Tertiary lymphoid structures sustain cutaneous B cell activity in hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a chronic skin condition affecting approximately 1% of the US population. HS skin lesions are highly inflammatory and characterized by a large immune infiltrate. While B cells and plasma cells comprise a major component of this immune milieu, the biology and the contribution of these cells in HS pathogenesis are unclear. We aimed to investigate the dynamics and microenvironmental interactions of B cells within cutaneous HS lesions. Combining histological analysis, single-cell RNA sequencing, and spatial transcriptomics profiling of HS lesions, we defined the tissue microenvironment relative to B cell activity within this disease. Our findings identified tertiary lymphoid structures (TLSs) within HS lesions and described organized interactions among T cells, B cells, antigen-presenting cells, and skin stroma. We found evidence that B cells within HS TLSs actively underwent maturation, including participation in germinal center reactions and class switch recombination. Moreover, skin stroma and accumulating T cells were primed to support the formation of TLSs and facilitate B cell recruitment during HS. Our data definitively demonstrated the presence of TLSs in lesional HS skin and point to ongoing cutaneous B cell maturation through class switch recombination and affinity maturation during disease progression in this inflamed nonlymphoid tissue.

Murine immunosuppression with mycoviral dsRNA

The effect of three different size molecular weight species of mycoviral dsRNA on the immune response to sRBC was tested in C57Bl/6 mice. The various dsRNA species were extracted from electrophoresis polyacrylamide-agarose slab gels. Their molecular weights ranged from 1.0 x 10(6) daltons to 3.5 x 10(6) daltons. All three sizes of mycoviral dsRNA significantly (p less than 0.0001) suppressed the hemolytic antibody titer of mice 8 days after immunizations with 15 micrograms dsRNA/mouse and 10(8) sRBC when compared to control mice which received only sRBC. No immune suppression was observed in any of the mice challenged with a second sRBC immunization 60 days after the first inoculations. Hemagglutination titers at this time were typical of a secondary antibody response to sRBC. In conclusion these three molecular weight mycoviral dsRNA species appeared to be potent immunosuppressors when approximately 15 micrograms/mouse were used.

Common antigens among systemic disease fungi analyzed by two-dimensional immunoelectrophoresis

The interpretation of immunological results in systemic mycoses has been complicated by cross-reactions among specimens from patients with blastomycosis, coccidioidomycosis, and histoplasmosis. The fungal preparations used in these tests evidently contained one or more antigens in common. Two-dimensional immunoelectrophoresis techniques were used to determine the number of antigens contained in several soluble extracts from Blastomyces dermatitidis and Histoplasma capsulatum that were common with those demonstrable in a coccidiodin-anticoccidioidin reference system. A total of 12 and 10 common antigens were found in preparations from B. dermatitidis and H. capsulatum, respectively. In addition, the crude preparations from each species of fungus exhibited some qualitative and quantitative differences in composition of antigens. Use of two-dimensional immunoelectrophoresis for standardization of fungus extracts, for monitoring separation of species-specific antigens, and for testing humoral antibody response should add further refinement to correlations with clinical disease.