Alpha 1 anti trypsin

CRP, IL-6 and soluble CD14 were measured in maternal and infant plasma by ELISA using R&D Systems Quantikine kits according to the manufacturer’s instructions. Soluble CD163 was measured in maternal and plasma by ELISA using R&D Systems DuoSet kits according to the manufacturer’s instructions. I-FABP was measured by ELISA in plasma (Hycult Biotechnology, Uden, The Netherlands). Stool samples were tested by ELISA for neopterin (GenWay Biotech Inc, San Diego, CA, USA), myeloperoxidase (Immundianostik, Bensheim, Germany), alpha-1 anti-trypsin (BioVendor, Brno, Czech Republic), and REG‐1β (TECHLAB Inc, Blacksburg, VA, USA).

All laboratory analyses were performed in the laboratories at icddr,b in Dhaka, Bangladesh. Alpha-1-anti-trypsin (Biovendor, Chandler, NC), NEO (GenWay Biotech, San Diego, CA), and MPO (Alpco, Salem, NH) were measured in the stool samples using commercially available enzyme-linked immunosorbent assay kits, following the manufacturer’s instructions. Plasma zinc was measured by atomic absorption spectometry method. Ferritin and sTfR levels were measured using chemiluminescence immunoassay and immunoturbidimetry method, respectively.

Enteric inflammation was assessed by measuring the levels of MPO (Alpco, Salem, NH), NEO (GenWay Biotech, San Diego, CA), and alpha-1-anti-trypsin (Biovendor, Chandler, NC) from the monthly nondiarrheal stool samples by using quantitative commercial ELISA kits. Environmental enteric dysfunction score, ranging from 0 to 10, was calculated from the three biomarkers, as described previously,³⁹ (link) and was used as the noninvasive indicator for childhood enteropathy. Categories were assigned with the values 0 (low), 1 (medium), or 2 (high). Myeloperoxidase, NEO, and AAT values were log‐transformed before subsequent analysis. The formula used for the calculation of the EED score is as follows¹³ (link): $$\text{EED} \text{score}\hspace{0.17em}=\hspace{0.17em}2\hspace{0.17em}\times \hspace{0.17em}\text{AAT} \text{category}\hspace{0.17em}+\hspace{0.17em}2\hspace{0.17em}\times \hspace{0.17em}\text{MPO} \text{category}+\hspace{0.17em}1\hspace{0.17em}\times \hspace{0.17em}\text{NEO} \text{category}$$
On the other hand, a customized multiplex real-time polymerase chain reaction (PCR) platform involving a compartmentalized primer–probe assay system, known as TaqMan Array Cards (TAC), was used for the detection of enteropathogens.⁴⁰ (link)^,41 (link) A cycle threshold (Ct) value of 35 was considered as the cutoff value, whereby values lower than 35 were considered to be positive for the particular enteropathogen.