Mouse Anti guinea Pig transglutaminase, tissue Hybridoma [5D2]

Background: Mycobacterium tuberculosis (TB) is a widespread life-threatening infection worldwide. There is an uncertainty in the association between the emergence of autoimmune antibodies and TB. Objectives: We hereby aimed to screen anti-tissue transglutaminase (anti-tTG) IgA in patients with TB in an Iranian population. Methods: This was a cross sectional study conducted on smear positive TB patients admitted to the Respiratory Diseases Management Center of the city of Zabol, Sistan and Baluchestan Province of Iran during 2017 - 2018. Anti-tTG IgA level was determined using an ELISA kit (Pars Azmoun, Iran). Statistical analyses were performed in SPSS 19 software. Results: Overall, 162 patients were evaluated. Females and males constituted 87 (53.7%) and 75 (46.3%) of the patients respectively. The mean age was 51.7 +/- 22.3 years (range of 1 - 83). Afghan patients constituted 16 (9.9%) and the remaining were Iranians. The therapy course was successfully completed in 78 (48.1%) patients, and 67 (41.4%) improved following treatments. Overall, 5 patients had active TB with 2 drug-resistant cases. Pulmonary tuberculosis was diagnosed in 127 (78.4%) while 35 (21.6%) had extra-pulmonary disease. The mean titer of anti-tTG IgA was 22.59 +/- 107.7 (range of 0.8 - 940). Overall, 19 (11.9%) of the patients showed elevated levels of the antibody. There was no significant association between anti-tTG IgA titer with neither demographic nor clinical variables. Conclusions: Although anti-tTG IgA antibody test was positive in a relatively high ratio of our patients with TB, the clinical implications of this phenomenon were not significant.

Background: The clinical presentation of celiac disease (CD) varies between children. The objective of this study was to document the pre-test probability for CD based on symptoms and routine laboratory test and to evaluate the performance of two IgA anti-tissue transglutaminase (tTG) assays. We critically reviewed the concept of using multiples of the manufacturer's upper limit of normal (ULN), as proposed in the ESPGHAN guidelines (if IgA tTG is > 10 times ULN, no biopsy is needed). Methods: The retrospective study included 91 children with newly diagnosed CD and 605 controls ( < 16 years). All underwent upper endoscopy with small bowel biopsies. Four laboratory parameters and 16 symptoms were registered. All patients were tested for IgA anti-tTG antibodies with assays from Inova Diagnostics and Thermo Fisher Scientific. Results: Some combinations of clinical symptoms and laboratory parameters had a high pre-test probability for CD, such as (combinations of) anorexia, failure to thrive, low ferritin level and elevated AST. The diagnostic performance of both IgA anti-tTG assays was excellent and comparable (no difference in ROC curve area under the curve). At a threshold that corresponds to a specificity of 100% (5 times ULN for Inova Diagnostics and 2 times ULN for Thermo Fisher), the sensitivity was 82% for both assays. At the 10 times ULN threshold, the sensitivity differed between the assays (77% vs. 57%), indicating that such threshold does not completely align interpretation across companies. Conclusions: Our study showed that some combinations of symptoms and aberrant laboratory parameters had a high pre-test probability. The use of the ESPGHAN non-biopsy approach could reduce small bowel biopsies, but thresholds for IgA-tTG levels are not aligned across assays and should be based on predefined likelihood ratios or specificity.