linear growth, and brain development. Less than required iodine intake compromised thyroid function WHO (2010). disorders of Iodine deficiency are a significant global problem even in the well-developed counties such as the United States of America (U.S.)  Wu et al.  (2002). For the first time thyroid hormone was isolated in the year 1914 by Kendall Kendall (1919). and latter firstly synthesized in the year 1925 by Harrington Harington (1926). T4 is the principal hormone secreted by the thyroid gland. It is about (~80%) of the thyroid hormones secreted in human, the remaining (~20%) is triiodothyronine T3. T3, is regarded as the primary biologically active form., since T4 has limited affinity for the nuclear thyroid hormone receptors. T4 has to be converted to T3 by outer ring deiodination. Both T4 and T3 can be inactivated by inner ring deiodination. These reactions are catalyzed by the iodothyronine deiodinases type 1, 2 and 3 (D1, D2 and D3), expressed in a multitude of peripheral tissues, Bianco et al. (2002). Evaluation of thyroid function is carried out by measurement of thyroid stimulation hormone (TSH) as the main test Dufour (2007). The majority of cases of primary overt thyroid diseases can be excluded if TSH value is within the reference interval limit. fT4 is measured for confirmation of diagnosis if TSH is abnormal Thyroid Foundation of Canada (2009). The serum level of TSH may be slightly   elevated in the presence of normal level of fT4. Ogedebe (2007), therefore measurement of fT4 and fT3 are indicated other than that of TT4 and TT3 levels.  Furthermore, checking of fT3 is not indicated in hypothyroidism. Int Assoc of Medical Laboratories (2007).

Thyroid peroxidase (TPO) is the key enzyme for the synthesis of the thyroid hormone., as it catalysed both the iodination and coupling reaction. TPO is membrane bound and found in the cytoplasm and in high concentration on the apical microvillar surface of thyrocytes. It has molecular weight of (100 to 150 KDa). It is known before as thyroid microsomal antigen, McLachlan and Rapoport (1992). Multiple T – and B – ce ll epitopes exist within the molecule, and the antibody response to TPO is restricted at the level of the germ line heavy and light chain variable V region. McIntosh et al. (1998). In over (90%) of patients with autoimmune hypothyroidism and Graves’ disease., Anti-TPO autoantibodies are detected. Anti-TPO autoantibodies and thyroglobulin (Tag) antibodies are the predominant antibodies in autoimmune hypothyroidism. Anti- TPO antibodies are predominantly of the IgG class 1 and IgG4 subclasses in excess. Njemini et al. (2002), Hawa et al. (2006). Thyroglobulin (Tag) is glycoprotein of molecular weight (660-KDa) and composed of two identical subunits of (330 KDa) each. It is secreted by the thyroid follicular cells into the follicular lumen and stored as a colloid substance within the thyroid follicles.  Each Tag molecule has around (100) tyrosine residues, a quarter of which are iodinated. These residues couple to for triiodothyronine T3 and thyroxine T4. When TSH stimulates the thyroid cells, Tag is endocytosing and hydrolyzed in lysosome releasing T3 and T4. The exact location of T- and B- cell epitopes within Tag is uncertain. Carayanniotis and Rao (1997). Thyroglobulin autoantibodies are found in less than (60%) of patients with lymphocytic thyroiditis and (30%) of Graves’ disease patients.  They are polyclonal and mainly of IgG class with all four subclasses represented. TSH controls the cell surface expressions of TPO and Tag altering the transcription of these two proteins, possibly at the gene promoter level. These effects are mimicked by blocking and stimulating autoantibodies in sera of patients with Graves’ disease. Collison et al. (1991)

Mild iodine deficiency is associated with lower prevalence of Hashimoto’s disease and hypothyroidism, while excessive iodine intake is associated with a higher prevalence. Gbadebo and Oyesanya (2005). In China, autoimmune thyroiditis was found only in (0.3%) of those having mild iodine deficiency, and (1.3%) of those with excessive iodine intake. Walsh et al. (2006).

 

2.    RATIONALE

There is existent gap in knowledge about autoimmune thyroid disease and its association with thyroid antibodies (Anti-thyroid peroxidase and antithyroglobulin). This study was expected to provide sound knowledge for scientist and physician as well for better management of patients with thyroid diseases in Shendi Locality and beyond.

 

3.      OBJECTIVES 

 The general objective of this research is to evaluate the association between thyroid autoimmune antibodies and thyroid function tests and among patients with nonneoplastic thyroid disease in Shendi Locality.

 

4.    SUBJECTS AND METHODS

The current research was prospective, case - control, hospital-based study carried out from 2013-2017 in Elmek Nimir University hospital in Shendi town- Northern Sudan.-. River Nile State.

The study included patients with non-neoplastic thyroid diseases attending outpatient clinic Elmek Nimir University hospital in Shendi for routine follow up, as case group. while the control group are healthy subjects without thyroid diseases and match with study group in age and sex distribution.        

Random sampling was used to select suitable sample size.  Two hundred and eighty-three (283) participants selected as study population; divided into three categories:

1)     Control group (healthy); Hundred (100) subjects.

2)     Hypothyroidism patients; Hundred and eleven (111) subjects

3)     Hyperthyroidism patients; Seventy-two (72) subjects

Structural interview questionnaire was applied to collect the following data: personal data, social customs, food habits, exercise, medical history, weight, height, duration of the disease, type of thyroid drugs.

 Three (3) ml of venous blood samples were drawn from every participant in heparinized blood collection tubes, using sterile syringes and centrifuged (1500 r.p.m) for five (5) minutes to obtain heparinized plasma for analysis of thyroid hormones profile (TSH, T4, T3, fT3, and fT4). 

 Other aliquots of two (2) ml were collected in plain container and were allowed to clot and then centrifuged (1500 r.p.m) for five minutes, the supernatant sera were transferred into a plastic tube (eppindorff tube) and stored at (-80 C) for the analysis of thyroid antibodies (antithyroid peroxidase, antithyroglobulin antibodies)

TSH, T4, fT4, T3, and fT3, were measured by TOSOH AIA system analyzer, employing standard reagents and procedures; (ST AIA – PACK TS H, Cat. No. 0025294), (ST AIA – PACK T4), Cat. No 0025258), (ST AIA – PACK FT4, Cat. No 0025268), (ST AIA – PACK TT3, Cat. No 0025282), (ST AIA – PACK iFT3, Cat. No 0025231). respectively.

Thyroid antibodies (Anti-thyroid peroxidase) and antithyroglobulin were measured by sequential ELISA method employing (Anti-TPO) ELISA, and (Anti-Tag) ELISA respectively.

 

 

5.    DATA INTERPRETATION AND ANALYSIS

The collected data was analyzed using Statistical Package for Social Sciences (SPSS) version (11.5). Mean, Standard SD, frequency, percentage, T-test, and correlation were used. Significant level was set at P ≤ (0.05).

 

6.    ETHICAL CLEARANCE

The study was firstly approved by ethical committee of the Faculty of Graduate Studies and Scientific Research (Institute Research Board) of Shendi University.  Permission was also taken from Elmek Nimr University Hospital administration. Verbal informed consent was taken from all participants Names, personal data were completely secured and transferred to codes so as to keep patients’ identities private, taking into account the trust and strict confidentiality with respect to patients and information about them,

 

7.    RESULTS

Table 1 Sociodemographic and personal data
	Hypothyroidism		Hyperthyroidism
	N=111		N=72
Sex distribution among the study group
Sex groups	Frequency	Percentage %	Frequency	Percentage %
Male	9	8.1	11	15.3
Female	102	91.9	61	84.7
Family history among the study group
Yes	37	33.3	27	37.5
First degree	24	64.9	19	70.4
Second degree	13	11.7	8	29.6
No	74	66.7	45	62.5
Classification of cases among the study group
New case	56	50.5	30	41.7
Old case under treatment	55	49.5	42	58.3
Age and weight among the study group
	Mean	SD	Mean	SD
Age	50.4	14.7	43.6	13.4
Weight	68.1	15.5	64.9	13.5

 

Table 2 Over all status of thyroid antibodies
	Hypothyroidism		Hyperthyroidism
	N=111		N=72
Thyroid peroxidase antibodies among the case group
TPOAb results	Frequency	Percentage %	Frequency	Percentage %
Negative	39	35.1	37	51.4
Positive	72	64.9	35	48.6
Thyroglobulin antibodies among the case group
TgAb	Frequency	Percentage	Frequency	Percentage
results		%		%
Negative	60	54.1	50	69.5
Positive	51	45.9	22	30.5
Focal thyroid signs among the study group
Focal thyroid sings	Frequency	Percentage %	Frequency	Percentage %
Solitary nodule	21	18.9	20	27.8
Multinodular	12	10.8	7	9.7
Diffuse	9	8.1	15	20.8
Bruit	0	0	1	1.4
No Goiter	69	62.2	29	40.3
Other diseases among the study group
Other Diseases	Frequency	Percentage %	Frequency	Percentage
Diabetes Mellitus	11	9.9	2	2.8
Rheumatoid arthritis	1	0.9	1	1.4
Pregnancy	0	0	1	1.4
Hypertension	7	6.3	2	2.8

 

Table 3 Correlation of TPOAb and thyroid hormones in hyperthyroidism patients
TPOAb results	Frequency	Percentage %	Mean of:
			TSH	T4	FT4	T3	FT3
Negative (< 40 IU/ml)	37	51.4	1.22	135.3	28.9	2.8	7.3
Positive (>40IU/ml)	35	48.6	0.59	146.9	35.2	3.6	12.8
P. value			0.122	0.488	0.3	0.147	0.032*

 

Table 4 Correlation of thyroid peroxidase antibodies and thyroid hormones in hypothyroidism patients
TPOAb results	Frequency	Percentage %	Mean of:
			TSH	T4	FT4	T3	FT3
Negative (< 40 IU/ml)	39	35.1	18.5	63.6	12.5	1.36	3.3
Positive (>40IU/ml)	72	64.9	22.7	63.6	11.8	1.35	3.7
P. value			0.561	0.999	0.513	0.874	0.029*

 

Table 5 Correlation of thyroglobulin antibodies and thyroid hormones in hyperthyroidism patients
TgAb Results	Frequency	Percentage %	Mean of:
			TSH	T4	FT4	T3	FT3
Negative (< 125 IU/ml)	50	69.5	0.95	129.1	28.1	2.7	7.7
Positive (>125IU/ml)	22	30.5	0.82	167.8	40.8	4.2	15.4
P. value			0.776	0.030*	0.048*	0.014*	0.004**

 

Table 6 Correlation of thyroglobulin Antibodies and thyroid hormones in hypothyroidism patients
TgAb Results	Frequency	Percentage %	Mean of:
			TSH	T4	FT4	T3	FT3
Negative (< 125 IU/ml)	60	54.1	16.9	67.3	12.4	1.35	3.5
Positive (>125IU/ml)	51	45.9	26.3	59.2	11.7	1.37	3.7
P. value			0.169	0.106	0.467	0.809	0.554

 

Table 7 Correlation between serum thyroid hormones in case and control groups
	Hypothyroidism		Hyperthyroidism
	N=111		N=72
TSH
Group	Frequency	Mean	Sig. (2- tailed)	Frequency	Mean	Sig. (2- tailed)
Case	111	21.19	0.000**	72	0.9	0.000**
Control	100	2.1		100	2.1
TT4
Case	111	63.6	0.000**	72	140.9	0.000**
Control	100	93.1		100	93.1
FT4
Case	111	12.1	0.000**	72	31.97	0.000**
Control	100	17.6		100	17.6
TT3
Case	111	1.17	0.000**	72	3.36	0.000**
Control	100	1.58		100	1.58
FT3
Case	111	3.58	0.000**	72	10.04	0.000**
Control	100	4.26		100	4.26

 

8.    DISCUSSION

The population of this study were distributed according to occurrence of thyroid disease into (111) participants (60.7%) with hypothyroidism, and: (72) participant (39.3%) with hyperthyroidism, then into sex according to disease as follows: (91.9%) of hypothyroidism were females and just (8.1%) were males, in hyperthyroidism; (84.7%) were females and (15.3%) were males

Family history: (33.3%) of hypothyroidism were with family history, (64.9%) of them with first degree and (35.1%) with second degree of family history and (66.7%) without a family history, in hyperthyroidism; (37.5%) were with positive family history (70.4%) of them with first degree and (29.6%) with second degree and (62.5%) without family history. (50.5%) of hypothyroidism and (41.7%) of hyperthyroidism patients were newly discovered. The age in hypothyroidism; the mean of age was (50.4± 14.7 years), in hyperthyroidism was (43.6±13.4 years). The body weight in hypothyroidism was (68.1±15.5 Kg), and in hyperthyroidism was (64.9±13.5kg). The mean level of TSH in hypothyroidism was significant increased than control group (P. value=0.000), that means there was highly significant statistical different between the means, and it is out of range (0.4 – 4.3 µIU/mL), the mean in hyperthyroidism had statistically significant difference (P. value=0.000) but within reference range. There were highly significant statistically differences between the mean of thyroid parameters, in hypothyroidism, control and hyperthyroidism group (P. value=0.000). The results of this study were consistent with study conducted in China by Hong Li, et al., indicating that the correlation of TT4, and fT4 with TSH was statistically significant in healthy individuals (P < 0.01).  The correlation of TT4, fT4, TT3, and fT3 with TSH was statistically significant in patients with hyperthyroidism, The correlation of TT4, fT4, TT3, and fT3 with TSH was statistically significant in patients with hypothyroidism, TSH and fT4 are the most valuable indicators in assessing thyroid function in a healthy population, and TSH and TT4 are the most meaningful in hyperthyroidism and hypothyroidism. The current study showed that: 107 (58.5%) patients were positive when evaluated  to  TPO Ab  with  level more  than  (40.0  IU/ml),  72  (64.9%)  of hypothyroidism  group  were  TPO Ab  positive  and  35  (48.6%)  of hyperthyroidism have positive  titter of TPO Ab,  in  evaluation of Tag Ab, 73 (39.9%) of  the population  studied were positive, 51  (69.9%) of  them were hypothyroidism, and 22  (30.1%) of  them were hyperthyroidism. Regarding the correlation between TPO Ab and Tg Ab in hypothyroidism the study findings were in agreement with a study found that:  the TPO Ab positive patients, (60.7%) were found to be hypothyroid and TgAb positive patients;(53.1%) patients were hypothyroid, while the correlation between thyroid antibodies and hyperthyroidism appear to be. also similar to the findings of the study conducted in Iran by Aminorroaya et al. (2006) who found that; positive autoantibodies were detected in (75.5%) of patients with hypothyroidism, and in (73.6%) of those with hyperthyroidism.

In hyperthyroidism patients, the mean level of fT3 with positive TPO Ab was statistically increased more than the negative TPO Ab (P. value= 0.032) that means there was statistically significant effect of presence of TPO Ab on serum level of fT3

 

9.     CONCLUSION

·        Most of thyroid patients were with hypothyroidism.

·        Most thyroid dysfunctions were females.

·        Free fractions of thyroid hormones have more correlations with clinical findings.

·        (58.5%) of thyroid patients had TPO Ab, (39.9%) had Tag Ab.

·        Two third of hypothyroidisms had positive titter of TPO Ab and Tag Ab.

·        One half of hyperthyroidisms had TPO Ab positive titter and one third had Tag Ab.

 

10.      RECOMMENDATIONS 

Based on the results, obtained from this study, it is recommended that:

1)     Evaluation of thyroid antibodies must be done for all thyroid patients.

2)     As concern thyroid hormones evaluation, free fraction, total thyroxine, and measurement of binding protein also important to distinguish between thyroid dysfunction and deficiency of binding proteins.

3)     Further studies should be done for elucidation of genetic and environmental factors triggering production of autoantibodies.

4)     Presence of thyroid antibodies should be taken in consideration with hormonal assays to give precise diagnosis of thyroid disease.

 

REFERENCES

Ajit S. Shinto, Leena Pachen, Sreekanth, Deepu George (2010) : Prevalence of Antithyroid Antibodies in Histologically Proven Autoimmune Thyroid Diseases and Correlation with Thyroid Dysfunction in South India. Thyroid Science 5(9) :1-5,

Aminorroaya A, Momenzadeh M, Hovsepian, S. Haghighi S, and Amini M. (2006) : Thyroid autoantibodies in women with and without thyroid disorders in an iodine-replete area Eastern Mediterranean Health Journal, Vol. 14, No. 2,

Anke Hannemann, Nele Friedrich, Robin Haring, Alexander Krebs, Henry Völzke, Dietrich Alte, Matthias Nauck, Thomas Kohlmann, Hans-Christof Schober, Wolfgang Hoffmann,and Henri Wallaschofski. (2010) : Thyroid function tests in patients taking thyroid medication in Germany : Results from the population-based Study of Health in Pomerania (SHIP). BMC Res Notes. ; 3 : 227. Retrieved from https://doi.org/10.1186/1756-0500-3-227

Bianco AC, Salvatore D, Gereben B, Berry MJ, Larsen PR (2002) : Biochemistry, cellular and molecular biology, and physiological roles of the of the iodothyronine selenodeiodinases. Endocr Rev 23 :38-89. Retrieved from https://doi.org/10.1210/edrv.23.1.0455

Carayanniotis G, and Rao V. P, (1997) : "Searching for pathogenic epitopes in thyroglobulin : parameters and caveats," Immunology Today,, vol. 18, no. 2, pp. 83-88, Retrieved fromm https://doi.org/10.1016/S0167-5699(96)10073-6

Collison K.S, Banga J. P, Barnett P. S, Huang G.C, and McGregor A. M, (1991) : "Autoantibody stimulation of the human thyrotropin receptor : regulation of adenylate cyclase activity, thyroglobulin and thyroid peroxidase mRNA levels in primary cultures of Graves' thyroid tissue,”. Clinical and Experimental Immunology, Vol.86, no.1, pp.61-65, Retrieved from https://doi.org/10.1111/j.1365-2249.1991.tb05774.x

Dufour D. (2007) : Laboratory Tests of Thyroid Function : Uses and limitations. Endocrinol Metab Clin N AM. 2007 ; 36 : 579- 594. Retrieved from https://doi.org/10.1016/j.ecl.2007.04.003

Faranak Sharifi, Leila Ghasemi, and Nouraddin Mousa vinasab. (2008) : Thyroid Function and Anti-Thyroid Antibodies in Iranian Patients with Type 1 Diabetes Mellitus : Influences of Age and Sex Iran J Allergy Asthma Immuno; 7(1): 31-36 Retrieved from https://doi.org/10.1016/j.clim.2007.03.214

Gbadebo A. M, and Oyesanya T. M, (2005) : "Assessment of iodine deficiency and goitre incidence in parts of Yewa area of Ogun state, South western Nigeria," Environmental Geochemistry and Health, vol.27, no.5-6, pp.491-499, Retrieved from https://doi.org/10.1007/s10653-005-6982-z

Harington CR (1926) Chemistry of Thyroxine : Constitution and Synthesis of Desiodo-Thyroxine. Biochem J 20 :300-313. Retrieved from https://doi.org/10.1042/bj0200300

Hawa M. I, Picardi A, Costanza F. et al. (2006) : "Frequency of diabetes and thyroid autoantibodies in patients with autoimmune endocrine disease fromCameroon," Clinical Immunology, vol.118, no. 2-3, pp. 229-232, Retrieved from https://doi.org/10.1016/j.clim.2005.09.016

Int Assoc of Medical Laboratories. (2007) : Guideline for the Use of Laboratory Tests to Detect Thyroid Dysfunction CLP 015,

Jayakumar RV : (2011) : Clinical Approach to Thyroid Disease, supplement to japi.. vol. 59.

Kendall EC (1919) Isolation of the Iodine Compound Which Occurs in the Thyroid. J.Biol. Chem. 39, 125-147. Retrieved from https://doi.org/10.1016/S0021-9258(18)87324-0

McIntosh R, Watson P, and Weetman A, (1998) : 'Somatic hypremutation in autoimmune thyroid disease,' Immunological Reviews, vol. 162, pp. 219- 231, Retrieved from https://doi.org/10.1111/j.1600-065X.1998.tb01444.x

McLachlan S.M. and Rapoport B. (1992) : 'The molecular biology of thyroid peroxidase : cloning, expression and role as autoantigen in autoimmune thyroid disease,' Endocrine Reviews, vol. 13, no.2, pp. 192-206, 1992. Retrieved from https://doi.org/10.1210/edrv-13-2-192

Njemini R, Meyers I, Demanet C, Smitz J, Sosso M, and Mets T, (2002) : "the prevalence of autoantibodies in an elderly sub-Saharan African population," Clinical and Experimental Immunology, vol.127, no.1, pp.99 -106. Retrieved from https://doi.org/10.1046/j.1365-2249.2002.01713.x

Noboru Hamada, Jaeduk Yoshimura Noh, Yasuyuki Okamoto, Miki Ueda, Toshiaki Konishi, Toshimichi Fujisawa, Koichi Ito and Kunihiko Ito. (2010) : Measuring thyroglobulin autoantibodies by sensitive assay is important for assessing the presence of thyroid autoimmunity in areas with high iodine intake, Endocrine Journal, 57 (7), 645-649. Retrieved from https://doi.org/10.1507/endocrj.K09E-353

Ogedebe H. (2007) : Thyroid function test : à clinical lab perspective. Medical Laboratory Observer, :10-19. Retrieved from https://europepmc.org/article/med/17375841

Pallavi Chaurasia, Bhautik Modi, Sarita Mangukiya, Pranay Jadav, Rita Shah, (2011) : Variation in thyroid hormones levels among people of different age, gender and seasons, Piparia, Gujarat. National journal of medical research, Vol 1 Issue 2 : ISSN 2249 4995 P57-59.

Sowerby Centre for Health Informatics at Newcastle. (1999) : Hypothyroidism, PRODIGY ; Available from : URL : Retrieved from http://www.prodigy.nhs.uk. 

Thyroid Foundation of Canada. Health Guides on Thyroid Disease. (2009) : http://www.thyroid.ca/Guides/HG02.html#1, Accessed March 5 2009.

WHO. (2010) : World Health Assembly Progress Reports (A63/27) : Sustaining the elimination of iodine deficiency disorders (resolution WHA60.21). (2010) 63rd.available at URL http://www.who.int/ 2630, 2006.

Walsh J. P, Ward L. C, Burke V, et al., (2006) : "Small change in thyroxine dosage do not produce measurable changes in hypothyroid symptoms, well-being, or quality of life : results of a doublé blind, randomized clinical trial," Journal of Clinical Endocrinology and Metabolism, vol.91, no.7, pp. 2624-2630, Retrieved from https://doi.org/10.1210/jc.2006-0099

Wu T, Liu GJ, Li P, and Clar C : (2002) : Iodised salt for preventing iodine deficiency disorders. Cochrane Database Syst Rev, (3) : CD003204 Retrieved from https://doi.org/10.1002/14651858.CD003204