The use of Bruton’s tyrosine kinase (BTK) inhibitors has changed the management of patients with B-cell lymphoid malignancies. BTK is an important molecule that interconnects B-cell antigen receptor (BCR) signaling. BTK inhibitors (BTKis) are classified into three categories, namely covalent irreversible inhibitors, covalent reversible inhibitors, and non-covalent reversible inhibitors. Ibrutinib is the first covalent, irreversible BTK inhibitor approved in 2013 as a breakthrough therapy for chronic lymphocytic leukemia patients. Subsequently, two other covalent, irreversible, second-generation BTKis, acalabrutinib and zanubrutinib, have been developed for lymphoid malignancies to reduce the ibrutinib-mediated adverse effects. More recently, irreversible and reversible BTKis have been under development for immune-mediated diseases, including autoimmune hemolytic anemia, immune thrombocytopenia, multiple sclerosis, pemphigus vulgaris, atopic dermatitis, rheumatoid arthritis, systemic lupus erythematosus, Sjögren’s disease, and chronic spontaneous urticaria, among others. This review article summarizes the preclinical and clinical evidence supporting the role of BTKis in various autoimmune, allergic, and inflammatory conditions.

Systemic lupus erythematosus (SLE) is an autoimmune disease of unknown aetiology. The results of experimental studies point to the involvement of innate immunity receptors—toll-like receptors (TLR)—in the pathogenesis of the disease. The aim of the study was to assess the expression of TLR3, 7, and 9 in the population of peripheral blood mononuclear cells (PBMC) and in B lymphocytes (CD19⁺), T lymphocytes (CD4⁺and CD8⁺) using flow cytometry. The study group included 35 patients with SLE and 15 healthy controls. The patient group presented a significantly higher percentage of TLR3- and TLR9-positive cells among all PBMCs and their subpopulations (CD3⁺, CD4⁺, CD8⁺, and CD19⁺lymphocytes) as well as TLR7 in CD19⁺B-lymphocytes, compared to the control group. There was no correlation between the expression of all studied TLRs and the disease activity according to the SLAM scale, and the degree of organ damage according to the SLICC/ACR Damage Index. However, a correlation was observed between the percentage of various TLR-positive cells and some clinical (joint lesions) and laboratory (lymphopenia, hypogammaglobulinemia, anaemia, and higher ESR) features and menopause in women. The results of the study suggest that TLR3, 7, and 9 play a role in the pathogenesis of SLE and have an impact on organ involvement in SLE.

Leukemia cutis (LC) is defined as the leukemic infiltration of the epidermis, the dermis, and the subcutaneous tissue. Leukemia cutis may follow or occur simultaneously with the diagnosis of systemic leukemia. However, cutaneous lesions are occasionally diagnosed as the primary manifestation of leukemia. Leukemic skin infiltrations demonstrate considerable variation regarding a number of changes, distribution, and morphology. The highest incidence of LC is observed in chronic lymphocytic leukemia, monocytic and myelomonocytic acute myeloid leukemia, and T-cell lineage leukemia. Although the pathogenic mechanism of the invasion of leukemic cells into the skin is not well understood, chemokine receptors and adhesion molecules as well as the genetic characteristics of leukemia are thought to play a role. Leukemic skin lesions may be localized or disseminated and may occur alone or in combination on any site of the skin, most frequently in the trunk and extremities. The most common clinical presentations of leukemia cutis are papules, nodules, macules, plaques, and ulcers. In most patients, the complete or partial resolution of cutaneous infiltrations occurs simultaneously with hematologic remission. However, in patients with resistant disease or recurrent skin infiltration, local radiotherapy can be used. This review presents recent data on the pathogenesis, diagnosis, and treatment of leukemic skin involvement in different types of leukemia.

Systemic lupus erythematosus (SLE) is an autoimmune disease of multifactorial pathoaetiology. Different organs and blood vessels may be affected by chronic inflammation. A direct cause of the disease has not yet been found, so research is being carried out to this effect. The role of the recently identified helper T lymphocyte CD4+, described as Th17, and its dependent cytokines have been of particular interest. The aim of the study was to evaluate IL-17A, IL-17B, IL-17F and IL-23 in 60 SLE patients and 26 age-matched, healthy volunteers and also to investigate the correlation between levels of the investigated cytokines and VEGF, PIGF, as well as number of endothelial cells. IL-17A, IL-17B, IL-17BR and IL-17F levels were found to be higher in SLE patients than in the control group. However, only IL-17F levels showed a statistically significant correlation with the number of endothelial cells (aCEC) and disease activity. Correlations between levels of IL-17F and VEGF and PIGF as well as VEGF and IL-17A and IL-23 were statistically significant. Increased levels of the selected cytokines from the IL-17 family in SLE patients suggest a role for them not only in the inflammatory process but also in angiogenesis. This also highlights the role of IL-17F in activating vascular endothelial cells and consequently blood vessel formation, and in the relationship between the inflammatory reaction and angiogenesis in the development of SLE.

Introduction Immune system activation, microvascular abnormalities and extracellular matrix deposition in tissues play roles in systemic sclerosis (SSc). Th17 cells producing interleukin (IL)-17 are involved in the pathogenesis of many autoimmune-mediated inflammatory diseases; however, the...

Plaque psoriasis is a chronic, immune-mediated inflammatory skin disease characterized by the formation of thick, scaly plaques. The disease is driven by dysregulation of the immune response, primarily involving T-helper cells, which create a persistent inflammatory environment. In recent years, several biomarkers reflecting systemic inflammation have been identified, including indices derived from a complete blood count, such as the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and Systemic Immune-Inflammation Index (SII). The aim of our study was to explore the role of these markers in patients with psoriasis undergoing biological treatment. Medical records of 159 patients with plaque psoriasis receiving biologics were retrospectively reviewed. The NLR, PLR, and SII values were calculated from the hemograms of the patients. Additionally, demographic and psoriasis severity data were analyzed. During the 18-month follow-up, the mean NLR, PLR, SII, and CRP values were significantly decreased in comparison to the baseline (p < 0.05). No significant differences between anti-TNF, anti-IL-12/23, anti-IL-17, and anti-IL-23 drugs were identified (p > 0.05). The initial values of NLR, PLR, and SII were positively correlated with psoriasis severity. No relationship between the analyzed biomarkers and age, sex, psoriasis duration, and prior exposure to biological drugs was identified. CBC-derived biomarkers may be useful for monitoring inflammation reduction in psoriasis patients treated with biological drugs.