Pharmacokinetics/pharmacodynamics by race: Analysis of a peginterferon ß-1a phase 1 study.

BACKGROUND: Black/African American participants are underrepresented in clinical trials for multiple sclerosis but can experience a greater burden of disease than other racial groups in the United States. A phase 1, open-label, crossover study that demonstrated bioequivalence of subcutaneous and intramuscular injection of peginterferon ß-1a in healthy volunteers enrolled similar proportions of Black and White participants, enabling a post hoc subgroup analysis comparing these groups. METHODS: Peginterferon ß-1a (125 µg) was administered by subcutaneous or intramuscular injection, followed by a washout period before a second injection using the alternative method. The primary pharmacokinetic and pharmacodynamic endpoints were maximum observed concentration (Cmax) and area under the concentration-time curve from hour 0 to infinity (AUCinf) of study drug and serum concentration of neop-terin, respectively. Safety and tolerability were included as secondary endpoints. FINDINGS: This analysis included 70 (51.5%) Black and 59 (43.3%) White participants. Peginterferon ß-1a Cmax was 29.8% higher in Black than in White participants following subcutaneous administration but was similar following intramuscular administration. Mean AUCinf was 31.0% and 11.8% greater in Black than in White participants with subcutaneous and intramuscular administration, respectively. Pharmacodynamics and safety signals were similar between groups, although Black participants reported numerically fewer adverse events. CONCLUSIONS: No clinically meaningful differences were identified between Black and White participants related to peginterferon ß-1a administration, supporting the approved dose of 125 µg/mL peginterferon ß-1a. Future clinical studies should include sufficiently diverse populations to ensure accurate assessments of treatment response. FUNDING: Funding for medical writing support was provided by Biogen (Cambridge, MA, USA).

The Minority Scientists' Experience: Challenging and Overcoming Barriers to Enhancing Diversity and Career Advancement.

Minority groups face barriers in accessing quality health care, professional advancement, and representation in immunology research efforts as a result of institutional racism that if unaddressed can perpetuate a lack of diversity. In 2021, the AAI Minority Affairs Committee convened a cross section of academic and industry scientists from underrepresented groups at various stages of their professions to discuss how best to address the toll racism takes on study design and scientific careers. Panelists drew directly from their own experiences as scientists to share perspectives and strategies for countering a lack of representation in clinical research, responding to microaggressions, navigating academic advancement, and providing effective mentorship. The session reinforced the need for minority scientists to take an active role in advocating for diversity, engaging mentors, and taking responsibility to face rather than avoid institutional obstacles. Overall, increased dialogue and institutional awareness of the experience of scientists from underrepresented groups in research remain the best tools to ensure a health equity mindset and advancement of their careers.

Bioequivalence of intramuscular and subcutaneous peginterferon beta-1a: results of a phase I, open-label crossover study in healthy volunteers.

BACKGROUND: Peginterferon beta-1a administered every 2 weeks via subcutaneous (SC) injection is approved to treat adult patients with relapsing-remitting multiple sclerosis (RRMS) and relapsing forms of multiple sclerosis (RMS). However, associated injection site reactions (ISRs) can lead to treatment discontinuation. Prior studies with interferon beta-1a reported a lower frequency of ISRs with intramuscular (IM) administration than with SC administration. IM administration of peginterferon beta-1a may therefore represent a useful alternative treatment option. METHODS: A phase I, open-label, two-period crossover study randomized healthy volunteers to receive a single dose of peginterferon beta-1a 125 mcg administered IM followed by a single 125 mcg dose administered SC after a 28-day washout or vice versa. Blood samples were collected up to 504 h post dose to determine pharmacokinetic (PK) and pharmacodynamic (PD) profiles. The primary endpoint was assessment of bioequivalence based on maximum serum concentration (Cmax) and area under the curve from time zero extrapolated to infinity (AUCinf). Other PK parameters, as well as PD (serum neopterin) and safety profiles, were also evaluated. RESULTS: The study enrolled 136 participants. Bioequivalence of IM and SC peginterferon beta-1a was established for both Cmax ([least squares (LS)] mean IM/SC ratio: 1.083 [90% confidence interval (CI), 0.975-1.203]) and AUCinf (LS mean IM/SC ratio: 1.089 [90% CI, 1.020-1.162]). Other PK and PD parameters were similar between administration routes, although moderate to high inter-subject variability was observed for IM and SC. Safety profiles were generally balanced between IM and SC administration. ISRs occurred at a lower frequency with IM [14.4% (95% CI, 8.89-21.56%)] than with SC [32.1% (95% CI, 24.29-40.70%)] administration (p = 0.0005). CONCLUSIONS: These results demonstrate bioequivalence between peginterferon beta-1a IM and SC and support the consideration of IM injection of peginterferon beta-1a as a viable treatment option in patients with RRMS and RMS.

Prime-boost strategies to embrace diversity and inclusion in immunology.

Immunologists appreciate the need for creative approaches to tackle complex scientific questions, which can involve not only the use of novel technologies but also the experience of scientists from diverse backgrounds. Here, we highlight measures to prime for the inclusion of women and underrepresented individuals in science to boost immunology research.

Compounded Bioidentical Hormones in Endocrinology Practice: An Endocrine Society Scientific Statement.

This Scientific Statement finds that there is no rationale for routine prescribing of unregulated, untested, and potentially harmful custom compounded bioidentical hormone therapies.

Anti-CD20 as the B-Cell Targeting Agent in a Combined Therapy to Modulate Anti-Factor VIII Immune Responses in Hemophilia a Inhibitor Mice.

Neutralizing antibody formation against transgene products can represent a major complication following gene therapy with treatment of genetic diseases, such as hemophilia A. Although successful approaches have been developed to prevent the formation of anti-factor VIII (FVIII) antibodies, innovative strategies to overcome pre-existing anti-FVIII immune responses in FVIII-primed subjects are still lacking. Anti-FVIII neutralizing antibodies circulate for long periods in part due to persistence of memory B-cells. Anti-CD20 targets a variety of B-cells (pre-B-cells to mature/memory cells); therefore, we investigated the impact of B-cell depletion on anti-FVIII immune responses in hemophilia A mice using anti-CD20 combined with regulatory T (Treg) cell expansion using IL-2/IL-2mAb complexes plus rapamycin. We found that anti-CD20 alone can partially modulate anti-FVIII immune responses in both unprimed and FVIII-primed hemophilia A mice. Moreover, in mice treated with anti-CD20+IL-2/IL-2mAb complexes+rapamycin+FVIII, anti-FVIII antibody titers were significantly reduced in comparison to mice treated with regimens targeting only B or T cells. In addition, titers remained low after a second challenge with FVIII plasmid. Treg cells and activation markers were transiently and significantly increased in the groups treated with IL-2/IL-2mAb complexes; however, significant B-cell depletion was obtained in anti-CD20-treated groups. Importantly, both FVIII-specific antibody-secreting cells and memory B-cells were significantly reduced in mice treated with combination therapy. This study demonstrates that a combination regimen is highly promising as a treatment option for modulating anti-FVIII antibodies and facilitating induction of long-term tolerance to FVIII in hemophilia A mice.

Immunotherapy targeting inhibitory Fcγ receptor IIB (CD32b) in the mouse is limited by monoclonal antibody consumption and receptor internalization.

Genetic deficiency of the inhibitory Fc receptor, FcγRIIB (CD32b), has been shown to augment the activity of activatory FcγR and promote mAb immunotherapy. To investigate whether mAbs capable of blocking FcγRIIB have similar capacity, we recently generated a panel of specific anti-mouse FcγRIIB mAbs that do not cross-react with other FcRs, allowing us to study the potential of FcγRIIB as a therapeutic target. Previous work revealed a number of these mAbs capable of eliciting programmed cell death of targets, and in the present study we demonstrated their ability to promote target cell phagocytosis. However, in a variety of murine tumor models, anti-FcγRIIB mAbs demonstrated limited therapeutic activity despite optimized treatment regimens. Unexpectedly, we observed that the anti-FcγRIIB mAbs are rapidly and extensively consumed in vivo, both by the tumor and host cells, including B cells, leading to a precipitous loss from the circulation. Closer analysis revealed that the anti-FcγRIIB mAbs become extensively internalized from the cell surface within 24 h in vivo, likely explaining their suboptimal efficacy. Subsequent studies revealed that anti-FcγRIIB mAb immunotherapy was effective when used against FcγRIIB(+) tumors in FcγRIIB(-/-) recipients, indicating that consumption of the mAb by nontumor cells is the primary limitation of these reagents. Importantly, similar rates of internalization were not seen on human target cells, at least in vitro. These studies further highlight the need to determine the propensity of mAb therapeutics to internalize target receptors and also identify potential key differences between human and mouse cells in this respect.

Intercommunication between the neuroendocrine and immune systems: focus on myasthenia gravis.

Crosstalk exists between the nervous, endocrine, and immune systems, and perturbations in these interactions have been associated with disease. This includes production of neuroendocrine factors that alter immune system activity and increase susceptibility to or severity of immune-related conditions, such as myasthenia gravis (MG)--a T-cell-dependent, B-cell-mediated autoimmune disorder. MG results from impairment of transmission to the neuromuscular junction and involves the thymus--especially in early-onset disease, but the exact mechanism by which the thymus impacts disease is unclear. MG afflicts millions of individuals worldwide each year, and both men and women can develop symptoms. However, prevalence and age of onset differs between men and women. Women exhibit higher incidence and earlier age of onset compared to men, and disease fluctuates during pregnancy. This suggests that sex hormones play a role in influencing disease outcome. In this review, we will consider what is known about the manifestation of MG, theories on how different forms of MG are influenced or alleviated by steroid hormones, current treatment options, and what measures could be important to consider in the future.

Tissue expression of steroid hormone receptors is associated with differential immune responsiveness.

Glucocorticoids have been used as treatments against a number of diseases, especially autoimmune/inflammatory conditions in which the immune system is overactive. These treatments have varying degrees of responsiveness among individuals and in different tissues (including brain); therefore, it is important to determine what could account for these differences. In this study, we evaluated expression of stress hormone receptors in immune cells from lymphoid and non-lymphoid tissues (including brain) as a possible explanation. We analyzed leukocytes (CD45(+)) in kidney, liver, spleen, and thymus tissues from healthy mice for expression of the receptor for stress hormone (glucocorticoid-GR) as well as other steroid hormones (androgen-AR, progesterone-PR) and found that all tissues expressed these steroid hormone receptors but with varying patterns. To determine whether tissue-specific differences were related to immune cell composition, we examined steroid hormone receptor expression in T lymphocytes from each of these tissues and found similar patterns of expression in these cells regardless of tissue source. Because glucocorticoids can also impact brain function, we further examined expression of the stress hormone receptor in brain tissue and found GR expressed in immune cells at this site. In order to investigate the potential impact in an area of neuropathology, we utilized a mouse model of West Nile Virus (WNV). We observed pathological changes in brains of WNV-infected animals and T lymphocytes in the areas of inflammation; however, these cells did not express GR. These data indicate that tissue-specific differences in steroid hormone receptor expression by immune cells could determine responsiveness to steroid hormone treatment.

Flow cytometry as a tool for measurement of steroid hormone receptor protein expression in leukocytes.

Measurement of protein expression in live, intact cells using flow cytometry (FC) has been employed for several decades in the areas of immunology, cell biology, and molecular biology. More recently, this technique has found appreciation in applied scientific fields, including cancer biology and endocrinology, to serve as a tool for identifying cells more likely to respond to specific treatments. FC, also referred to as fluorescence-activated cell sorting (FACS), is an antibody-based method that provides the user with an ability to identify proteins expressed on surfaces of cells as well as in the cytoplasm, including steroid hormone receptors. This technique is most useful for examining specific cell types in a heterogeneous population and therefore can be used to identify cells more likely to respond to treatments based on expression of the appropriate receptor. Isolation of purified subpopulations for further manipulation and investigation of functional capacity is also possible using a cell sorter, which uses similar technology to isolate cells for use by the researcher. This is especially important for studying responses of less abundant cell populations in tissues that express high levels of a target protein or receptor of interest. Furthermore, FACS analysis is clinically useful to identify and isolate responsive cell populations, which may be less appreciable in whole tissues because of the diluting effects of surrounding, nonresponding cell types. Immune cells are commonly utilized as a source of cell populations in the FC technique and have previously been shown to express steroid hormone receptors and respond to steroid hormone treatment. Here, we demonstrate that FC is a useful tool for identifying immune cells expressing steroid hormone receptor protein. This method can also be easily expanded to include other, nonimmune cell populations to address specific research questions related to steroid hormone receptor biology.

Inhibitory effects of progesterone differ in dendritic cells from female and male rodents.

BACKGROUND: Steroid hormones, such as progesterone, are known to have immunomodulatory effects. Our research group previously reported direct effects of progesterone on dendritic cells (DCs) from female rodents. Primarily affecting mature DC function, progesterone effects included inhibition of proinflammatory cytokine secretion, downregulation of cell surface marker (major histocompatibility complex class II, CD80) expression, and decreased T-cell proliferative capacity, and were likely mediated through progesterone receptor (PR) because the PR antagonist RU486 reversed these effects. OBJECTIVE: The goal of this study was to assess differences in response to progesterone by DCs from female and male rodents. METHODS: Using real-time reverse-transcriptase polymerase chain reaction, transcriptional expression of steroid hormone receptors was measured in immature bone marrow-derived DCs (BMDCs) from male and female rats. Expression of steroid hormone receptor protein was also assessed in these cells using flow cytometry and fluorescence microscopy. To evaluate functional differences between BMDCs from female and male rats in response to the steroid hormone progesterone, levels of secreted cytokines were measured using enzyme-linked immunosorbent assay. RESULTS: Higher numbers of immature BMDCs from males expressed glucocorticoid receptor (GR) and androgen receptor (AR) proteins compared with females (males vs females, mean [SD]: GR = 68.75 [7.27] vs 43.61 [13.97], P = NS; AR = 75.99 [15.38] vs 8.25 [1.88], P = 0.002), whereas higher numbers of immature BMDCs from females expressed PR protein compared with males (females vs males: PR = 74.19 [12.11] vs 14.14 [4.55], P = 0.043). These differences were not found at the level of transcription (females vs males: GR = 0.088 vs 0.073, P = NS; AR = 0.076 vs 0.069, P = NS; PR = 0.075 vs 0.065, P = NS). Compared with those from females, mature BMDCs from males produced higher quantities of cytokines (tumor necrosis factor-alpha [TNF-alpha], interleukin [IL]-1beta, IL-10) (females vs males: TNF-alpha = 920.0 [79.25] vs 1100.61 [107.97], P = NS; IL-1beta = 146.60 [38.04] vs 191.10 [10.47], P = NS; IL-10 = 167.25 [4.50] vs 206.15 [23.48], P = NS). Conversely, BMDCs from females were more sensitive to progesterone, as indicated by a more dramatic reduction in proinflammatory cytokine secretion (females vs males, highest concentration of progesterone: TNF-alpha = 268.94 [28.59] vs 589.91 [100.98], P = 0.04; IL-1beta = 119.50 [10.32] vs 154.35 [6.22], P = NS). CONCLUSIONS: These findings suggest that progesterone effects on DCs in rodents may be more pronounced in females than in males, and this is likely due to differences in PR protein expression. Our observations may help elucidate disparities in the incidence and severity of autoimmune disorders between females and males, and the role specific steroid hormones play in regulating immune responses.

The role of glucocorticoids and progestins in inflammatory, autoimmune, and infectious disease.

A bidirectional communication exists between the CNS and the immune system. The autonomic nervous system, through neurotransmitters and neuropeptides, works in parallel with the hypothalamic-pituitary-adrenal axis through the actions of glucocorticoids to modulate inflammatory events. The immune system, through the action of cytokines and other factors, in turn, activates the CNS to orchestrate negative-feedback mechanisms that keep the immune response in check. Disruption of these interactions has been associated with a number of syndromes including inflammatory, autoimmune, and cardiovascular diseases, metabolic and psychiatric disorders, and the development of shock. The hypothalamic-pituitary-gonadal axis also plays an important part in regulating immunity through the secretion of sex hormones. Although numerous studies have established a role for immunomodulation by estrogen and testosterone, the role of progesterone is less well understood. Progesterone is crucial for reproductive organ development and maintenance of pregnancy, and more recent studies have clearly shown its role as an important immune regulator. The main focus of this review will be about the role of steroid hormones, specifically glucocorticoids and progesterone, in inflammatory responses and infectious diseases and how dysregulation of their actions may contribute to development of autoimmune and inflammatory disease.

Neuroendocrine factors alter host defense by modulating immune function.

An increasing body of evidence demonstrates that there is bidirectional communication between the neuroendocrine and immune systems. Interaction between these systems results in a variety of outcomes, including the well documented "sickness behavior" elicited by cytokines of the immune system that can enter the brain and activate second messengers that modify neuronal activity. Crosstalk between the neuroendocrine and immune systems can also result in production of factors by the nervous and endocrine systems that alter immune cell function and subsequent modulation of immune responses against infectious agents and other pathogens. Continued exposure to molecules produced by the neuroendocrine system has also been known to increase susceptibility and/or severity of disease. Furthermore, neuroendocrine factors are thought to play a major role in gender-specific differences in development of certain disorders, including autoimmune/inflammatory diseases that have a two to tenfold higher incidence in females compared to males. Neuroendocrine factors can affect immune cells at the level of gene transcription but have also been shown to modify immune cell activity by interacting with intracellular molecules, resulting in modified ability of these cells to mount a potent immune response. In this review, we will consider various effects of the neuroendocrine system and its proteins on specific populations of immune cells and associated responses in host immunity against pathogens. We will further discuss how this modification of immune cell activity by the neuroendocrine system can contribute to susceptibility/severity of disease development.

Evaluation of steroid hormone receptor protein expression in intact cells using flow cytometry.

Several methods are currently employed to evaluate expression of steroid hormone receptors in tissues and cells, including real-time reverse-transcriptase polymerase chain reaction (real-time RT-PCR) and western blot assays. These methods require homogenization of cells, thereby preventing evaluation of individual cells or specific cell types in a given tissue sample. In addition, methods such as real-time RT-PCR assess mRNA levels, which may be subject to posttranslational modifications that prevent subsequent production of functional proteins. Flow cytometry is a fluorescence-based technique commonly used to evaluate expression of cell surface and intracellular proteins. This method is especially useful as it allows for single-cell analysis and can be utilized to determine the amount of receptor expressed by individual cells. Flow cytometry is commonly used to analyze immune cell activity and determine functionality based on changes in expression of cell surface molecules, as well as intracellular proteins (such as cytokines). Here, we describe a method to identify protein expression of steroid hormone receptors by rat leukocytes from different organs (spleen, liver and thymus) using flow cytometry. We examined expression of glucocorticoid receptor (GR), androgen receptor (AR) and progesterone receptor (PR) by cells at these sites and were able to demonstrate expression of receptors, as well as the intensity of expression of each receptor. This method is useful for rapid, high throughput measurement of steroid hormone receptors at the protein level in single, intact cells and would be valuable to determine which cells are more likely to respond to steroid hormone treatment.

Progesterone inhibits mature rat dendritic cells in a receptor-mediated fashion.

A variety of extraimmune system factors, including hormones, play a critical role in regulating immunity. Progesterone has been shown to affect immunity in rodents and humans, mainly at concentrations commensurate with pregnancy. These effects are primarily mediated via the progesterone receptor (PR), which acts as a transcription factor, although non-genomic effects of PR activation have been reported. In this study, we evaluated the effects of progesterone on rat dendritic cells (DCs) at ranges encompassing physiologic and pharmacologic concentrations to determine whether progesterone plays a role in modulating DC-mediated immune responses. DCs were derived by culturing rat bone marrow cells in granulocyte macrophage colony-stimulating factor and IL-4. Cells were analyzed for expression of PR using FACS analysis, real-time reverse transcriptase-PCR and fluorescent microscopy. Progesterone treatment of LPS-activated, mature bone marrow-derived dendritic cells (BMDCs) suppressed production of the pro-inflammatory response-promoting cytokines tumor necrosis factor-alpha and IL-1beta in a dose-dependent manner but did not affect production of the pro-inflammatory response-inhibiting cytokine IL-10. Treatment of cells with progesterone also resulted in down-regulation of co-stimulatory molecule CD80 and MHC class II molecule RT1B expression. In addition, progesterone inhibited DC-stimulated proliferation of T cells. Suppression of pro-inflammatory response-promoting cytokine production by progesterone was prevented using the PR antagonist RU486. There was no dose-dependent effect of progesterone treatment on immature DC capacity to take up antigenic peptide. These data indicate that progesterone directly inhibits mature rat BMDC capacity to drive pro-inflammatory responses. This mechanism could contribute to or account for some of the differential expression of autoimmune/inflammatory disease in females.