Development and validation of equilibrium dialysis UHPLC-MS/MS measurement procedures for total and unbound concentrations of bictegravir, dolutegravir, darunavir and doravirine in human plasma. Application to patients with HIV.

BACKGROUND: Fixed-dose combinations of antiretroviral drugs are commonly used to treat HIV infection and therapeutic monitoring is not part of routine clinical practice. However, drug concentrations monitoring might have role in different clinical scenarios as well as for research purposes. This study aimed to develop and validate UHPLC-MS/MS procedures for measuring total and unbound concentrations of bictegravir, dolutegravir, darunavir and doravirine in human plasma. MATERIAL AND METHODS: Equilibrium dialysis preceded sample preparation (based on protein precipitation) for measuring unbound antiretroviral concentrations. Chromatographic separations were achieved on an Acquity®-UPLC® HSS™-T3 column (50 mm × 2.1 mm; 1.8 µm) using a non-linear water/acetonitrile gradient containing 0.1 % formic acid at a 0.5 mL/min flow rate. Antiretrovirals were detected by tandem mass spectrometry in positive electrospray ionisation and multiple reaction monitoring modes. RESULTS: No significant interferences or carry-over were observed. Imprecisions, absolute relative biases, normalised matrix effects and recoveries were ≤15.0 %, ≤11.1 %, (94.7-104.1)% and (96.7-105.5)%, respectively. Non-linear measuring intervals were observed between (25-10,000) µg/L for total/plasma dialysate concentrations and linearity schemes (1.00-100) µg/L for buffer dialysate concentrations. CONCLUSIONS: The UHPLC-MS/MS procedures developed could be used for research purposes and therapeutic drug monitoring of antiretrovirals in routine clinical practice.

Measurement uncertainty estimation of free drug concentrations in clinical laboratories using equilibrium dialysis.

OBJECTIVES: Developing procedures based on equilibrium dialysis (ED) that allow measuring the free drug concentration in plasma improves therapeutic drug monitoring (TDM) in those cases where its measurement is justified. However, this procedure requires specific sample preparation and presents different pitfalls, which are not error-free. As with any result provided by a clinical laboratory, this one should be as accurate as possible to allow a correct clinical interpretation. The measurement uncertainty (MU) is a parameter that enables the accuracy of results to be known, and that is mandated by ISO 15189. Herein, this study suggests how the MU for the results of the free drug concentrations in serum could be estimated when an ED is used. METHODS: A combination of the top-down and bottom-up approaches was used to estimate the MU based on the ISO/TS 20914:2019 and JCGM 100:2008 guidelines, including the concentration of free phenytoin in serum, as an example. Different scenarios were incorporated considering or not a significant bias related to the primary drawbacks of ED: the non-specific binding, the volume shift effect and the Gibbs-Donnan effect. RESULTS: The expanded uncertainties estimated ranged between 13.0 and 30.9 %. The highest MU corresponded to the free drug concentrations in serum results when significant biases related to the volume shift and Gibbs-Donnan effects exist. CONCLUSIONS: A detailed estimation of MU for free drug concentrations is presented using ED, considering different scenarios. This study could stimulate clinical laboratories to perform MU studies and its application in TDM.

Evaluation of Humoral and Cellular Immune Responses to the SARS-CoV-2 Vaccine in Patients With Common Variable Immunodeficiency Phenotype and Patient Receiving B-Cell Depletion Therapy.

Introduction: SARS-CoV-2 vaccines' effectiveness is not yet clearly known in immunocompromised patients. This study aims to assess the humoral and cellular specific immune response to SARS-CoV-2 vaccines and the predictors of poor response in patients with common variable immunodeficiency (CVID) phenotype and in patients treated with B-cell depletion therapies (BCDT), as well as the safety of these vaccines. Methods: From March to September 2021, we performed a prospective study of all adult patients who would receive the SARS-CoV-2 vaccination and were previously diagnosed with (i) a CVID syndrome (CVID phenotype group; n=28) or (ii) multiple sclerosis (MS) treated with B-cell depleting therapies three to six months before vaccination (BCD group; n=24). Participants with prior SARS-CoV-2 infection; or prior SARS-CoV-2 vaccine administration; or use of any immunosuppressant (except BCDT in MS group) were excluded. A group of subjects without any medical condition that confers immunosuppression and who met all study criteria was also assessed (control group; n=14). A chemiluminescence immunoassay was used to determine pre- and post-SARS-CoV-2 vaccine anti-S IgG antibodies. T-cell specific response was assessed by analysis of pre- and post-SARS-CoV-2 vaccination blood samples with an interferon-gamma release assay. The baseline blood sample also included several biochemical, haematological and immunological analyses. Results: SARS-CoV-2 vaccines are safe in immunocompromised patients, although their effectiveness was lower than in healthy individuals. CVID phenotype patients showed impaired humoral (29%) and cellular (29%) response, while BCD patients fundamentally presented humoral failure (54%). Low IgA values, low CD19+ peripheral B cells, low switched memory B cells, and a low CD4+/CD8+ ratio were predictors of inadequate specific antibody response in CVID phenotype patients. No factor was found to predict poor cellular response in CVID phenotype patients, nor a defective humoral or cellular response in BCD patients. Conclusion: The effectiveness of SARS-CoV-2 vaccines in CVID phenotype and BCD patients is lower than in healthy individuals. Knowledge of predictive factors of humoral and cellular response failure in immunocompromised patients could be very useful in clinical practice, and thus, studies in this regard are clearly needed.

Early Versus Late Diagnosis of Complement Factor I Deficiency: Clinical Consequences Illustrated in Two Families with Novel Homozygous CFI Mutations.

The complement system is an important effector arm of innate immunity and plays a crucial role in the defense against common pathogens. But effective defense and maintenance of homeostasis requires a careful balance between complement activation and regulation. Factor I (FI) is one of the most important regulators of the complement system. Complete FI deficiency is a rare autosomal recessive disorder typically resulting in severe, recurrent infection by encapsulated bacteria. In the present study, we describe two patients from unrelated families with complete FI deficiency diagnosed at very different ages: Patient 1 is a 60-year-old man who had experienced several severe infections (pneumonia, meningitis, sepsis) since childhood, one of which caused significant and permanent neurologic sequelae. In contrast, patient 2 was diagnosed at the age of 4 years after a single infectious episode (otitis media) and through detection of a flat beta2 peak on serum protein electrophoresis. This early diagnosis of FI deficiency enabled prompt implementation of a therapeutic intervention consisting of vaccination with encapsulated bacteria and prophylactic antibiotics. The two patients had novel homozygous mutations in the CFI gene (p.Gly162Asp and p.His380Arg) that disrupted protein function. Interestingly, p.His380Arg is the first mutation described affecting a residue of the highly conserved FI catalytic triad (His380, Asp429, and Ser525). This study illustrates the importance of early versus late diagnosis of FI deficiency and, in general, highlights the clinical relevance of prompt detection of complement system deficiencies.

Epithelial antigenic specificities of circulating autoantibodies in mucosal lichen planus.

BACKGROUND: Mucosal lichen planus (LP) is an inflammatory disease of the mucous membranes of unknown origin. The antigen-specific autoantibodies or T cells responsible for this disease have not yet been established. OBJECTIVES: This study was designed to study the antigenic specificities of circulating antibodies in patients with mucosal LP and to review previous findings on this topic. METHODS: We tested a series of consecutive cases of mucosal LP in our clinic by enzyme-linked immunosorbent assay using desmoglein 3 (Dsg3) and BP180 fusion proteins. RESULTS: Three of 22 patients were positive for anti-NC16A antibodies. Interestingly, we found a middle-aged woman with severe disease with circulating anti-Dsg3 antibodies at high levels, typical of pemphigus vulgaris. Levels of these antibodies positively correlated with the severity of clinical manifestations. We failed to detect anti-desmoglein antibodies in any other patient in our series and in the literature review. CONCLUSIONS: Some patients with mucosal LP may present with circulating anti-BP180 antibodies at low levels. We also report the first case with positive anti-Dsg3 antibodies. The pathogenic relevance of these autoantibodies remains unknown.

Surfactant protein A genetic variants associate with severe respiratory insufficiency in pandemic influenza A virus infection.

INTRODUCTION: Inherited variability in host immune responses influences susceptibility and outcome of Influenza A virus (IAV) infection, but these factors remain largely unknown. Components of the innate immune response may be crucial in the first days of the infection. The collectins surfactant protein (SP)-A1, -A2, and -D and mannose-binding lectin (MBL) neutralize IAV infectivity, although only SP-A2 can establish an efficient neutralization of poorly glycosylated pandemic IAV strains. METHODS: We studied the role of polymorphic variants at the genes of MBL (MBL2), SP-A1 (SFTPA1), SP-A2 (SFTPA2), and SP-D (SFTPD) in 93 patients with H1N1 pandemic 2009 (H1N1pdm) infection. RESULTS: Multivariate analysis showed that two frequent SFTPA2 missense alleles (rs1965708-C and rs1059046-A) and the SFTPA2 haplotype 1A(0) were associated with a need for mechanical ventilation, acute respiratory failure, and acute respiratory distress syndrome. The SFTPA2 haplotype 1A(1) was a protective variant. Kaplan-Meier analysis and Cox regression also showed that diplotypes not containing the 1A(1) haplotype were associated with a significantly shorter time to ICU admission in hospitalized patients. In addition, rs1965708-C (P = 0.0007), rs1059046-A (P = 0.0007), and haplotype 1A(0) (P = 0.0004) were associated, in a dose-dependent fashion, with lower PaO2/FiO2 ratio, whereas haplotype 1A(1) was associated with a higher PaO2/FiO2 ratio (P = 0.001). CONCLUSIONS: Our data suggest an effect of genetic variants of SFTPA2 on the severity of H1N1pdm infection and could pave the way for a potential treatment with haplotype-specific (1A(1)) SP-A2 for future IAV pandemics.