Tehran University Medical Journal

Background: Immunoglobulins are a group of proteins have important role in defense against microorganisms. Human immunoglobulins are divided into five classes: IgA, IgM, IgD, IgE and IgG. Immunoglobulin G (IgG) is the highest abundant antibody in serum and extravascular fluids. The extent of serum IgG is related to severity of several diseases such as infections, so IgG has great diagnostic worth. Accurate measurement of IgG, needs exact and sensitive diagnostic instruments such as human IgG- specific monoclonal antibodies. Moreover, targeting of IgG has been useful in treatment of a number of diseases. According to experimental studies the Fc region of human IgG is highly immunogenic. Immunoinformatic is a division of immunology uses the computational biology for more precise diagnosis of diseases. The aim of this study was determination of conformational epitopes in the fragment of crystallizable (Fc) fragment of human IgG by immunoinformatic.
Methods: The amino acid residues and third structure of reference human IgG were found in protein data bank (PDB). Second IgG structure was defined by Phyre2 software (http://www.sbg.bio.ic.ac.uk/~phyre2/). Conformational epitopes of the Fc fragment in human IgG were specified by ElliPro (http://tools.iedb.org/ellipro/) and DiscoTope (http://www.cbs.dtu.dk/services/DiscoTope) softwares.
Results: In this study two conformational epitopes (one in constant heavy chain 2 (CH2) domain and another one common between CH2 and CH3 domains) sited in Fc fragment of human IgG were determined by ElliPro software. Also, two conformational epitopes (Both common between CH2 and CH3 domains) located to Fc fragment of human IgG were determined by DiscoTope software.
Conclusion: In this study a number of conformational epitopes located to Fc fragment of human IgG were determined by two immunoinformatic softwares (ElliPro and DiscoTope). The epitopes recognized by both softwares were situated in CH2, CH3 or both of these domains in the human IgG heavy chain. Thus, it seems that CH2 and CH3 domains of Fc region in human IgG are highly immunogenic. Moreover, ElliPro and DiscoTope softwares can be useful tools for identification of epitopes located to Fc fragment of human IgG.

Background: Sjögren’s syndrome is the second most common systemic autoimmune disease after rheumatoid arthritis, RA, with a prevalence of about 0.5% in the general population. It occurs primarily in perimenopausal women (at a ratio of women to men of 9: 1) Sjögren’s syndrome is characterized by lymphocytic infiltration to exocrine glands. The specific autoantibodies of this syndrome are against Ro (SSA) and La (SSB). B cell dysfunction occurs in patients with Sjögren's syndrome. B lymphocyte cells produce monoclonal immunoglobulin heavy and light chains addition to producing Ro (SSA) and La (SSB). Up to 25% of patients in this situation are associated with antibody production. This study aimed to evaluate the prevalence of monoclonal immunoglobulin in patients with primary Sjögren's syndrome.
Methods: 31 patients with primary Sjogren's syndrome diagnosed according to the American College of Rheumatology (ACR) criteria referred to Rheumatology Clinics of Firoozgar Hospital, Tehran, during first six months of 2016, were studied. Clinical examinations and tests carried out. We analyzed serum monoclonal immunoglobulins by immunofixation electrophoresis (IFE) on agarose gels with specific antisera to IgG, IgM, IgA, and κ and λ chains. The IFE was performed with a Helena immunofixation agarose kit (Helena Laboratories, Beaumont, TX, USA) following the manufacturer's recommended procedure. The measures of Anti-Ro, anti-La, rheumatoid factor (RF), antinuclear antibodies (ANA) with immunofluorescent method, complete blood count (CBC) with differential by peripheral blood smear, an erythrocyte sedimentation rate with western green tube, dip stick urine analysis, urine specific gravity (SG) with Refractometer (Mesu Lab Instruments Co., Guangzhou, China), turbidimetry serum complement, and the complement CH50 with ELISA were done.
Results: Most of (87%) patients were female. The mean age of patients was 45.32±12.02 years. The majority of the patients (94%, 29 cases), ocular sign was observed. Xerostomia were common in 84% cases (n=26). Arthralgia/arthritis and submandibular enlargement were common 48% and 19% of patients, respectively. Lymphadenopathy, lung involvement and parathyroid, each was prevalent in 16% of patients. Vasculitis in 13% and Raynaud's phenomenon in 6% of the patients were common. Liver and kidney involvements with the lowest prevalence, each was prevalent in 3% (1 person) patients. RF and the erythrocyte sedimentation rate (ESR) were abnormal in 22.58% and 12.90% of patients, respectively. The immunofluorescent antinuclear antibody (ANA or FANA) pattern, C3 and C4 complements levels were abnormal in 16.12%, 12.90% and 6.4% of patients, respectively. In 29% (n=9), monoclonal antibodies were higher than normal. IgG, IgM and IgG, were abnormal in 19.3% (n=6), 6.4% (n=2) and 3.3% (n=1), respectively.
Conclusion: Monoclonal immunoglobulin levels in patients with primary Sjogren's syndrome increases. To achieve more definitive and reliable results, this study should be repeated with larger sample size and at different times.

Background: Brucellosis is one of the most common infectious diseases transmitted from animal to human. Different methods of blood culture, serology, PCR and ELISA are used to diagnose brucellosis. The aim of this study was to compare the diagnostic value of ELISA tests with Brucella serological tests in patients with brucellosis.
Methods: In this cross-sectional descriptive study that was conducted from the beginning of April 2018 to the end of March 2019, 231 patients referred to the Infectious Diseases Clinic of Sina Hospital in Hamadan with clinical symptoms and possible diagnosis of brucellosis were included in the study. 5 cc of blood was taken from the patients to prepare serum, at the same time as Wright, Combs Wright and 2ME serology tests, IgG and IgM ELISA tests were also performed using the ELISA kit of Pishtaz Teb Company (Made in Iran), which is designed with the cut-off method. Then the test results were analyzed with SPSS software, version 16 (SPSS Inc., Chicago, IL, USA).

Results: 231 patients suspected of brucellosis including 147(63.64%) men and 84(36.36%) women with an average age of 44.60±16.16 years and a minimum of 10 years and a maximum of 80 years were examined. IgG and IgM results were positive with brucellosis in 80.1% and 30.30%, respectively. The results of IgG and IgM were positive in 1/80 and 30.30%, respectively, and they were diagnosed with brucellosis. In comparison with 2ME, Wright and Coombs-Wright serology tests, the sensitivity of IgG was between 83.80% and 94.28% and its specificity was between 20 and 33.34%, the sensitivity of IgM was also between 34.78 and 40.0% and its specificity was between 78.67% and 89.47% at different cut points. Conclusion: Compared to diagnostic serological tests for brucellosis, IgG is more sensitive and IgM is more specific. If serological tests are not available, ELISA can be used to diagnose brucellosis. But because of their lower diagnostic value, they cannot be replaced.

Results: Among the 2469 surveyed people, 658 people (26.65%) were men and 1811 people (73.35%) were women. Based on ELISA test, antibody titer was reported positive in 1157 people (46.9%), including 315 men and 842 women, and 1312 people (53.1%) had negative antibody titer. The highest number of positives is related to IgG, and in IgM, the test results are mostly negative. IgM prevalence showed no gender correlation but demonstrated a significant association with patient age. Meanwhile, IgG prevalence exhibited significant relationships with both age and gender Conclusion: Considering that the city of Shiraz is considered as one of the centers of treatment in the country and a large number of patients from all parts of the country and even neighboring countries come to this city for treatment and especially for the purpose of organ transplantation; also with Considering the 46.9% prevalence of CMV infection in the region, it is recommended to use preventive methods such as vaccine and immunotherapy against CMV infection in patients