In the area of Autoimmunity, autoantibodies studies are carried out that are useful in the diagnosis and monitoring of both systemic and organo-specific autoimmune diseases. The area of Autoimmunity is dedicated to the laboratory diagnosis of autoimmune diseases by analyzing the detection and quantification of autoantibodies and / or immune mediators involved. The clinical importance of the presence of autoantibodies can have a diagnostic (criteria), prognosis or therapeutic monitoring value. The pathologies included are classified as:

• Autoimmune endocrine diseases: Type I Mellitus Diabetes, Tiroidal Diseases, Addison Disease, Autoimmune Poliglandular Syndrome
• Autoimmune kidney diseases: membranous glomerulonephritis
• Autoimmune diseases of the skin: ampuloid diseases and dermatomiositis
• Autoimmune liver diseases: Autoimmune Hepatitis, Primary Biliary Colangitis, Sclerosant Colangitis.
• Autoimmune gastrointestinal diseases: Inflammatory Intestinal Disease, Celiac Disease, Autoimmune Gastritis.
• Autoimmune diseases of the Nervous System: Optical neuroitis spectrum syndromes, Grave Myasthenia, Peripheral autoimmune polyneuropathy, Autoimmune Encephalitis, Paraneoplastic Neurological syndromes.
• Systemic rheumatic diseases: Lupus Eritematosus, Sj.gren Syndrome, Autoimmune Sclerodermia, Rheumatoid Arthritis, Myositis, Connective Tissue Diseases, Antiphospholipid Syndrome.
• Autoimmune Vasculitis ANCA Positive

The equipment and techniques available in the area of Autoimmunity to direct studies of autoimmune diseases are:

• Indirect Immunofluorescence on cells and tissues: it is based on the detection of autoantibodies using the fluorescence microscope. The expert interpretation of patterns or structures against cellular or tissue structures allows the study of screening towards different monospecific techniques. It is also the method of confirmation of different monospecific solid phase tests.
• Fixed Cell Based Assay (CBA): Study of monospecific antibodies using indirect immunofluorescence using transfected cells.
• Solid phase immunoassays with specific purified or recombinant antigens by techniques such as ELISA (enzyme immunoassays), CLIA (chemoluminescence), Inmunoblot (line and dotblots). These techniques are used both for the characterization and quantification of autoantibodies with the use of accredited calibrators and reference controls that validate their use in clinical practice.

In the area of Immunochemistry, the determinations of plasma components of the immune system that participate in the humoral response (immunoglobulins G, A, M and subclasses of IgG), complement system, are carried out, as well as inflammation markers (FR, PCR, cytokines or calprotectin).

These tests are mainly useful for the diagnosis and monitoring of immunodeficiencies, inflammatory/immunomediate diseases and for the diagnosis and monitoring of patients with multiple myeloma.

The different techniques used in the area and the pathologies in which their study is important are:

• Immunofixation: In the characterization of the isotype of immunoglobulin for the diagnosis and monitoring of monoclonal gammopathies and cryoglobulin-associated vasculitis
• Isoelectrofocus: For the study of oligoclonal bands in the diagnosis of multiple sclerosis
• Turbidimetry: quantification of immunoglobulins IgG, IgA, IgM IgD and subclasses of IgG. Quantification of free k and lambda strings. Study of complement proteins (C3 and C4) and CH50 functional activity. For the diagnosis and monitoring of immunodeficiencies, autoimmunity and hematological diseases.
• ELISA: monitoring treatment with biological drugs by quantifying drug levels and anti-drug antibodies.
• Chemoluminescence: quantification of inflammation mediators such as FR, calprotectin and interleukin-6

In the area of cellular Immunology, the diagnosis and monitoring of patients with immunodeficiencies, both primary and secondary, are carried out. These include those caused by infections, such as HIV, as well as those derived from pharmacological treatments with immunomodulatory and immunodepleting drugs.

Phenotyping tests of lymphocyte subpopulations using flow cytometry are used, including multiparametric studies that allow a detailed analysis of a wide range of minority subpopulations and cellular markers.

In addition, we have several techniques to evaluate the functionality of immune system cells. These techniques include studies of lymphocyte proliferation against specific mitogens and antigens, studies of phagocyte functionality, and the measurement of interferon production in response to different viruses.

In collaboration with the cytometry platform of the IGTP, the service has three flow cytometers, capable of analyzing up to 13 simultaneous parameters, and a full spectrum cytometer that allows the analysis of up to 40 parameters.

In the area of Immunoallergy, a series of techniques are carried out to complement and guide the diagnosis of allergic processes, such as specific IgE determinations, the assessment of tryptase levels to identify an anaphylactic table or the study of allergenic components using microarrays. Functional studies are also carried out for the diagnosis of drug hypersensitivity based on the basophil activation test (TAB) and the lymphocyte transformation test (TTL).

The equipment and techniques available in the area are:

• Determination of specific IgE levels (chemoluminescence).
• Determination of triptase levels (chemoluminescence).
• Study of allergenic components using microarray
• Basophile activation test to study IgE hypersensitivity to drugs.
• Lymphocyte proliferation test to study delayed hypersensitivity to drugs.

In the area of Hystocompatibility, several techniques are used for the study of HLA genes (Human Leukocyte Antigens). The HLA system is one of the most polymorphic in the body, and the different versions of these genes can significantly influence the susceptibility to various pathologies, such as celiac disease, Behcet disease or ankylosing spondylitis. In addition, the analysis of these genes and compatibility studies are crucial to the success of transplants.

The equipment and techniques available in the area are:

• Extraction of nucleic acids (Maxwell' RSC)
• DNA quantification (NanoDrop)
• DNA amplification (Veriti 96 Well)
• HLA and susceptibility to Behcet's disease by PCR-Real Time (LightCycler la 480)
• HLA and susceptibility to ankylosing spondylitis by PCR-Real Time (LightCycler l 480)
• HLA and Abacavir hypersensitivity by PCR-Real Time (LightCycler' 480)
• HLA and susceptibility to celiac disease by PCR-SSO (Xponent Luminex)
• HLA and susceptibility to other pathologies such as autoimmune diabetes, retinopathies, rheumatoid arthritis... (LightCycler® 480)
• Family studies for Transplantation of Hematopoietic Progenitors by PCR-SSO (Xponent Luminex)

The immunotherapy and monitoring area is one of the main lines of growth in the Immunology service of the Germans Trias Hospital. We work intensively on the development and implementation of various methodologies for the monitoring of therapies that act selectively on the immune system. Currently, the monitoring tests carried out in healthcare practice include two types of studies:

• Measurement of serum-soluble parameters: Both the levels of biological drugs in serum and the anti-drug antibodies generated by immunogenicity are quantified. Applications:
  • Levels and detection of Ac against adalimumab,
  • Levels and detection of Ac against infliximab
  • Levels and detection of Ac against etanercept.

• Measurement of cellular parameters in total blood: Based on flow cytometry, this technique allows measuring the expression of different molecules on the cell surface (such as receptors) or lymphocyte subpopulations that have been identified as biomarkers for the monitoring of various drugs. Applications:
  • Post-rituximab reconstitution
  • Occupation of CD49d receptor in treatment with natalizumab
  • Post-alemtuzumab reconstitution
  • Lymphocyte subpopulations in response to phingolimod
  • Lymphocyte subpopulations in response to fumarate dimethyl
  • Post-therapy monitoring with CAR-T cells
  • Post-therapy reconstruction with CAR-T cells

Monitoring these parameters is very useful in clinical practice to adjust the treatment. This allows optimizing the dose in responsive patients, avoiding side effects, and identifying the causes of the lack of response in nonresponsive patients, such as the presence of antibodies against the drug, which could suggest a change of drug or therapeutic target. The objective of monitoring biological therapies is to turn this tool into a key part of decision making, providing benefits for both the patient and the clinician.