An improved capillary isoelectric focusing-mass spectrometry method for high-resolution characterization of monoclonal antibody charge variants

Routine and high-resolution characterization of monoclonal antibody (mAb) charge variants is vital for controlling mAb quality as therapeutics. Capillary isoelectric focusing-mass spectrometry (cIEF-MS) has emerged as a powerful tool for...

Comparative Study of Haiti and Miami Cohorts of Sickle Cell Disease (CSHSCD): Methods, Accomplishments, and Implementation

Background: There are significant limitations in Haiti for the diagnosis and management of sickle cell disease (SCD), including the non-availability of universal newborn screening (NBS) and transcranial Doppler (TCD) ultrasound screening, and the lack of diagnostic laboratory resources, oral penicillin and hydroxyurea (HU). Methods: Beginning in September 2019, CSHSCD (R01HL149121), a 5-year NIH-sponsored observational comparative study of children with SCD from Haitian ethnicity in Miami and in Haiti compared to children of African American ethnicity with SCD, was designed to increase access to care in Haiti. The study aims are 1) to compare the incidence of SCD among newborns from Haitian and African American ethnicity in Miami, 2) to establish NBS programs for hemoglobinopathies in Haiti, and 3) to compare cohorts of children in SCD at the study sites. The participating sites are the University of Miami (UM, Miami, Florida), Hôpital Saint Damien (HSD, Tabarre, Haiti), Hôpital de l'Université d'Etat d'Haïti (HUEH, Port-au-Prince, Haiti), Hôpital Universitaire Justinien (HUJ, Cap Haitien, Haiti), and Hôpital Sacré Coeur (HSC, Milot, Haiti). HUJ and HSC use two NBS screening methods (isoelectric focusing and Sickle SCAN rapid test) and HSD and HUEH use isoelectric focusing only. CSHSCD supplies penicillin and HU and trains TCD examiners to implement stroke risk screening. Data are collected in REDCap. Results: During the first 2 years and despite the COVID-19 pandemic, we established NBS sites with a cohesive network of physicians and nurses trained in the care of children with SCD in Haiti. This capacity building will support sustainability of the program. We successfully identified at least 15 new cases of SCD via newborn screening, trained six TCD examiners, and enrolled 130 children with SCD in follow up, providing them with penicillin prophylaxis and hydroxyurea for severe cases according to local protocols . Implementation activities which have helped are close communications between the investigators, monthly Zoom meetings to coordinate efforts with enrollment updates every month, the availability of rapid tests (Sickle SCAN and Gazelle miniature cellulose acetate electrophoresis) for the diagnosis of SCD, especially when there is no laboratory equipment on site. Implementation challenges we have faced are mostly two. The first is the timely completion of DUNS and SAM registration for the two public hospitals, with one site achieving this after 9 months and the other site taking 18 months to complete. The reasons for the delay are the inability for the UM site to direct these efforts, following strict rules, and the Haitian hospital officers' lack of familiarity with website requirements. We were able to achieve these registrations with the assistance of one Haitian study staff who is very acquainted with internet navigation and became familiarized with requirements. Outsourcing materials to Haiti is another major challenge, with either gaps in the delivery of supplies because of multiple steps involved in ordering and shipping or with delays in releasing equipment once it is at the Port-au-Prince customs, resulting in gaps in NBS in one of the sites for 8 weeks. We have minimized these issues by opening a one-year ticket to order materials from the different companies involved. Also, Haiti's lack of infrastructure, available materials and medications, and political instability limit health care delivery. Conclusion: Since its inception, we have achieved major milestones, including capacity building and implementation of NBS, TCD training, and enrollment of children with SCD into the prospective cohorts despite the current COVID-19 pandemic. Material outsourcing challenges have been the major implementation problem we have faced due to systemic factors. We anticipate that these factors will be corrected or minimized as we have learned how to handle them. These problems were expected as part of conducting an international study in a low-resource setting. Acknowledgment: We acknowledge NHLBI for supporting this work. Disclosures Alvarez: Forma Therapeutics: Membership on an entity's Board of Directors or advisory committees; GBT: Membership on an entity's Board of Directors or advisory committees. Romano: Genentech: Research Funding; Vycor: Current holder of individual stocks in a privately-held company; NovaVision: Consultancy.

Prevalence of Congenital Disorders of Glycosylation in Childhood Epilepsy and Effects of Anti-Epileptic Drugs on the Transferrin Isoelectric Focusing Test

Introduction: Childhood epilepsy is one of the most common neurological problems. The transferrin isoelectric focusing (TIEF) test is a screening test for congenital disorders of glycosylation (CDG). We identified abnormal TIEF test in children with epilepsy in our epilepsy genetics clinic. To determine if an abnormal TIEF test is associated with anti-epileptic medications or abnormal liver functions, we performed a retrospective cohort study. Methods: This study was performed between January 2012 and March 2020. Electronic patient charts were reviewed. Standard non-parametric statistical tests were applied using R statistical software. Fischer’s exact test was used for comparisons. Results: There were 206 patients. The TIEF test was abnormal in 11% (23 out of 206) of the patients. Nine patients were diagnosed with CDG: PMM2-CDG (n = 5), ALG3-CDG (n = 1), ALG11-CDG (n = 2), SLC35A2-CDG (n = 1). We report 51 different genetic diseases in 84 patients. Two groups, (1) abnormal TIEF test; (2) normal TIEF test, showed statistically significant differences for abnormal liver functions and for valproic acid treatment. Conclusion: The TIEF test guided CDG diagnosis in 2.9% of the patients. Due to the high prevalence of CDG (4.4%) in childhood epilepsy, the TIEF test might be included into the diagnostic investigations to allow earlier and cost-effective diagnosis.

Molecular Level Characterization of Diatom and Coccolithophore-Associated Biopolymers That Are Binding 210Pb and 210Po in Seawater

Through a combination of selective extractions and molecular characterization techniques including Isoelectric Focusing Chromatography and Electrospray Ionization Fourier-Transform Ion Cyclotron Resonance Mass spectrometry, molecular structures of diatom (Phaeodactylum tricornutum) and coccolithophore (Emiliania huxleyi)-associated biopolymers that are responsible for the distinct partitioning behavior between 210Pb and 210Po were determined. Our results show that diatom-derived biopolymers have distinctive elemental grouping distributions as compared to those excreted by the coccolithophore, with the former consisting of more heterogeneous elements (i.e., nitrogen, sulfur and phosphorus-containing organic compounds). For the coccolithophore culture, two 210Pb-enriched biopolymers (non-attached exopolymeric substances and coccosphere shell-associated biopolymers) have a higher abundance of CHO-type compounds, suggesting CHO-only-type compounds as the main binding moieties for 210Pb. In contrast, such association was not evident in the diatom culture. Different with 210Pb, 210Po enrichment in coccolithophore-derived attached exopolymeric substances and Fe-Mn-associated metabolites coincided with the higher abundance of nitrogen/sulfur-containing organic compounds in these two biopolymer fractions, suggesting the strong parallel of Po with the production of nitrogen-rich organic matter as well as sulfur-containing amino acids. These different associations between 210Pb/210Po and organic functional groups were further explored by separating 210Pb or 210Po-labeled coccolithophore-derived biopolymers via isoelectric focusing. This technique suggests that phosphate group-containing molecules but not the other molecules that contain heterogeneous elements (e.g., CHONS, CHON, and CHOS) as the strongest binding agents for 210Pb, while the more hydrophobic (high protein to carbohydrate ratio) nitrogen/sulfur-enriched organic moieties acted as the main 210Po-binding ligands. It is concluded that the deficiency of 210Po with respect to 210Pb can be influenced by the relative abundance of nitrogen/sulfur-enriched organic moieties to the nitrogen/sulfur-depleted organic compounds in the water column. This behavior constrains the application of 210Po-210Pb approach to quantify the particulate organic carbon (POC) export flux in the ocean. It also explains that differences in chemical binding of the 210Po as compared to those of other radionuclides (e.g., thorium-234) as the main factor. That suggests that differences in decay half-lives or physical factors are less important when these nuclides are applied to estimate the POC flux in the ocean.