The median CD4+ T-cell count at the time of discontinuation and at the most recent determination were 120 (range, 34-184) and 138 (range, 6-201) cells/microl, respectively. To date, patients have been off PCP prophylaxis for a mean of 13.7 +/- 10.6 months and a median of 9.0 (range 3-39) months for a total of 261 patient-months. To date, no patient has developed PCP. This is significantly different from the risk of developing PCP with a CD4+ T-cell count of < 200 cells/microl in untreated HIV infection (rate difference 9.2%; 95% confidence interval, 5.7 to 12.8%; P < 0.05).

CONCLUSION

With sustained suppression of viral replication, PCP prophylaxis may not be necessary, regardless of CD4+ T-cell count. This illustrates a degree of immune recovery that occurs with virologic suppression that is not reflected in absolute CD4+ T-cell count or percentage and suggests that guidelines for P. jiroveci pneumonia prophylaxis may need to be re-evaluated.

Prophylaxis for Pneumocystis pneumonia (PCP) in non-HIV immunocompromised patients

BACKGROUND

Pneumocystis pneumonia (PCP) is a disease affecting immunocompromised patients. PCP among these patients is associated with significant morbidity and mortality.

OBJECTIVES

To assess the effectiveness of PCP prophylaxis among non-HIV immunocompromised patients. To define the type of immunocompromised patients for whom evidence suggests a benefit for PCP prophylaxis.

SEARCH STRATEGY

Electronic searches of The Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library Issue 1, 2007), PubMed (March 2007), LILACS (March 2007), relevant conference proceedings; references of identified trials; the first author of each included trial was contacted.

SELECTION CRITERIA

RCTs or quasi- RCTs comparing prophylaxis with an antibiotic effective against Pneumocystis versus placebo, no intervention, an antibiotic/s with no activity against Pneumocystis or another antibiotic effective against Pneumocystis for immune-compromised non-HIV patients. Only trials pre-defining Pneumocystis infections as an outcome were included.

DATA COLLECTION AND ANALYSIS

Two authors independently appraised the quality of each trial and extracted data from included trials. Relative risks (RR), with 95% confidence intervals (CI) were estimated and pooled using the random effects model.

MAIN RESULTS

Eleven trials including 1155 patients (520 children), performed between the years 1974 and 1997, were included. Compared to no treatment or treatment with fluoroquinolones (inactive against Pneumocystis), there was a 91% reduction in the occurrence of PCP in patients receiving prophylaxis with trimethoprim/sulfamethoxazole, RR 0.09 (95% CI 0.02 to 0.32), eight trials, 821 patients. No significant difference was encountered in all cause mortality, RR 0.81 (95% CI 0.27 to 2.37), five trials, 509 patients, while PCP-related mortality was significantly reduced, RR 0.17 (95% CI 0.03 to 0.94), seven trials, 701 patients. Occurrence of leukopenia, neutropenia and their duration were not reported consistently. No significant difference in any adverse event was seen comparing trimethoprim/sulfamethoxazole to no treatment/ placebo (four trials, 470 patients). No differences between once daily versus thrice weekly trimethoprim/sulfamethoxazole were seen (two trials, 207 patients).

AUTHORS' CONCLUSIONS

Given an event rate of 7.5% as in included trials' control group, prophylaxis for PCP using TMP/SMX is highly effective among non-HIV patients, with a number needed to treat of 15 patients (95% CI 13 to 20). Prophylaxis should be considered for the types of patients with hematological malignancies, bone marrow transplantation and solid organ transplantation included in these trials.

A two-stage sampling method for clinical surveillance of individuals in care for HIV infection in the United States

OBJECTIVES

The goals of this study were two-fold: (1) to describe methods for drawing a population-based sample of individuals in care for HIV infection and (2) to compare data from the sample with data from existing surveillance systems that describe care for HIV.

METHODS

The authors implemented a two-stage sampling method, using local HIV/AIDS surveillance data as a sampling frame of HIV care providers in three states. At selected providers, medical records of a random sample of patients were abstracted.

RESULTS

The medical records of a number of patients, ranging from 253 to 374 individuals per state, were abstracted. The demographics of sampled individuals and of individuals reported to the local HIV/AIDS surveillance program were similar; however, differences existed in the proportion of individuals receiving HIV care consistent with treatment guidelines between the sample and a contemporary facility-based supplemental surveillance project. The median design effect for outcomes collected in the sample was 1.8 (range=0.5-29.6).

CONCLUSIONS

This survey method is feasible for collecting population-based data on patients in care for HIV. Sample size and some design elements should be changed in future studies to increase precision of estimates and usefulness of data for local planning and evaluation.

Mutations in the Pneumocystis jirovecii DHPS gene confer cross-resistance to sulfa drugs

Pneumocystis jirovecii is a major opportunistic pathogen that causes Pneumocystis pneumonia (PCP) and results in a high degree of mortality in immunocompromised individuals. The drug of choice for PCP is typically sulfamethoxazole (SMX) or dapsone in conjunction with trimethoprim. Drug treatment failure and sulfa drug resistance have been implicated epidemiologically with point mutations in dihydropteroate synthase (DHPS) of P. jirovecii. P. jirovecii cannot be cultured in vitro; however, heterologous complementation of the P. jirovecii trifunctional folic acid synthesis (PjFAS) genes with an E. coli DHPS-disrupted strain was recently achieved. This enabled the evaluation of SMX resistance conferred by DHPS mutations. In this study, we sought to determine whether DHPS mutations conferred sulfa drug cross-resistance to 15 commonly available sulfa drugs. It was established that the presence of amino acid substitutions (T(517)A or P(519)S) in the DHPS domain of PjFAS led to cross-resistance against most sulfa drugs evaluated. The presence of both mutations led to increased sulfa drug resistance, suggesting cooperativity and the incremental evolution of sulfa drug resistance. Two sulfa drugs (sulfachloropyridazine [SCP] and sulfamethoxypyridazine [SMP]) that had a higher inhibitory potential than SMX were identified. In addition, SCP, SMP, and sulfadiazine (SDZ) were found to be capable of inhibiting the clinically observed drug-resistant mutants. We propose that SCP, SMP, and SDZ should be considered for clinical evaluation against PCP or for future development of novel sulfa drug compounds.

Analysis ofPneumocystis jiroveciiDHPS Alleles Implicated in Sulfamethoxazole Resistance Using anEscherichia coliModel System

Pneumocystis jirovecii is a major opportunistic pathogen that causes Pneumocystis pneumonia (PCP). Drug treatment failure has been associated epidemiologically with point mutations in the gene for dihydropteroate synthase which is part of a gene that encodes three covalently linked enzymes involved in folic acid synthesis (FAS). The evaluation of whether mutations found in P. jirovecii FAS lead to sulfa drug resistance is hampered by the lack of a culture system for P. jirovecii as well as the failure of P. jirovecii FAS to complement in a heterologous system. Therefore, we chose to model the P. jirovecii mutations in the Saccharomyces cerevisiae FAS protein (encoded by FOL1) via its expression in Escherichia coli. An optimized drug diffusion assay was used to evaluate the FAS mutants against 15 sulfa drugs. It was established that the single amino acid substitution, P599S, in the (DHPS) domain of FAS led to sulfa drug resistance, whereas the T597A substitution led to increased sensitivity. The presence of both mutations (T597A and P599S) was cooperative and led to increased sulfa drug resistance. Analysis of a novel double mutant, (T597V P599S) was found to have significantly higher sulfa drug resistance than the T597A P599S mutant. These data suggest that further amino acid substitutions may lead to the evolution of higher sulfa drug resistance. Two sulfa drugs (sulfachloropyridazine and sulfathiazole) were identified that had higher inhibitory potential than sulfamethoxazole, which is currently the preferred treatment for PCP.

Current epidemiology of Pneumocystis pneumonia

Changes in incidence of PCP, groups at risk for PCP, and possible trends in the disease are discussed.

Pneumocystis pneumonia (PCP) has historically been one of the leading causes of disease among persons with AIDS. The introduction of highly active antiretroviral therapy in industrialized nations has brought about dramatic declines in the incidence of AIDS-associated complications, including PCP. In the adult population, the incidence of PCP has significantly decreased, but it remains among the most common AIDS-defining infections. Similar declines have been documented in the pediatric population. In much of the developing world, PCP remains a significant health problem, although its incidence among adults in sub-Saharan Africa has been debated. This review discusses the epidemiology of PCP during the current era of the AIDS epidemic. Although fewer cases of PCP occur in industrialized countries, increasing drug-resistant HIV infections, possible drug-resistant PCP, and the tremendous number of AIDS cases in developing countries make this disease of continued public health importance.

Prevention of opportunistic infections in adult and adolescent patients with HIV infection. GESIDA/National AIDS Plan guidelines, 2004 [correction]

OBJECTIVE

To provide an update of guidelines from the Spanish AIDS Study Group (GESIDA) and the National AIDS Plan (PNS) committee on the prevention of opportunistic infections in adult and adolescent HIV-infected patients.

METHODS

These consensus recommendations have been produced by a group of experts from GESIDA and/or the PNS after reviewing the earlier document and the scientific advances in this field in the last years. The system used by the Infectious Diseases Society of America and the United States Public Health Service has been used to classify the strength and quality of the data.

RESULTS

This document provides a detailed review of the measures for the prevention of infections caused by viruses, bacteria, fungi and parasites in the context of HIV infection. Recommendations are given for preventing exposure and for primary and secondary prophylaxis for each group of pathogens. In addition, criteria are established for the withdrawal of prophylaxis in patients who respond well to highly active antiretroviral therapy (HAART).

CONCLUSIONS

HAART is the best strategy for the prevention of opportunistic infections in HIV-positive patients. Nevertheless, prophylaxis is still necessary in countries with limited economic resources, in highly immunodepressed patients until HAART achieves beneficial effects, in patients who refuse to take or who cannot take HAART, in those in whom HAART is not effective, and in the small group of infected patients with inadequate recovery of CD4+ T lymphocyte counts despite good inhibition of HIV replication.

Discontinuation of secondary prophylaxis for Pneumocystis carinii pneumonia in human immunodeficiency virus-infected patients: a randomized trial by the CIOP Study Group

This subgroup analysis assessing secondary prophylaxis for Pneumocystis carinii pneumonia (PCP) describes a multicenter, open-labeled, randomized, controlled trial evaluating the discontinuation of PCP prophylaxis. The main inclusion criterion was a history of PCP and an increase in the CD4 cell count to >200 cells/microL associated with receipt of highly active antiretroviral therapy for >or=3 months. The primary end point was the development of definitive or presumptive PCP. A total of 146 patients were enrolled (77 in the treatment discontinuation arm). After >2 years, 1 definitive and 1 presumptive case of PCP were observed, both of which occurred in patients who discontinued therapy. In most patients, secondary prophylaxis for PCP can be safely discontinued after potent antiretroviral therapy is initiated, but the threshold of >200 CD4 cells/microL may not be considered absolutely safe. Patients who present with symptoms after discontinuation of secondary prophylaxis should be evaluated for PCP despite high CD4 count and complete virus suppression.

Risk factors for pneumonia in urban-dwelling HIV-infected women: a case-control study in Nairobi, Kenya

In sub-Saharan Africa, respiratory tract infections (RTI) are the leading cause of serious morbidity and mortality in HIV-infected persons. This study sought to investigate demographic, socioeconomic, and environmental risk factors for pneumonia in a cohort of HIV-infected women. The authors performed a nested case-control study in a cohort of HIV-1-infected adults followed in Nairobi, Kenya. Thirty-nine women who developed pneumonia during the follow-up period were selected as cases, and 66 women who did not develop pneumonia were randomly chosen to serve as control subjects. A questionnaire was administered in subjects' homes that assessed demographics, home environment, and socioeconomic status. Women were followed in the cohort for a median of 36.8 months (range, 27.3-39.3). Adjusting for length of follow-up period, factors associated with lower socioeconomic status (lower monthly spending [OR = 3.2; 95% CI, 1.2-8.4 per 10,000 Kenyan shilling decrease], having no savings [OR = 4.1; 95% CI, 1.4-11.9], less sturdy home construction material such as mud or cement walls [OR = 2.6; 95% CI, 1.1-5.9] or dirt floors [OR = 2.8; 95% CI, 1.0-7.6], and lack of a window in the home [OR = 5.5; 95% CI, 0.9-32.2]) and being widowed (OR = 4.3; 95% CI, 1.2-15.1) or single (OR = 3.3; 95% CI, 1.0-11.2) were associated with an increased risk of pneumonia. In multivariate analysis, widowed (AOR = 5.9; 95% CI, 1.3-26.3), single (AOR = 7.7; 95% CI, 1.6-36.4), and divorced (AOR = 4.5; 95% CI, 1.0-20.1) women, those without savings (AOR = 3.7; 95% CI, 1.2-11.7), and those living in more crowded and contagious conditions (AOR = 1.5; 95% CI, 1.1-2.1) remained at increased risk of pneumonia. If confirmed by prospective investigation, these findings could help identify persons and subpopulations of HIV-infected women with the greatest risk of pneumonia.

The role of person-to-person transmission in an epidemiologic study of Pneumocystis carinii pneumonia

OBJECTIVE

Recent laboratory studies suggest that may be transmitted from person-to-person. Recent exposure to persons with pneumonia (PCP) among HIV-infected persons with and without PCP was assessed to evaluate the person-to-person transmission hypothesis.

DESIGN

A case-control study design was used.

METHODS

In Seattle and Los Angeles, a history of contact with persons with PCP was compared between HIV-infected patients with laboratory-confirmed PCP (n = 209) and HIV-infected patients with no history of PCP (n = 254).

RESULTS

No association was found between past exposures to persons with PCP and an increased odds for PCP [odds ratio (OR), 0.6; 95% confidence interval (CI), 0.3-1.1] in the total study group. In addition, no association was observed when the analysis was restricted to cases and controls who were not on adequate PCP prophylaxis in the previous 3 months (OR, 0.7; 95% CI, 0.3-1.5). Most cases in Los Angeles (95%) and Seattle (96%) were not receiving PCP prophylaxis in the 3 months prior to a PCP diagnosis. Many controls in Los Angeles (54%) and Seattle (47%) were also not on prophylaxis. In addition, 23% of the Seattle cases and 42% of the Los Angeles cases were unaware of their HIV infection at the time of their PCP diagnosis.

CONCLUSIONS

Although most participants were not on adequate prophylaxis, we found no evidence of person-to-person transmission of Pneumocystis carinii in a population with advanced HIV disease. The difficulty quantifying past exposures to persons with PCP is a limitation of this type of research.

Management of Opportunistic Infection Prophylaxis in the Highly Active Antiretroviral Therapy Era

Prophylaxis and maintenance therapy against opportunistic infections are a mainstay of management of HIV-infected patients and have led to a significant improvement in quality of life and survival. Antiretroviral combination therapy (ART) has markedly changed the natural course of HIV infection. Incidence of opportunistic infections (OIs) has declined and survival after an OI has improved. Achieving a CD4 count of 200 cells/L after 6 months of ART is a valuable marker for low risk of OI afterwards. Therefore, recommendations on prophylaxis and maintenance therapy need to be redefined. Criteria for discontinuation, such as a CD4 count rise above threshold values and time above threshold values as response to ART, should be evaluated for the most frequent OIs. Reliable data in favor of discontinuation of primary prophylaxis against Pneumocystis carinii pneumonia, toxoplasmic encephalitis, and Mycobacterium avium infection have been published. Discontinuation of maintenance therapy against P. carinii pneumonia is possible, and may be safe against cytomegalovirus retinitis, M. avium, and cryptococcosis and toxoplasmosis in selected patients. Pharmacologic interactions between drugs used for OI prophylaxis and antiretroviral drugs need to be taken into account.