Comparative analysis of human microglial models for studies of HIV replication and pathogenesis.

BACKGROUND: HIV associated neurocognitive disorders cause significant morbidity and mortality despite the advent of highly active antiretroviral therapy. A deeper understanding of fundamental mechanisms underlying HIV infection and pathogenesis in the central nervous system is warranted. Microglia are resident myeloid cells of the brain that are readily infected by HIV and may constitute a CNS reservoir. We evaluated two microglial model cell lines (C20, HMC3) and two sources of primary cell-derived microglia (monocyte-derived microglia [MMG] and induced pluripotent stem cell-derived microglia [iPSC-MG]) as potential model systems for studying HIV-microglia interactions. RESULTS: All four microglial model cells expressed typical myeloid markers with the exception of low or absent CD45 and CD11b expression by C20 and HMC3, and all four expressed the microglia-specific markers P2RY12 and TMEM119. Marked differences were observed upon gene expression profiling, however, indicating that MMG and iPSC-MG cluster closely together with primary human microglial cells, while C20 and HMC3 were similar to each other but very different from primary microglia. Expression of HIV-relevant genes also revealed important differences, with iPSC-MG and MMG expressing relevant genes at levels more closely resembling primary microglia. iPSC-MG and MMG were readily infected with R5-tropic HIV, while C20 and HMC3 lack CD4 and require pseudotyping for infection. Despite many similarities, HIV replication dynamics and HIV-1 particle capture by Siglec-1 differed markedly between the MMG and iPSC-MG. CONCLUSIONS: MMG and iPSC-MG appear to be viable microglial models that are susceptible to HIV infection and bear more similarities to authentic microglia than two transformed microglia cell lines. The observed differences in HIV replication and particle capture between MMG and iPSC-MG warrant further study.

Emerging reverse transcriptase inhibitors for HIV-1 infection.

INTRODUCTION: There are 36.7 million people living with HIV with 20.9 million having access to antiretroviral therapy (ART). Nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) remain the 'backbone' of ART. However, the currently available nine NRTIs and five non-nucleoside reverse transcriptase inhibitors (NNRTIs) have significant side effects and resistance profiles. Areas covered: We summarize the mechanisms of resistance and other limitations of the existing NRTIs/NNRTIs. GS-9131, MK-8591, Elsulfavirine and Doravirine are four new agents that are furthest along in development. Expert opinion: ART development has evolved with several new promising agents. Longer-acting agents, like MK-8591 are extremely attractive to enhance drug adherence and patient satisfaction. Doravirine offers an NNRTI effective against common mutations that has fewer side effects, limitations on dosing and drug interactions. GS-9131 is very potent and active against a variety of NRTI mutants but it is too early in its development to understand its full risks and benefits. Finally, Elsulfavirine has a long half-life and preliminary data suggests fewer side effects than the most commonly used NNRTI, efavirenz. Each of these new agents shows promise and potential to improve ART in the future. The newer generation of reverse transcriptase inhibitors have longer half-lives, more favorable adverse effect profiles, and fewer drug interactions.

HLA correlates in a cohort of slow progressors from China: effects on HIV-1 disease progression.

We looked at our HIV + slow progressors cohort to determine if there were any human leukocyte antigen (HLA) correlates for protection. No statistically significant allelic differences were found between the HIV + and control cohorts using regression analysis, though trends were noted. Data for Elite Controllers showed an increased frequency of B*57. Likewise, no correlation was inferred with the clinical data of the HIV + cohort. We hypothesize that the protective effect of HLA alleles may have been lost over time.

Evidence for a "Founder Effect" among HIV-infected injection drug users (IDUs) in Pakistan.

BACKGROUND: We have previously reported a HIV-1 subtype A infection in a community of injection drug users (IDUs) in Karachi, Pakistan. We now show that this infection among the IDUs may have originated from a single source. METHODS: Phylogenetic analysis was performed of partial gag sequences, generated using PCR, from 26 HIV-positive IDU samples. RESULTS: Our results showed formation of a tight monophyletic group with an intra-sequence identity of < 98% indicating a "founder effect". Our data indicate that the HIV-1 epidemic in this community of IDUs may have been transmitted by an HIV positive overseas contract worker who admitted to having contact with commercial sex workers during stay abroad. CONCLUSION: Specific measures need to implemented to control transmission of HIV infection in Pakistan through infected migrant workers.

Educating the power: HIV/AIDS and parliamentarians of Pakistan.

Increasing rates of HIV have been recorded amongst the Injection Drug User community from all parts of Pakistan. This has mobilized the health authorities into definitive action before there is a general spread of the epidemic into the Pakistani populace. Lacking any formal research as pertains to HIV policy development in Pakistan, international collaborating agencies, including the United Nations, are aiding in the formulation of a national policy to tackle HIV/AIDS. This article discusses the progress and importance of interventions being conducted amongst the Parliamentarians of Pakistan, relatively unchartered waters. The series of Seminars help to appraise the Parliamentarians of the ground situation as pertains to HIV in their constituencies, aiming to ultimately generate federal and provincial governmental policies, and a solid strategy to combat the spread of HIV/AIDS in Pakistan.

XDR tuberculosis and the Indian-subcontinent: effective prevention strategies needed.

The Indian-subcontinent is becoming, what could be, the next big battle ground for the control of Extensively Drug Resistant Tuberculosis (XDR-TB). The region caters to not only an ever-increasing incidence of new TB cases, but also a huge burden of already existing TB cases, thereby facing a dual threat for spread of XDR-TB. Most of the health-care facilities are devoid of essential laboratory-based infra-structure which is essential for diagnosing XDR-TB. Coupled to this is the lack of knowledge regarding TB diagnosis and treatment amongst the General Practitioners of India and Pakistan, who still treat the bulk of the TB cases. The element of AIDS is also slowly creeping into the equation. Questions have already been raised about the effectiveness of the governmental responses to curb the TB threat. What is needed right away is an effective strategy, incorporating a broad-tiered approach between the government and social sector. This can facilitate greatly in preventing further spread of these resistant strains.

Prevalence of HCV and HIV infections in 2005-Earthquake-affected areas of Pakistan.

BACKGROUND: On October 8, 2005, an earthquake of magnitude 7.6 hit the Northern parts of Pakistan. In the post-earthquake scenario, overcrowding, improper sewage disposal, contamination of food and drinking water, hasty surgical procedures, and unscreened blood transfusions to earthquake victims most likely promotes the spread of infections already prevalent in the area. OBJECTIVE: The objective of the study reported here was to determine the prevalence of Human Immunodeficiency and Hepatitis C viruses (respectively, HIV and HCV) in the earthquake-affected communities of Pakistan. The samples were analyzed 2 months and then again 11 months after the earthquake to estimate the burden of HIV and HCV in these areas, and to determine any rise in the prevalence of these viral infections as a result of the earthquake. METHODS: Blood samples were initially collected during December, 2005 to March 2006, from 245 inhabitants of the earthquake-affected areas. These samples were screened for HCV and HIV, using immunochromatography and Enzyme-Linked Immuno-Sorbent Assay (ELISA). RESULTS: Out of 245 samples tested, 8 (3.26%) were found positive for HCV, and 0 (0.0%) for HIV, indicating the existence of HCV infection in the earthquake-stricken areas. The same methods were used to analyze the samples collected in the second round of screening in the same area, in September, 2006 - 11 months after the earthquake. This time 290 blood samples were collected, out of which 16 (5.51%) samples were positive for HCV, and 0 for HIV. CONCLUSION: A slightly higher prevalence of HCV was recorded 11 months after the earthquake; this increase, however, was not statistically significant. None of the study participants was found HIV-infected.

Polio: the Indian Sub-Continent's loosing war.

The recent debate about 'effective control' rather than 'complete eradication' for polio has put the whole Global Polio Initiative into question. The implications for this are indeed daunting, more so for the Indian Sub-Continent, which hosts a huge chunk of the global polio load every year. The tremendous success achieved in combating polio during the previous decade in India and Pakistan is reason enough to continue on with the vaccination efforts. However, other subsidiary issues including social stigma and a weak infra-structure have also to be put into the eradication equation to meet the goal. The Sub-Continent stands at the cross-roads, and time is ripe now to formulate a multi-faceted strategy to eliminate this crippling disease from this part of the world, and consequently give a much-needed boast to global eradication efforts.

Crimean-Congo hemorrhagic fever in Pakistan.

Crimean-Congo virus, the causative agent of Crimean-Congo Virus Fever (CCVF) is endemic in Pakistan. Cases are documented sporadically ever year, mostly at and around the time of Eid-ul-Adha, an Islamic festival, celebrated on day 10 through 13 of the 12th month of each lunar calendar year. At this time of the year in Pakistan, livestock are brought down to the urban areas from the rural parts of the country. Animals are housed in open spaces and private houses until they are slaughtered during the 3 days of Eid-ul-Adha. This allows the CCHF virus, which is carried by a tick that inhabits the animal hide, to be transmitted through unprotected contact with live animals as well as through contact with animal blood subsequent to its slaughter. In this report, a typical case of CCVF is described that was encountered in Rawalpindi, Pakistan. A number of issues pertaining to the management of recurrent outbreaks of CCVF in the country are discussed.

Gastroenteritis and the Indian Sub-Continent: need for diarrhea-defying vaccines.

The current gastroenteritis outbreaks in the India Sub-Continent have served to re-emphasise the dire importance and need for vaccines to curb diarrhoea and dysentary.

HIV/AIDS in Pakistan: the battle begins.

Pakistan, the second most populous Muslim nation in the world, has started to finally experience and confront the HIV/AIDS epidemic. The country had been relatively safe from any indigenous HIV cases for around two decades, with most of the infections being attributable to deported HIV positive migrants from the Gulf States. However, the virus finally seems to have found a home-base, as evidenced by the recent HIV outbreaks among the injection drug user community. Extremely high-risk behavior has also been documented among Hijras (sex workers) and long-distance truck drivers. The weak government response coupled with the extremely distressing social demographics of this South-Asian republic also helps to compound the problem. The time is ripe now to prepare in advance, to take the appropriate measures to curtail further spread of the disease. If this opportunity is not utilized right now, little if at all could be done later.

Human papillomavirus subtype 16 is common in Pakistani women with cervical carcinoma.

INTRODUCTION: Human papillomavirus (HPV) is recognized as a major causative agent for cervical carcinomas. Based on their oncogenic potential, HPV subtypes have been divided into high- and low-risk. In Pakistan, screening for HPV in female patients is not commonly practiced, and as a consequence, the degree of HPV prevalence and its correlation with cervical cancer is unknown. OBJECTIVE: In this study, we have attempted to estimate the prevalence of HPV infection, and also the HPV subtype profile, among Pakistani women with cervical cancer from varied geographical, racial, and social backgrounds within Pakistan. METHODOLOGY: Women visiting two tertiary care hospitals in Karachi, diagnosed with carcinoma of the cervix within the past 15 years, were analyzed for HPV subtypes in their cancer specimens. Retrospectively, 60 paraffin-embedded cervical cancer biopsies were examined for the presence of HPV DNA. After DNA extraction from these samples, polymerase chain reaction (PCR) was used to amplify the HPV L1 gene using the consensus (general) primers, and primers specific for subtypes 16 and 18. RESULTS: Of the 60 samples analyzed, only one sample was HPV negative; the rest of the samples were positive for the presence of HPV. Of the 59 HPV positive samples, 56 showed the presence of HPV16 and one sample was positive for HPV18; HPV subtype could not be determined in two samples. CONCLUSION: Our results show a strong relationship between HPV infection and cervical cancer among Pakistani women. These results underscore the need to implement regular HPV screening for Pakistani women. An early diagnosis of HPV infection will allow better health management to reduce the risk of developing cervical cancer.

HIV-1 subtype A infection in a community of intravenous drug users in Pakistan.

BACKGROUND: Data on the subtypes of HIV in a population help in predicting the potential foci of epidemic, tracking the routes of infection and following the patterns of the virus' genetic divergence. Globally, the most prevalent HIV infection is the HIV-1 subtype C. In Asia, predominant subtypes of HIV-1 are B, C, and CRF-01AE. During the last few years, HIV prevalence in Pakistan has taken the form of a concentrated epidemic in at least two high risk groups, namely, Intravenous Drug Users (IDUs) and Male Sex Workers (MSWs). Factors that have facilitated the proliferation of HIV infection include transmission through a large number of repatriates and needle-sharing intravenous drug users, unscreened blood transfusions, and sexual illiteracy. The HIV subtypes infecting Pakistani populations have not been explored to date. In this study, we analyzed HIV-1 subtypes from in a high-risk community of IDUs in Karachi, the largest city of Pakistan. METHODS: Samples were collected from 34 IDUs after their informed consent. In addition, the study subjects were administered a questionnaire regarding their sexual behavior and travel history. For HIV analysis, DNA was extracted from the samples and analyzed for HIV types and subtypes using subtype-specific primers in a nested polymerase chain reaction (PCR). The results from this PCR were further confirmed using the Heteroduplex Mobility Assay (HMA). RESULTS: We found HIV-1 subtype A in all the 34 samples analyzed. A few of the study subjects were found to have a history of travel and stay in the United Arab Emirates. The same subjects also admitted to having contact with commercial sex workers during their stay abroad. CONCLUSION: Our study therefore shows clade A HIV-1 to be prevalent among the IDUs in Karachi. As the prevalence of HIV in Pakistan continues to rise, more work needs to be done to track the infection, and to analyze the strains of HIV spreading through the country.