CALPRO - THE CALPROTECTIN COMPANY
Calpro AS was founded by the inventors of the technology behind the ELISA kits for determination of calprotectin in stools and other biological materials. Those who discovered and characterized Calprotectin later went on to create Calpro, and the company is one of the major suppliers of diagnostic tools based around the protein. Calpro AS is a part of Svar Life Science.
Located in Olso, Norway the company has the benefit of close professional links with many of the major clinical research departments and medical establishments in Scandinavia, Europe and the USA.
Focussing on one specific biomarker, the company has a knowledge base unlike any other and is dedicated to research on and developement of Calprotectin based diagnostic tests.
Calprotectin is a rather small protein making up around 60% the cytocol of Neutrophiles. It is released to the surrounding environment when the immune system is activated as a response to microbial or fungal infections, and is used in diagnosis of inflammatory bowel disease (IBD) to differentiate it from the functional irribable bowel syndrom (IBS). It is also routinely used in follow up of patients with IBD to predict relapse or determine response to treatment.
Calprotectin is a non-specific biomarker, such as the more commonly used C-Reactive Protein (CRP); however, the stability of the protein, robustness and local release without need for synthesis makes it a preferred biomarker for IBD. As such, the protein can be and is used in diagnosis and follow-up of a variety of diseases.
In 2016 the CalproSmart rapid test for clinic and home use was launched. The CalproSmart™ kit is validated and approved for self-testing, and is used for monitoring IBD treatment using a SMART phone, trending the quantitative levels of Calprotectin, and improving patient quality of life.
In 2000 an improved assay was developed by Tøn et al. Whereas the initial cut off value for fecal calprotectin between normal and patients with organic bowel disease was 10 mg/kg, it was now increased to 50 mg/kg, which is still recommended for the Calpro kits. Samples with high calprotectin values were increased to a slightly higher degree than low calprotectin samples, thus improving the separation between high and low calprotectin levels.
In the 20th century there was no commercial test kit available except Nycomed ELISA based on Calpro technology, but after standardized extraction methods had been developed and some gastroenterologists described faecal calprotectin as a promising noninvasive marker to differentiate IBD from IBS, the interest “exploded” around 2000. Up to now more than 2000 studies on calprotectin are published in peer review journals. Several issues regarding the use of fecal calprotectin testing in clinical medicine are discussed, included methodological and economic aspects.
Calpro AS was established in 1993, and based on the technology of Calpro the first commercial ELISA kit, Nycomed ELISA, for determination of calprotectin in faeces was launched in 1994. A patented buffer for extraction of calprotectin from feces, which had been developed by Calpro, was included in the test kit.
In 1991 Inge Dale did his doctoral thesis on these studies. During the first half of the nineties 3 Scandinavian ph.d.’s were published; all based on the original quantitative technology, using our purified calprotectin and polyclonal antibodies.
Quantitative methods for assessment of calprotectin in blood and tissues were established in 1984, including an ELISA, and during the eighties immunohistochemical studies were performed by Inge Dale, showing that the protein is abundantly found in neutrophil granulocytes, counting for 60 % of the proteins in the cytoplasm. Blood monocytes, like tissue macrophages, which are monocytes that have passed through the walls of vessels and migrated into the tissues, are also calprotectin positive. In addition, squamous epithelium of internal organs (esophaguis, mouth, vagina), and the cells of squamous cell carcinoma are also calprotectin positive.
In 1983 the study “Purification and Partial Characterization of a Highly Immunogenic Human Leucocyte Protein, the L1 Antigen” was published. Further investigations showed that each molecule binds 6 Ca-atoms, and as purified protein also inhibits the growth of certain bacteria in vitro, we renamed the protein “Calprotectin”.
Back in 1980 Inge Dale and Magne K. Fagerhol immunized rabbits with fractionated samples of leukocytes; among many antibodies one differed markedly from the others, forming distinct immunoprecipitates in gel containing Ca++-ions.