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Immunostimulants

Q: What is the fundamental difference between interferons and interferon inducers?

Interferon preparations (such as interferon alfa-2a or beta-1b) contain preformed proteins that are introduced into the body exogenously. Interferon inducers (such as tylron) do not contain these proteins themselves; instead, their mechanism of action stimulates the host's cells to synthesize their own endogenous interferon.

Q: Which drugs belong to the colony-stimulating factors group?

This group includes molgramostim, filgrastim, pegfilgrastim, lenograstim, and sargramostim. They belong to the cytokine class.

*Immunostimulantia*

For medical students2 min readUpdated 2026-10-10

Immunostimulants are pharmacological agents designed to activate the immune system as a whole or stimulate its individual components and links. In modern clinical practice, these drugs play a crucial role in treating immunodeficiency states, chronic persistent infections, and are utilized in combination regimens for certain oncological diseases.

Primary TargetImmune system (as a whole or its individual links and components)

Main IndicationsImmunodeficiencies, chronic persistent infections, certain types of malignancies

DiversityIncludes synthetic, microbial, endogenous, and herbal preparations

InducersStimulate the production of endogenous interferon

General Characteristics and Indications

Immunostimulating agents represent a vast group of pharmacological preparations. Their main therapeutic objective is to activate the body's defense mechanisms. Notably, the specific target of these drugs is the immune system itself, rather than the hypothalamo-pituitary axis, the reticuloendothelial system, or the complement system in isolation.

In clinical practice, three primary categories of indications for immunostimulants are distinguished:

Immunodeficiency states of various etiologies.
Chronic persistent infections where the patient's immune system is unable to clear the infectious agent independently.
Certain oncological diseases (used as part of combination therapy to support the immune response).

Colony-Stimulating Factors and Interleukins

Cytokine preparations constitute a significant portion of immunostimulants. They are actively used for targeted regulation of immune processes.

The group of colony-stimulating factors (CSFs) includes the following agents:

Molgramostim.
Filgrastim and its derivative pegfilgrastim.
Lenograstim.
Sargramostim.

Another important cytokine subgroup comprises interleukin preparations. This category includes drugs such as aldesleukin, betaleukin, and oprelvekin.

Interferon Preparations

Interferons are classified into three major groups based on the type of active substance (alpha, beta, or gamma).

Interferons alpha: include interferon alfa, interferon alfa-2a, interferon alfa-2b, and interferon alfa-n1.
Interferons beta: represented by interferon beta-1a and interferon beta-1b.
Interferons gamma: the primary representative in this classification is interferon gamma.

Classification of Other Agents by Origin

The group of "other immunostimulants" is subdivided into several categories depending on the source of the active substance:

Endogenous polypeptides (and their analogs). These include thymalin and immunofan.
Synthetic agents. Notable representatives include levamisole and azoximer bromide (widely known as polyoxidonium).
Microbial-derived preparations (and their analogs). These include agents created from bacterial components, such as Broncho-Vaxom, Ribomunyl, and prodigiosan.
Interferon inducers. Unlike exogenous interferon preparations, these agents stimulate the patient's cells to produce their own endogenous interferon. Examples include tylron and meglumine acridoneacetate.
Miscellaneous immunostimulants. This mixed group includes herbal and other preparations, such as echinacea extracts, galavit, ersibol, and estifan.

Mnemonic

To quickly memorize the classes of immunostimulants by origin, use the phrase "SEMI Plants": Synthetic (levamisole), Endogenous (thymalin), Microbial (ribomunyl), Interferon inducers (tylron), Plants and others (echinacea/immunal).

Frequently asked questions

Which immunostimulants are of herbal origin?

Herbal immunostimulants include echinacea preparations and potato shoot polysaccharides.

Immunal — categorized among miscellaneous herbal-based immunostimulants.
Estifan — represents a dry extract of Echinacea purpurea.
Potato shoot polysaccharide fraction — used as a herbal antiviral agent in combination therapy.

What are the contraindications for prescribing immunostimulants?

Contraindications depend heavily on the specific agent. For echinacea preparations (e.g., estifan), typical restrictions include:

Tuberculosis.
Leukemias.
Collagen vascular diseases (connective tissue diseases).
Multiple sclerosis.

For the synthetic agent azoximer bromide, contraindications include:

Hypersensitivity to the components of the drug.
Pregnancy.
Breastfeeding period.

What is the mechanism of action of azoximer bromide?

The mechanism of action of azoximer bromide involves the activation of innate resistance factors and pronounced immunomodulatory activity. The drug enhances the functional activity of cells, particularly when their baseline parameters are depressed. Key effects:

Activation of the monocytic-macrophage system, neutrophils, and natural killer (NK) cells.
Enhancement of T-cell proliferation and dendritic cell maturation.
Increased antibody production.
Upregulation of cytokine production (interleukins, interferon-alpha).
Nonspecific protective action against a broad spectrum of pathogens.

What adverse effects are characteristic of interferon preparations?

Interferons are associated with a wide range of adverse reactions affecting multiple organ systems. The most common is a flu-like syndrome, including fever, myalgia, arthralgia, and headache. Other side effects:

CNS — dizziness, depression, insomnia, tremor, confusion.
GI tract — nausea, vomiting, diarrhea, anorexia.
Hematologic — thrombocytopenia, neutropenia, transient leukopenia.
Renal — proteinuria, potential development of nephritis.
Cardiovascular — symptoms of heart failure.
Other — hepatotoxicity, pneumonitis, skin rash, alopecia.

What is the fundamental difference between interferons and interferon inducers?

Interferon preparations (such as interferon alfa-2a or beta-1b) contain preformed proteins that are introduced into the body exogenously. Interferon inducers (such as tylron) do not contain these proteins themselves; instead, their mechanism of action stimulates the host's cells to synthesize their own endogenous interferon.

In what types of infections are immunostimulants indicated?

According to general indications, immunostimulatory agents are used for chronic persistent infections. In such scenarios, the immune system is exhausted or functioning suboptimally, requiring pharmacological support.

Which drugs belong to the colony-stimulating factors group?

This group includes molgramostim, filgrastim, pegfilgrastim, lenograstim, and sargramostim. They belong to the cytokine class.

Go deeper

Pharmacodynamics of colony-stimulating factors: mechanisms of action of filgrastim and molgramostim.
Comparative profile of interferon preparations: alpha, beta, and gamma.
Synthetic immunostimulants: clinical pharmacology of levamisole and azoximer bromide.
Microbial-derived preparations (Broncho-Vaxom, Ribomunyl): mechanism of action and clinical indications.
Interferon inducers: how tylron and related agents stimulate the immune response.