A.J.A.M. van der Ven

The effect of combined antiretroviral therapy on the overall mortality of HIV-infected individuals

Objective:To estimate the effect of combined antiretroviral therapy (cART) on mortality among HIV-infected individuals after appropriate adjustment for time-varying confounding by indication. Design:A collaboration of 12 prospective cohort studies from Europe and the United States (the HIV-CAUSAL Collaboration) that includes 62 760 HIV-infected, therapy-naive individuals followed for an average of 3.3 years. Inverse probability weighting of marginal structural models was used to adjust for measured confounding by indication. Results:Two thousand and thirty-nine individuals died during the follow-up. The mortality hazard ratio was 0.48 (95% confidence interval 0.41–0.57) for cART initiation versus no initiation. In analyses stratified by CD4 cell count at baseline, the corresponding hazard ratios were 0.29 (0.22–0.37) for less than 100 cells/μl, 0.33 (0.25–0.44) for 100 to less than 200 cells/μl, 0.38 (0.28–0.52) for 200 to less than 350 cells/μl, 0.55 (0.41–0.74) for 350 to less than 500 cells/μl, and 0.77 (0.58–1.01) for 500 cells/μl or more. The estimated hazard ratio varied with years since initiation of cART from 0.57 (0.49–0.67) for less than 1 year since initiation to 0.21 (0.14–0.31) for 5 years or more (P value for trend <0.001). Conclusion:We estimated that cART halved the average mortality rate in HIV-infected individuals. The mortality reduction was greater in those with worse prognosis at the start of follow-up.

FUNCTIONAL CONSEQUENCES OF TOLL-LIKE RECEPTOR 4 POLYMORPHISMS

Toll-like receptor 4 (TLR4) is an important pathogen recognition receptor that recognizes mainly lipopolysaccharide (LPS) of Gram-negative bacteria, but also structures from fungal and mycobacterial pathogens, as well as endogenous ligands. Two nonsynonymous polymorphisms of TLR4, Asp299Gly and Thr399lle, have been suggested to alter the function of the receptor. Some, but not all, studies have proposed that these polymorphisms lead to reduced cytokine response and increased susceptibility to Gram-negative infections. In this review, we compare studies that assessed the effect of the Asp299Gly and Thr399lle polymorphisms on susceptibility to Gram-negative infections and examine the phenotypic consequences of these polymorphisms. In addition, we review the geographical distribution of TLR4 polymorphisms and present a model for evolutionary pressures on the TLR4 genetic make-up.

Assessment of Urinary Concentrations of Hepcidin Provides Novel Insight into Disturbances in Iron Homeostasis during Malarial Infection

Disturbances in iron homeostasis are frequently observed in individuals with malaria. To study the effect of malaria and its treatment on iron homeostasis and to provide a mechanistic explanation for observed alterations in iron distribution, we studied the course of the iron regulatory hormone hepcidin in anemic Tanzanian children with febrile Plasmodium falciparum malaria. Before initiation of antimalarial treatment, urinary concentrations of hepcidin were strongly elevated and were associated with iron maldistribution, as was suggested by the presence of hypoferremia and high serum concentrations of ferritin. Antimalarial treatment resulted in a rapid decrease in urinary concentrations of hepcidin and reversal of the hypoferremia. Exploration of regulatory pathways of hepcidin production by analysis of iron, erythropoietic, and inflammatory indices suggested that reduced erythropoietic activity and inflammation stimulated hepcidin production. We conclude that high concentrations of hepcidin explain the observed disturbances in host iron homeostasis associated with malaria and may contribute to malarial anemia and an impaired erythropoietic response to iron supplementation.

Long-term complications in patients with poor immunological recovery despite virological successful HAART in Dutch ATHENA cohort.

Objective:We investigated the risk of AIDS and serious non-AIDS-defining diseases (non-ADDs) according to the degree of immunological recovery after 2 years of virological successful antiretroviral therapy (HAART). Design:Retrospective observational cohort study including HIV-infected patients treated with HAART resulting in viral suppression (<500 copies/ml). Methods:Patients were grouped according to their CD4 cell count after 2 years of HAART: CD4 cell count less than 200 cells/&mgr;l (group A), 200–350 cells/&mgr;l (group B), 351–500 cells/&mgr;l (group C) or more than 500 cells/&mgr;l (group D). Analysis was done to assess predictors for poor immunological recovery and the occurrence of a composite endpoint [death, AIDS, malignancies, liver cirrhosis and cardiovascular events (CVEs)], non-ADDs, CVEs and non-AIDS-defining malignancies (non-ADMs). Results:Three thousand and sixty-eight patients were included. Older age, lower CD4 cell nadir and lower plasma HIV-RNA at the start of HAART were independent predictors for a poor immunological recovery. The composite endpoint, non-ADDs and CVE were observed most frequently in group A (overall log rank, P < 0.0001, P = 0.002 and P = 0.01). In adjusted analyses, age was a strong independent predictor for all endpoints. Compared with group A, patients in group D had a lower risk for the composite endpoint [hazard ratio 0.54 (95% confidence interval [CI] 0.33–0.87]; patients in group B had a lower risk for CVEs [hazard ratio 0.34 (95% CI 0.14–0.86)]. Conclusion:Poor immunological recovery despite virological successful HAART is associated with a higher risk for overall morbidity and mortality and CVEs in particular. This study underlines the importance of starting HAART at higher CD4 cell counts, particularly in older patients.

Toxoplasmosis after Renal Transplantation: Implications of a Missed Diagnosis

ABSTRACT We describe a renal transplant patient with a primary Toxoplasma gondii infection presenting as pneumonitis, with subsequent chorioretinitis and encephalitis. The diagnostic challenges of T. gondii infection in immunocompromised patients are discussed.

Genetic Variation of Innate Immune Genes in HIV-Infected African Patients With or Without Oropharyngeal Candidiasis

Background:The occurrence of oropharyngeal candidiasis (OPC) in combination with HIV disease progression is a very common phenomenon. However, not all HIV-infected patients develop OPC, even when they progress to low CD4+ T-cell counts. Because T-cell immunity is defective in AIDS, the innate defence mechanisms are likely to have a central role in antifungal immunity in these patients. We investigated whether genetic variations in the innate immune genes DECTIN-1, TLR2, TLR4, TIRAP, and CASPASE-12 are associated with the presence of OPC in HIV-infected subjects from East Africa. Methods:A total of 225 HIV patients were genotyped for several single nucleotide polymorphisms (SNPs), and this was correlated with the occurrence of OPC in these patients. In addition, primary immune cells obtained from individuals with different genotypes were stimulated with Candida albicans, and cytokine production was measured. Results:The analysis revealed that no significant differences in the polymorphism frequencies could be observed, although a tendency toward a protective effect on OPC of the DECTIN-1 I223S SNP was apparent. Furthermore, interferon γ production capacity was markedly lower in cells bearing the DECTIN-1 SNP I223S. It could also be demonstrated that the 223S mutated form of the DECTIN-1 gene exhibits a lower capacity to bind zymosan. Conclusions:These data demonstrate that common polymorphisms of TLR2, TLR4, TIRAP, and CASPASE-12 do not influence susceptibility to OPC in HIV-infected patients in East Africa but suggest an immunomodulatory effect of the I223S SNP on dectin-1 function and possibly the susceptibility to OPC in HIV patients.

Functional and morphological monocyte abnormalities in a patient with malakoplakia

netic resonance images of bone marrow in vertebral bones and femora were entirely normal. Ultrasonography of the abdomen did not show any organ involvement or detectable lymphadenopathy. Endoscopic examination of the upper gastrointestinal tract did not reveal any alterations. With these results, the patient was diagnosed with primary pulmonary plasmacytoma, and the intermittent administration of melphalan and prednisolone (MP) was introduced. After six cycles of therapy, the patient became free of complaints, and there was a remarkable improvement of reticulonodular infiltrate on chest roentgenograms and a reduction of serum IgA concentrations. At the submission of this report, the patient has received 16 cycles of the MP therapy and is alive and well. Differential diagnosis in the present case should include pulmonary small lymphocytic lymphoma with plasmacytoid differentiation (6,7). However, in diffuse small lymphocytic lymphoma, tumor cells express surface immunoglobulins, mostly IgM (8), and the isotype of paraprotein detected in such patients has been reported to be exclusively IgM (7). The present case has shown a good clinical response to melphalan-based chemotherapy, which may also support the diagnosis of plasmacytoma. Our experience implies that pulmonary plasmacytoma has to be considered for differential diagnosis in patients with diffuse pulmonary infiltrates accompanied by monoclonal gammopathy.

Glutathione homeostasis is disturbed in CD4-positive lymphocytes of HIV-seropositive individuals

Numerous in vitro tests have suggested that a disturbed cellular glutathione homeostasis plays an important role in the pathogenesis of human immunodeficiency virus (HIV) infection.

Platelet function alterations in dengue are associated with plasma leakage

Severe dengue is characterised by thrombocytopenia, plasma leakage and bleeding. Platelets are important for preservation of endothelial integrity. We hypothesised that platelet activation with secondary platelet dysfunction contribute to plasma leakage. In adult Indonesian patients with acute dengue, we measured platelet activation status and the response to the platelet agonist TRAP using flow cytometer-based assays. Patients were monitored daily for plasma leakage by ultrasonography. Acute dengue was associated with platelet activation with an increased expression of the activated fibrinogen receptor (αIIbβ3), the lysosomal marker CD63 and the alpha-granule marker CD62P (P-selectin). Upon maximal platelet activation by TRAP, platelet function defects were observed with a significantly reduced maximal activated αIIbβ3 and CD63 expression and reduced platelet-monocyte and platelet-neutrophil complexes. Patients in the lowest tertile of activated αIIbβ3 and CD63 expression had an odds ratio for plasma leakage of 5.2 (95% confidence interval [CI] 1.3-22.7) and 3.9 (95% CI 1.1-13.7), respectively, compared to the highest tertile. Platelet-derived serotonin has previously been related to plasma leakage and we found increased intra-platelet serotonin concentrations in our patients. In conclusion, platelet activation with platelet function alterations can be found in patients with acute dengue and this may contribute to dengue-associated plasma leakage.

The effect of efavirenz versus nevirapine-containing regimens on immunologic, virologic and clinical outcomes in a prospective observational study.

Objective:To compare regimens consisting of either efavirenz or nevirapine and two or more nucleoside reverse transcriptase inhibitors (NRTIs) among HIV-infected, antiretroviral-naive, and AIDS-free individuals with respect to clinical, immunologic, and virologic outcomes. Design:Prospective studies of HIV-infected individuals in Europe and the US included in the HIV-CAUSAL Collaboration. Methods:Antiretroviral therapy-naive and AIDS-free individuals were followed from the time they started an NRTI, efavirenz or nevirapine, classified as following one or both types of regimens at baseline, and censored when they started an ineligible drug or at 6 months if their regimen was not yet complete. We estimated the ‘intention-to-treat’ effect for nevirapine versus efavirenz regimens on clinical, immunologic, and virologic outcomes. Our models included baseline covariates and adjusted for potential bias introduced by censoring via inverse probability weighting. Results:A total of 15 336 individuals initiated an efavirenz regimen (274 deaths, 774 AIDS-defining illnesses) and 8129 individuals initiated a nevirapine regimen (203 deaths, 441 AIDS-defining illnesses). The intention-to-treat hazard ratios [95% confidence interval (CI)] for nevirapine versus efavirenz regimens were 1.59 (1.27, 1.98) for death and 1.28 (1.09, 1.50) for AIDS-defining illness. Individuals on nevirapine regimens experienced a smaller 12-month increase in CD4 cell count by 11.49 cells/&mgr;l and were 52% more likely to have virologic failure at 12 months as those on efavirenz regimens. Conclusions:Our intention-to-treat estimates are consistent with a lower mortality, a lower incidence of AIDS-defining illness, a larger 12-month increase in CD4 cell count, and a smaller risk of virologic failure at 12 months for efavirenz compared with nevirapine.