1:Neonatal Linear IgA Bullous Dermatosis Mediated by Breast Milk-Borne Maternal IgA.

JAMA Dermatol.

2021 Jul 4. doi: 0.00/jamadermatol.2021.2392.

Shohei Egami, Chihiro Suzuki, Yuichi Kurihara, Jun Yamagami, Akiharu Kubo, Takeru Funakoshi, Wataru Nishie, Kazuya Matsumura, Takahiro Matsushima, Miho Kawaida, Michiie Sakamoto, Masayuki Amagai

Neonatal linear IgA bullous dermatosis is a rare disease that causes blisters and erosions mediated by IgA that reacts with the dermoepidermal junction. Lesions frequently occur not only on the skin but also on the mucous membranes of the respiratory tract, leading to a potentially fatal condition. While many neonatal autoimmune skin diseases are caused by maternal autoantibodies in the blood passing through the placenta to the fetus, in linear IgA bullous dermatosis, past reports have shown no pathogenic antibodies in the maternal blood, and their origin was unknown. In this study, we demonstrated the presence of IgA that binds to the dermoepidermal junction in the breast milk of the affected infant's mother using indirect immunofluorescence. Furthermore, by immunostaining the perilesional skin for the J chain, we found that the IgA deposited on the infant's skin was the secretory type (different from the IgA in serum), which is specifically present in breast milk. This proved that pathogenic IgA was transferred to the infant via breast milk. This suggests that in neonatal IgA bullous dermatosis, promptly discontinuing breastfeeding can prevent the infant's condition from becoming severe and can be life-saving.

(Shohei Egami, 89th Graduating Class, Department of Dermatology)

Proc Natl Acad Sci U S A.

2021 Jun 1;118(22):e2018840118. doi: 10.1073/pnas.2018840118.

Xiaoyan Jiang, Machelle T Pardue, Kiwako Mori, Shin-Ichi Ikeda, Hidemasa Torii, Shane D'Souza, Richard A Lang, Toshihide Kurihara, Kazuo Tsubota

In recent decades, the prevalence of myopia has increased dramatically worldwide, and it is said that one-third of the human population is now myopic. Most cases of myopia are classified as axial myopia, the essence of which is an elongation of the eye's front-to-back length (axial length). This deformation of the eyeball can lead to complications that cause blindness, such as retinal detachment and macular disease. In recent years, the myopia-suppressing effect of violet light (360 nm–400 nm, a short-wavelength region of visible light) abundant in outdoor ambient light has been clarified, and it is speculated that a lack of violet light due to reduced outdoor activities is a contributing factor to the rapid increase in myopia prevalence. This study elucidated the mechanism by which violet light suppresses myopia progression by maintaining choroidal thickness. This process is initiated when violet light is received by the photoreceptor OPN5 (neuropsin), which is expressed in retinal ganglion cells in the inner layer of the mouse retina and is involved in local retinal circadian rhythms, intraocular vascular development, and deep body temperature regulation. This finding not only clarifies the molecular mechanism of violet light's effect on suppressing myopia progression but also contributes to elucidating the function of the recently discovered non-visual photoreceptor OPN5. It is expected to aid in the future development of useful interventions targeting myopia progression.

(Toshihide Kurihara, equivalent to 80th Graduating Class, Department of Ophthalmology)