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B cell activating factor (BAFF or BLyS), an important cytokine for B cell survival and humoral immune responses, is targeted in the clinic for the treatment of systemic lupus erythematosus. This review focuses on the structure, function and inhibition profiles of membrane-bound BAFF, soluble BAFF 3-mer and soluble BAFF 60-mer, all of which have distinct properties. BAFF contains a loop region not required for receptor binding but essential for receptor activation via promotion of BAFF-to-BAFF contacts. This loop region additionally allows formation of BAFF 60-mer, in which epitopes of the BAFF inhibitor belimumab are inaccessible. If 60-mer forms in humans, it is predicted to be short-lived and to act locally because adult serum contains a BAFF 60-mer dissociating activity. Cord blood contains elevated levels of BAFF, part of which displays attributes of 60-mer, suggesting a role for this form of BAFF in the development of foetal or neonate B cells.

Purpose : Brain abnormalities have been associated with glaucoma, which damages the ganglion cell complex (GCC). In this study, we will directly associate the GCC thickness with brain parameters in subjects without glaucoma. Methods : From the large population-based LIFE-Adult study (Leipzig Research Centre for Civilization Diseases), we extracted the machine-segmented GCC thickness from macular optical coherence tomography (SD-OCT) scans. We applied an artificial intelligence method termed non-negative matrix factorization to determine GCC thickness patterns. The brain parameters used include left and right hippocampal volumes, white matter volume and white matter hyperintensity volume, which were measured using automatic segmentation tools (FreeSurfer and LesionTOADS) on magnetic resonance imaging scans. The global average GCC thickness and each of the GCC thickness patterns were associated with the brain parameters by linear regression with adjusted effects for age, gender, scan focus and intracranial volume. P values were corrected for multiple comparisons for the GCC thickness patterns by the false discovery rate method. For linear regression analyses, subjects with glaucoma diagnosis were excluded and one random eye per subject was selected if data for both eyes were available. Results : We determined 12 GCC thickness patterns (Figure 1) using 17,877 OCT scans from 17,877 eyes of 9,029 subjects (Age: 57.5 ± 12.4 years, 52.1% female). The brighter regions in the GCC thickness patterns indicate the more informative zones with greater variations across subjects than the blue regions. 1,747 eyes from 1,747 subjects (Age: 58.2 ± 15.8 years, 45.6% female) were used to link the GCC parameters with the brain parameters. The global average GCC thickness was not significantly associated with any of the brain parameters (Table 1). A lower Pattern 3 coefficient was correlated with lower left (p < 0.001) and right (p = 0.006) hippocampal volumes. A lower Pattern 5 coefficient was correlated with lower right hippocampal volume and higher white matter hyperintensity volume (p = 0.04 for both). A lower Pattern 5 coefficient was also correlated with lower white matter volume with borderline significance (p = 0.07; p = 0.005 before p value corrections). Conclusions : Our results suggest that parafovea ring-shape thinning and inferior-nasal arcuate-shape thinning in GCC are specifically linked with unfavorable brain parameters. This is a 2021 Imaging in the Eye Conference abstract.