古巴现“侵略性”艾滋病毒株 感染者发病更快

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古巴现“侵略性”艾滋病毒株 感染者发病更快

中新网2月15日电 据“中央社”报道，研究人员日前在古巴部分患者身上发现艾滋病毒(HIV)新病毒株，侵略性更强大，感染3年内就能发展成简称AIDS的后天免疫缺乏症候群。研究人员表示，该种新毒株过程之快，抗反转录病毒药物疗法或许都为时已晚。

据报道，根据比利时鲁汶大学医学教授范达姆的研究，没有治疗情况下，HIV感染往往要5到10年才会转变成AIDS。然而，古巴卫生官员通知范达姆新侵略性HIV病毒株，想一探究竟。最新研究结果发表在国际期刊EBioMedicine。范达姆表示：“这群患者发病速度很快，且全都是新感染病例。”她说：“他们1年前，最多2年前才刚受检，HIV都呈阴性。”这群病人没有人接受病毒治疗，且带有突变HIV病毒株的患者，全都在感染3年内发展出AIDS。HIV转变成AIDS的快慢通常与哪种HIV亚型无关，而是取决于患者免疫系统的强弱；然而，古巴的情形却不同。

范达姆说：“有1种HIV变体，只在转变速度快的组别中找得到，其他2个对照组都没有。我们聚焦这个变体，试图找出不同点。我们发现这个变体是3种亚型的重组。”新的变体名称为CRF19，是HIV亚型A、D和G的综合体。这种变体在非洲出现过，不过病例过少无法充分研究。研究人员说，这个病毒株在古巴较为普遍。侵略型HIV多半会对抗反转录病毒药物出现反应，不过患者发现染病时，大多为时已晚，药物无法产生任何作用。范达姆说，有多名性伴侣且没有安全性行为的民众，HIV检测不仅要早早做，还要常常做。

New, aggressive form of HIV identified in Cuba
In Cuba, a variant of HIV that is much more aggressive than other known forms of the virus has been documented. Patients infected with this new variant progress to AIDS so rapidly that they may not even know they are infected, with AIDS symptoms occurring within 3 years of infection.

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[color=inherit !important][backcolor=inherit !important]HIV anchors itself to proteins on the membranes of cells before it is able to penetrate the cell.

If a person contracts multiple strains of HIV - typically by engaging in unprotected sex with multiple infected partners - then these strains can recombine into a new variant of HIV within the host. The new Cuban variant of HIV is one such recombinant version of the virus.

HIV anchors itself to co-receptors - proteins on the membranes of cells - before the virus is able to penetrate the cell. The first co-receptor that HIV anchors to is known as CCR5. Then, after a number of years of normal health, the virus switches to the anchor point CXCR4, which results in a faster progression to AIDS.

In the recombinant form of HIV identified in Cuba, HIV makes the transition to CXCR4 shortly after infection, reducing the healthy phase and initiating the progression to AIDS.

An international team of researchers compared the blood of 73 recently-infected patients with this recombinant form of HIV - of whom 52 had been diagnosed with AIDS - with blood from 22 patients who had progressed to AIDS after the normal "healthy" period of infection with HIV.

The patients with the recombinant HIV were found to have abnormally high doses of the virus and defensive molecules called RANTES.

RANTES is part of the human immune response and binds to CCR5 - the co-receptor that HIV initially anchors onto after infection.

Because RANTES is present at higher concentrations in these patients than normal, it suggests that most of the CCR5 proteins were unavailable as anchor points for HIV. Therefore, the recombinant HIV would have to bypass its usual anchor point, heading straight to CXCR4 instead.

Protease in recombinant variant boosts virus replication

One of the HIV subtypes implicated in the recombinant variant was also found to contain a protease - an enzyme that cleaves proteins in new viruses - that enables the virus to replicate in greater numbers. The researchers suggest that this protease makes it easier for the transition to CXCR4 to occur.

Normally, say the authors of the study - which is published in the journal EBioMedicine - the transition from CCR5 to CXCR4 is "very difficult."

Recently, Medical News Today reported on a study published in the journal Cell that explored the theory that pools of dormant HIV lurking in DNA may hold a potential cure for the infection.

We also looked at a new smartphone accessory purportedly capable of diagnosing HIV and syphilis from one finger prick of blood within 15 minutes. This accessory - or "dongle" - has been piloted among health care workers in Rwanda, with 97% of patients recommending the device. With a manufacturing cost of just $34, the dongle is much more affordable than the standard forms of diagnostic testing, which typically cost $18,450.

Written by David McNamee

Copyright: Medical News Today