The Blood Resource

Plasma is the clear, liquid fraction of the blood which remains when the white blood cells, red blood cells, and platelets are removed. It is composed of water (90%), proteins (7-8%), and smaller substances such as salts, gases, and nutrients. Plasma performs several vital functions, including transportation of essential compounds needed in different parts of the body, balancing the fluid exchange of all tissues by regulating the osmotic pressure, and as a key player in the immune system. Most cells in the body communicate with plasma directly or indirectly through other fluids. Analysis of the proteins present in plasma can therefore provide important information about a patient's health.

In this Human Protein Atlas resource, we focus on the protein levels in blood of both healthy individuals and patients diagnosed with various diseases. These analyses are performed with antibody-based proximity extension assay and mass spectrometry-based proteomics. Here you can explore:

• the levels of more than 1000 proteins in plasma across 59 diseases
• the longitudinal plasma levels of blood proteins in healthy individuals
• the levels of plasma proteins using immune assays and proteomics

Disease

The Human Disease Blood Atlas contains information on blood protein levels in patients with different diseases, and highlights proteins associated with these diseases using differential expression analysis. This version covers a pan-disease study consisting of 1162 proteins quantified by Proximity Extension Assay (PEA) and 146 proteins quantified by isotope dilution strategies based on the addition of recombinant protein fragment standards – the gold standard of quantitative mass spectrometry. Protein profiles have been quantified across 59 diseases with PEA and 12 diseases with targeted mass spectrometry. More information about the specific content and the generation and analysis of the data in the section can be found in the Methods Summary.

Learn about

• comprehensive and precise protein levels in blood covering 59 diseases
• proteins associated with each of the analyzed diseases

Blood plasma proteome

The proteins in blood, specifically the plasma proteome exibit an extraordinarily dynamic range. This range spans over 10 orders of magnitude between the concentration of the most abundant protein albumin (ALB), which acts as a transporter and helps maintain colloid osmotic pressure, and the rarest proteins detectable today, which include interleukins and tissue leakage proteins. Notably, over 90% of the plasma proteome is comprised of the ten most abundant proteins. Along with albumin, these include fibrinogen, involved in blood clotting, and immunoglobulins, mainly involved in immune processes.

Here we present estimated plasma concentrations of the proteins detected in human blood from mass spectrometry-based proteomics studies, published immune assay data, and a longitudinal study based on proximity extension assay (PEA). More information about the specific content, and the generation and analysis of the data in this section can be found in the Methods Summary.

Learn about:

• the plasma levels of blood proteins in a longitudinal study of healthy individuals
• the levels of plasma proteins using immune assays and mass spectrometry-based proteomics