Pyrimethamine for primary prophylaxis of toxoplasmic encephalitis in patients with human immunodeficiency virus infection: a double-blind, randomized trial. ANRS 005-ACTG 154 Group Members. Agence Nationale de Recherche sur le SIDA. AIDS Clinical Trial Group

Long-Term Low-Dose Pyrimethamine Use for the Prevention of Ocular Toxoplasmosis Recurrences: A Cohort Study

PURPOSE

To describe the effect of long-term, low-dose pyrimethamine for the prevention of ocular toxoplasmosis (OT) recurrences.

METHODS

Sixty-three consecutive patients with inactive ocular toxoplasmosis and positive toxoplasma IgG serology were included. Pyrimethamine (25 mg) + folinic acid (15 mg) were administered every other day (three times weekly) for 12 months. Eighteen patients received the treatment for an additional six months as part of an extension study.

RESULTS

Thirty-eight patients (60.3%, n = 63) were female; 38 (60.3%) had a previous history of recurrence and 37 (58.7%) had active OT within the preceding 12 months. Three (4.8%) patients had unilateral recurrences at 8, 12 and 18 months after starting intermittent pyrimethamine treatment. Five patients (7.9%) were discontinued due to hematological, renal and hepatic changes. Treatment was considered successful in 42 patients (84%).

CONCLUSION

Long-term, low-dose pyrimethamine can be considered as a treatment option for the prevention of ocular toxoplasmosis recurrence in selected patients, with only a few, mild and reversible systemic adverse events.

Guidelines for the management of Toxoplasma gondii infection and disease in patients with haematological malignancies and after haematopoietic stem-cell transplantation: guidelines from the 9th European Conference on Infections in Leukaemia, 2022

Patients with haematological malignancies might develop life-threatening toxoplasmosis, especially after allogeneic haematopoietic stem-cell transplantation (HSCT). Reactivation of latent cysts is the primary mechanism of toxoplasmosis following HSCT; hence, patients at high risk are those who were seropositive before transplantation. The lack of trimethoprim-sulfamethoxazole prophylaxis and various immune status parameters of the patient are other associated risk factors. The mortality of toxoplasma disease-eg, with organ involvement-can be particularly high in this setting. We have developed guidelines for managing toxoplasmosis in haematology patients, through a literature review and consultation with experts. In allogeneic HSCT recipients seropositive for Toxoplasma gondii before transplant, because T gondii infection mostly precedes toxoplasma disease, we propose weekly blood screening by use of quantitative PCR (qPCR) to identify infection early as a pre-emptive strategy. As trimethoprim-sulfamethoxazole prophylaxis might fail, prophylaxis and qPCR screening should be combined. However, PCR in blood can be negative even in toxoplasma disease. The duration of prophylaxis should be a least 6 months and extended during treatment-induced immunosuppression or severe CD4 lymphopenia. If a positive qPCR test occurs, treatment with trimethoprim-sulfamethoxazole, pyrimethamine-sulfadiazine, or pyrimethamine-clindamycin should be started, and a new sample taken. If the second qPCR test is negative, clinical judgement is recommended to either continue or stop therapy and restart prophylaxis. Therapy must be continued until a minimum of two negative PCRs for infection, or for at least 6 weeks for disease. The pre-emptive approach is not indicated in seronegative HSCT recipients, after autologous transplantation, or in non-transplant haematology patients, but PCR should be performed with a high level of clinical suspicion.

Persistence of Human Immunodeficiency Virus-Associated Cerebral Toxoplasmosis Lesions in Successfully Treated Patients Receiving Combination Antiretroviral Therapy

Background

Toxoplasmic encephalitis (TE) is a life-threatening complication of people with human immunodeficiency virus (PWH) with severe immunodeficiency, especially those with a CD4+ T-cell count <100 cells/µL. Following a clinical response to anti-Toxoplasma therapy, and immune reconstitution after initiation of combination antiretroviral therapy (ART), anti-Toxoplasma therapy can be discontinued with a low risk of relapse.

Methods

To better understand the evolution of magnetic resonance imaging (MRI)-defined TE lesions in PWH receiving ART, we undertook a retrospective study of PWH initially seen at the National Institutes of Health between 2001 and 2012, who had at least 2 serial MRI scans. Lesion size and change over time were calculated and correlated with clinical parameters.

Results

Among 24 PWH with TE and serial MRI scans, only 4 had complete clearance of lesions at the last MRI (follow-up, 0.09-5.8 years). Of 10 PWH off all anti-Toxoplasma therapy (median, 3.2 years after TE diagnosis), 6 had persistent MRI enhancement. In contrast, all 5 PWH seen in a pre-ART era study who were followed for >6 months had complete clearance of lesions. TE lesion area at diagnosis was associated with the absolute change in area (P < .0001).

Conclusions

Contrast enhancement can persist even when TE has been successfully treated and anti-Toxoplasma therapy has been stopped, highlighting the need to consider diagnostic alternatives in successfully treated patients with immune reconstitution presenting with new neurologic symptoms.

Systemic Inflammation Associated with Immune Reconstitution Inflammatory Syndrome in Persons Living with HIV

Antiretroviral therapy (ART) has represented a major advancement in the care of people living with HIV (PLWHH), resulting in significant reductions in morbidity and mortality through immune reconstitution and attenuation of homeostatic disruption. Importantly, restoration of immune function in PLWH with opportunistic infections occasionally leads to an intense and uncontrolled cytokine storm following ART initiation known as immune reconstitution inflammatory syndrome (IRIS). IRIS occurrence is associated with the severe and rapid clinical deterioration that results in significant morbidity and mortality. Here, we detail the determinants underlying IRIS development in PLWH, compiling the available knowledge in the field to highlight details of the inflammatory responses in IRIS associated with the most commonly reported opportunistic pathogens. This review also highlights gaps in the understanding of IRIS pathogenesis and summarizes therapeutic strategies that have been used for IRIS.

Malaria and HIV coinfection in sub-Saharan Africa: prevalence, impact, and treatment strategies

Malaria and HIV, two of the world's most deadly diseases, are widespread, but their distribution overlaps greatly in sub-Saharan Africa. Consequently, malaria and HIV coinfection (MHC) is common in the region. In this paper, pertinent publications on the prevalence, impact, and treatment strategies of MHC obtained by searching major electronic databases (PubMed, PubMed Central, Google Scholar, ScienceDirect, and Scopus) were reviewed, and it was found that the prevalence of MHC in SSA was 0.7%-47.5% overall. Prevalence was 0.7%-47.5% in nonpregnant adults, 1.2%-27.8% in children, and 0.94%-37% in pregnant women. MHC was associated with an increased frequency of clinical parasitemia and severe malaria, increased parasite and viral load, and impaired immunity to malaria in nonpregnant adults, children, and pregnant women, increased in placental malaria and related outcomes in pregnant women, and impaired antimalarial drug efficacy in nonpregnant adults and pregnant women. Although a few cases of adverse events have been reported in coinfected patients receiving antimalarial and antiretroviral drugs concurrently, available data are very limited and have not prompted major revision in treatment guidelines for both diseases. Artemisinin-based combination therapy and cotrimoxazole are currently the recommended drugs for treatment and prevention of malaria in HIV-infected children and adults. However, concurrent administration of cotrimoxazole and sulfadoxine-pyrimethamine in HIV-infected pregnant women is not recommended, because of high risk of sulfonamide toxicity. Further research is needed to enhance our understanding of the impact of malaria on HIV, drug-drug interactions in patients receiving antimalarials and antiretroviral drugs concomitantly, and the development of newer, safer, and more cost-effective drugs and vaccines to prevent malaria in HIV-infected pregnant women.

Prophylaxis of human toxoplasmosis: a systematic review

Toxoplasmosis is an infection caused by the intracellular protozoan parasite Toxoplasma gondii, and is associated with clinically significant infection in immunocompromised individuals. Vertical transmission during pregnancy can manifest as congenital toxoplasmosis in the neonate, and can have serious consequences. This review aims to describe the modalities for prophylaxis of toxoplasmosis in susceptible populations, and focuses on the following: (1) prophylaxis of congenital toxoplasmosis; (2) prophylaxis of toxoplasmosis in patients with HIV/AIDS; and (3) prophylaxis of toxoplasmosis in transplant recipients.

Immune reconstitution inflammatory syndrome associated with toxoplasmic encephalitis in HIV-infected patients

OBJECTIVES

To investigate the incidence and risk factors of immune reconstitution inflammatory syndrome (IRIS) associated with toxoplasmic encephalitis (TE) in patients starting combination antiretroviral therapy (cART).

DESIGN

A historical multicenter cohort study.

METHODS

We included all HIV-infected patients diagnosed with toxoplasmic encephalitis in six Dutch hospitals between 1996 and 2016. Diagnosis of TE-IRIS was made using predefined IRIS criteria. We distinguished paradoxical TE-IRIS (worsening of underlying treated infection) from unmasking TE-IRIS (unmasking of subclinical infection after start of cART). We compared CD4 cell count, plasma viral load and timing of cART initiation between patients with and without paradoxical TE-IRIS.

RESULTS

A total of 211 toxoplasmic encephalitis cases were included. Among 143 cases at risk for paradoxical TE-IRIS, we identified five cases of paradoxical TE-IRIS (3.5%). In six other cases, we could not differentiate paradoxical TE-IRIS from recurrence of disease due to inadequate secondary Toxoplasma prophylaxis. There was no difference in time between start of toxoplasmic encephalitis treatment and cART initiation for patients who did or did not develop paradoxical TE-IRIS (P = 0.50). Within the group of 2228 patients who started cART while having a CD4 cell count below 200 × 10 cells/l and receiving adequate primary prophylaxis, we identified eight cases of unmasking TE-IRIS (0.36%). Unmasking TE-IRIS could not be differentiated from a newly occurring toxoplasmic encephalitis in six other patients, as they were not receiving adequate primary prophylaxis against Toxoplasma.

CONCLUSION

Unmasking TE-IRIS was rare in this cohort, whereas paradoxical TE-IRIS did occur more often. We found no relationship between the timing of cART initiation and the occurrence of paradoxical TE-IRIS.

Clonal types of Toxoplasma gondii among immune compromised and immune competent individuals in Accra, Ghana

There are three major clonal lineages, types I, II, and III, of Toxoplasma gondii known to cause human toxoplasmosis worldwide. Toxoplasma gondii infections have, however, not been genotyped in Ghana. This study detected the clonal types infecting immune compromised and immune competent individuals in Accra, Ghana. Blood samples were obtained from 148 HIV seropositive pre-antiretroviral therapy individuals (0 ≤ CD4(+) T-cell count/μl blood ≤ 200) at the Fevers Unit and 149 HIV seronegative apparently healthy blood donors at the blood bank, all of the Korle-Bu Teaching Hospital. Genomic DNA was extracted and multilocus genotyping conducted by nested PCR-RFLP analysis using GRA6, SAG3, and BTUB gene markers. Among the HIV seropositive participants, 54.7% (81/148) were T. gondii DNA positive for any of the markers. Out of the 81, 42.0% (34) were positive for SAG3 only, 30.9% (25) for GRA6 only, 24.7% (20) for both SAG3 and GRA6, and 2.5% (2) for SAG3, GRA6, and BTUB. Overall, 93.8% of the positives were of clonal type II, 1.2% type I, while 4.9% (4) were atypical or mixed types (I and II). In the healthy blood donors, prevalence of T. gondii DNA positivity was 3.4% (5/149) by SAG3 and/or GRA6; among them, 60.0% (3/5) were type I, and the remaining 40.0%, type II. This study showed a relatively high prevalence of active T. gondii infections in immune compromised patients and low prevalence in immune competent individuals in Accra. Type II was highly prevalent. Detection of T. gondii in blood donors raises public health concerns and screening for T. gondii should be considered.

Toxoplasmosis in HIV infection: An overview

Toxoplasma gondii is an obligate intracellular protozoan parasite presenting as a zoonotic infection distributed worldwide. In HIV-positive individuals, it causes severe opportunistic infections, which is of major public health concern as it results in physical and psychological disabilities. In healthy immunocompetent individuals, it causes asymptomatic chronic persistent infections, but in immunosuppressed patients, there is reactivation of the parasite if the CD4 counts fall below 200 cells/μl. The seroprevalence rates are variable in different geographic areas. The tissue cyst or oocyst is the infective form which enters by ingestion of contaminated meat and transform into tachyzoites and disseminate into blood stream. In immunocompetent persons due to cell-mediated immunity the parasite is transformed into tissue cyst resulting in life long chronic infection. In HIV-infected people opportunistic infection by T. gondii occurs due to depletion of CD4 cells, decreased production of cytokines and interferon gamma and impaired cytotoxic T-lymphocyte activity resulting in reactivation of latent infection. The diagnosis can be done by clinical, serological, radiological, histological or molecular methods, or by the combination of these. There is various treatment regimen including acute treatment, maintenance therapy should be given as the current anti T. gondii therapy cannot eradicate tissue cysts. In HIV patients, CD4 counts <100; cotrimoxazole, alternately dapsone + pyrimethamine can be given for 6 months. Hence, early diagnosis of T. gondii antibodies is important in all HIV-positive individuals to prevent complications of cerebral toxoplasmosis.

Effect of cyclic, low dose pyrimethamine treatment in patients with Late Onset Tay Sachs: an open label, extended pilot study

BACKGROUND

Late Onset Tay- Sachs disease (LOTS) is a rare neurodegenerative lysosomal storage disease which results from mutations in the gene encoding the α subunit (HEXA) of β-hexosaminidase enzyme (HexA). At the present time, no effective treatment exists for LOTS and other neurodegenerative diseases involving the central nerve system (CNS). Pyrimethamine (PMT) was previously shown to act as a HexA chaperone in human fibroblasts in vitro carrying some (e.g., αG269S), but not all LOTS-related mutations. The present study assessed the effect of cyclic, low dose and long term pyrimethamine treatment on HexA in subjects with LOTS.

METHODS

In an open label trial in 4 LOTS patients, PMT was initiated at an average daily dose of ~2.7 mg and administered cyclically guided by blood lymphocyte HexA activity for a mean duration of 82.8 (±22.5; SD) weeks (~1.5 year).

RESULTS

HexA activity rose in all subjects, with a mean peak increase of 2.24 folds (±0.52; SD) over baseline activity (range 1.87-3). The mean treatment time required to attain this peak was of 15.7 (±4.8; SD) weeks. Following increase in activity, HexA gradually declined with the continued use of PMT, which was then stopped, resulting in the return of HexA activity to baseline. A second cycle of PMT treatment was then initiated, resulting again in an increase in HexA activity. Three of the patients experienced a measurable neuropsychiatric deterioration whereas one subject remained entirely stable.

CONCLUSIONS

Cyclic low dose of PMT can increase HexA activity in LOTS patients. However, the observed increase is repeatedly transient and not associated with discernible beneficial neurological or psychiatric effects.

Prevention of HIV-associated opportunistic infections and diseases in the age of highly active antiretroviral therapy

Since the introduction of highly active antiretroviral therapy (HAART), the rates of opportunistic infections have decreased markedly as has overall morbidity and mortality from HIV infection in developed countries. However, opportunistic infections remain the most important cause of death in HIV-infected people due to both late presentation of HIV infections and failure of HAART to adequately restore cell-mediated immunity in all individuals. While prophylaxis may be discontinued in patients who have responded to HAART with sustained increases of their CD4 counts above risk thresholds, for those patients who fail HAART, those who are unable to tolerate it, or whose treatments are interrupted, opportunistic-infection prophylaxis remains essential. Some HIV-associated diseases, such as anogenital human papilloma virus-induced neoplasia and hepatitis C infection, have not decreased in frequency with the advent of HAART. For these conditions, effective screening and treatment programs will be necessary to prevent ongoing morbidity. This review will provide an update on HIV-associated opportunistic infections and their prevention in the age of HAART, as well as discuss novel presentations of opportunistic illnesses, such as immune restoration syndromes.

Chaperone therapy for GM2 gangliosidosis: effects of pyrimethamine on β-hexosaminidase activity in Sandhoff fibroblasts

Sphingolipidoses are inherited genetic diseases due to mutations in genes encoding proteins involved in the lysosomal catabolism of sphingolipids. Despite a low incidence of each individual disease, altogether, the number of patients involved is relatively high and resolutive approaches for treatment are still lacking. The chaperone therapy is one of the latest pharmacological approaches to these storage diseases. This therapy allows the mutated protein to escape its natural removal and to increase its quantity in lysosomes, thus partially restoring the metabolic functions. Sandhoff disease is an autosomal recessive inherited disorder resulting from β-hexosaminidase deficiency and characterized by large accumulation of GM2 ganglioside in brain. No enzymatic replacement therapy is currently available, and the use of inhibitors of glycosphingolipid biosynthesis for substrate reduction therapy, although very promising, is associated with serious side effects. The chaperone pyrimethamine has been proposed as a very promising drug in those cases characterized by a residual enzyme activity. In this review, we report the effect of pyrimethamine on the recovery of β-hexosaminidase activity in cultured fibroblasts from Sandhoff patients.

Quantifying the risks and benefits of efavirenz use in HIV-infected women of childbearing age in the USA

OBJECTIVES

The aim of the study was to quantify the benefits (life expectancy gains) and risks (efavirenz-related teratogenicity) associated with using efavirenz in HIV-infected women of childbearing age in the USA.

METHODS

We used data from the Women's Interagency HIV Study in an HIV disease simulation model to estimate life expectancy in women who receive an efavirenz-based initial antiretroviral regimen compared with those who delay efavirenz use and receive a boosted protease inhibitor-based initial regimen. To estimate excess risk of teratogenic events with and without efavirenz exposure per 100,000 women, we incorporated literature-based rates of pregnancy, live births, and teratogenic events into a decision analytic model. We assumed a teratogenicity risk of 2.90 events/100 live births in women exposed to efavirenz during pregnancy and 2.68/100 live births in unexposed women.

RESULTS

Survival for HIV-infected women who received an efavirenz-based initial antiretroviral therapy (ART) regimen was 0.89 years greater than for women receiving non-efavirenz-based initial therapy (28.91 vs. 28.02 years). The rate of teratogenic events was 77.26/100,000 exposed women, compared with 72.46/100,000 unexposed women. Survival estimates were sensitive to variations in treatment efficacy and AIDS-related mortality. Estimates of excess teratogenic events were most sensitive to pregnancy rates and number of teratogenic events/100 live births in efavirenz-exposed women.

CONCLUSIONS

Use of non-efavirenz-based initial ART in HIV-infected women of childbearing age may reduce life expectancy gains from antiretroviral treatment, but may also prevent teratogenic events. Decision-making regarding efavirenz use presents a trade-off between these two risks; this study can inform discussions between patients and health care providers.

Malaria and HIV co-infection in pregnancy in sub-Saharan Africa: impact of treatment using antimalarial and antiretroviral agents

Malaria and HIV infection represent severe public health problems in sub-Saharan Africa, and pregnant women are at increased risk because the two diseases intersect in pregnancy, causing adverse perinatal outcome. As access to antiretroviral drugs is increasing in the sub-region, and new combinations of antimalarial drugs are being implemented while more are being evaluated, there is potential for interactions between these therapies. In this report, the impact of treatment using antimalarial and antiretroviral agents in pregnant women with malaria and HIV co-infection was reviewed, using scientific publications identified through a Medline Entrez-Pubmed search with reference to sub-Saharan Africa. The safety and operational feasibility of use of antimalarial and antiretroviral agents to treat co-infected pregnant women were evaluated. Although use of these therapies was shown to improve the health of pregnant women with co-infection, low adherence, poor-quality drugs, resource scarcity, lack of infrastructure and inadequate treatment in sub-Saharan Africa continue to hamper treatment outcome. The absence of studies on interaction between antimalarials and antiretrovirals, as well as mounting evidence of treatment failure due to drug resistance and adverse drug reactions, in most parts of sub-Saharan Africa, make the establishment of new guidelines for the prevention of malaria and HIV infection during pregnancy imperative.

Lending a helping hand, screening chemical libraries for compounds that enhance beta-hexosaminidase A activity in GM2 gangliosidosis cells

Enzyme enhancement therapy is an emerging therapeutic approach that has the potential to treat many genetic diseases. Candidate diseases are those associated with a mutant protein that has difficulty folding and/or assembling into active oligomers in the endoplasmic reticulum. Many lysosomal storage diseases are candidates for enzyme enhancement therapy and have the additional advantage of requiring only 5-10% of normal enzyme levels to reduce and/or prevent substrate accumulation. Our long experience in working with the beta-hexosaminidase (EC 3.2.1.52) isozymes system and its associated deficiencies (Tay-Sachs and Sandhoff disease) lead us to search for possible enzyme enhancement therapy-agents that could treat the chronic forms of these diseases which express 2-5% residual activity. Pharmacological chaperones are enzyme enhancement therapy-agents that are competitive inhibitors of the target enzyme. Each of the known beta-hexosaminidase inhibitors (low microm IC50) increased mutant enzyme levels to >or= 10% in chronic Tay-Sachs fibroblasts and also attenuated the thermo-denaturation of beta-hexosaminidase. To expand the repertoire of pharmacological chaperones to more 'drug-like' compounds, we screened the Maybridge library of 50,000 compounds using a real-time assay for noncarbohydrate-based beta-hexosaminidase inhibitors and identified several that functioned as pharmacological chaperones in patient cells. Two of these inhibitors had derivatives that had been tested in humans for other purposes. These observations lead us to screen the NINDS library of 1040 Food and Drug Administration approved compounds for pharmacological chaperones. Pyrimethamine, an antimalarial drug with well documented pharmacokinetics, was confirmed as a beta-hexosaminidase pharmacological chaperone and compared favorably with our best carbohydrate-based pharmacological chaperone in patient cells with various mutant genotypes.

Pyrimethamine as a potential pharmacological chaperone for late-onset forms of GM2 gangliosidosis

Late-onset GM2 gangliosidosis is composed of two related, autosomal recessive, neurodegenerative diseases, both resulting from deficiency of lysosomal, heterodimeric beta-hexosaminidase A (Hex A, alphabeta). Pharmacological chaperones (PC) are small molecules that can stabilize the conformation of a mutant protein, allowing it to pass the quality control system of the endoplasmic reticulum. To date all successful PCs have also been competitive inhibitors. Screening for Hex A inhibitors in a library of 1040 Food Drug Administration-approved compounds identified pyrimethamine (PYR (2,4-diamino 5-(4-chlorophenyl)-6-ethylpyrimidine)) as the most potent inhibitor. Cell lines from 10 late-onset Tay-Sachs (11 alpha-mutations, 2 novel) and 7 Sandhoff (9 beta-mutations, 4 novel) disease patients, were cultured with PYR at concentrations corresponding to therapeutic doses. Cells carrying the most common late-onset mutation, alphaG269S, showed significant increases in residual Hex A activity, as did all 7 of the beta-mutants tested. Cells responding to PC treatment included those carrying mutants resulting in reduced Hex heat stability and partial splice junction mutations of the inherently less stable alpha-subunit. PYR, which binds to the active site in domain II, was able to function as PC even to domain I beta-mutants. We concluded that PYR functions as a mutation-specific PC, variably enhancing residual lysosomal Hex A levels in late-onset GM2 gangliosidosis patient cells.

Challenges in the concurrent management of malaria and HIV in pregnancy in sub-Saharan Africa

Approximately one million pregnancies are complicated by both malaria and HIV infection in sub-Saharan Africa annually. Both infections have been associated with maternal and infant morbidity and mortality. Intermittent preventive treatment, usually with sulfadoxine-pyrimethamine, has been shown to prevent pregnancy-related malaria and its complications. Several different regimens of antiretroviral therapy are now available to prevent mother-to-child transmission of HIV and/or progression of maternal HIV infection during pregnancy. However, no published studies have yet shown whether standard intermittent preventive treatment and antiretroviral regimens are medically and operationally compatible in pregnancy. We reviewed existing policies regarding prevention and treatment of HIV and malaria in pregnancy, as well as published literature on adverse effects of antiretrovirals and antimalarials commonly used in pregnancy in developing countries, and found that concurrent prescription of sulfadoxine-pyrimethamine, co-trimoxazole (trimethoprim-sulfamethoxazole), and antiretroviral agents including nevirapine and zidovudine per existing protocols for prevention of malaria and vertical HIV transmission may result in adverse drug interactions or overlapping, diagnostically challenging drug toxicities. Insecticide-treated bednets should be provided for HIV-infected pregnant women at risk for malaria. Sulfadoxine-pyrimethamine should be prescribed cautiously in women concurrently receiving daily nevirapine and/or zidovudine, and should be avoided in women on daily co-trimoxazole. Further research is urgently needed to define safe and effective protocols for concurrent management of HIV and malaria in pregnancy, and to define appropriate interventions for different populations subject to differing levels of malaria transmission and antimalarial drug resistance.

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.

Antibiotics for toxoplasmic retinochoroiditis: an evidence-based systematic review

PURPOSE

To determine the effectiveness of systemic antibiotic treatment for toxoplasmic retinochoroiditis.

CLINICAL RELEVANCE

Toxoplasma retinochoroiditis is a significant cause of visual morbidity. Multiple different antibiotic regimens are used, but controversy about treatment effectiveness remains.

LITERATURE REVIEWED

Searches were conducted of Cochrane Controlled Trials Register, Medline (1966 onward), Embase (1980 onward), Dissertation Abstracts (1861 onward), Lilacs (1982 onward), and Pascal (1984 onward). Pharmaceutical companies were contacted for unpublished data. Any randomized controlled trials that compared antibiotics versus placebo in immunocompetent patients with toxoplasmic retinochoroiditis were retrieved. Primary outcome measures were long-term visual acuity and risk of recurrent retinochoroiditis. Secondary outcomes included duration and severity of acute symptoms, size of the lesion at end of follow-up, and adverse effects of treatment.

RESULTS

Only 3 studies (total of 173 participants) were randomized controlled trials and hence met the inclusion criteria (level II). All 3 were methodologically poor, and 2 were carried out more than 35 years ago. None reported the effect on long-term visual outcome. We found no evidence for a beneficial effect on the duration and severity of signs of acute toxoplasmic retinochoroiditis (A,II). There was weak evidence for an effect of long-term treatment for chronic recurrent toxoplasmic retinochoroiditis on lesion recurrence. Treatment was associated with adverse effects.

CONCLUSIONS

There is a lack of evidence to support routine antibiotic treatment for acute toxoplasmic retinochoroiditis. Placebo-controlled randomized trials of antibiotic treatment in patients presenting with acute or chronic toxoplasmic retinochoroiditis arising in any part of the retina are required.

Synergistic bone marrow toxicity of pyrimethamine and zidovudine in murine in vivo and in vitro models: mechanism of toxicity

Pyrimethamine (Pyr) is commonly used for treatment of toxoplasmic encephalitis in AIDS patients; however, in two clinical studies, an increased number of deaths were observed when Pyr was coadministered with zidovudine (ZDV). The BALB/c mouse was chosen as a model to study the mechanism underlying the unexpected toxicity from coadministration of these drugs. Daily administration by oral gavage of 60 mg/kg Pyr and 240 mg/kg ZDV resulted in 100% lethality after 30 days. These dose levels produced no effect when the drugs were given individually for the same period. Administration of combinations of Pyr and ZDV resulted in macrocytic anemia and leukopenia with synergistic decreases in lymphocyte and neutrophil numbers. To examine the mechanism of this hematotoxicity at the cellular level, mouse bone marrow colony-forming unit (mCFU) assays were employed. A combination of ZDV with various concentrations of Pyr resulted in synergistic decreases in numbers of erythroid and granulocyte-macrophage precursors (mCFU-E and mCFU-GM). mCFU-GM precursors appeared more sensitive than erythroid precursors to combinations of Pyr and ZDV. Incorporation of (14)C-ZDV into cellular DNA was increased in a dose-dependent manner in the presence of increasing concentrations of Pyr in the mCFU-GM assay. This suggested that inhibition of dihydrofolate reductase by Pyr and accompanying inhibition of dTTP synthesis allows preferential incorporation of ZDV into DNA, with resulting strand breakage and cell death. (14)C-ZDV incorporation was also observed when human GM cultures were analyzed, however, incorporation was less and required higher concentrations of Pyr.

Immunoblot profile as predictor of toxoplasmic encephalitis in patients infected with human immunodeficiency virus

In order to define more accurately human immunodeficiency virus-infected patients at risk of developing toxoplasmic encephalitis (TE), we assessed the prognostic significance of the anti-Toxoplasma gondii immunoglobulin G (IgG) immunoblot profile, in addition to AIDS stage, a CD4(+) cell count <50/mm(3), and an antibody titer > or =150 IU/ml, in patients with CD4 cell counts <200/mm(3) and seropositive for T. gondii. Baseline serum samples from 152 patients included in the placebo arm of the ANRS 005-ACTG 154 trial (pyrimethamine versus placebo) were used. The IgG immunoblot profile was determined using a Toxoplasma lysate and read using the Kodak Digital Science 1D image analysis software. Mean follow-up was 15.1 months, and the 1-year incidence of TE was 15.9%. The cumulative probability of TE varied according to the type and number of anti-T. gondii IgG bands and reached 65% at 12 months for patients with IgG bands of 25 and 22 kDa. In a Cox model adjusted for age, gender, Centers for Disease Control and Prevention (CDC) clinical stage, and CD4 and CD8 cell counts, the incidence of TE was higher when the IgG 22-kDa band (hazard ratio [HR] = 5.4; P < 0.001), the IgG 25-kDa band (HR = 4.7; P < 0.001), or the IgG 69-kDa band (HR = 3.4; P < 0.001) was present and was higher for patients at CDC stage C (HR = 4.9; P < 0.001). T. gondii antibody titer and CD4 cell count were not predictive of TE. Thus, detection of IgG bands of 25, 22, and/or 69 kDa may be helpful for deciding when primary prophylaxis for TE should be started or discontinued, especially in the era of highly active antiretroviral therapy.

[Contribution of clinical epidemiology to the management of HIV infections]

INTRODUCTION

The objective of this publication is to make clinicians more aware of clinical epidemiology through our experience in the field of human immunodefiency virus (HIV) infection.

CURRENT KNOWLEDGE AND KEY POINTS

Clinical epidemiology is aimed at studying diagnostic, therapeutic and prognostic aspects of diseases, and their consequences, with the objective of improving both scientific knowledge and patient's management. Examples, including longitudinal studies and clinical trials, illustrate the value of clinical epidemiology.

FUTURE PROSPECTS AND PROJECTS

Beyond HIV infection, the importance of both multidisciplinary collaboration and education of clinicians in regard to biostatistical and epidemiological methods is emphasized.

Human immunodeficiency virus infection, Part II

The acceptance of highly active antiretroviral therapy (HAART) among patients and health care providers has had a dramatic impact on the epidemiology and clinical characteristics of many opportunistic infections associated with human immunodeficiency virus (HIV). Previously intractable opportunistic infections and syndromes are now far less common. In addition, effective antibiotic prophylactic therapies have had a profound impact on the risk of patients developing particular infections and on the incidence of these infections overall. Most notable among these are Pneumocystis carinii, disseminated Mycobacterium avium complex, tuberculosis, and toxoplasmosis. Nevertheless, infections continue to cause significant morbidity and mortality among patients who are infected with HIV. The role of HAART in many clinical situations is unquestioned. Compelling data from clinical trials support the use of these therapies during pregnancy to prevent perinatal transmission of HIV. HAART is also recommended for health care workers who have had a "significant" exposure to the blood of an HIV-infected patient. Both of these situations are discussed in detail in this article. In addition, although more controversial, increasing evidence supports the use of HAART during the acute HIV seroconversion syndrome. An "immune reconstitution syndrome" has been newly described for patients in the early phases of treatment with HAART who develop tuberculosis, M avium complex, and cytomegalovirus disease. Accumulating data support the use of hydroxyurea, an agent with a long history in the field of myeloproliferative disorders, for the treatment of HIV. Newer agents, particularly abacavir and adefovir dipivoxil, are available through expanded access protocols, and their roles are being defined and clarified.

Azithromycin for ocular toxoplasmosis

AIMS

To investigate the efficacy of azithromycin in patients with ocular toxoplasmosis.

METHODS

11 immunocompetent patients with ocular toxoplasmosis were treated with azithromycin (500 mg the first day, followed by 250 mg/day for 5 weeks). Ocular and systemic examinations were performed during active retinitis episodes and all patients were followed for at least 1 year.

RESULTS

The intraocular inflammation disappeared within 4 weeks in seven patients, including two cases with progressive retinitis despite previous treatment with pyrimethamine, sulphadiazine, and folinic acid. Recurrence of retinitis occurred in three patients (27%) within the first year of follow up. No systemic side effects of azithromycin were encountered.

CONCLUSION

These results indicate that although azithromycin cannot prevent recurrent disease it may be an effective alternative for patients with ocular toxoplasmosis who cannot tolerate standard therapies.

Intention-to-treat vs. on-treatment analyses of clinical trial data: experience from a study of pyrimethamine in the primary prophylaxis of toxoplasmosis in HIV-infected patients. ANRS 005/ACTG 154 Trial Group

Randomized clinical trials analyzed by the intent-to-treat approach provide unbiased comparisons among treatment groups. To avoid dilution of treatment effect, many people also perform an analysis by treatment actually received, although this method may introduce bias into the results. This paper presents several approaches used for analyzing data of a recent trial and the difficulties encountered in interpreting the results of each approach. The ANRS 005/ACTG 154 Study was a double-blind, placebo-controlled, randomized, international (French, U.S., and Spanish) multicenter trial designed to assess the effectiveness of pyrimethamine for the primary prophylaxis of cerebral toxoplasmosis (CT) in HIV-infected patients with advanced immunodeficiency. In the intention-to-treat analysis, the cumulative probability of CT at 1 year did not differ significantly between the pyrimethamine arm (11.9%) and the placebo arm (13.1%), Hazard Ratio (HR) = 0.94 (95% Confidence Interval (CI) = 0.62-1.42), whereas an on-treatment analysis resulted in a significant difference: 4.2% in the pyrimethamine arm and 12.4% in the placebo arm, HR = 0.44 (95% CI = 0.24-0.80). The data showed a significant interaction between compliance and treatment outcome; and side effects were more frequently cited as reasons for compliance violations in the pyrimethamine group. Several different analytic approaches (censoring data at the time patients discontinued the study medication only for selected reasons) failed to explain the disparity between the estimation of effect of pyrimethamine by the intention-to-treat and on-treatment analyses. This experience led us to believe that comparing the results of both analyses was the best method to convince clinicians that intention-to-treat was the only interpretable analysis. We were concerned that even if pyrimethamine had a beneficial effect, it was very difficult (1) to quantify and (2) to apply to clinical practice unless one could predict the occurrence of study drug discontinuation for each patient at the time of treatment assignment. Although exploratory analyses may yield clinically relevant information and useful clarifications in the evaluation of treatments, intention-to-treat remains the only interpretable analysis of clinical trials.

[Epidemiologic characteristics of cerebral toxoplasmosis in 399 HIV-infected patients followed between 1983 and 1994]

OBJECTIVE

To describe the epidemiological characteristics of toxoplasmic encephalitis in HIV-infected patients with a more than 12-year follow-up.

METHODS

From a data base of 1,628 AIDS subjects hospitalized from 1983 to 1994, we studied the epidemiological characteristics of 399 patients with toxoplasmic encephalitis. Diagnosis of toxoplasmic encephalitis was based on the association of central neurological disorders, typical lesions on CT scan or MRI, and favorable outcome under appropriate toxoplasmosis therapy.

RESULTS

Four hundred sixty-four cases of toxoplasmic encephalitis were reported in 399 patients (24.5% of the patients with AIDS). The overall incidence was 20.5 per 100 patients-year. Toxoplasmic encephalitis was the first AIDS defining event in 51% of the cases and revealed HIV infection in 13% of the cases. In the remaining 49%, the mean delay from AIDS diagnosis to toxoplasmic encephalitis was 13 months (range: 1-71 months). At the time of diagnosis, mean CD4 count was 44/mm3 (range: 0-408/mm3). Antibodies to Toxoplasma gondii were found in 97% of the cases. Before the first episode of toxoplasmic encephalitis, 58% of the patients were given antiretroviral therapy (mean: 17.8 months; range: 1-64 months). Of the 399 patients with toxoplasmic encephalitis, 366 (92%) did not receive any primary toxoplasmosis prophylaxis. Among them, 205 (56%) did not receive any drug prophylaxis, and 161 (44%) had Pneumocystis carinii pneumonia prophylaxis alone (aerosolized pentamidine). Thirty-three failures were observed (8%) with cotrimoxazole: 14 cases (3%) were considered to have irregular compliance. Sixty-five relapses were observed in 52 patients. At the end of the study 334 patients had died (84%). The median survival was 11.4 months (95% confidence interval, range: 10.4-12.4 months).

CONCLUSIONS

Toxoplasmic encephalitis incidence has decreased since the introduction of appropriate drug prophylaxis.

Cotrimoxazole is effective as primary prophylaxis for toxoplasmic encephalitis in HIV-infected patients: a case control study

In a case-control study, prophylaxis with cotrimoxazole for toxoplasmic encephalitis (TE) in HIV-infected patients was evaluated. Cotrimoxazole had been given as PCP prophylaxis. 20 patients with TE were identified and 72 matching control cases were found. All patients had IgG-antibodies to Toxoplasma gondii and CD4+ T-cell counts < or = 100/microliter. The use and duration of cotrimoxazole prophylaxis were recorded. It was found that among the patients with TE, none had used cotrimoxazole for > 70% of the observation time, and that the 1-y incidence was 0% in the control group vs. 41% in those patients without sufficient cotrimoxazole use. The conclusion is that cotrimoxazole is effective as primary prophylaxis for TE, even in a dose of 480 mg daily.

Effects of 2',3'-dideoxyinosine on Toxoplasma gondii cysts in mice

The activity against Toxoplasma gondii of 2',3' dideoxyinosine (ddI), an anti-human immunodeficiency virus drug, was examined in an in vitro and in vivo study. Cell cultures infected with a strain known to cause chronic infections were used to show the dose-dependent effect of this drug compared with spiramycin and sulfadiazine. When a dose of 4 microg/ml was used, no infected THP-1 cells or parasites were found after 60 h of incubation. An electron-microscopic study confirmed that after 12 h at 1 microg/ml, the few parasites observed were severely altered. The treatment of chronically infected mice 3 months postinfection showed that a 30-day treatment with 2 mg of ddI/ml induced a significant reduction in the number of T. gondii cysts in the cerebral tissue. These cysts were not viable, as confirmed by immunofluorescence and reinfection experiments. These experiments suggest a possible role for ddI in the treatment of toxoplasmosis, and this possibility deserves further investigation.

Survival after AIDS-defining events in patients with < 200 lymphocytes CD4+ x 10(6)/L who are toxoplasmosis antibody positive. ANRS 005/ACTG 154 Trial Group

The objective of this study was to assess whether patients with CD4+ cell counts <200 x 10(6)/L have a decreased survival after the occurrence of any AIDS-defining event; 187 patients from the placebo arm of a clinical trial of toxoplasmosis prophylaxis (ANRS005-ACTG154) were included. For this analysis, patients were HIV infected without any AIDS-defining event, had a CD4+ lymphocyte count < 200 x 10(6)/L, had a positive serology for Toxoplasma gondii, and had no severe liver, renal, or hematologic abnormalities. We used proportional hazards regression to study the relationships between baseline variables. AIDS-defining events as time-dependent variables, and survival. The risk of dying was increased by 1.9 for a 10-year increase in age and by 1.3 when CD4+ decreased by 50 x 10(6)/L; after the occurrence of a pneumocystosis, a cytomegalovirus infection, or a toxoplasmosis, the risk of dying was multiplied, respectively, by 10.9 (3.0-40.2), 10.0 (2.8-35.4), and 10.0 (4.5-22.2). None of the other AIDS-defining events was associated with an increased risk of dying, but the power to detect such an association was limited. We conclude that the occurrence of pneumocystosis, cytomegalovirus infection, or toxoplasmosis; age; and CD4+ cell count are important determinants of survival for HIV1-infected patients with CD4+ counts < 200 x 10(6)/L who are toxoplasmosis antibody positive.

A prospective study of criteria for the diagnosis of toxoplasmic encephalitis in 186 AIDS patients. The BIOTOXO Study Group

OBJECTIVE

To define the factors associated with diagnosis of toxoplasmic encephalitis (TE) in AIDS patients; and to establish a rational procedure for the clinician faced with a decision concerning empiric antitoxoplasma therapy.

DESIGN

A 15-month prospective multicentre cohort study in France.

METHODS

One hundred and eighty-six consecutive HIV-positive inpatients undergoing empiric antitoxoplasma therapy for a first episode of presumed TE were monitored. The clinician's initial estimation of the probability of response to antitoxoplasma therapy was recorded. In addition, a validation committee classified cases as TE or non-TE.

RESULTS

Among the 186 patients, the following variables were significantly more frequent in TE (n = 113) than non-TE (n = 73) patients: fever (59% versus 40%). headache (55% versus 33%), seizures (22% versus 11%), suggestive lesions on the brain scan (98% versus 76%), positive Toxoplasma serology (97% versus 71%). Median CD4+ lymphocyte count was significantly higher in TE than in non-TE (27 x 10(6)/l versus 11 x 10(6)/l). The rate of TE in patients on systemic antiprotozoal prophylaxis at entry was 43% as compared with 75% in patients without previous prophylaxis. Pre-therapy estimation of response to empiric therapy was highly correlated with final diagnosis. Multivariate logistic regression analysis showed that the following variables contributed independently to the diagnosis of TE: clinician's estimation of response to treatment at entry > 75%; absence of systemic antiprotozoal prophylaxis; seizures; headache; suggestive lesions on CT or MRI brain scan; and positive Toxoplasma serology.

CONCLUSIONS

A linear logistic model is proposed which uses significant variables, which are readily available. This model gives good accuracy to classify suspected cases of TE.

Enhanced in vitro activity of pyrimethamine in combination with dapsone against Mycobacterium avium complex

The in vitro activities of pyrimethamine and dapsone alone and in combination were evaluated against 23 clinical isolates of Mycobacterium avium complex. The broth dilution MICs of dapsone and pyrimethamine alone ranged from 16 to > 64 micrograms/ml. Pyrimethamine in combination with a fixed concentration of dapsone at 0.5 microgram/ml showed enhanced activity, with an MIC range of 0.5 to 16 micrograms/ml.

Toxoplasmose chez les patients immunodéprimés. Apport à la connaissance de l'infection toxoplasmique

Toxoplasmosis can be a severe infection in immunosuppressed patients. In these patients it can present as collected encephalitis, diffuse hypoxemic pneumopathy, or disseminated infection with fatal outcome. These presentations are observed mainly in HIV-infected patients, and less frequently in bone-marrow transplanted, or heart or heart and lung transplanted patients, or in patients given long term steroids or immunosuppressive therapy. The disease is due most often to the reactivation of latent persistent forms of the parasite at a moment of depression of host defense mechanisms, with local reactivation, and/or hematogenous dissemination. In some cases, the disease is favored by an insufficient protective response after primary infection. Treatment, based on the pyrimethamine-sulfadiazine combination should be continued as long as a profound immunosuppression is present. Prevention is based on recommendations to avoid acquisition of the parasite for seronegative patients, and on chemoprophylaxis, using cotrimoxazole as first line regimen, in patients already infected with Toxoplasma gondii.