|Year : 2021 | Volume
| Issue : 2 | Page : 182-185
Autoimmunity in south Indian children with recently diagnosed type 1 diabetes mellitus
Sridevi A Naaraayan1, Raghavan V Dhakshayani2, Rema Chandramohan2
1 Department of Pediatrics, Government Kilpauk Medical College, Chennai, Tamil Nadu, India
2 Department of Pediatrics, Institute of Child Health and Hospital for Children, Chennai, Tamil Nadu, India
|Date of Submission||03-Aug-2020|
|Date of Decision||30-Sep-2020|
|Date of Acceptance||01-Oct-2020|
|Date of Web Publication||31-Mar-2021|
Dr. Sridevi A Naaraayan
Department of Pediatrics, Kilpauk Medical College, Chennai 600010, Tamil Nadu.
Source of Support: None, Conflict of Interest: None
Background: Type 1 diabetes mellitus is known to be associated with autoimmunity and hence autoantibodies. The primary objective of this study was to determine the prevalence of glutamic acid decarboxylase 65 (GAD) antibody in patients with newly diagnosed type 1 diabetes mellitus. Materials and Methods: This cross-sectional study was done in a government-run pediatric tertiary care center in South India from 2015 to 2017 and included 125 patients with newly diagnosed type 1 diabetes mellitus. Demographic and clinical data were captured and GAD antibody was detected by the ELISA technique and a titer of above 1.0 IU/mL was considered positive. Results: The prevalence (95% confidence interval) of GAD 65 antibody was found to be 79.2% (71%–86%). Glycated hemoglobin level was significantly higher in GAD negative when compared to GAD positive patients (P < 0.05). Conclusion: Type 1 diabetes mellitus is associated with high prevalence of autoantibodies in the current era.
Keywords: GAD antibody, prevalence, South India, type 1 diabetes mellitus
|How to cite this article:|
Naaraayan SA, Dhakshayani RV, Chandramohan R. Autoimmunity in south Indian children with recently diagnosed type 1 diabetes mellitus. J Diabetol 2021;12:182-5
| Introduction|| |
Type 1 diabetes mellitus is a common metabolic disorder in children whose pathogenesis is extensively studied. In genetically predisposed individuals, the immune system under the influence of certain triggers progressively destroys its own beta cells of pancreas. Patients become clinically symptomatic and are dependent on exogenous insulin for survival when approximately 90% of pancreatic beta cells are destroyed. Though the destruction of beta cells in type 1 diabetes mellitus is predominantly cell mediated, beta cell-specific autoantibodies have been detected in the serum of patients suggesting a probable role for humoral immune system as well.
The most frequently detected autoantibodies are glutamic acid decarboxylase 65KDa (GAD 65) autoantibodies, tyrosine phosphate associated islet antigen-related antibody (IA-2), insulin autoantibodies (IAA), and zinc transporter (ZnT8) autoantibodies. Of these, GAD 65 antibody is the most frequently encountered autoantibody and is universally accepted as a screening test of autoimmunity in type1 diabetes mellitus.
Various studies done across various regions in India have shown wide variation in prevalence of GAD 65 antibody in children with type 1 diabetes mellitus ranging from as high as 79.3% to as low as 25%., The low prevalence of autoantibodies was attributed to etiologic heterogeneity with idiopathic variety of type 1 diabetes mellitus being commoner in India than in western countries. With the studies done in more recent times showing increasing prevalence of autoantibodies, this study was undertaken with the primary objective of determining the prevalence of GAD 65 antibody in South Indian children with newly diagnosed type 1 diabetes mellitus. The secondary objective was to compare the clinical characteristics between children who were positive and negative for GAD 65 antibodies.
| Materials and Methods|| |
This cross-sectional study was done in the diabetes clinic of a government-run tertiary care center in South India that caters exclusively to children from 2015 to 2017. The study was commenced after obtaining approval from the Institutional Ethics Committee. All children above 1 year of age who were newly diagnosed with diabetes mellitus (within a week of diagnosis) based on the International Society for Pediatric and Adolescent Diabetes (ISPAD) criteria and insulinopenia as shown by decreased fasting and postprandial C peptide levels were included. Children with monogenic diabetes and drug-induced diabetes were excluded. Sample size was fixed at 125 based on a previous study by Shivprasad et al., which reported a GAD prevalence of 65% with an error margin of 8.5%.
Patients were recruited after obtaining written informed consent from one of the parents. Demographic data such as age and sex and clinical data like family history of type 1 diabetes, type 2 diabetes and hypothyroidism, mode of presentation (ketotic or nonketotic), and comorbidities such as thyroid disorders and other autoimmune conditions were captured in a structured proforma. Height and weight were recorded following standard procedure. Blood was drawn from all patients in two plain red-capped test tubes and an Ethylenediaminetetraacetic acid (EDTA) test tube, 3mL each and sent for analysis within 4h. GAD 65 antibody estimation was done from the sample sent in red-capped tube by ELISA technique and a titer of above 1.0 IU/mL was considered positive. Glycated hemoglobin (HbA1C) was measured from EDTA sample by high-performance liquid chromatography (HPLC) and thyroid-stimulating hormone (TSH) from plain test tube by chemiluminescence immune assay (CLIA). Patients were treated with insulin as per standard protocol and the dose of insulin required for glycemic control was noted.
Mode of onset was classified as ketotic onset if presenting with Diabetic ketoacidosis. The following criteria were adopted for diabetic ketoacidosis––blood glucose >11 mmol/L, pH<7.3, and/or bicarbonate less than 15, with ketonuria. WHO growth standards were used to interpret anthropometry in children below 5 years of age, whereas IAP growth charts 2015 were used to interpret them in those above 5 years of age., Hypothyroidism was defined as raised TSH (>4.5 mIU/L) with or without decrease in age appropriate free T3 and T4 levels.
Statistical analysis was done using SPSS version 24. Categorical variables were expressed in percentage and numerical variables in mean and standard deviation. Primary outcome was expressed as percentage with 95% confidence interval. Secondary outcome of comparison of clinical characteristics in GAD positive and negative patients was done using chi-square test for categorical variables and Student’s t test for numerical variables and level of significance was fixed at 5%.
| Results|| |
Totally 125 patients were included in the study. Mean (standard deviation) age was 7.26 (3.50). Patient’s age ranged from 1 year and 1 month to 15 years. There was a female preponderance with male–female ratio of 1:1.5. Two (1.6%) patients had a sibling with type 1 diabetes, whereas 47 (37.5%) patients had a parent/grandparent with type 2 diabetes. Four (3.2%) patients had mothers with hypothyroidism. Sixty-nine (55.2%) patients presented with diabetic ketoacidosis, whereas the rest presented with just osmotic symptoms. Eighteen (14.4%) patients had short stature and four (3.2%) had tall stature, whereas the rest 103 (82.4%) patients were of normal stature. Twenty (16%) children had thinness, four (3.2%) were overweight and three (2.2%) were obese, whereas the remaining 98 (78.6%) had a normal body mass index. One child had hypothyroidism for 3 years before diagnosis of diabetes and seven (5.6%) children were found to have coexistent hypothyroidism at the time of diagnosis of diabetes. Two (1.6%) patients had pubertal goiter, but were euthyroid. One child had vitiligo. Mean (standard deviation) HbA1c level was 12.50 (2.71). The mean (standard deviation) dose of insulin required for glycemic control was 1.29 (0.36) units/kg/day.
GAD 65 antibody was found to be positive in 99 (79.2%) patients, 95% confidence interval being 71% to 86%. Comparison of clinical characteristics between GAD 65 positive and negative patients is given in [Table 1]. Mean HbA1c was significantly higher in GAD 65 negative group than GAD 65 positive group, whereas other variables like age, sex, onset of disease, and insulin dose were insignificant. This difference is brought out in [Figure 1] which also shows the range of dispersion of HbA1c is more in GAD 65 negative patients.
|Table 1: Comparison of clinical characteristics between GAD positive and negative patients|
Click here to view
| Discussion|| |
The study showed that 79.2% patients with newly diagnosed type 1 diabetes tested positive for GAD 65 antibody. Further, the mean HbA1c was found to be higher in GAD 65 negative patients with type 1 diabetes mellitus.
GAD 65 positivity rate of 79.3% was reported by a recent study, in line with western studies. Many previous studies have reported a lower rate of GAD 65 antibody.,,, The reason for wide variation in frequencies of autoantibodies detected in various studies could be due to timing of estimation from disease onset, age of patients studied with higher positivity among younger age group, inappropriately small sample size, different period of time, difference in laboratory assays, and threshold limits. Inclusion of patients with recent onset of disease and younger age of patients could be the major reasons for the higher prevalence noted in our study. Hygiene hypothesis could be yet another reason for increasing incidence of type1 diabetes and autoimmunity in type 1 diabetes. Gut microbiota influences the developing immune system to establish self-tolerance and control inflammatory responses. This recent surge in autoimmunity in type1 diabetes mellitus could be triggered by increasing dysbiosis of gut of general population.
Our study population was similar to that described in a previous study with regard to age, gender ratio, and mode of onset of illness. While comparing clinical characteristics between GAD 65 positive and negative patients, it was previously reported that GAD 65 positive patients were younger and presented with diabetic ketoacidosis more often. Another study reported that boys were more commonly GAD 65 positive than girls. Such relations were not detected in our study. A previous study stated there was no relation between glycated hemoglobin level and GAD 65 positivity in contrast to our study.
The main limitation of the study is that other autoantibodies like IA-2, ICA, and ZnT8 were not assayed. A previous study has shown that GAD 65 has a sensitivity of 65% and specificity of 97% with area under curve (AUC) being 0.8. Prevalence of other antibodies like IA-2, ICA, and ZnT8 were found to be lower than GAD 65 antibody. Hence GAD 65 is considered to be a good screening test for detection of autoimmunity in patients with type 1 diabetes mellitus. Also, organ-specific autoantibodies like TPO, anti-thyroglobulin antibody, and tissue transglutaminase antibodies were not assayed as they were beyond the purview of the study.
In conclusion, this study has shown a high prevalence of GAD 65 autoantibody in South Indian children with recently diagnosed type 1 diabetes mellitus in the current era.
The authors acknowledge the technical role rendered by Professor Pushkala, Head of the Department of Immunology, The Tamil Nadu Dr M.G.R. Medical University, Chennai in performing GAD antibody assay done in the study.
Ethical policy and institutional review board statement
Ethical approval for this study was obtained from the Institutional Ethics Committee, Madras Medical College, Chennai-3 dated 03/03/2015 No. 14032015.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Mayer-Davis EJ, Kahkoska AR, Jefferies C, Dabelea D, Balde N, Gong CX, et al
. ISPAD clinical practice consensus guidelines 2018: Definition, epidemiology, and classification of diabetes in children and adolescents. Pediatr Diabetes 2018;19:7-19.
Baker PR II, Eisenbarth GS Type 1 diabetes: Pathogenesis, prediction, and prevention. US Endocrinol 2009;05:79.
Amutha A, Kalpana T, Mohan V Childhood and adolescent onset type 1 diabetes in India. MGM J Med Sci 2013;1:46-53.
Unnikrishnan R, Mohan V New directions for research into type 1 diabetes in India: An immunological perspective. Indian J Med Res 2014;140:336-8.
Basu M, Pandit K, Banerjee M, Mondal S, Mukhopadhyay P, Ghosh S Profile of auto-antibodies (disease related and other) in children with type 1 diabetes. Indian J Endocrinol Metab 2020;24:256.
Sanyal D, Batabyal SK, Maity S, Chatterjee S Changing profile of GAD and IA-2 antibody positivity in Indian children with recently diagnosed type 1 diabetes mellitus. Clin Diabetol 2019;8: 116-20.
Balasubramanian K, Dabadghao P, Bhatia V, Colman PG, Gellert SA, Bharadwaj U, et al
. High frequency of type 1B (idiopathic) diabetes in north Indian children with recent-onset diabetes. Diabetes Care 2003;26:2697.
Shivaprasad C, Mittal R, Dharmalingam M, Kumar PK Zinc transporter-8 autoantibodies can replace IA-2 autoantibodies as a serological marker for juvenile onset type 1 diabetes in India. Indian J Endocrinol Metab 2014;18:345-9.
Danne T, Phillip M, Buckingham BA, Jarosz-Chobot P, Saboo B, Urakami T, et al
. ISPAD clinical practice consensus guidelines 2018: Insulin treatment in children and adolescents with diabetes. Pediatr Diabetes 2018;19:115-35.
WHO | The WHO Child Growth Standards [Internet]. WHO | World Health Organization. Available from: http://www.who.int/childgrowth/standards/en/. [Last accessed on 2020 Sep 14].
Khadilkar V, Yadav S, Agrawal KK, Tamboli S, Banerjee M, Cherian A, et al
. Revised IAP growth charts for height, weight and body mass index for 5- to 18-year-old Indian children. Indian Pediatr 2015;52:47-55.
Kapelari K, Kirchlechner C, Högler W, Schweitzer K, Virgolini I, Moncayo R Pediatric reference intervals for thyroid hormone levels from birth to adulthood: A retrospective study. BMC Endocr Disord 2008;8:15.
Dhanwal DK, Agarwal S, Garg S, Agarwal P Clinical & immunological profile of newly diagnosed patients with youth onset diabetes mellitus. Indian J Med Res 2014;140:356-60.
Dayal D, Samprati M, Kaur N, Minz RW, Jayaraman D Prevalence of beta-cell, thyroid and celiac autoimmunity in north Indian children with recent onset type 1 diabetes (T1D). J Clin Diagn Res 2015;9:SM01-2.
Marita AR, Rane S, Mokal RA, Nair SR, Irani A Autoantibodies against GAD65 and IA-2 in recently diagnosed type 1 diabetic children from western India. Diabet Med 2004;21:956-7.
Curry A A Hygiene Hypothesis: Diabetes Forecast® [Internet]. Available from: http://www.diabetesforecast.org/2009/feb/a-hygiene-hypothesis.html. [Last accessed on 2020 Jul 29].
Siljander H, Honkanen J, Knip M Microbiome and type 1 diabetes. Ebiomedicine 2019;46:512-21.
Varadarajan P, Sangaralingam T Profile of diabetes mellitus at presentation in children under 12 years of age. J Pediatric Sci 2011;3:e94.
Billow A, Anjana RM, Ngai M, Amutha A, Pradeepa R, Jebarani S, et al
. Prevalence and clinical profile of metabolic syndrome among type 1 diabetes mellitus patients in southern India. J Diabetes Complications 2015;29:659-64.