Elevated aluminum excretion in patients by long-term subcutaneous immunotherapy - A cross-sectional case-control study.

BACKGROUND: Aluminum (Al) adjuvants have been used in vaccines and subcutaneous immunotherapy (SCIT) for decades. Despite indisputable neurotoxic properties of Al, there is no clear evidence of a causal relationship between their use and any neurotoxic side effects. However, recent rat studies have shown an accumulation of Al from adjuvants in tissues, especially in bones. OBJECTIVES: Since the human toxicokinetics of Al-adjuvants are poorly understood, this study aimed to evaluate whether up-dosed or long-term SCIT with Al-coupled extracts leads to increased Al load in humans. METHODS: This observational cross-sectional case-control study explored Al excretion in hymenoptera venom allergy patients recruited in 2020 before initiation (n = 10) and during ongoing (n = 12) SCIT with Al-based preparations. Urine samples were collected before and 24 h after the SCIT injections and analyzed for aluminum content by using atomic absorption spectrometry. The cumulative administered Al dose was extracted from patient records. Patients receiving long-term immunotherapy were treated between 2.8 and 13.6 years (mean 7.1). Other potential sources of Al exposure were surveyed. RESULTS: Patients who had received Al-coupled immunotherapy for several years showed significantly (p < 0.001) higher Al excretion than the controls at initiation of immunotherapy (mean 18.2 µg/gC vs. 7.9 µg/gC) and predominantly (73%) were above the 95th percentile of the general populations' exposure (>15 µg/gC), however, without reaching levels of toxicological concern (>50 µg/gC). Taking both groups together excreted Al levels correlated with the cumulative administered Al dose from SCIT (linear regression: Alurine = 8.258 + 0.133*Alcum; p = 0.001). DISCUSSION: These results suggest a relevant iatrogenic contribution of long-term SCIT to human internal Al burden and potential accumulation. Considering the medical benefits of Al-adjuvants and SCIT a differentiated risk-benefit analysis is needed. For certain scenarios of potential toxicological concern in clinical practice biomonitoring might be advisable.

Effect of an aluminum foil-processed diet on internal human aluminum burden.

BACKGROUND AND PURPOSE: Aluminum can be released into food by aluminum-containing food-contact materials (Al-FCM) during preparation or storage. There is considerable concern that extra aluminum intake may have negative effects on public health, especially with regard to its high background exposure and neurotoxic properties of aluminum in high exposures. Human in-vivo data on the additional aluminum load from Al-FCM, however, are lacking. As such, the objective of this study was to explore whether the consumption of a diet highly exposed to such products leads to an increased systemic Al load in real-world conditions. MATERIALS AND METHODS: An exploratory, single-arm intervention study with a partially standardized diet was designed and carried out with 11participants. The same 10-day sequence of dishes was repeated three times. Participants were exposed to Al-FCM from Days 11 to 20, whereas control-phase meals were prepared without Al-FCM during the first and last 10-day periods. Spot urine samples were collected each morning and evening and analyzed for their aluminum concentration; appropriate contamination countermeasures were taken. PRINCIPAL RESULTS: Urinary aluminum excretion showed a strong dependency on the creatinine concentration in urine and required adjustment in further analyses. The creatinine-adjusted aluminum excretion during the exposure phase (median 1.98 µg/g creatinine) was higher than in both control phases (1.78 µg/g creatinine each). Two different mixed-effects regression models showed a significant effect in the exposure phase. Considering a discrete time effect, the creatinine-adjusted mean increase in the exposure phase was estimated to be 0.19 µg/L (95% CI: 0.07-0.31; p = 0.0017). MAJOR CONCLUSIONS: This study demonstrated a measurable but fully reversible additional Al burden in humans from subacute Al-FCM exposure under real-world conditions. The estimated increase from Al-FCM corresponds to 8% of the baseline concentration. These data enable a more robust assessment of human health risks by Al-FCM.

Human urinary and blood toxicokinetics of beryllium after accidental exposure.

PURPOSE: Beryllium is known to have adverse health effects and is classified as carcinogenic to humans. However, data on systemic beryllium exposure in humans are rare and especially human toxicokinetics are largely uncharted. As such, the first reported multi-annual course of blood and urine concentrations after a high exposure scenario provides important new insights. METHODS: For a medical follow-up biomonitoring samples were collected for 56 months from a male subject after an accidental and multi-faceted high exposure. Sampling started on day 2 post-exposure for urine and day 147 for blood. The samples were analyzed by inductively coupled mass spectrometry (ICP-MS) and plotted longitudinally as a function of time. Terminal half-lives were calculated assuming a first-order elimination process. MAIN FINDINGS: Both matrices showed highly increased initial concentrations (about 100-fold), despite the 147-day delay in blood sampling, and a marked decline over time. In urine, a two-phase excretion process was suspected based on the longitudinal data. Calculations gave terminal half-lives of 117.5 days and 666.5 days for phases 1 and 2, respectively. Blood kinetics called for a terminal half-life of 103.5 days. Elimination kinetics in blood and urine were comparable, simultaneously gathered samples showed an excellent correlation (R² = 0.985). PRINCIPAL CONCLUSIONS: The long-term follow-up after a high initial exposure to beryllium provides the first detailed insights into the elimination course of systemically available beryllium in humans. Conform kinetics of beryllium in urine and blood and the strong correlation between both parameters indicate high data validity and support the good representation of the current systemically available beryllium by urine and blood concentration in humans. The relatively long terminal half-lives in both matrices suggest a possible accumulation in humans in case of repeated exposures.

Syncarcinogenesis of natural UV radiation and polycyclic aromatic hydrocarbons in the development of squamous cell carcinomas of the skin?

Squamous cell carcinomas (SCC) of the skin can be induced by occupational exposures to polycyclic aromatic hydrocarbons (PAHs), as in tar and soot, or to UV radiation and can be recognized and compensated as occupational diseases. A possible syncarcinogenic effect of these exposures in the development of SCC in humans is under discussion. For the scientific validation of this question, a systematic literature search was conducted using the databases PubMed, Web of Science, and Scopus. Studies on individuals with SCC of the skin and their precursors as well as occupational, non-occupational, or therapeutic exposure to UV radiation and PAHs were selected. In addition, animal studies with exposure to UV radiation and PAHs were evaluated. After screening the abstracts of 510 identified studies, the full texts of 131 studies were reviewed. None of the epidemiological studies provided robust evidence for a syncarcinogenesis of PAHs and UV radiation in the development of SCC of the skin in humans. Nevertheless, as there are indications for a (super-)additive effect of UV radiation and PAH exposure from animal studies and mechanistic investigations, syncarcinogenesis seems possible. However, quantitative dose-response relationships are lacking which would allow comparison of the onset of an adverse effect between the different exposure levels.

Impact of Daily Antiperspirant Use on the Systemic Aluminum Exposure: An Experimental Intervention Study.

BACKGROUND AND OBJECTIVES: Adverse health effects such as neurotoxic and carcinogenic effects through aluminum from cosmetic products have been repeatedly discussed. The dermal uptake and impact on the systemic aluminum load is still poorly understood. Therefore, we investigated the effect of daily antiperspirant use on the systemic aluminum load under real-life conditions. METHODS: 21 healthy subjects meeting certain selection criteria to ensure a low systemic aluminum background load were asked to use a commercial aluminum-containing antiperspirant for 14 days. A questionnaire enquired about shaving habits and other sources of aluminum. Aluminum levels were measured before and after the exposure in 24-h urine and plasma using atomic absorption spectroscopy. Urine samples (n = 6) with <700 mg/day creatinine excretion or more than 30% difference in 24-h creatinine excretion were excluded from further analysis. RESULTS: No significant increase in plasma aluminum concentration or total excreted aluminum per day before and after exposure was measurable. No sample exceeded the reference values of the general population (maximum: 9.42 µg/g creatinine and 2.1 µg/L plasma). Shaving habits did not have a significant influence on the systemic aluminum load. Also, no correlation between the total amount of antiperspirant applied and the systemic aluminum level could be demonstrated. CONCLUSIONS: No measurable contribution to the overall systemically available aluminum load due to daily use of an antiperspirant for 14 days could be shown, but real-life data concerning long-term use or higher concentrations are still lacking. Considering toxicological occupational exposure data, adverse neurotoxic changes are unlikely in the case of urinary excretion of <50 µg aluminum/g creatinine (= no observed adverse effect level), even following long-term exposure.

Systemic availability of lipophilic organic UV filters through dermal sunscreen exposure.

BACKGROUND: Chemical UV filters are common components in sunscreens and cosmetic products and used to protect the skin against harmful effects of sunlight like sunburn. However, the effectiveness of sunscreens in the prevention of skin cancer is in some parts still controversial. Meanwhile, questions about negative effects of the chemical UV filters on human health arise and request an effective risk assessment. Real-life exposure data in humans after application of these products are still rare. Thus, we explored whether and to what extent UV filters are absorbed through the skin into the human body. MATERIAL AND METHODS: Plasma and urine samples from 20 healthy volunteers were collected before, during and after a real-life exposure scenario (1st application: 2 mg/cm2; 2nd and 3rd (after 2 and 4 h): 1 mg/cm2 each) using a commercial sunscreen formulation for one day. These samples were analyzed for their content of the currently prominent UV filters octocrylene and avobenzone as well as 2-cyano-3,3-diphenylacrylic acid (CDAA) as the main octocrylene metabolite by using different liquid chromatography electrospray-ionization tandem mass spectrometric procedures. RESULTS: Following dermal sunscreen exposure, avobenzone, octocrylene and CDAA reached concentrations up to 11 µg/L, 25 µg/L and 1352 µg/L in plasma. In urine detection rates of avobenzone and octocrylene were low while CDAA showed a high detection rate and reached up to 5207 µg/g creatinine. Kinetic models could be fitted for octocrylene and CDAA in plasma and CDAA in urine. Concentration peaks were reached between 10 and 16 h after first application and half-life periods were in the range of 1.5 to 2 days. The lipophilic UV filter octocrylene and its metabolite CDAA showed a much slower elimination than other more hydrophilic UV filters. Concordantly, the metabolite CDAA in particular showed a markedly increased renal excretion over the whole sampling period and indicated high internal exposure to OC. DISCUSSION: Real-life sunscreen usage leads to considerable bioavailability of organic UV filters and their metabolites which is rarely seen for other environmental exposures. A combined monitoring of the parent compound and its metabolites is important to fully address internal exposure to the UV filter in humans. Considering the kinetic profiles a prolonged systemic release due to depot formation in skin and a potential accumulation through multi-day exposure is presumed. High in-vivo loads call for a critical toxicological assessment of the UV filters and their metabolites.

Retrospective evaluation of exposure to natural UV radiation: experiences with the online UV history tool in a field study.

BACKGROUND: Cutaneous squamous cell carcinoma and multiple actinic keratoses can be recognized as occupational diseases if the site affected has been subjected to additional occupational UV exposure of at least 40 %. An online UV history tool that allows for the quantification of occupational and recreational UV doses was now tested in a field study. PATIENTS AND METHODS: Ninety-nine patients with nonmelanoma skin cancer were examined. Patient history with respect to UV exposure was obtained using the online UV history tool. Initial validation was carried out with data from ten additional patients. In the context of a pilot study, the applicability of the tool was assessed using a questionnaire. RESULTS: Overall, patient history revealed a UV exposure between 3,792 and 53,163 SEDs. Patients with squamous cell carcinoma, actinic keratoses, or Bowen's disease (n  =  22) had significantly higher SED values and were significantly older (73 vs. 66 years) than patients with basal cell carcinoma (n  =  77). Occupational UV exposure was reported by 19 patients, two of whom showed an additional occupational UV exposure of more than 40 %, which prompted the filing of a (suspected) occupational disease report. With respect to validation, there was evidence of good inter-investigator reliability. The applicability of the tool was rated as good. CONCLUSIONS: The online UV history tool enables quick retrospective quantification of occupational and recreational UV exposure in case of suspicion of the occupational disease "cutaneous squamous cell carcinoma or multiple actinic keratoses caused by natural UV radiation".

Cytochrome P450s in human immune cells regulate IL-22 and c-Kit via an AHR feedback loop.

The mechanisms how environmental compounds influence the human immune system are unknown. The environmentally sensitive transcription factor aryl hydrocarbon receptor (AHR) has immune-modulating functions and responds to small molecules. Cytochrome P4501 enzymes (CYP1) act downstream of the AHR and metabolize small molecules. However, it is currently unknown whether CYP1 activity is relevant for immune modulation. We studied the interdependence of CYP1 and AHR in human primary immune cells using pharmacological methods. CYP1 inhibition increased the expression levels of the stem cell factor receptor (c-Kit) and interleukin (IL)-22 but decreased IL-17. Single cell analyses showed that CYP1 inhibition especially promoted CD4+ helper T (Th) cells that co-express c-Kit and IL-22 simultaneously. The addition of an AHR antagonist reversed all these effects. In addition to T cells, we screened other human immune cells for CYP and found cell-specific fingerprints, suggesting that similar mechanisms are present in multiple immune cells. We describe a feedback loop yet unknown in human immune cells where CYP1 inhibition resulted in an altered AHR-dependent immune response. This mechanism relates CYP1-dependent metabolism of environmental small molecules to human immunity.

Heterozygous STAT1 gain-of-function mutations underlie an unexpectedly broad clinical phenotype.

Since their discovery in patients with autosomal dominant (AD) chronic mucocutaneous candidiasis (CMC) in 2011, heterozygous STAT1 gain-of-function (GOF) mutations have increasingly been identified worldwide. The clinical spectrum associated with them needed to be delineated. We enrolled 274 patients from 167 kindreds originating from 40 countries from 5 continents. Demographic data, clinical features, immunological parameters, treatment, and outcome were recorded. The median age of the 274 patients was 22 years (range, 1-71 years); 98% of them had CMC, with a median age at onset of 1 year (range, 0-24 years). Patients often displayed bacterial (74%) infections, mostly because of Staphylococcus aureus (36%), including the respiratory tract and the skin in 47% and 28% of patients, respectively, and viral (38%) infections, mostly because of Herpesviridae (83%) and affecting the skin in 32% of patients. Invasive fungal infections (10%), mostly caused by Candida spp. (29%), and mycobacterial disease (6%) caused by Mycobacterium tuberculosis, environmental mycobacteria, or Bacille Calmette-Guérin vaccines were less common. Many patients had autoimmune manifestations (37%), including hypothyroidism (22%), type 1 diabetes (4%), blood cytopenia (4%), and systemic lupus erythematosus (2%). Invasive infections (25%), cerebral aneurysms (6%), and cancers (6%) were the strongest predictors of poor outcome. CMC persisted in 39% of the 202 patients receiving prolonged antifungal treatment. Circulating interleukin-17A-producing T-cell count was low for most (82%) but not all of the patients tested. STAT1 GOF mutations underlie AD CMC, as well as an unexpectedly wide range of other clinical features, including not only a variety of infectious and autoimmune diseases, but also cerebral aneurysms and carcinomas that confer a poor prognosis.

Chronic mucocutaneous candidiasis, from bench to bedside.

Chronic mucocutaneous candidiasis (CMC) defines a heterogeneous group of orphan and inherited syndromes characterised by chronic and recurrent infections of the skin and mucosa with the yeast Candida. Increasing evidence suggests that this inefficient defence against Candida species is reflected by a DC/T cell defect which results in an impaired Th17 and Th1 immune response and, consecutively, a failed immune instruction of tissue cells. Little is known about the incidence and prognosis of CMC. Clinically, the main complications are debilitating hands (Candida granuloma) and oesophageal stricture with potential mal-digestion/-absorption. Furthermore, the chronic infections are likely a risk factor for the development of squamous cell carcinoma. Since resistance to anti-mycotic drugs evolves rapidly, efficient and flexible therapeutic management is essential for CMC patients.