Neopterin ELISA

The Neopterin ELISA is IVDR certified and can be ordered as an IVDR product!

Intended Use

The Neopterin ELISA is intended for the quantitative determination of Neopterin in human serum, plasma (EDTA) and urine in adults.

Intended purpose

The Neopterin ELISA is intended for the quantitative determination of Neopterin in human serum, plasma (EDTA) and urine in adults. Elevated neopterin levels can be measured as physiological marker for the indication of inflammation in the body, immune system activation and response activity. Neopterin is an unspecific marker for immune activation or other disturbances of the immune system and can be applied as an aid for early diagnosis of immune reaction like viral infection or allograph rejection. The Neopterin ELISA is a solid phase enzyme-linked immunosorbent assay (ELISA), based on the principle of competitive binding and measured on an absorbance reader. The assay is semi-automated requiring general purpose laboratory instruments and consumables such as absorbance microplate reader/washer, vortexer and pipettes to execute the test. Test results may be calculated from a standard curve and compared to laboratory established reference ranges from healthy adults (i.e. normal ranges). The test kit is intended for manual use and can be adapted to different ELISA processors like Thunderbolt, DSX and BEP2000. The test kit is intended for professional laboratory use by trained personnel. The test kit is not for self-testing. The Neopterin ELISA is NOT intended for near patient testing.

Neopterin

is a small molecule with a low molecular weight (253.21 g/mol) and belongs to the group known as pteridines. It is synthesized upon a cellular immune reaction. When macrophages and dendritic cells are stimulated by interferon-ɣ, neopterin is released. Neopterin values reflect the entire immunological processes for monocytes/ macrophages and dendritic cells and can be seen as a global immune response marker.

Figure 1: Release of Neopterin during cellular immune reaction [1].

An increase in neopterin concentration marks the onset of an infection in the body before antibodies are present. As soon as the immune system is triggered by interferon-ɣ, neopterin is released by macrophages.

Neopterin is related to:

• Early indication of viral infections (e.g. SARS-CoV-2, HIV)
• Differentiation of acute viral and bacterial infections
• Indications of autoimmune diseases (e.g. Sjörgren-syndrome, rheumatic diseases)
• Early indication of complications in allograft rejection episodes
• Follow-up control of chronic infections, therapy and treatment

Insights and cues from neopterin about the pathology of SARS-Cov-2: Synthesized upon stimulation of macrophages and dendritic cells, neopterin is an early, well-characterized biochemical marker of an ongoing immune reaction to viral infection [2]. There is evidence that neopterin levels correlate with the severity of COVID-19 progression and may be prognostic in COVID-19 patients [3–6]. The Neopterin ELISA kit sensitively detects this small molecule prior to clinical symptoms of infection and thus, may be a tool for early detection of SARS-CoV-2 infection.

Figure 2: Schematic time course of neopterin concentration in blood in relation to the rise and fall of antibody presence in response to viral infection [2].

Measurement in bodily fluids: The determination of neopterin levels in human body fluids offers a useful and innovative tool to monitor diseases associated with the activation of cell-mediated immunity. The ELISA is validated for measuring neopterin in serum, plasma (EDTA) and urine. Neopterin has higher stability in body fluids which makes sample handling and measurement easier compared to other cytokines. The low molecular weight enables neopterin molecules to pass rapidly through the intravascular area, where it is released into urine after glomerular filtration. The half-life in the human body is only affected by renal excretion. As a non-invasive method, urinary Neopterin to creatinine ratio determination is also helpful in monitoring disease progression and the effects of therapies, as well.

Increasing neopterin levels in various infections precede the clinical manifestation and seroconversion. Normally samples are not tested for all possible infections. Therefore, the measurement of neopterin in blood donor samples is a useful tool in order to reduce the risk of infections via blood transfusion [2].

Elevated neopterin levels predict fatal outcome in SARS-CoV-2-infected patients

Neopterin indicates a plethora of infections before the onset of symptoms and research is investigating neopterin levels and Covid-19 [6].

Key message:

Innate immune activation during Covid-19 infection is associated with pernicious clinical outcomes.

Background:

• Coronavirus disease 2019 (Covid-19) became a pandemic.
• Pre-existing comorbidities play a detrimental role in the course of Covid-19.
• Previous coronavirus epidemics, notably SARS-CoV, were associated with increased serum neopterin levels.
• Neopterin serves as a sign of acute innate immunity in response to viral infection. Authors propose neopterin may serve as:
  1. A biomarker of SARS-CoV-2 viral infection.
  2. An indicator of Covid-19 disease severity.

Neopterin levels and survival of patients

Figure 3: Neopterin is a biomarker of fatal outcome in SARS-CoV-2 infected patients [6].

The authors investigated the course of patients from the time symptoms occurred to discharge or death. The survival curves for Covid-19 patients (above) indicate that elevated neopterin levels (>53nm) correlated with a lower probability of survival, while lower levels (<53nM) in serum concentration led to a higher chance of survival.

Figure 4: Distinction between healthy and Covid-19 patients. Red symbols represent deceased patients. Blue symbols represent patients who recovered within one month-follow-up (survivors) [6].

A principal component analysis (PCA) was applied and neopterin levels in serum were measured with the Tecan Neopterin ELISA. In order to determine the effect of some combinations of comorbidities the PCA was generated, which would allow for stratification of the patients according to fatal clinical outcome. This principal component analysis allowed to make a clear distinction between Covid-19 patients who recovered from those who died.

For concrete data please consult the Instruction for Use in the download box on the top right side.