Generality
Immunosuppression, or immunodeficiency, is the medical condition in which an individual's immune system works less effectively than normal or does not work at all.
To diagnose immunodepression, the following are essential: physical examination, medical history, white blood cell count, T cell count and immunoglobulin count.
Therapy depends on the triggering causes: some causes involve more tractable forms of immunodeficiency than others.
Brief review of the immune system
The immune system is an organism's defensive barrier against threats from the external environment - such as viruses, bacteria, parasites, etc. - but also from within - such as, for example, cells that have gone mad (cancer cells) or are malfunctioning.
To fulfill its protective functions, the immune system can count on various organs, particular cells and glycoproteins; together, all these elements make up a sort of "army" deputed to activate and attack anything that constitutes a potential threat to the organism.
Among the organs constituting the immune system are the spleen, tonsils, bone marrow, thymus and lymph nodes ; among the cells of the immune system, the white blood cells (granulocytes, monocytes and lymphocytes) deserve a mention; finally, among the immune system glycoproteins, antibodies are remembered.
What is immunosuppression?
Immunosuppression, or immunodeficiency, is the medical condition for which an individual's immune system works less effectively than normal, or does not work at all.
Therefore, a person suffering from immunodepression - also called immunodepressed subject - is a person who has little or no immune defenses and is therefore more prone to infections, to develop cancer, etc.
Types and causes
There are at least two classifications of immunosuppression.
For one of these two classifications, the criterion of distinction is the component of the immune system that fails to fulfill its functions ( classification based on the affected component ).
For the other of the two classifications, instead, the criterion of distinction is the congenital or acquired origin of the condition ( classification based on the origin ).
Regardless of the criteria of distinction, classifying the immunosuppression has made it possible to simplify the consultation of the numerous causes.
CLASSIFICATION ACCORDING TO THE AFFETTAENT COMPONENT
The classification based on the affected component of the immune system recognizes the existence of:
- An immunodepression due to a lack / absence of so-called humoral immunity .
Humoral immunity is that part of the immune response that belongs to B lymphocytes, plasma cells or antibodies. Thus, immunodeficiency due to deficiency / absence of humoral immunity is a deficiency / absence of B lymphocytes, plasma cells or antibodies.
Main causes: multiple myeloma, chronic lymphoid leukemia and AIDS.
Most dangerous infectious agents, for humans, in such circumstances:
- Streptococcus pneumoniae
- Haemophilus influenzae
- Pneumocystis jirovecii
- Giardia intestinalis
- Cryptosporidium parvum
- An immunodepression following a deficiency / absence of T lymphocytes .
T lymphocytes are a component of white blood cells.
Main causes: lymphoma, cancer chemotherapy, AIDS, bone marrow transplantation, organ transplants in general and glucocorticoid-based drug therapies.
Most dangerous infectious agents, for humans, in such circumstances:
- Herpes simplex virus
- Mycobacterium
- Listeria
- Intracellular pathogenic fungi
- An immunodepression due to a deficiency / absence of so-called neutrophilic granulocytes (part of the white blood cells). In the medical field, the deficiency / absence of neutrophilic granulocytes is known as neutropenia .
Main causes: cancer chemotherapy, bone marrow transplantation and chronic granulomatosis.
Most dangerous infectious agents, for humans, in such circumstances:
- Enterobacteriaceae (or Enterobacteriaceae)
- Streptococcus oralis
- Pseudomonas aeruginosa
- Bacteria of the genus Enterococcus
- Mushrooms of the genus Candida
- Mushrooms of the genus Aspergillus
- An immunodepression resulting from the absence of the spleen . In medicine, the absence of the spleen is a condition that is called asplenia .
Main causes: splenectomy, spleen trauma and sickle cell disease.
Most dangerous infectious agents, for humans, in such circumstances:
- Bacteria provided with a polysaccharide capsule (eg: Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis )
- Protozoa of the genus Plasmodium
- Protozoa of the genus Babesia
- An immunodepression resulting from a generalized functional deficiency of all components of the immune system .
Main causes: congenital dysfunctions of the immune system.
Most dangerous infectious agents, for humans, in such circumstances:
- Bacteria of the genus Neisseria
- Streptococcus pneumoniae
CLASSIFICATION ON THE BASIS OF ORIGIN
The classification of immunosuppression based on origin recognizes the existence of two types of immunodeficiency: primary immunodepression (or congenital immunodepression ) and secondary immunodepression (or acquired immunodepression ).
To the type "primary immunodepression" belong all those conditions that determine a certain degree of immunodeficiency since birth (NB: the term "congenital", used as an alternative to "primary", means precisely "present from birth"). Transmissible from parents to offspring (hereditary diseases), the conditions responsible for congenital immunodepression are the result of chromosomal abnormalities, which could be located on autosomal chromosomes or on sex chromosomes.
According to the most recent studies, there would be at least 80 conditions associated with congenital immunodeficiency; among these, they deserve a quotation:
agammaglobulinemia linked to sex chromosome X, variable common immunodeficiency, severe combined immunodeficiency (SCID), DiGeorge syndrome and congenital hypogammaglobulinemia.
Taking therefore into consideration the typology "secondary immunodepression", to this belong all those medical conditions that a human being can develop in the course of life and that affect the effectiveness of the immune system in a more or less serious way (NB: the term "acquired" ", Used as an alternative to" secondary ", means" developed in the course of life "). The conditions responsible for secondary immunodeficiency can derive from:
- A serious state of malnutrition ;
- A drug therapy based on chemotherapeutic agents, disease-modifying antirheumatic drugs (DMARD), immunosuppressants or glucocorticoids ;
- Tumors, such as leukemia, lymphoma or multiple myeloma;
- Some chronic infections, such as AIDS or viral hepatitis ;
- Absence of the spleen (asplenia).
Other conditions associated with primary immunodepression:
- Chediak-Higashi syndrome
- Leukocyte adhesion deficiency
- Job syndrome (or hyper-IgE syndrome)
- Panipogammaglobulinemia
- Selective IgA deficiency
- Wiskott-Aldrich syndrome
RISK FACTORS
All subjects with a family history of primary immunodepression are at risk of immunodeficiency, as, as stated, the conditions responsible for this type of immunodepression are generally heritable.
They are then at risk of immunodepression:
- Those who, for different reasons, came into contact with the body fluids of an AIDS patient and developed the same infectious pathology;
- Those who, due to a tumor, the rupture of the spleen, an infection etc., had to undergo splenectomy to remove the spleen;
- The elderly, as aging causes the organs producing white blood cells to be less effective;
- Those who, due to lack of availability or for other reasons, do not take an adequate amount of protein. Proteins are essential for a highly efficient immune system;
- Those who do not sleep an adequate number of hours during the night. During nighttime sleep, the human body re-elaborates the proteins introduced by the diet and uses them, to fight potential pathogens. Those who do not sleep enough during the night cannot effectively use proteins for this purpose, so they are more vulnerable to infections;
- Color which, due to a tumor, must undergo chemotherapy.
Symptoms, signs and complications
When we talk about the symptoms and signs of immunodepression, we refer to the symptoms and signs of infectious diseases that can arise from a lowering or, in the most serious cases, from the absence of immune defenses.
Infectious diseases deriving from a state of immunodepression can be of bacterial, viral, fungal or parasitic nature and may have the symptomatic characteristics of pneumonia, a cold, flu, sinusitis, conjunctivitis, etc.
Diagnosis
In general, the diagnostic procedure to which patients with a suspected form of immunodepression is subjected includes:
- An accurate physical examination;
- A careful medical history;
- A test for the quantification of white blood cell levels;
- A test for the quantification of T lymphocyte levels;
- A test for the quantification of immunoglobulin (or antibody) levels.
If doubts persist after this series of diagnostic tests, doctors can count on another, very reliable test known as an antibody test (in English it is antibody test ).
The antibody test consists of giving the patient a vaccine and evaluating, after a few days or weeks, how the patient's immune system reacts to the vaccination. If the subject under examination does not suffer from immunodepression, his immune system works properly and produces, following the vaccine, the right amounts of antibodies; vice versa, if the subject examined suffers from immunodepression, his immune system is malfunctioning or not working at all and, despite the stimulation of the vaccine, does not produce any useful antibody.
Therapy
The treatment of immunosuppression depends mainly on what has affected the functioning of the immune system, ie the triggering causes.
Some triggers are treatable and this allows healing to be achieved; other causes, on the other hand, are difficult to cure or are not at all and this makes it essential to resort to therapies that remedy the deficiencies of the immune system and therapies against possible consequences (eg infections).
Regardless of the causes of immunosuppression, a valid advice for those with a pathological decline in immune defenses is to minimize exposure to pathogens .
Some tips to reduce exposure to infectious pathogens:
- Avoid frequenting crowded places
- Lead a healthy lifestyle and take care of your personal hygiene
- Take care of your dental hygiene
- Use antibiotic prophylaxis
- Avoid contact with sick people of some infection (even a simple cold)
PRIMARY OR CONGENED IMMUNODEPRESSION
Congenital immunosuppression is the result of incurable chromosomal abnormalities. Therefore, a person suffering from a chromosomal defect, which causes immunodepression from birth, is destined to coexist with an ineffective immune system and the risk of easily developing infections.
In such circumstances, however, there are remedies, which are intended to compensate for deficiencies in the immune system; the aforementioned remedies include:
- Replacement therapy with immunoglobulins . This treatment involves the administration of antibodies intravenously or subcutaneously.
- Hematopoietic stem cell transplantation . Hematopoietic stem cells are the cells that give rise to all the blood cells.
- The administration of specific cytokines .
The purpose of these treatments is to prevent the onset of infections and other diseases related to a decline in immune defenses.
SECONDARY OR ACQUIRED IMMUNODEPRESSION
The treatment of secondary immunosuppression is a broad and complex topic, as the possible triggering causes are numerous, sometimes curable and sometimes not.
For some forms of acquired immunodeficiency (eg, leukemia, multiple myeloma, etc.), the aforementioned hematopoietic stem cell transplantation, the aforementioned immunoglobulin replacement therapy or bone marrow transplant are valid.
For secondary immunodeficiency due to AIDS, there are various therapies (for example antiretroviral therapy), but none really 100% effective in any individual.
For acquired immunodepression resulting from conditions such as malnutrition or chemotherapy, the only solution is simply to remedy the triggering factor (eg: in the case of malnutrition, the remedy is to restore proper nutrition).
THERAPIES AGAINST POSSIBLE CONSEQUENCES
An immunodepressed subject can very easily develop bacterial, viral, fungal and / or parasitic infections.
In the presence of infections, the possible remedies consist of:
- Antiviral drugs and interferon, if the infection is due to viruses. Examples of antiviral drugs used are: amantadine, ramantadine and acyclovir.
- Antibiotics, if the infection is due to bacteria.
- Antifungal (or antifungal) drugs, if the infection is due to fungi.
Prognosis
If treated properly, many forms of primary immunosuppression enjoy a favorable prognosis. In fact, despite the triggers are incurable conditions, early and regular treatment of deficiencies in the immune system guarantees patients a normal life span.
Moving on to secondary immunosuppression, the prognosis for this problem depends very much on the severity of the triggering causes. For example, an acquired immunodeficiency due to leukemia has a much poorer prognosis, compared to an acquired immunodeficiency due to a state of malnutrition, as leukemia is a more complex condition to treat.
Prevention
Primary immunodepression is not preventable in any way, as it depends on chromosomal anomalies that appear during embryogenesis or uterine development, for unknown reasons. Secondary immunodepression, on the other hand, is preventable only if the triggering causes are. Consider, for example, acquired immunodeficiency due to AIDS: by avoiding any contact with the body fluids of a person with AIDS, the same infection does not develop, and therefore neither is immunodepression.
