HPV type 51: detection, treatment

Of the many strains of human papillomavirus known today, more than three dozen infect the genital and anal areas, and among them are potentially oncogenic ones, in particular, HPV 51 or HPV 51.

Why is HPV 51 dangerous?

The most oncogenic are considered to be strains of the human papillomavirus HPV 16 and HPV 18, which are associated with 70% of cases of cervical cancer, as well as bowenoid papulosis. Almost a third of cases of cervical adenocarcinoma are associated with strains of HPV 31 and HPV 45, but type 51, transmitted mainly through sexual contact, also poses a danger.

What is the danger of HPV 51? This strain of the virus, which affects the epithelium in the genital and anal area, is dangerous not only because it can provoke cervical dysplasia and cause the formation of genital warts (condyloma acuminata). Genotype 51 HPV has a high risk of developing cancer, since, penetrating healthy epithelial cells, it can trigger the process of their uncontrolled proliferation, leading to the formation of condylomas and their malignant degeneration.

As a result, one may encounter the development of cervical carcinoma (cervical cancer, which accounts for 25% of all cancer cases in women) or squamous cell carcinoma of the vagina; cancer of the anus, perianal region and rectum; malignant tumors of the external genitalia of women and men; oncology of the mucous membrane of the oropharyngeal region (oropharynx).

Gynecologists warn that any pathological changes in the tissues of the vagina and/or cervix in combination with papillomavirus infection, for example, when there is flat or warty leukoplakia of the cervix and HPV type 51, significantly increase the risk of developing cancer. The same danger exists if HPV types 16, 18, 31 or 45 join the erosion of the cervix.

Structure HPV type 51

HPV 51, like all strains of the Papillomavirus genus, is a species-specific DNA virus. The structure of each virion is an icosahedral shell (capsid), the diameter of which does not exceed 0.055 μm. It consists of several dozen structural protein subunits - capsomeres, containing capsid proteins L1 and L2, which protect the viral DNA.

The entire protein coding sequence, the double-stranded circular DNA of HPV 51, consists of a single molecule containing approximately 8,000 base pairs associated with protein globules. Three functional regions have been identified in the viral genome:

• non-coding region NCR with the p97 core promoter, regulating DNA replication;
• E region with ORF (open reading frame) and coding nucleotides E1, E2, E4, E5, E6 and E7, which are involved in viral replication and oncogenesis;
• LCR region encoding the structural proteins L1 and L2 for the viral capsid.

Viral genes E1 and E2 are responsible for its replication and DNA transcription; E4 – for the maturation and release of viral particles in host cells; E5, E6 and E7 – for the transformation of affected epithelial cells and their unlimited reproduction without natural apoptosis (immortalization).

The study of the papillomavirus has shown its peculiarity: gene expression and replication of the virus occur not in the cytoplasm of the host cell, but in its nucleus. And the basal keratinocytes are most suitable for this - cells of the Malpighian (germ) layer of the epidermis, where HPV is introduced. The cells of this layer have a spherical nucleus, which ensures mitosis (indirect division) and constant tissue regeneration.

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Life cycle HPV type 51

After penetration into epidermal cells, the HPV life cycle begins with suppression of local immunity: at the gene level, the viral oncoprotein E6 blocks the release of proinflammatory cytokines (interleukin IL-18) by macrophages. In addition, the proteins E6 and E7, directly associated with the oncogenic potential of HPV 51, inactivate the cellular proteins p53 (transcription growth factor) and the protein pRb (a cell cycle-inhibiting suppressor of atypical cell formation). Thus, the loss of p53 and pRb functions removes all barriers to the uncontrolled proliferation of modified (with mutated DNA) cells of the germinal and spinous layers of the epidermis.

Moreover, months and even years pass from the moment of infection to its clinical manifestations, that is, HPV has a latent life cycle, and the presence of the virus on the skin of healthy people confirms the latent nature of the papillomavirus infection.

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Symptoms

The timing of the manifestation of papillomavirus infection in patients depends on the state of their immune system. And the obvious symptoms of HPV 51 in women are genital warts of the cervix or vagina - asymptomatic or causing itching and burning dense, similar to warts on legs, single or multiple growths on the skin and mucous membranes, often causing discomfort during sexual intercourse, abnormal discharge, etc. Read more in the material - Genital warts in women

During the formation of condylomas, the symptoms of the disease may not manifest themselves. Often, patients notice something is wrong only when the formations grow rapidly, which manifests itself in the appearance of pronounced discharge (which often irritates the skin of the vagina and external genitalia), as well as an itching and burning sensation in the vagina.

Read about how HPV 51 can manifest itself in men in the publication – Genital warts in men

Doctors pay special attention to such a problem as HPV 51 and pregnancy. First of all, when planning a pregnancy, it is best to make sure in advance that the woman does not have this virus. If HPV 51 (or another strain) is detected, the infection should be cured before pregnancy.

When the formation of condylomas begins during pregnancy (which is associated with physiological immunosuppression of the woman's body during this period), then, as experts say, the newborn can become infected with the virus during childbirth. Studies by British pediatricians have shown that the number of infants born to infected mothers with HPV is about 5%. In rare cases, such children are diagnosed with palillomatosis of the larynx or vocal cords.

But the risk of miscarriage, premature birth, or other complications is low. Rarely, vaginal or cervical warts grow large enough to block the birth canal during pregnancy. But if this happens, a cesarean section is performed.

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Diagnostics

Diagnosis of HPV 51 involves:

• detection of HPV 51 DNA in a urogenital smear (using PCR genotyping);
• Digene test (detects virus concentrations);
• colposcopy;
• PAP test and cervical cytology (histological examination of a biopsy for atypical cells).

Detailed information in the material - Papillomavirus infection: detection of the human papillomavirus

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Treatment

What to do if HPV type 51 is detected? Treat cervical condylomas, perianal condylomatosis and genital warts.

The methods used to treat HPV 51 and the medications prescribed are described in detail in the publications:

• Treatment of genital warts
• Ointment for condylomas
• Suppositories for HPV
• Removal of genital warts

Prevention HPV type 51

Specific prevention of infection with human papillomavirus, including HPV type 51, is not guaranteed even by barrier methods of contraception, although the use of a condom somewhat reduces the risk of infection.

And for the earliest possible detection of an infection, which, as noted above, may not show any symptoms, it is necessary to undergo gynecological examinations periodically.

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Forecast

According to some data, the number of cases of cancer development due to HPV 51 infection does not exceed 3%. But even without causing cancer, the virus weakens the body and can affect the reproductive functions of both women and men.

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