Expression Of IL-31 In Serum And Skin Lesions Of Patients With Chronic Actinic Dermatitis And Its Clinical Significance

Objectives:1.To collect and collate the clinical and pathological manifestations of patients with Chronic actinic dermatitis（CAD）,and to summarize their clinical and pathological features;2.To investigate the serum level of Interleukin 31（IL-31）,the expression of IL-31 and its receptors in skin lesions and the clinical significance of CAD patients.Methods:From January 2022 to January 2023,46 patients with CAD diagnosed and hospitalized in the Department of Dermatology of our hospital were selected as the experimental group（46 cases of serum samples and 34 cases of skin tissues）,20normal individuals who had their blood drawn for physical examination in our outpatient clinic,14 patients with atopic dermatitis（AD）who had completed pathological examination of the exposed area,and 10 healthy individuals who had plastic surgery in our hospital as the control group（20 cases of normal individuals,14cases of AD patients with skin lesions,and 10 cases of normal skin tissues）.10 cases of healthy people who underwent plastic surgery in our hospital were used as the control group（including 20 cases of normal human serum,14 cases of AD patients with skin lesions and 10 cases of normal skin tissue）:1.Relevant clinical data of the patients were collected and analyzed,including:1)general conditions:gender,age,disease duration,lesion type,lesion distribution location,lesion area,whether suffering from other diseases;2)test results:absolute value of lymphocytes,absolute value of monocytes,absolute value of eosinophils,absolute value of basal granulocytes,total Ig E in blood routine;3)histopathological examination results of lesions.2.Eczema area and severity index（EASI）and Severity scoring of atopic dermatitis（SCORAD）were used to score the clinical severity of the patients and to group them into different severity groups;3.To detect the expression level of IL-31 in serum of CAD patients and normal subjects by using enzyme linked immunosorbent assay（ELISA）,and to evaluate the correlation with clinical severity,age,age of onset,disease duration,blood count and other clinical data;to detect the expression level of IL-31 in CAD and normal subjects by using immunohistochemical method.The expression of IL-31 and IL-31 Receptor（IL-31R）in the skin lesions of CAD and AD patients was measured by immunohistochemistry,and the relationship between IL-31 expression in the skin lesions of CAD patients and its clinical severity was analyzed to lay the clinical foundation for the use of IL-31 antagonists to improve the clinical symptoms of AD patients.Results:1.Among the 46 patients with CAD included in the study,the male to female ratio was approximately 5.57:1,37 patients（80.4%）were over 50 years of age,and 33（71.7%）had a disease length of more than 1 year.2.The main clinical manifestations of CAD were:red/dark red patches on exposed areas in 46 cases（100%）,papules/plaques in 43 cases（93.5%）,mossy lesions in 37cases（80.4%）,and oozing/crusting in 36 cases（78.3%）;patients were divided into three groups of mild,moderate,and severe according to EASI scores:all mild patients had erythema and papules;all severe patients had erythema,papules,mossy lesions,and oozing/crusting;and moderate patients had clinical manifestations in between,The clinical manifestations of lesions in moderate patients were in between.28 of 46patients（60.9%）had lesions on non-exposed areas,and 4（40%）,16（59.2%）,and 8（88.9%）of mild,moderate,and severe patients had systemic involvement,respectively.3.The histopathological findings of 34 CAD patients with subacute spongioedema dermatitis were 27（79.4%）,which mainly showed hypertrophy of the spinous layer in32（94.1%）,spongioedema in 32（94.1%）,keratosis imperfecta in 31（91.1%）,perivascular lymphatic and histiocytic infiltration in 29（85.3%）,with eosinophilic infiltration in 16（47.1%）.4.The serum IL-31 level of the patients was 149.17（456.00）pg/m L,which was significantly higher than that of the control group,which was 7.11（26.38）pg/m L（z=-4.722,P<0.001）;there was no significant correlation between serum IL-31level and ESAI score,objective SCORAD score,age,age of onset,and duration of disease(P_EASI=0.106,P_SCORAD=0.774,P_age=0.134,P_{age at onset}=0.097,P_{duration of disease}=0.606);Serum IL-31 levels did not correlate significantly with the levels of Lymphocyte,Monocyte,Eosinophilic granulocyte,Basinophilic granulocyte,and total Ig E in the blood routine(P_Lym=0.588,P_Mon=0.513,P_Eos=0.331,P_Bas=0.484,P _{total Ig E}=0.341).5.Three groups were divided into mild,moderate and severe according to EASI scores,and the difference in each routine blood test index was analyzed,and only the Mon group had statistically significant differences among the three subgroups（H=14.786,P<0.05）,and the severe group was significantly higher than the mild and moderate groups（P<0.05）;the patients were divided into systemic and local groups according to whether they were involved in non-exposure sites for the comparison of serum IL-31 levels,Lym,Mon,Eos,Bas,and total Ig E levels in routine blood were compared,and only serum IL-31 levels（z=-2.431,P=0.015）and Mon（t=-2.431,P=0.041）were statistically significant in the two groups（all P<0.05）:serum IL-31 levels in the systemic group were 262.10（1141.54）pg/m L in the systemic group was higher than 57.02（207.76）pg/m L in the local group（z=-2.431,P=0.015）,and the absolute value of Mon was 0.56±0.18 in the systemic group than 0.46±0.14 in the local group（t=-2.104,P=0.041）.6.The positive fraction of IL-31 in skin lesions was different between the three groups of mild,moderate and severe CAD compared to the normal group（H=24.610,P<0.001）,but the difference in positive fraction between the three groups was not statistically significant（all P>0.05）;the positive fraction of IL-31 in skin lesions of moderate AD patients was 5.00（0.7）,compared to 5.50（0.4）in the moderate CAD group,the difference between the two was not statistically significant（z=-1.202,P=0.229）;the positive fraction in the severe AD group was 5.46±0.28,compared with 5.69±0.23 in the severe CAD group,the difference between the two was not statistically significant（t=-1.859,P=0.082）.7.The positive fraction of IL-31R in skin lesions differed between the three subgroups of mild,moderate and severe CAD compared with the normal group（H=24.144,P<0.0001）,but the difference in positive fraction between the three groups was not statistically significant（all P>0.05）;the positive fraction of IL-31R in skin lesions of patients with moderate AD was 5.72±0.27,which was not statistically significant compared with the moderate CAD group 5.62±0.37 compared to 5.62±0.37 in the moderate CAD group,and the difference was not statistically significant（z=-0.533,P=0.603）;the positive fraction in the severe AD group was 6.00（0.30）compared to 6.00（0.20）in the severe CAD group,and the difference between the two was not statistically significant（z=-0.203,P=0.839）.Conclusions:IL-31 was significantly elevated in serum and lesions of patients with chronic actinic dermatitis compared to normal controls,but did not correlate with disease severity;therefore,IL-31 may play a role in the pathogenesis of CAD,but cannot be used as an indicator to monitor disease severity.