HPV related infections
Acronym of Human Papilloma Virus, HPV is involved in hyperprolifrative lesions located in various mucosal and cutaneous districts, including vulva, cervix, vagina, anus and lining of mouth and throat;
It is believed that HPV infections are among the most frequent sexually transmitted diseases: it is estimated that a large proportion of women (between 75 and 90%) have contracted the virus at least once in their life. To underline that, fortunately, the efficiency of the immune system of many women is able to eradicate the virus without the need for pharmacological intervention.
The likelihood that Papilloma Virus infection will not be eradicated in a short time by the immune system is strongly influenced by the contracted HPV genotype and is clearly higher for variants with a high oncogenic risk.
Microbiological analysis
The HPV virion is a pathogen devoid of pericapside (naked virus), with an icosahedral structure: it is covered by an icosahedral capsid of 50 nm in diameter. The capsid, in turn, consists of 72 capsomeres (12 pentamers and 60 hexamers), originating in a 5-pointed protuberance, with a sort of central nucleus. There are two proteins that form the capsid:
- Protein L1, or major protein, common to all variants of Human Papilloma virus: it constitutes 80% of the proteins of the virus. It is believed that most antibodies are produced against this protein.
- Minor protein or L2: complete the remaining 20%. It is not constant in the various forms of Human Papilloma Virus.
From microbiological scientific research, it is observed that 7, 900 base pairs constitute a single molecule of viral genome: the DNA of the virus is circular and covalently closed .
Genotypes and classification
The term Papilloma is composed of a prefix "papilla", of Latin derivation, and of a suffix "-oma", which literally means "tumoral pustule".
The Papilloma Viruses, extremely heterogeneous in terms of composition, belong to the Papillomaviridae family and to the Papillomavirus genus.
There are numerous Papilloma Virus strains: to date, over 120 have been identified, but the number of genotypes is assumed to be growing continuously. Among the more than 100 scientifically isolated serotypes of Papilloma virus, a classification was carried out in 16 groups, distinguished with the letters of the Greek alphabet between A and P. More precisely, these viruses are classified on the basis of several factors:
- nucleotide sequence
- phylogenetic position
- oncogenic potential
Furthermore, the Papilloma Virus are cataloged according to the site of action: some exercise their pathogenic power at the level of the skin (mainly HPV type beta ), others are specific to damage the mucous membranes (HPV alpha ).
The genotypes of Human Papilloma Virus are also classified into three levels, depending on the possible oncogenic risk:
- Some of the high-risk HPV genotypes are HPV 13, HPV 16, HPV 18, HPV 31, HPV 33, HPV 35, HPV 39, HPV 45, HPV 51, HPV 52, HPV 56, HPV 58, HPV 59, HPV 68, HPV 73, HPV.
- The HPVs 26, 53 and 66 are classified as "genotype with probable high risk "
- The other HPV genotypes, in particular the 6 and the 11 (the most widespread), present a very low risk of degeneration in tumor: it is, in fact, the genotypes involved in the formation of genital warts.
Fortunately, the vast majority of viruses belonging to the Papillomaviridae family do not cause dangerous or alarming injuries, just think of cutaneous warts which, although annoying, are certainly not among the serious dermatological lesions. However, among the papillomaviruses, a small minority is accused of inducing a malignant transformation of the cells involved, therefore tumor, especially at the level of the cervix, anus, esophagus, larynx and oral cavity.
The image below clearly shows how HPV 16 is the serotype responsible for the largest number (53.5%) of cervical carcinomas attributable to the human papilloma virus; the additional contribution of HPV 18 and 17.2%: as anticipated, HPV 16 and HPV 18 are therefore responsible, alone, for over 70% of cervical carcinomas attributable to human papilloma virus.
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X Watch the video on youtubeAfter breast cancer, the malignant tumor due to HPV is the most widespread among women: it is estimated that every year, in our country, more than 3, 000 new women are affected by this tumor that affects the cervix
