SARS-CoV-2 Vaccine-Elicited Immunity after B Cell Depletion in Multiple Sclerosis

The impact of B cell deficiency on the humoral and cellular responses to SARS-CoV2 mRNA vaccination remains a challenging and significant clinical management question. We evaluated vaccine-elicited serological and cellular responses in 1) healthy individuals who were pre-exposed to SARS-CoV-2 (n = 21), 2) healthy individuals who received a homologous booster (mRNA, n = 19; or Novavax, n = 19), and 3) persons with multiple sclerosis on B cell depletion therapy (MS-αCD20) receiving mRNA homologous boosting (n = 36). Pre-exposure increased humoral and CD4 T cellular responses in immunocompetent individuals. Novavax homologous boosting induced a significantly more robust serological response than mRNA boosting. MS-α CD20 had an intact IgA mucosal response and an enhanced CD8 T cell response to mRNA boosting compared with immunocompetent individuals. This enhanced cellular response was characterized by the expansion of only effector, not memory, T cells. The enhancement of CD8 T cells in the setting of B cell depletion suggests a regulatory mechanism between B and CD8 T cell vaccine responses.

RARE-32. Phase 0 and feasibility single-institution clinical trial of intravenous tocilizumab for adamantinomatous craniopharyngioma

BACKGROUND: Adamantinomatous craniopharyngioma (ACP) is a devastating skull-base tumor believed to derive from epithelial remnants of the primordial craniopharyngeal duct (Rathke’s pouch), which gives rise to the anterior pituitary gland. ACP lacks medical antitumor therapies. Current standard therapy with surgery and radiation is associated with poor quality of life. Clinical and preclinical data indicate that IL-6 blockade may contribute to ACP tumor control. METHODS: Children aged 2–21 years with newly diagnosed or previously treated ACP with measurable disease are eligible for the Phase 0/feasibility single-institution clinical trial (NCT03970226) of intravenous (IV) tocilizumab at Children’s Hospital Colorado. The phase I stratum involves IV tocilizumab prior to a standard-of-care surgical resection. The feasibility portion of the trial involves IV tocilizumab every two weeks for up to 13 28-day cycles. Tocilizumab is administered at the established weight-based pediatric dosage of 8 mg/kg for patients who weigh ≥30kg or 12 mg/kg for patients who weigh <30kg. RESULTS: To date, three patients have been enrolled on the Phase 0 component of the trial. These patients demonstrated clinically relevant levels of tocilizumab (≥ 4µg/mL) in serum, cyst fluid, and/or tumor tissue, compared to undetectable levels in control samples. Two patients (1 male and 1 female; median age 10.5 years) have enrolled on the feasibility stratum; one patient had best response of minor response but met definition of progressive disease at cycle 11. One patient with extensive disease required dose reduction for myelosuppression. CONCLUSION: Systemic delivery of tocilizumab at the established pediatric dosage is promising for treatment of ACP based on preclinical work and its demonstrated penetration into cystic and solid portions of ACP tumors. The therapy to date has been well tolerated overall. Further study is planned through a CONNECT consortium international Phase II trial.

RARE-10. ADAMANTINOMATOUS CRANIOPHARYNGIOMA RESIDES OUTSIDE THE BLOOD BRAIN BARRIER

BACKGROUND

Adamantinomatous craniopharyngioma (ACP) is a devastating skull-base tumor believed to derive from epithelial remnants of the primordial craniopharyngeal duct (Rathke’s pouch), which gives rise to the anterior pituitary gland. Genetically engineered mouse models of ACP demonstrate that perturbation of the fetal anterior pituitary can generate tumors analogous to ACP. Clinical and preclinical data indicate that IL-6 blockade may contribute to ACP tumor control, with the most common agent being the humanized monoclonal antibody, tocilizumab. This agent demonstrated poor blood-brain barrier (BBB) penetration in primates. We present findings from two children enrolled on a phase 0 clinical trial (NCT03970226) of a single dose of preoperative intravenous tocilizumab prior to resection of newly diagnosed ACP.

METHODS

Blood samples were obtained at multiple timepoints. Serum was isolated via ficoll separation. Tumor tissue and cyst fluid were obtained 4–6 hours following the single IV dose of tocilizumab. Tissue was snap-frozen. Tumor was homogenized in RIPA buffer. Free tocilizumab in serum, cyst fluid, and tumor tissue was measured using enzyme-linked immunosorbent assay (ELISA) against a standard curve.

RESULTS

Both patients in this trial demonstrated clinically relevant levels of tocilizumab (≥ 4µg/mL) in serum, cyst fluid, and tumor tissue, compared to undetectable levels in control samples.

CONCLUSION

ACP resides outside BBB protection. In addition to demonstrating the feasibility of systemic delivery of tocilizumab, these findings indicate that other large molecules, including those known to have poor BBB penetration, may be systemically delivered as part of an antitumor regimen in the treatment of ACP.

Nanostructured Cu2O Synthesized via Bipolar Electrochemistry

Cuprous oxide (Cu2O) was synthesized for the first time via an open bipolar electrochemistry (BPE) approach and characterized in parallel with the commercially available material. As compared to the reference, Cu2O formed through a BPE reaction demonstrated a decrease in particle size; an increase in photocurrent; more efficient light scavenging; and structure-correlated changes in the flat band potential and charge carrier concentration. More importantly, as-synthesized oxides were all phase-pure, defect-free, and had an average crystallite size of 20 nm. Ultimately, this study demonstrates the impact of reaction conditions (e.g., applied potential, reaction time) on structure, morphology, surface chemistry, and photo-electrochemical activity of semiconducting oxides, and at the same time, the ability to maintain a green synthetic protocol and potentially create a scalable product. In the proposed BPE synthesis, we introduced a common food supplement (potassium gluconate) as a reducing and complexing agent, and as an electrolyte, allowing us to replace the more harmful reactants that are conventionally used in Cu2O production. In addition, in the BPE process very corrosive reactants, such as hydroxides and metal precursors (required for synthesis of oxides), are generated in situ in stoichiometric quantity, providing an alternative methodology to generate various nanostructured materials in high yields under mild conditions.

Pleuroperitoneal leak complicating peritoneal dialysis: a case series

Pressure related complications such as abdominal wall hernias occur with relative frequency in patients on peritoneal dialysis. Less frequently, a transudative pleural effusion containing dialysate can develop. This phenomenon appears to be due to increased intra-abdominal pressure in the setting of congenital or acquired diaphragmatic defects. We report three cases of pleuroperitoneal leak that occurred within a nine-month period at our institution. We review the literature on this topic, and discuss management options. The pleural effusion resolved in one patient following drainage of the peritoneum and a switch to haemodialysis. One patient required emergency thoracocentesis. The third patient developed a complex effusion requiring surgical intervention. The three cases highlight the variability of this condition in terms of timing, symptoms and management. The diagnosis of a pleuroperitoneal leak is an important one as it is managed very differently to most transudative pleural effusions seen in this patient population. Surgical repair may be necessary in those patients who wish to resume peritoneal dialysis, or in those patients with complex effusions. Pleuroperitoneal leak should be considered in the differential diagnosis of a pleural effusion, particularly a right-sided effusion, in a patient on peritoneal dialysis.

Encapsulating peritoneal sclerosis: experience of a tertiary referral center

AIM

Encapsulating peritoneal sclerosis (EPS) is arguably the most serious complication of chronic peritoneal dialysis (PD) therapy with extremely high mortality rates. We aimed to establish the rates of EPS and factors associated with its development in a single center.

METHODS

We retrospectively reviewed the records of all our PD patients from 1 January 1989 until 31 December 2008. All suspected cases were confirmed at laparotomy. Multifactorial models adjusted for potentially confounding variables such as age and sex.

RESULTS

Eleven cases of EPS were identified giving a prevalence rate of 1.98%. Median duration on PD was substantially longer in affected versus unaffected patients (42.5 months versus 13.8 months; p = 0.0002). EPS patients had experienced a mean of 3.54 previous cases of peritonitis (1 infection per year versus 0.71 per year in unaffected patients; p = 0.075). Six patients died (54.5%) due to intra-abdominal sepsis including all five who presented with small bowel obstruction. Three patients had an omentectomy and adhesiolysis performed with a successful outcome.

CONCLUSION

Our study reinforces the link between duration on PD and EPS. While mortality was high in our cohort, emerging surgical techniques demonstrate a favorable outcome that can be achieved even in severely affected cases.

Effects of social status, age, and season on androgen and cortisol levels in wild male golden lion tamarins (Leontopithecus rosalia)

This study examines factors affecting androgen and cortisol levels in wild, male golden lion tamarins (Leontopithecus rosalia). Golden lion tamarins are a cooperatively breeding species in which groups often contain two potentially breeding males. Brothers frequently emigrate together and develop a clear dominance hierarchy, but interactions between them are primarily affiliative. Duos in which the males are not related are less stable. In addition, reproductive skew theory predicts that dominant males will be less likely to share reproduction with related subordinates. As such, we predicted that both androgens and cortisol would be higher in subordinate males unrelated to the dominant male. We also predicted that androgens in breeding males would be higher during the mating season than the birth/infant care season, as per Wingfield's "challenge hypothesis" (1990). Fecal samples were collected from 24 males in 14 social groups and assayed by enzyme immunoassay. Androgen levels were higher in breeding males during the mating season, thus supporting the challenge hypothesis. However, while subordinate males unrelated to the dominant male had significantly lower androgens than any other group, cortisol levels were not correspondingly higher. These results suggest that unrelated subordinate males show measurable reproductive suppression and may use strategies such as infantilization to avert aggression from dominant males.

A comparison study of plantar foot pressure in a standardized shoe, total contact cast, and prefabricated pneumatic walking brace

Total contact casting is the current recommended treatment for Wagner Stage 1 and 2 neuropathic plantar ulcers. The rationale for this treatment includes the equalization of plantar foot pressures and generalized unweighting of the foot through a total contact fit at the calf. Total contact casting requires meticulous technique and multiple cast applications to avoid complications before ulcer healing. An alternative to total contact casting is the use of a prefabricated brace designed to maintain a total contact fit. This study compares plantar foot pressure metrics in a standardized shoe (SS), total contact cast (TCC), and prefabricated pneumatic walking brace (PPWB). Five plantar foot sensors (Interlink Electronics, Santa Barbara, CA) were placed at the first, third, and fifth metatarsal heads, fifth metatarsal base, and midplantar heel of 10 healthy male subjects. Each subject walked at a constant speed over a distance of 280 meters in a SS, PPWB, and TCC. A custom-made portable microprocessor-based system, with demonstrated accuracy and reliability, was used to acquire the data. No significant differences in peak pressure or contact duration were found between the initial and repeat SS trials (P > 0.05). Peak pressures were reduced in the PPWB as compared to the SS for all sensor locations (P < 0.05). Similarly, peak pressures were reduced in the TCC compared to the SS for all sensor locations (P < 0.05) with the exception of the fifth metatarsal base (P = 0.45). Our results are summarized as follows: (1) the methods used in the current study were found to be reliable through a test-retest analysis; (2) the PPWB decreased peak plantar foot pressures to an equal or greater degree than the TCC in all tested locations of the forefoot, midfoot, and hindfoot; (3) compared to a SS, contact durations were increased in both the TCC and PPWB for most sensor locations; and (4) the relationship of peak pressure over time, the pressure-time integral, is lower in the brace compared to the shoe at the majority of sensor locations. The values are not significantly different between the cast and shoe. These findings suggest an unweighting of the plantar foot and equalization of plantar foot pressures with both the PPWB and TCC. Based on these findings, the PPWB may be useful in the treatment of neuropathic plantar ulcerations of the foot.

Common mutation in methylenetetrahydrofolate reductase. Correlation with homocysteine metabolism and late-onset vascular disease

BACKGROUND

Increased homocysteine levels are a risk factor for atherosclerosis and its sequelae. A common genetic mutation in methylenetetrahydrofolate reductase (MTHFR), an enzyme required for efficient homocysteine metabolism, creates a thermolabile enzyme with reduced activity. We determined the prevalence of this mutation in many subjects with and without vascular disease and related it to homocysteine and folate levels.

METHODS AND RESULTS

DNA from 247 older subjects with vascular disease and 594 healthy subjects without vascular disease (in three different control groups) was screened for the MTHFR 677 C-to-T mutation. Within each group, 9% to 17% of the subjects were homozygous for this mutation, and the mutant allele frequency was 31% to 39%. The genotype distributions, homozygote frequencies, and allele frequencies did not differ significantly between the study groups. In the vascular disease subjects, despite significantly lower folate levels in MTHFR homozygotes, there was no significant difference in homocysteine levels among the MTHFR genotype groups. The negative slope of the regression line relating homocysteine and folate was significantly steeper for those with a homozygous MTHFR mutation compared with those without this mutation.

CONCLUSIONS

Although the thermolabile MTHFR mutation is very common, it does not appear to be a significant genetic risk factor for typical late-onset vascular disease. Because MTHFR homozygotes have increased homocysteine with low folate levels, this mutation may contribute to early-onset or familial vascular disease. The genotype dependence of the folate-homocysteine correlation further suggests that homozygotes for this mutation may have both an exaggerated hyperhomocysteinemic response to folic acid depletion and a better response to folic acid therapy.