**Viral Diseases in Transplant and Immunocompromised Patients**

Liliya Ivanova, Denitza Tsaneva, Zhivka Stoykova and Tcvetelina Kostadinova

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/61232

#### **Abstract**

For the last few years, the number of immunocompromised individuals is growing fast, due to more intensive antitumor therapy, transplantations and the concomitant immunosuppressive therapy, and the HIV epidemic, as well. Immunosuppressed pa‐ tients very often are affected with nosocomial infections in hospitals, and with infec‐ tions in the society. The defense from viral diseases depends mainly on the immune system. When there is immune deficiency, the illness is taking severely longer and has complicated outcome. Usually immunocompromised individuals have one or more defects in the defensive mechanisms and leading cause of death is infection.The virus‐ es taking part in this process are Epstein Barr virus (EBV), Cytomegalovius (CMV), Herpes simplex viruses (HSV1, HSV2), Varicella zoster virus (VZV), Hepatitis B virus (HBV), Hepatitis C virus (HCV), and Human Polyomaviruses (BKV, JC). Many virus‐ es (HIV, CMV, EBV) are depressing the immune resistance and are leading to co-in‐ fections with other microbial agents. Some viruses (HSV1/2, HPV, CMV, EBV, BKV, JC) are at latent condition in the infected persons for life. They become activated when decline in the immunity occurs, leading to serious illnesses. For this reason, accurate screening and prompt and precise diagnosis can be performed to prevent exacerba‐ tion of diseases and provide appropriate treatment.

**Keywords:** immunosupression, immunocompromised individuals, transplantation, viral infections

#### **1. Introduction**

According to several studies during the last few years, a tendency toward decreasing immune protection in human population has been under review. In the second half of the 20th century,

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the number of immunocompromised individuals is growing fast, due to more intensive antitumor therapy, transplantations, and the concomitant application of immunosuppressors and the HIV epidemic, as well. New syndromes and diseases appear, such as post-transplant lymphoproliferative disease (PTLD), caused in most cases by Epstein-Barr virus (EBV), and pneumonia by Cytomegalovirus (CMV). Other viruses taking part in this process are Herpes simplex viruses (HSV1, HSV2), Varicella zoster virus (VZV), Hepatitis B virus (HBV), Hepatitis C virus (HCV), and Human Polyomaviruses (BKV, JC). Usually immunocompromised individuals have one or more defects in the defensive mechanisms and leading cause of death is infection. The problem with viral causers of infections and diseases has become complicated for a few reasons:


The immune deficiency can be primary (congenital) and secondary (acquired).

Primary immunodeficiency is developed because of genetic block in differentiation of immunocompetent cells and impairment of immune mechanisms in antibody and/or Tlymphocytes production. There are three groups of primary immune deficiency:


Other than the primary immune deficits mentioned above, there are others, such as defect in the enzyme assuring purine nucleotides' phosphorylation and structural defects in the 14th chromosome.

The congenital B cell insufficiency leads to serious diseases after live vaccine application (poliomyelitis, measles, mumps, rubella). There is affecting of central nervous system and development of paresis and frequent recurrent viral infections of respiratory track. After infections caused by enteroviruses, encephalitis and myositis can occur. Chronic diarrhea is typical in rotavirus infection.

The congenital T-cell insufficiency brings about systematic infections caused by different viruses such as CMV, EBV, VZV, and by viruses of families ortho- and paramyxoviridae also.

Patients with interferon failure suffer from frequent respiratory diseases.

Secondary immune deficiency can be seen in:

the number of immunocompromised individuals is growing fast, due to more intensive antitumor therapy, transplantations, and the concomitant application of immunosuppressors and the HIV epidemic, as well. New syndromes and diseases appear, such as post-transplant lymphoproliferative disease (PTLD), caused in most cases by Epstein-Barr virus (EBV), and pneumonia by Cytomegalovirus (CMV). Other viruses taking part in this process are Herpes simplex viruses (HSV1, HSV2), Varicella zoster virus (VZV), Hepatitis B virus (HBV), Hepatitis C virus (HCV), and Human Polyomaviruses (BKV, JC). Usually immunocompromised individuals have one or more defects in the defensive mechanisms and leading cause of death is infection. The problem with viral causers of infections and diseases has become complicated

**1.** The defense from viral diseases depends mainly on the immune system. When there is immune deficiency, the illness is taking severely longer from its normal course and has complicated outcome. In such patients, the disease often becomes chronic or lead to

**2.** Many viruses (HIV, CMV, EBV) are depressing the immune resistance and are leading to

**3.** Some viruses (HSV1/2, HPV, CMV, EBV, BKV, JC) are at latent condition in the infected persons for life. They become activated when decline in the immunity occurs, leading to

**4.** In seronegative pregnant women and those with immune deficiency, the risk for congen‐

Primary immunodeficiency is developed because of genetic block in differentiation of immunocompetent cells and impairment of immune mechanisms in antibody and/or T-

**1.** Combined immune deficiency affecting T and B cell population with insufficient cellular

**2.** Immunodeficiency due to a defect in the function of B cells with hypo- and agammaglo‐ bulinaemia and especially IgA deficiency (agammaglobulinaemia of Bruton, common

**3.** Immunodeficiency based on T cell insufficiency with thymus aplasia (DiGeorge Syn‐

Other than the primary immune deficits mentioned above, there are others, such as defect in the enzyme assuring purine nucleotides' phosphorylation and structural defects in the 14th

The congenital B cell insufficiency leads to serious diseases after live vaccine application (poliomyelitis, measles, mumps, rubella). There is affecting of central nervous system and development of paresis and frequent recurrent viral infections of respiratory track. After

The immune deficiency can be primary (congenital) and secondary (acquired).

lymphocytes production. There are three groups of primary immune deficiency:

and humoral immunity (hypogammaglobulinaemia of Glanzmann-Riniker).

for a few reasons:

102 Immunopathology and Immunomodulation

neoplasms.

serious illnesses.

chromosome.

co-infections with other microbial agents.

ital infections rises substantially.

variable hypogammaglobulinaemia).

drome), defect in α- and γ-interferon synthesis.


Etiology and pathogenesis of viral infections in immunocompromised patients depends on the type of the immune deficiency. Clinical disease usually includes nonspecific symptoms. In most cases, it cannot be differentiated from organ rejection in patients with transplantation. The specific laboratory virological and serological tests are important for diagnosis.

More significant viral infections and diseases in immunocompromised patients are described below.
