Reassessing Halm's clinical stability criteria in community-acquired pneumonia management.

INTRODUCTION: Halm's clinical stability criteria have long guided antibiotic treatment and hospital discharge decisions for patients hospitalised with community-acquired pneumonia (CAP). Originally introduced in 1998, these criteria were established based on a relatively small and select patient population. Consequently, our study aims to reassess their applicability in management of CAP in a contemporary real-world setting. METHODS: This cohort study included 2918 immunocompetent patients hospitalised with CAP from three hospitals in Denmark between 2017-2020. The primary outcome was time to achieve clinical stability as defined by Halm's criteria. Additionally, we examined recurrence of clinical instability and severe complications. Cumulative incidence function or Kaplan-Meier survival curves were used to analyse these outcomes, considering competing risks. FINDINGS: The study population primarily comprised elderly individuals (median age: 75 years) with significant comorbidities. The median time to clinical stability according to Halm's criteria was 4 days, with one-fifth experiencing recurrence of instability after early clinical response (stability within 3 days). Severe complications within 30 days mainly comprised mortality, with rates of 5.1% (64/1257) overall in those with early clinical response, 1.7% (18/1045) in the subgroup without do-not-resuscitate orders, and 17.3% (276/1595) among the rest. INTERPRETATION: Halm's clinical stability criteria effectively classify CAP patients with different disease courses, yet achieving stability required more time in this aging population with substantial comorbidities and more severe disease. Early clinical response indicates reduced risk of complications, especially in those without do-not-resuscitate orders.

No evidence of a synergistic effect of HIV infection and diabetes mellitus type 2 on fat distribution, plasma adiponectin or inflammatory markers.

BACKGROUND: Altered fat distribution and chronic inflammation are found in both persons living with HIV (PLWH) and persons with diabetes mellitus type 2 (DM2) and are known risk factors for cardiovascular diseases (CVD). We aimed to investigate if a synergistic effect of HIV infection and DM2 was found on fat distribution and inflammation. METHODS: A cross-sectional study was performed including PLWH with HIV RNA < 200 copies/mL (18 with DM2 (HIV + DM2+), 18 without DM2 (HIV + DM2-)) and controls (19 with DM2 (controls with DM2) and 25 without DM2 (healthy controls). We measured fat distribution using dual-energy X-ray absorptiometry scan. Plasma concentrations of adiponectin, interleukin-6 (IL-6), tumor necrosis factor-alfa (TNF- α) and soluble CD14 (sCD14) was measured using snap-frozen plasma. RESULTS: HIV + DM2+ and HIV + DM2- had comparable trunk/limb fat ratio. In contrast, HIV + DM2+ had a higher trunk/ limb fat ratio than controls with DM2 and healthy controls (p = 0.013 and p < 0.001, respectively). However, HIV + DM2+ and controls with DM2 had comparable amount of trunk fat mass (kg) (p = 0.254). A lower concentration of plasma adiponectin and higher concentration of IL-6 was found in HIV + DM2+ than in HIV + DM2-(p = 0.037 and p = 0.039) and in healthy controls (p = 0.001 and p = 0.012). In contrast, plasma adiponectin and IL-6 concentrations were comparable in HIV + DM2+ and controls with DM2 (p = 0.345 and p = 0.825). Concentration of sCD14 was comparable in HIV + DM2+ and HIV + DM2-(p = 0.850), but elevated in HIV + DM2+ compared to controls with DM2 (p < 0.001) and healthy controls (p = 0.007). No statistical interactions were found between HIV infection and DM2 for any of the depending variables. CONCLUSION: A synergistic effect of HIV and DM2 was not found for any of the outcomes. However, HIV + DM2+ had features related to both HIV infection and DM2 with a high trunk/limb ratio, high trunk fat mass, low concentration of plasma adiponectin and elevated concentrations of IL-6 and sCD14. This could contribute to elevated risk of CVD.

HIV-infected persons with type 2 diabetes show evidence of endothelial dysfunction and increased inflammation.

BACKGROUND: Increased incidence of cardiovascular diseases (CVD) in both HIV infection and type 2 diabetes (T2D) compared to the general population has been described. Little is known about the combined effect of HIV infection and T2D on inflammation and endothelial function, both of which may contribute to elevated risk of CVD. METHODS: Cross-sectional study including 50 HIV-infected persons on combination anti-retroviral therapy (cART), with HIV RNA <200 copies/mL (n = 25 with T2D (HIV + T2D+), n = 25 without T2D (HIV + T2D-)) and 50 uninfected persons (n = 22 with T2D (HIV-T2D+) and n = 28 without T2D (HIV-T2D-)). Groups were matched on age and sex. High sensitive C-reactive protein (hsCRP) was used to determine inflammation (cut-off 3 mg/L). The marker of endothelial dysfunction asymmetric dimethylarginine (ADMA) was measured using high performance liquid chromatography. Trimethylamine-N-oxide (TMAO), a microbiota-dependent, pro-atherogenic marker was measured using stable isotope dilution LC/MS/MS. RESULTS: The percentage of HIV + T2D+, HIV + T2D-, HIV-T2D+, and HIV-T2D- with hsCRP above cut-off was 50%, 19%, 47%, and 11%, respectively. HIV + T2D+ had elevated ADMA (0.67 µM (0.63-0.72) compared to HIV + T2D- (0.60 µM (0.57-0.64) p = 0.017), HIV-T2D+ (0.57 µM (0.51-63) p = 0.008), and HIV-T2D- (0.55 µM (0.52-0.58) p < 0.001). No differences in TMAO between groups were found. However, a positive correlation between ADMA and TMAO was found in the total population (rs = 0.32, p = 0.001), which was mainly driven by a close correlation in HIV + T2D+ (rs = 0.63, p = 0.001). CONCLUSION: Elevated inflammation and evidence of endothelial dysfunction was found in HIV-infected persons with T2D. The effect on inflammation was mainly driven by T2D, while both HIV infection and T2D may contribute to endothelial dysfunction. Whether gut microbiota is a contributing factor to this remains to be determined.

Dysregulation of CD4+CD25+CD127lowFOXP3+ regulatory T cells in HIV-infected pregnant women.

Pregnancy represents a major challenge to immunologic tolerance. How the fetal "semiallograft" evades maternal immune attack is unknown. Pregnancy success may involve alteration of both central (thymic) and peripheral tolerance mechanisms. HIV infection is characterized by CD4(+) T-cell depletion, chronic immune activation, and altered lymphocyte subsets. We studied immunologic consequences of pregnancy in 20 HIV-infected women receiving highly active antiretroviral therapy (HAART), and for comparison in 16 HIV-negative women. Lymphocyte subsets, thymic output, and cytokine profiles were measured prospectively during pregnancy and postpartum. A significant expansion of CD4(+)CD25(+)CD127(low)FoxP3(+) regulatory T cells indicating alteration of peripheral tolerance was seen during second trimester, but only in HIV-negative women. HIV-infected women had lower CD4 counts, lower thymic output and Th-2 cytokines, and more immune activation at all time points compared with controls. Immune activation was decreased in HIV-infected patients during pregnancy. In contrast, CD4 counts were increased in both groups. In conclusion, the study does not indicate that pregnancy adversely affects the immunologic course of HIV infection. However, despite HAART during pregnancy, HIV-infected women display different immunologic profiles from HIV-negative women, which may have importance for the induction of fetal-maternal tolerance and in part explain the increased risk of abortion in HIV-infected women.

Short-course antibiotic therapy for hospitalized patients with early clinical response in community-acquired pneumonia: a multicentre cohort study.

OBJECTIVES: To explore whether short-course antibiotic therapy is efficient and safe in routine clinical settings among patients hospitalized with community-acquired pneumonia (CAP) who achieve an early clinical response. METHODS: During 2017-2019, we conducted a cohort study of patients admitted with CAP to four hospitals in Denmark. Data were prospectively gathered from medical records and enriched with data from nationwide registries. In the present study, we included patients with early clinical response and divided them into treatment groups based on antibiotic duration, as decided by the attending physician: short-course (4-7 days) or prolonged-course (8-14 days). The primary outcome was post-treatment mortality within 30 days. Secondary outcomes included readmissions or new antibiotics. Logistic regression models were used to estimate ORs with 95% CIs, and inverse probability weighting was applied to adjust for confounding. RESULTS: The study cohort included 1151 patients with a median age of 74 years, predominantly presenting with mild-moderate disease. The 30-day post-treatment mortality was 3.36% (11/327) in the short-course group and 3.40% (28/824) in the prolonged-course group (adjusted OR 1.05, 95% CI 0.38-1.88). Readmission occurred in 15.6% (42/269) vs. 14.0% (102/727) (adjusted OR 1.07, 95% CI 0.75-1.69) and new prescription of antibiotics in 11.9% (32/269) vs. 12.1% (88/727) (adjusted OR 0.99, 95% CI 0.61-1.49). DISCUSSION: In patients hospitalized with CAP and early clinical response, similar outcomes were observed between short-course and prolonged-course therapies. These results support the use of short-course therapy in routine clinical settings.

Correlation of increases in 1,25-dihydroxyvitamin D during vitamin D therapy with activation of CD4+ T lymphocytes in HIV-1-infected males.

BACKGROUND: In HIV-1-infected individuals, levels of CD4+ T lymphocytes are depleted and regulatory T-lymphocytes (Tregs) are elevated. In vitro studies have demonstrated effects of vitamin D on the growth and differentiation of these cells. We speculated whether supplementation with vitamin D could have an effect on CD4+ T lymphocytes or Tregs in HIV-1-infected males. METHODS: We conducted a placebo-controlled randomized study that ran for 16 weeks and included 61 HIV-1-infected males, of whom 51 completed the protocol. The participants were randomized to 1 of 3 daily treatments: (1) 0.5-1.0 µg calcitriol and 1200 IU (30 µg) cholecalciferol, (2) 1200 IU cholecalciferol, (3) placebo. Percentages of the following T-lymphocyte subsets were determined: naïve CD4+ and CD8+ cells, activated CD4+ and CD8+ cells, and CD3+CD4+CD25+CD127low Tregs. Furthermore 1,25-dihydroxyvitamin D, 25-hydroxyvitamin D, and parathyroid hormone were measured. RESULTS: No significant changes of the studied T-lymphocyte subsets occurred in the treatment groups compared to the placebo group. Increases in 1,25-dihydroxyvitamin D were associated with increases in activated CD4+ T lymphocytes (P = .001) and Tregs (P = .01) in adjusted models. Changes in parathyroid hormone correlated inversely with Tregs (P = .02). Smokers had higher levels of naïve CD4+ T lymphocytes (37% vs 25%;P = .01), naïve CD8+ T lymphocytes (28% vs 19%; P = .03), and Tregs (9% vs 7%; P = .03). CONCLUSION: Cholecalciferol and calcitriol administered during 16 weeks did not change the levels of T-lymphocyte fractions compared to placebo. However, increases in 1,25-dihydroxyvitamin D were associated with an expansion of activated CD4+ cells and Tregs.

Risk factors for fatigue and impaired function eight months after hospital admission with COVID-19.

INTRODUCTION: We aimed to evaluate post-COVID-19 fatigue, change in functional capacity and health-related quality of life (HRQoL) eight months after discharge from hospital due to COVID-19. METHODS: A total of 83 patients (35 women) admitted to the Copenhagen University Hospital - North Zealand Hospital, Denmark, for COVID-19 during the period from March to June 2020 were evaluated eight months after discharge using validated questionnaires quantifying fatigue, HRQoL and post-COVID-19 functional status. Follow-up data were correlated with measures of pre-COVID-19 status (anthropometrics, comorbidities) and measures of severity of the acute infection. RESULTS: A total of 22 (65%) women and 12 (26%) men reported excessive fatigue. In all, 20 women (67%) and 17 men (37%) reported decreased physical function. Female sex was associated with fatigue. Loss of physical function was associated with pre-COVID-19 presence of heart disease and absence of lung disease. Severity of the acute COVID-19 infection was not associated with fatigue or change in functional status. Fatigue and functional status were correlated with both generic HRQoL and lung disease-specific HRQoL. CONCLUSIONS: Female sex was associated with a higher risk of fatigue eight months after hospitalisation with COVID-19 infection. Regarding loss of functional capacity after COVID-19, we found an apparently protective effect of pre-COVID-19 lung disease. Our findings underscore the urgent need for further research and the importance of evaluating those recovering from COVID-19 for symptoms of excessive fatigue and change in functional capacity irrespective of the severity of the initial infection. FUNDING: none. TRIAL REGISTRATION: not relevant.

The impact of a stewardship program on antibiotic administration in community-acquired pneumonia: Results from an observational before-after study.

BACKGROUND: A majority of patients with community-acquired pneumonia (CAP) receive antibiotics. According to the evidence, 5-7 days of treatment should be sufficient for most patients. Many, however, are treated longer than recommended. We have previously conducted a quality improvement study to ensure guideline-conform treatment for CAP. However, the impact of the interventions on antibiotic use has not been investigated. OBJECTIVE: To estimate the impact of an eight-month stewardship program on antibiotic use. METHODS: We conducted a before-after study comparing a four-month baseline period with data from a corresponding follow-up period. We performed univariable and multivariable logistic regression to compare odds for ≤7 days of total antibiotic treatment, ≤3 days of intravenous treatment and the proportion of correct empiric antibiotics. As sensitivity analysis, we repeated the univariable logistic regression on a propensity score-matched cohort by using the same variables we used for adjustments in the multivariable analysis. We also performed subgroup analyses for patients stable ≤72 h of admission. RESULTS: In total, 771 patients were included. Compared to preintervention, the unadjusted odds ratio (OR) for ≤7 days of total antibiotic treatment were 1.84 (95% CI 1.34-2.54) for the whole population and 2.08 (1.41-3.10) for the stable patients. The OR for ≤3 days of intravenous antibiotics were 1.16 (0.87-1.54) and 1.38 (0.87-2.22), respectively. The OR for correct empiric antibiotics were 1.96 (1.45-2.68) and 1.82 (1.23-2.69). Comparable results regarding all outcomes were derived from the other analyses. CONCLUSION: The program resulted in a significantly lower overall antibiotic exposure and a higher proportion of patients treated with the recommended antibiotics without a the reduction of exposure to intravenous antibiotics significantly.

The increasing importance of Haemophilus influenzae in community-acquired pneumonia: results from a Danish cohort study.

BACKGROUND: Numerous studies have shown that the aetiology of community-acquired pneumonia (CAP) varies considerably among different healthcare settings. Because empiric therapies for CAP should cover the major pathogens, reports examining CAP aetiology are considered crucial, particularly in Nordic countries that still rely on penicillin G or V treatments for most patients with CAP. The primary objective of our study was to report CAP aetiology. Secondary objectives included the estimation of positivity rates for different tests and the odds of a positive test for various subgroups. METHODS: In this cohort study, microbiological data were analysed for an overall cohort (variable degree of microbiological testing) and for a subgroup that was tested for both, bacteria, viruses and fungi, using routine methods (defined as extensive testing). RESULTS: The overall cohort comprised 2,264 patients, including 315 who were extensively tested. Bacterial and viral monoinfections were the most commonly identified infections. The dominant pathogen identified among extensively tested patients was Haemophilus influenzae (23.7%), followed by Streptococcus pneumoniae (20.6%). The tests with the highest positivity rates were sputum cultures (34.7%) and viral polymerase chain reaction (PCR, 24.4%). The odds of achieving a microbiological diagnosis increased significantly when extensive testing was performed compared with selective testing (OR 2.86, 95% CI 2.24-3.64). CONCLUSION: Our study indicated that H. influenzae is the dominant responsible pathogen for bacterial CAP in Denmark. Thus, we believe that the current treatment recommendations that encourage the use of penicillin G or V for the majority of patients with CAP need to be revised.

A case of thrombocytopenia and multiple thromboses after vaccination with ChAdOx1 nCoV-19 against SARS-CoV-2.

Recently, reports of severe thromboses, thrombocytopenia, and hemorrhage in persons vaccinated with the chimpanzee adenovirus-vectored vaccine (ChAdOx1 nCoV-19, AZD1222, Vaxzevria; Oxford/AstraZeneca) against severe acute respiratory syndrome coronavirus 2 have emerged. We describe an otherwise healthy 30-year-old woman who developed thrombocytopenia, ecchymosis, portal vein thrombosis, and cerebral venous sinus thrombosis the second week after she received the ChAdOx1 nCoV-19 vaccine. Extensive diagnostic workup for thrombosis predispositions showed heterozygosity for the prothrombin mutation, but no evidence of myeloproliferative neoplasia or infectious or autoimmune diseases. Her only temporary risk factor was long-term use of oral contraceptive pills (OCPs). Although both the prothrombin mutation and use of OCPs predispose to portal and cerebral vein thrombosis, the occurrence of multiple thromboses within a short time and the associated pattern of thrombocytopenia and consumption coagulopathy are highly unusual. A maximum 4T heparin-induced thrombocytopenia (HIT) score and a positive immunoassay for anti-platelet factor 4/heparin antibodies identified autoimmune HIT as a potential pathogenic mechanism. Although causality has not been established, our case emphasizes the importance of clinical awareness. Further studies of this potentially new clinical entity have suggested that it should be regarded as a vaccine-induced immune thrombotic thrombocytopenia.

Efficacy of the TMPRSS2 inhibitor camostat mesilate in patients hospitalized with Covid-19-a double-blind randomized controlled trial.

BACKGROUND: The trans-membrane protease serine 2 (TMPRSS2) is essential for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cell entry and infection. Efficacy and safety of TMPRSS2 inhibitors in patients with coronavirus disease 2019 (Covid-19) have not been evaluated in randomized trials. METHODS: We conducted an investigator-initiated, double-blind, randomized, placebo-controlled multicenter trial in patients hospitalized with confirmed SARS-CoV-2 infection from April 4, to December 31, 2020. Within 48 h of admission, participants were randomly assigned in a 2:1 ratio to receive the TMPRSS2 inhibitor camostat mesilate 200 mg three times daily for 5 days or placebo. The primary outcome was time to discharge or clinical improvement measured as ≥2 points improvement on a 7-point ordinal scale. Other outcomes included 30-day mortality, safety and change in oropharyngeal viral load. FINDINGS: 137 patients were assigned to receive camostat mesilate and 68 to placebo. Median time to clinical improvement was 5 days (interquartile range [IQR], 3 to 7) in the camostat group and 5 days (IQR, 2 to 10) in the placebo group (P = 0·31). The hazard ratio for 30-day mortality in the camostat compared with the placebo group was 0·82 (95% confidence interval [CI], 0·24 to 2·79; P = 0·75). The frequency of adverse events was similar in the two groups. Median change in viral load from baseline to day 5 in the camostat group was -0·22 log10 copies/mL (p <0·05) and -0·82 log10 in the placebo group (P <0·05). INTERPRETATION: Under this protocol, camostat mesilate treatment was not associated with increased adverse events during hospitalization for Covid-19 and did not affect time to clinical improvement, progression to ICU admission or mortality. ClinicalTrials.gov Identifier: NCT04321096. EudraCT Number: 2020-001200-42.

Improved treatment of community-acquired pneumonia through tailored interventions: Results from a controlled, multicentre quality improvement project.

BACKGROUND: Community-acquired pneumonia (CAP) is one of the leading causes of healthcare utilisation and death worldwide. Treatment according to evidence-based clinical guidelines can reduce mortality, antibiotic exposure and length of hospital stay related to CAP. LOCAL PROBLEM: Several studies, including a pilot study from one of our sites, indicate that physicians show a low grade of guideline adherence when managing patients with CAP. METHODS: To improve the guideline-based treatment of patients with CAP admitted to hospital, we designed a quality improvement study. Four process indicators were combined in a CAP care bundle: chest X-ray, CURB-65 severity score, lower respiratory tract samples and antibiotics within 8 hours from admission. After a 4-month baseline period, we applied multiple interventions at three hospitals during 8 months. Progression in our process indicators was measured continuously and compared with a control site without interventions. After the 8-month intervention period, we continued with a 4-month follow-up period to assess the sustainability of the improvements. RESULTS: The care bundle utilisation rate within 8 hours increased from 11% at baseline to 41% in the follow-up period at the intervention sites, whereas it remained below 3% at the control site. The most considerable improvements have been observed regarding documentation of CURB-65 (34% at baseline, 68% at follow-up) and the collection of lower respiratory tract samples (43% at baseline, 63% at follow-up). CONCLUSION: Our study has demonstrated poor adherence to CAP guidelines at all sites at baseline. After implementing multiple tailored interventions, guideline adherence increased substantially. In conclusion, we recommend that CAP guidelines should be actively adapted in order to be followed in a daily routine.

Quantitative B-lymphocyte deficiency and increased TCRγδ T-lymphocytes in acute infectious spondylodiscitis.

Acute infectious spondylodiscitis (AIS) is a serious infection of the spine with rising incidence and a mortality of 3-6%. The role of the immune system in AIS is largely unknown. We performed extensive B and T-lymphocyte phenotyping in patients with AIS at diagnosis and after treatment cessation. In this prospective multicentre study, flow cytometric analysis of T and B-lymphocyte subsets was performed in 35 patients at diagnosis and 3 months after treatment cessation. We additionally analysed levels of immunoglobulins and IgG subclasses, serum level and genetic variants of mannose-binding lectin, and somatic hypermutation. A total of 22 (61%) patients had B-lymphocytes below reference limit at baseline, persisting in 7 (30%) patients at follow-up. We found a lower proportion of CD19 + CD27 + IgD+ marginal zone B-lymphocytes and a higher proportion of γδ+ T-lymphocyte receptors compared with controls at both time points. Immunoglobulin levels were elevated at baseline compared to follow-up, and not associated with absolute B-lymphocyte count. In conclusion, a large proportion of AIS patients presented with profound B-lymphocyte deficiency, only partly reversible at follow-up. Identification of immune dysfunction related to AIS may allow for future targeted therapeutic interventions to restore host immunity.

T-lymphocyte subset dynamics in well-treated HIV-infected men during a bout of exhausting exercise.

In healthy individuals the substantial lymphocytosis during a bout of exhausting exercise constitutes primarily mature T cells from the peripheral lymphoid organs but naïve T cells are also recruited. This study investigated whether the defective CD4 + T-lymphocyte count in peripheral blood during rest in human immunodeficiency virus (HIV)-infected patients would also be observed following a maximal output ergometer bicycle test. At rest, in 45 well-treated HIV-infected patients, mature and naïve CD4 + T-lymphocyte counts were decreased whereas the less immune active CD8 + T lymphocytes were increased compared with 10 healthy control subjects. In response to exercise mature and naïve CD4 + T lymphocytes increased less and mature and naïve CD8 + T lymphocytes increased most in HIV-infected patients. In conclusion, defective resting mature and naïve CD4 + T lymphocytes in well-treated HIV-infected patients are also reflected in defective acutely mobilized active immune cells following exhausting exercise. The CD4 + T-lymphocyte count is highly sensitive to physical activity.

The immune system in children with malnutrition--a systematic review.

BACKGROUND: Malnourished children have increased risk of dying, with most deaths caused by infectious diseases. One mechanism behind this may be impaired immune function. However, this immune deficiency of malnutrition has not previously been systematically reviewed. OBJECTIVES: To review the scientific literature about immune function in children with malnutrition. METHODS: A systematic literature search was done in PubMed, and additional articles identified in reference lists and by correspondence with experts in the field. The inclusion criteria were studies investigating immune parameters in children aged 1-60 months, in relation to malnutrition, defined as wasting, underweight, stunting, or oedematous malnutrition. RESULTS: The literature search yielded 3402 articles, of which 245 met the inclusion criteria. Most were published between 1970 and 1990, and only 33 after 2003. Malnutrition is associated with impaired gut-barrier function, reduced exocrine secretion of protective substances, and low levels of plasma complement. Lymphatic tissue, particularly the thymus, undergoes atrophy, and delayed-type hypersensitivity responses are reduced. Levels of antibodies produced after vaccination are reduced in severely malnourished children, but intact in moderate malnutrition. Cytokine patterns are skewed towards a Th2-response. Other immune parameters seem intact or elevated: leukocyte and lymphocyte counts are unaffected, and levels of immunoglobulins, particularly immunoglobulin A, are high. The acute phase response appears intact, and sometimes present in the absence of clinical infection. Limitations to the studies include their observational and often cross-sectional design and frequent confounding by infections in the children studied. CONCLUSION: The immunological alterations associated with malnutrition in children may contribute to increased mortality. However, the underlying mechanisms are still inadequately understood, as well as why different types of malnutrition are associated with different immunological alterations. Better designed prospective studies are needed, based on current understanding of immunology and with state-of-the-art methods.

Thymic function in HIV-infection.

This thesis is based on seven previously published articles. The work was performed during my employment at The Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, as a scholarship student from 2000-2001 and as a research assistant in the period 2004-2010. HIV-infection is characterized by CD4+ cell depletion. The differences between patients in the degree of CD4+ cell recovery upon treatment with highly active antiretroviral therapy (HAART) may in part be due to differences in the supply of naïve CD4+ cells from the thymus. The thymus atrophies with increasing age for which reason the adult thymus was previously assumed to be without function. The aim of these investigations was to examine the role of the thymus in different aspects of HIV-infection: In adult HIV-infected patients, during HIV-positive pregnancy, and in HIV-exposed uninfected (HIV-EU) children born to HIV-infected mothers. Thymic size and output were determined in 25 adult HIV-infected patients receiving HAART and in 10 controls. Larger thymic size was associated with higher CD4 counts and higher thymic output. Furthermore, patients with abundant thymic tissue seemed to have broader immunological repertoires, compared with patients with minimal thymic tissue. The study supports the mounting evidence of a contribution by the adult thymus to immune reconstitution in HIV-infection. In a follow-up study conducted till 5 years of HAART, the importance of the thymus to the rate of cellular restoration was found to primarily lie within the first two years of HAART. The effect of recombinant human growth hormone (rhGH) was then investigated in a randomized, double-blinded placebo controlled trial in 46 adult HIV-infected patients on HAART. Daily treatment with a low dose of rhGH of 0.7mg for 40 weeks stimulated thymopoiesis as expressed by thymic size, density, and output strongly supporting the assumption that rhGH possesses the potential to stimulate the ageing thymus, holding promise as a future means to complete CD4 restoration and renew the TCR repertoire in patients who respond insufficiently to HAART. Apart from naïve T cells, regulatory T cells (Tregs) are developed in the thymus. Tregs play a critical role in peripheral tolerance and suppress inappropriate immune activation such as induced by HIV. We studied levels of Tregs in adult HIV-infected patients with known thymic output. Our studies demonstrate increased levels of Tregs in HIV-infected patients despite long-term treatment with HAART, suppressed viral loads, and normalized CD4 counts and immune activation suggesting that Tregs expand irreversibly in HIV-infection independently of viral load, CD4 depletion or level of immune activation. Our data further suggest that elevated levels of Tregs in HIV-infected adults may in part be due to increased thymic production of naive Tregs. During pregnancy, establishing fetal-maternal tolerance is essential to pregnancy success. In a prospective study on HIV-positive and HIV-negative pregnant women we found alterations in thymic output and Treg levels in HIV-negative pregnant women compatible with such an establishment. HIV-infected women, however, displayed different immunological profiles from HIV-negative women, and this immune unbalance may interfere with the prevention of fetal rejection and may partly explain the increased risk of abortion in HIV-infected women. We finally examined thymic function in 20 HIV-EU children at 15 months of age. The thymus was reduced in size in HIV-EU children compared with children born to HIV-negative mothers, but no evidence of impaired thymic function, immune regulation, or antibody vaccination response was detected, suggesting that no qualitative immune deficits persist in HIV-EU children beyond infancy. In conclusion, the thymus is functional in adults, and it contributes to immunological recovery in HIV-infected patients primarily during the first two years of HAART. Treg levels are increased in HIV-infected patients independent of viral load, CD4 cell depletion or level of immune activation, and this may be due to increased thymic production of naïve Tregs. Alteration of thymic function in adults is possible, both by stimulation of thymopoiesis with rhGH therapy and as a result of pregnancy. Finally, immunological abnormalities detected in HIV-EU infants are recovered at 15 months of age, and even if diminished in size, thymic function is normalized at this age.

The effect of cholecalciferol and calcitriol on biochemical bone markers in HIV type 1-infected males: results of a clinical trial.

HIV-1-infected patients have an increased risk of osteoporosis and fractures. The main objective of this study was to evaluate the bone metabolism in HIV-1-infected patients exposed to calcitriol and cholecalciferol. We also investigated the relationship between T cells and bone markers. We conducted a placebo-controlled randomized study running for 16 weeks including 61 HIV-1-infected males, of whom 51 completed the protocol. Nineteen participants were randomized to daily treatment with (A) 0.5-1.0 µg calcitriol and 1,200 IU (30 µg) cholecalciferol, 17 participants to (B) 1,200 IU cholecalciferol, and 15 participants to (C) placebo. At baseline and after 16 weeks, we determined collagen type 1 trimeric cross-linked peptide (CTx), procollagen type 1 N-terminal peptide (P1NP), parathyroid hormone (PTH), ionized calcium, 25-hydroxyvitamin D (25OHD), and 1,25-dihydroxyvitamin D [1,25(OH)2D]. We determined naive CD4(+) and CD8(+), activated CD4(+) and CD8(+), and regulatory CD4(+)CD25(+)CD127(low) T lymphocytes. Baseline levels of P1NP and CTx correlated (coefficient 0.5, p<0.001) with each other but not with PTH, 25OHD, or 1,25(OH)2D. In patients receiving calcitriol and cholecalciferol, the mean levels of P1NP (p<0.001) and CTx (p= 0.002) declined significantly compared to our placebo group. Based on changes in P1NP and CTx, we estimated that net bone formation occurred more frequently in group A compared to groups B and C. PTH correlated inversely with naive CD4(+) and CD8(+) cells. Otherwise, no relationships between bone markers and T lymphocytes were demonstrated. Supplementation with calcitriol and cholecalciferol induced biochemical indications of bone formation in HIV-1 patients.

Reduced thymic size but no evidence of impaired thymic function in uninfected children born to human immunodeficiency virus-infected mothers.

BACKGROUND: HIV-exposed, uninfected (HIV-EU) infants present hematologic and immunologic abnormalities at birth, and it remains to be clarified whether these abnormalities persist beyond infancy, for instance, affecting vaccination responses. METHODS: Thymic size and thymic output were evaluated in 20 HIV-EU children at 15 months of age and compared with 10 age- and gender-matched controls. Regulatory T-cells (Tregs) and immune activation as well as cytokine profiles were determined, and the antibody response to Haemophilus influenzae Type b (Hib) vaccination was evaluated. RESULTS: Thymic size was significantly lower in HIV-EU children (P = 0.011). However, CD4 and CD8 counts did not differ between HIV-EU and control children. Likewise, thymic output estimated as CD4 cells expressing naive (CD45RA+CD62L+CD27+, P = 0.31) or recent thymic naive (CD45RA+CD27+CD31+, P = 0.13) phenotype, or CD4 cells containing T-cell receptor excision circles (P = 0.47) were comparable. HIV-EU children and controls had similar levels of activated cells (CD4+CD38+HLA-DR+, P = 0.87; CD8+CD38+HLA-DR+, P = 0.22), Tregs (CD4+CD25+CD127(low)FOXP3+, P = 0.53), and naive Tregs (CD4+CD25+CD127(low)FOXP3+CD45RA+CD27+, P = 0.65). Finally, comparable titers of Haemophilus influenzae Type b antibodies in the 2 groups were found (P = 0.43). CONCLUSION: The study demonstrates reduced thymic size in HIV-EU children compared with children born to HIV-negative mothers, but no evidence of impaired thymic function, immune regulation, or antibody vaccination response was detected, suggesting that no qualitative immune deficits persist in HIV-EU children at 15 months of age.

Improved thymic index, density and output in HIV-infected patients following low-dose growth hormone therapy: a placebo controlled study.

OBJECTIVES: To investigate the effect of low-dose, long-term recombinant human growth hormone (rhGH) therapy on immune reconstitution in human immunodeficiency virus (HIV)-infected patients with focus on thymic index, density and output. DESIGN: Randomized, placebo-controlled, double-blind, single-centre trial. METHODS: Forty-six HIV-infected Caucasian men on highly active antiretroviral therapy, 21-60 years of age, were included. Twenty-eight patients were randomized to 0.7 mg/day rhGH and 18 patients to placebo, administrated as daily subcutaneous injections between 1300 and 1500 h for 40 weeks. Endpoints were changes from baseline in thymic size and thymic output measured as T-cell receptor rearrangement excision circles (TREC) frequency and total TREC content, and total and naive CD4 cells. RESULTS: Thymic density and thymic index increased in the GH group, compared with the placebo group (28 versus 4 Hounsfield units, P = 0.006 and 1 versus 0, P = 0.004). TREC frequency and total TREC content increased in the GH group, compared with the placebo group (37 versus -8%, P = 0.049 and 51 versus -14%, P = 0.026). Total CD4 cells and naive CD4+ cells increased insignificantly more in the GH than the placebo group [11.4%, 95% confidence interval (CI) -6.0 to 28.9; P = 0.19 and 18%, interquartile range (IQR) -4, 40 versus 13%, IQR -12, 39; P = 0.79]. Therapy was well tolerated. CONCLUSIONS: Daily treatment with a low dose rhGH of 0.7 mg for 40 weeks stimulated thymopoiesis expressed by thymic index, density and area, TREC frequency and total TREC content in CD4 cells in HIV-infected patients on highly active antiretroviral therapy.

Thymic involvement in immune recovery during antiretroviral treatment of HIV infection in adults; comparison of CT and sonographic findings.

In adult HIV-infected patients, thymic size evaluated from CT scans seems to be important to the degree of immune reconstitution obtainable during treatment with highly active antiretroviral therapy (HAART). To examine whether ultrasound is as reliable as CT for estimating thymic size and predicting immune recovery, CT and ultrasound scans were performed in 25 adult HIV-infected patients and 10 controls. CD4 counts and naive CD4 counts were measured in order to determine immune reconstitution. Furthermore, the CD4+ T-cell receptor excision circle (TREC) frequency and T-cell receptor (TCR) repertoire were determined. The study demonstrated no correlation between the 2 scanning methods (r = 0.201, p = 0.358 in patients and r = 0.457, p = 0.184 in controls). Among the patients, no association was found between the sonographically estimated thymic size and immunological parameters such as CD4 count (r = 0.083, p = 0.706), naive CD4 count (r = 0.067, p = 0.762), CD4 + TREC frequency (r = 0.028, p = 0.900) and CD4 + TCR repertoire (r = -0.057, p = 0.828). These findings show that CT remains superior for assessing thymic size in adults and is preferable to ultrasound when evaluating the importance of a large thymus to immune recovery during HAART.