Katharina Jüngert

This study investigated the distribution of IgA-expressing cells in human ocular tissues and IgA subclass profiles in Schirmer strip extracts from patients with dry eye disease (DED) and primary Sjögren’s syndrome (pSS). Immunofluorescence staining was performed on paraffin-embedded lacrimal gland, conjunctival, and corneal tissues from body donors. Independently, Schirmer strip extracts from healthy controls (n = 18), patients with DED (n = 75), and patients with pSS (n = 10) were analyzed. Total protein concentrations were determined using a bicinchoninic acid assay, while total IgA, IgA1, and IgA2 were quantified by ELISA and normalized to total protein. CD38⁺ and CD38⁻ IgA-expressing cells were detected in the lacrimal gland and conjunctival stroma, with IgA1-expressing cells predominating over IgA2-expressing cells. No IgA-positive cells were detected in the examined corneal sections. Total protein concentrations were lower in pSS than in DED. Normalized IgA2 abundance was reduced in both DED and pSS compared with controls, while normalized total IgA was additionally reduced in pSS. Unnormalized extract concentrations showed broadly similar patterns. These independent findings demonstrate differences in recovered IgA subclass profiles, although differences in collection materials and patient characteristics preclude attributing these alterations exclusively to the underlying diseases.

To characterize the distribution of IgA-producing plasma cells across the human ocular surface and to assess alterations in tear IgA subclass profiles in Schirmer strip extracts from patients with dry eye disease (DED) and primary Sjögren’s syndrome (pSS). Immunofluorescence staining was performed on paraffin-embedded lacrimal gland, conjunctival, and corneal tissues to identify IgA- and subclass-producing B/plasma cells. Samples were collected from controls (n = 18), patients with DED (n = 75), and patients with pSS (n = 10). Total protein concentrations in Schirmer strip extracts were deter-mined using a bicinchoninic acid assay. Total IgA, IgA1 and IgA2 were quantified by ELISA and normalized to total protein. IgA-producing plasma cells were abundant in the lacrimal gland and conjunctival stroma but absent from the corneal sections. In both tissues, IgA1-producing cells predominated over IgA2-producing cells. Total protein concentrations in Schirmer strip extracts were significantly lower in pSS than in DED. The most consistent change was reduced normalized IgA2 abundance in Schirmer strip extracts, whereas changes in IgA1 were less consistent across the analyzed disease groups. IgA-producing plasma cells are prominent in the lacrimal gland and conjunctiva. DED and pSS are associated with reduced normalized IgA2 abundance and altered IgA sub-class profiles.

Background and Purpose: In magnetic resonance (MR)-only radiotherapy, synthetic computed tomography (sCT) replaces computed tomography (CT) for dose calculation and patient positioning. Quality assurance (QA) surrogates with native bone morphology and complex tissue–air interfaces are lacking. Therefore, we evaluated preserved human body-donor head specimens for anatomy-realistic cranial sCT QA.Materials and Methods: Ten head specimens spanning four preservation pathways were imaged at 1.5 T: plastinated (n = 3), formalin-fixed and ethanol-preserved (n = 5), nitrite-pickling-salt-ethanol-polyethylene-glycol (NEP)-embalmed (n = 1), and fresh-frozen (n = 1). One plastinate was ferromagnetic and excluded. Six specimens were scanned three times, without and with re-setup. Two-dimensional (2D) slice-wise and three-dimensional (3D) volume-based algorithms received identical T1-weighted Dixon input. Bone and soft-tissue agreement was quantified by Dice similarity coefficient (DSC), 95th-percentile Hausdorff distance (HD95), Hounsfield unit (HU) mean error (ME) in the sCT-derived and reference-CT-derived masks, and dose-volume histogram deviations.Results: Bone DSC was highest for a formalin-fixed head (0.72) and lowest for a plastinate (0.11). Bone ME was positive under sCT-derived and negative under reference-CT-derived masking throughout. Mean dose deviation was smallest for a dissection-course specimen (1.3%); the fresh-frozen head failed dosimetrically (75%). Re-setup changed metrics more than repetition alone. 3D improved all bone metrics (p ≤ 0.039) but not soft-tissue or dose agreement.Conclusions: Preserved head specimens can complement phantoms for anatomy-realistic cranial sCT QA. Suitability appears to depend on complete neurocranial anatomy, fixation preserving MR signal, absence of ferromagnetic components, room-temperature scanning, and standardized positioning.