Dear Editor, In atopic dermatitis (AD) patients, B cells are not examined as well as T cells. It is not yet known what is the count of CD23 and CD200 B lymphocytes and their subsets in pollen season and out of pollen season in AD patients with and without dupilumab therapy. B cells play important roles in immune defense, including immunoglobulin production, antigen presentation, and cytokine secretion; some data suggest that B-cell dysregulation might affect the pathogenesis of T cell-mediated diseases, such as AD (Citation1–6). Pollen is a common trigger for allergic reactions, including AD. When exposed to pollen, the immune system of individuals with AD may react abnormally, leading to an exacerbation of symptoms. The number and function of B lymphocytes can be affected by allergen exposure, including pollen. In our region, the significant role play allergens from PR 10 proteins Bet v 1 (Birch), Aln g 1 (Alder) and Cor a1.0103 (Corylus avellana) (Citation7), beta expansin (Lol p 1, Phl p 1), molecular components from Timothy and cultivated rye (Secc pollen) (Citation7).
We selected for our investigation the molecule CD23 and CD200 on B lymphocytes and on their subsets. A main function attributed to CD23 is the regulation of IgE synthesis (Citation7). CD23 can absorb and clear IgE from the serum in a non‐inflammatory fashion, CD23 reduces the synthesis of IgE from B cells and the molecule CD23 regulates antigen‐specific IgG and T cell responses (Citation8). The molecule CD200 is a type-1 cell membrane glycoprotein of the immunoglobulin supergene family, present on both cells with myeloid/lymphoid origin as well as on epithelial cells and many cancer cells (Citation9). The interaction of CD200 with its receptor(s), CD200R(s) leads to attenuation of a variety of immune responses in control of autoimmunity, infection, allergy, transplantation, and cancer (Citation9).
Suppression of inflammatory changes in AD is demonstrated in the case of dupilumab therapy, which inhibits the production of key cytokines IL-4 and IL-13. Patients with AD, certain types of asthma, chronic rhinosinusitis with nasal polyposis, prurigo nodularis, and eosinophilic esophagitis produce high levels of IL-4 and IL-13, which can cause inflammation of the skin, respiratory tract, and esophagus leading to symptoms of these diseases. Dupilumab, a monoclonal antibody is designed to block IL-4 and IL-13 receptors. By blocking these receptors, dupilumab prevents the action of IL-4 and IL-13 and alleviates the symptoms of the disease (Citation10).
The aim of the study is to measure the expression of these molecules on B lymphocytes and on their subsets (memory, naive, non-switched, total B lymphocytes) in patients suffering from moderate and severe form of AD (with and without dupilumab therapy) in pollen season (June–August) and out of pollen season (October–February) and compare it with these counts in healthy subjects. Complete dermatological examination was performed in all patients included in the study. All these patients were examined in the Department of Dermatology, Faculty Hospital Hradec Králové, Charles University, Czech Republic. The diagnosis of AD was determined according to Hanifin–Rajka’s diagnostic criteria. Inclusion criteria: (1) age 14 years and over, (2) AD as defined by the criteria of Hanifin and Rajka. Patients with moderate and severe form of AD without dupilumab and patients with dupilumab therapy lasting at least 18 months were included. Exclusion criteria: pregnancy, breastfeeding, and systemic therapy (cyclosporin, systemic corticoids).
During pollen season and out of pollen season, we examined two groups of AD patients; one group consisted of patients suffering from moderate and severe form of AD without dupilumab treatment (21 patients – six men, 15 women, age 36.2 years (first and third quartile 27.2–40.5)) and the other group consisted of patients treated with dupilumab (13 patients – seven men, six women, age 43.4 years (first and third quartile 38.6–48.3)). Laboratory tests to determine the parameters of interest were performed in these patients during the pollen season (June–August) and outside the pollen season (October–February). For the evaluation of pollen allergy, we analyzed the results of specific IgE to molecular components of pollen in all AD patients (with and without dupilumab therapy) included in the study. The specific IgE was examined with the use of ALEX2 Allergy Xplorer test. The representation of AD patients was identical in both these periods. The patients underwent a comprehensive dermatological examination. As a control group, 40 healthy individuals in pollen season and 30 healthy individuals out of pollen season, all blood donors with negative total IgE, were examined at Faculty Hospital Hradec Králové, Charles University, Czech Republic. The representation of the control group matched with regard to gender and age to AD patients.
The characteristic of patients with evaluation of severity of AD and the quality of life and the characteristic of control group are recorded in . In , we show the number of patients (%) with positive result to molecular components of pollen according to ALEX2 Allergy Xplorer.
Table 1. Characteristic of patients.
Table 2. The number of patients (%) with positive result to molecular components according to ALEX2 Allergy Xplorer.
The expression of activation molecules CD23 and CD200 of B lymphocytes was evaluated with the immunophenotyping with flow cytometry. For statistical analysis, we used non-parametric Kruskal–Wallis one-factor analysis of variance with post hoc (follow-up multiple comparison) and Dunn’s test with Bonferroni’s modification of significance level. The Wilcoxon test for pairwise comparisons between AD patients and the Mann–Whitney and Kolmogorov–Smirnov test for controls were used. We used statistical software: NCSS 2021 Statistical Software (2021). NCSS, LLC, (Kaysville, UT), ncss.com/software/ncss. The expression of activation molecules CD23 and CD200 of B lymphocytes was compared between AD patients with and without dupilumab therapy and healthy subjects in pollen season and out of pollen season.
The results of laboratory examinations with statistical analysis are presented in tables. In , we show the count of absolute leukocytes and absolute lymphocytes; in , the count of CD23 B lymphocytes with their subsets; and in , the count of CD200 B lymphocytes with their subsets.
Table 3. The count of leukocytes and lymphocytes in AD patients with and without dupilumab therapy in pollen season and out of pollen season compared to control group-horizontal comparison.
Table 4. The count of CD23 B lymphocytes and their subsets in AD patients with and without dupilumab therapy in pollen season and out of pollen season compared to control group – horizontal comparison.
Table 5. The count of CD200 B lymphocytes and their subsets in AD patients with and without dupilumab therapy in pollen season and out of pollen season compared to control group – horizontal comparison.
In statistical analysis, we made these comparisons:
The results of AD patients are compared to control group in pollen season and out of pollen season (horizontal comparison in ). In AD patients with and without dupilumab therapy, we confirmed in both seasons the significantly higher expression of CD23 on memory, naive, non-switched, and total B lymphocytes compared to control group. The higher expression of CD23 on switched B lymphocytes is confirmed in AD patients with and without dupilumab therapy only out of pollen season compared to control group. As for the expression of the molecule CD200 on B lymphocytes in AD patients compared to control group, we confirmed only some changes in the relative count of CD200 on memory B lymphocytes in AD patients with and without dupilumab therapy and in the relative count of CD200 on non-switched B lymphocytes in AD patients with dupilumab therapy.
The results of AD patients and of control group in pollen season are compared to the results out of pollen season to see if the values obtained in the pollen season differed significantly from the values obtained outside the pollen season (vertical comparison in ). We have shown that during the pollen season there is a significant decrease in expression of CD200 on memory, naive, non-switched, and total CD200 B lymphocytes in AD patients without dupilumab therapy, a significant increase of expression CD23 on naive B lymphocytes in AD patients with dupilumab therapy. Our results show, that molecule CD200 on B cells may have regulatory functions.
As for the control group, we confirmed a significant increase of expression CD23 on switched B lymphocytes and the significant decrease of relative count of CD23 memory, naive, non-switched, and total B lymphocytes in pollen season compared to out of pollen season and a significant increase of expression CD23 on switched B lymphocytes in control group. During pollen season, exposure to allergens may trigger an immune response. Increased CD23 expression on switched B lymphocytes in healthy subjects could be part of the immune system’s response to modulate the allergic reaction. The decrease in the relative count of CD23-expressing B lymphocytes may suggest a shift in the distribution or activation state of B cells during pollen season.
The review of monitored parameters in AD patients with and without dupilumab therapy in pollen season and out of pollen season in comparison to control group is recorded in . The intercomparison of monitored parameters in AD patients (with and without dupilumab therapy) and in control group in pollen season compared to the count out of pollen season is recorded in .
Table 6. The review of monitored parameters in AD patients with and without dupilumab therapy in pollen season and out of pollen season in comparison to control group.
Table 7. The intercomparison of monitored parameters in AD patients (with and without dupilumab therapy) and in control group in pollen season compared to the count out of pollen season.
In conclusion, the results of our study show that the expression of CD23 and CD200 molecules on B lymphocytes differs in the pollen season and out of pollen season in both patients with AD (treated and not treated with dupilumab) and in the control group. We confirmed the regulatory functions of the molecule CD200 and CD23 on B lymphocytes. The results of our study suggest that dupilumab affects the expression of CD200 and CD23 on B lymphocytes. When assessing the expression of CD23 and CD200 on B lymphocytes, it is necessary to take into account the period of the year in which the examination was performed.
Author contributions
Jarmila Čelakovská: selection of the patients, dermatological examination and recommendations for the laboratory examination; processing of all results; writing of the manuscript. Eva Čermáková: statistical analysis. Ctirad Andrýs – control of laboratory examination. Petra Boudkova: laboratory examination and flow cytometry. Jan Krejsek: professional cooperation and supervision.
Ethics statement
This study was approved by Ethics Committee of the Faculty Hospital Hradec Králové, Charles University of Prague, Czech Republic. Reference number is: 2021 10 P 03. The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Institutional Review Board – Ethics Committee of the Faculty Hospital Hradec Králové, Charles University of Prague, Czech Republic. Data of Approval 4 September 2021.
Consent form
Informed consent was obtained from all subjects involved in the study.
Acknowledgements
Medical writing/Editorial assistance: The article was written by the main author; no other services and Editorial assistance were needed.
Prior publication: This manuscript is not based on work that has been previously presented/published.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Data availability statement
The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.
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Funding
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