CD19+ B cell subsets in the peripheral blood and skin lesions of psoriasis patients and their correlations with disease severity

Abstract

T lymphocytes are important in the pathogenesis of psoriasis, and increasing evidence indicates that B cells also play an important role. The mechanisms of action, however, remain unclear. We evaluated the ratios of CD19+ B cells in peripheral blood mononuclear cells (PBMCs) from 157 patients with psoriasis (65 patients with psoriasis vulgaris, 32 patients with erythrodermic psoriasis, 30 patients with arthropathic psoriasis, and 30 patients with pustular psoriasis) and 35 healthy controls (HCs). Ratios of CD19+ B cells in skin lesions were compared with non-lesions in 7 erythrodermic psoriasis patients. The Psoriasis Area Severity Index (PASI) was used to measure disease severity. CD19+ B cell ratios in PBMCs from psoriasis vulgaris (at both the active and stationary stage) and arthropathic psoriasis patients were higher compared with HCs (P<0.01), but ratios were lower in erythrodermic and pustular psoriasis patients (P<0.01). CD19+ B cell ratios in erythrodermic psoriasis skin lesions were higher than in non-lesion areas (P<0.001). Different subsets of CD19+CD40+, CD19+CD44+, CD19+CD80+, CD19+CD86+, CD19+CD11b+, and CD19+HLA-DR+ B cells in PBMCs were observed in different psoriasis clinical subtypes. PASI scores were positively correlated with CD19+ B cell ratios in psoriasis vulgaris and arthropathic psoriasis cases (r=0.871 and r=0.692, respectively, P<0.01), but were negatively correlated in pustular psoriasis (r=-0.569, P<0.01). The results indicated that similar to T cells, B cells activation may also play important roles in different pathological stages of psoriasis.

Is the humoral immunity dispensable for the pathogenesis of psoriasis?

“…[7][8][9][10] As precursors of differentiated plasma cells, B lymphocytes not only produce antibodies, but also play an important immunological role as antigen-presenting cells and producers of a broad array of cytokines, which control early and established T-cell-mediated responses. 11 In psoriasis, B cells were indeed detected in lesional skin, 12,13 and altered frequencies of circulating B lymphocytes in psoriasis have been described. 14 However, it is still unclear whether B cells have a functional role in the disease-specific immunology of psoriasis or whether alterations only occur as a bystander phenomenon.…”

“…In psoriasis, B cells were indeed detected in lesional skin, and altered frequencies of circulating B lymphocytes in psoriasis have been described . However, it is still unclear whether B cells have a functional role in the disease‐specific immunology of psoriasis or whether alterations only occur as a bystander phenomenon.…”

Studies of the Systemic Inflammation in Psoriasis

“…The increased expression of the inflammasomes in the B cells of psoriasis patients is particularly interesting. An increase in circulating B lymphocytes and CD19+ B cell ratios in PBMCs, positively correlated to the PASI, has been described in psoriasis patients in comparison to controls (277,278). Furthermore, B-cell depletion has been connected to the development of psoriasis in patients undergoing treatment with rituximab (279).…”

Advances in Understanding the Immunological Pathways in Psoriasis

“…In a study published in 2016, the authors reported higher levels of CD19+ B cells in the peripheral blood of psoriatic patients than in healthy controls. Moreover, CD19+ B cells ratios were positively correlated with disease severity and the authors therefore concluded that B cells might play a role in different pathological stages of psoriasis [99]. B regulatory cells are a subset of B cells that can negatively regulate immune responses.…”