Clinical Characteristics Of Brucellosis Arthritis In Inner Mongolia And Its Correlation With Immunological Abnormalities

Background & Objective Brucellosis is a natural epidemic zoonotic infectious disease caused by the genus Brucella,and the epidemic area is widely distributed.Epidemiological investigations have found that the incidence of brucellosis in Mongolia is about 64.86~77.79/100,000 person per years.The clinical manifestations of brucellosis are highly heterogeneous.If the treatment is not timely and non-standard,it is prone to protracted,repeated and chronic,and various complications can occur which seriously affect the prognosis.Bone and joint involvement is the most common clinical manifestation of brucellosis,mainly manifested as arthritis,which can lead to bone and joint damage,and even serious dysfunction.There is a high rate of treatment failure.Some foreign studies have shown that brucellosis arthritis can detect positive serum autoantibodies,and there is no similar report in China.The distribution of affected joints in brucellosis arthritis in China is also different from foreign studies.In this study,a questionnaire was used to collect clinical data and imaging data of patients with brucellosis arthritis in Inner Mongolia,and blood samples were collected for serum autoantibody testing to study the incidence of brucellosis arthritis in Inner Mongolia.The characteristics of clinical manifestations and the correlation of serological immune abnormalities provide a new basis for immunological treatment of brucellosis arthritis.Methods The cases of Brucellosis patients admitted to hospitals in Inner Mongolia from January 1,2019 to January 1,2020 were reviewed.The diagnosis of Brucellosis cases was based on WS 269-2019 "Diagnosis of Brucellosis".Choose the symptoms of joint involvement and have clear imaging data,and exclude other diseases that may cause joint symptoms(such as rheumatoid arthritis,osteoarthritis,psoriatic arthritis,etc.)and other known joints that may cause joints symptoms or infectious diseases of reactive arthritis(such as rheumatic fever,viral hepatitis,Lyme disease,etc.).Use the self-designed questionnaire to register and record the detailed information of the enrolled cases,including population characteristics,epidemiology,brucellosis laboratory test methods and results,pathogenic separation results,auxiliary test results,clinical staging,extra-articular manifestations,and involvement joint distribution,imaging examination and treatment plan,etc.The enrolled patients signed a informed consent form and collected blood samples.After centrifuging the blood samples,the supernatant was removed and transferred to a cryopreservation tube,which was stored in a-80℃ medical ultra-low temperature refrigerator.Match and number the questionnaire and blood samples,use the turbidimetric method to detect serum Ig M rheumatoid factor(RF),enzyme-linked immunosorbent assay to detect serum anti-cyclic citrullinated peptide antibody(anti-CCP antibody),indirect immunofluorescence detection of serum Ig G1 antinuclear antibody(ANA).Use Epidata 3.1 software to input data,and use IBM SPSS 25.0 software for statistical analysis.Counting data is expressed in cases and percentages;measurement data is expressed in mean ± standard deviation,and those who do not obey the normal distribution are expressed in the range of median and quartile.Count data was compared using χ2 test or Fisher’s exact probability method.The comparison of measurement data between two groups uses independent sample t test,the comparison between multiple groups of variables uses multivariate analysis of variance,the further pairwise comparison uses LSD test,and Levene method tests the homogeneity of variance.The analysis of the influencing factors of Ig M type RF,anti-CCP antibody and Ig G1 type ANA was performed by binary and ordinal logistic regression analysis,and P<0.05 was considered statistically significant.Results A total of 234 eligible patients with brucellosis arthritis were included in this study,the male to female sex ratio was 2.71: 1;the age range was 6-78 years,the average age was45.97±13.90,and the proportion of 41-60 years old was the highest account 57.69%;the ethnic group is dominated by the Han nationality with 64.96%,and the Mongolian with32.90%.The majority of occupations are farmers,65.81%,followed by herders 18.80%.The animal contact history mainly includes cattle and sheep in 204 cases,accounting for 88.31%,and the main contact method is feeding and grazing in 198 cases,accounting for 84.62%.The clinical stage is predominantly in the acute phase,accounting for 44.02%,followed by the chronic phase,accounting for 32.05%;the Brucella isolation rate is 37.18%,and the positive rate of blood culture in the acute phase is significantly higher than that in the subacute and chronic phases(P<0.001);in the auxiliary examination,the HGB is lower than the subacute phase(P<0.05),the ALT and AST in the acute phase are higher than the subacute phase and the chronic phase(P<0.05),and the TP and ALB in the acute phase are lower than the subacute phase and chronic phase(P<0.05),CRP and ESR in the acute phase were higher than those in the subacute phase and the chronic phase(P<0.05).The extra-articular manifestations were mainly 133 cases of fever(56.84%),149 cases of fatigue(63.67%),125 cases of hyperhidrosis(53.42%),101 cases of low back pain(43.16%),and 55 cases of wasting(23.59%).The most common joint involvement is peripheral arthritis,followed by spondylitis and sacroiliitis.Among them,peripheral arthritis included knee arthritis in 96cases(41.03%),hip arthritis in 64 cases(27.35%),shoulder arthritis in 43 cases(13.68%),ankle arthritis in 20 cases(8.55%),finger and toe joints 11 cases(4.70%),10 cases of wrist joint(4.27%),6 cases of elbow joint(2.14%),2 cases of sternoclavicular joint(0.85%);55cases(23.50%)of lumbar spondylitis and 22 cases of thoracic spine(9.40%),7 cases of cervical spine(2.99%),3 cases of sacral spine(1.28%);5 cases of sacroiliac arthritis(2.14%),2 cases of unilateral involvement(0.85%),3 cases of bilateral involvement(1.28%).There were 57 cases(24.36%)with single joint involvement,136 cases(58.12%)with oligoarticular involvement,and 41 cases(17.52%)with multi-joint involvement.Peripheral large joints are mostly involved,mainly weight-bearing joints.Both arthritis and polyarthritis can be seen.Among them,the knee and hip joints are more involved.In spondylitis,the lumbar spine is most commonly affected,followed by the thoracic,cervical and sacral spine,and sacroiliac joints.There are almost as many single and bilateral involvements,and more joints(>3)are involved.16 cases(6.84%)were positive for autoantibody Ig M type RF,17 cases(7.26%)were positive for anti-CCP antibody,and 81 cases(34.62%)were positive for Ig G1 type ANA.Univariate analysis of demographic characteristics,extra-articular manifestations,joint involvement distribution,course of disease,etc.was performed on the differences between the three autoantibodies positive / negative,and the binary logistic regression analysis of the extra-articular manifestations and post-treatment effects.The ordinal logistic regression analysis was performed on the joints affected quantity.After multivariate analysis,Ig M type RF positive patients may have extra-articular manifestations that are higher than negative patients,and multi-joint involvement may be higher than negative patients.The effect after conventional treatment is worse than negative patients(P<0.05);anti-CCP antibody positive patients with extra-articular manifestations may be higher than negative patients,and the effect after routine treatment is worse than negative patients(P<0.05);Ig G1 type ANA positive patients may have extra-articular manifestations higher than negative patients,and more joint involvement may be higher.The effect of negative patients and conventional treatment is worse than that of negative patients(P<0.05).Conclusions 1.Among the brucellosis arthritis in Inner Mongolia,peripheral arthritis,spondylitis and sacroiliac arthritis are the most common.Among the three,peripheral arthritis is the most common,followed by spondylitis and sacroiliitis.Peripheral large joints are mostly involved,including the knee and hip joints,followed by the spine,the sacroiliac joints are affected as much as unilateral and bilateral,and multiple joints(>3)are more involved.2.Patients with brucellosis arthritis have serum antibody detection and may be related to chronicity of the disease.Brucellosis arthritis may be the result of direct bacterial erosion and/or secondary immunopathological damage.Autoantibodies may be involved in the process of immunological damage or a sign of chronicity of immunoreactive arthritis.