Reduction of Diagnostic Window by New Fourth-Generation Human Immunodeficiency Virus Screening Assays

In order to reduce the diagnostic window between the time of human immunodeficiency virus (HIV) infection and laboratory diagnosis, new screening enzyme-linked immunosorbent assays (ELISAs) which permit the simultaneous detection of HIV antigen and antibody have been developed. Two fourth-generation assays, HIV DUO (Biomérieux) and HIV Combi (Boehringer Mannheim), for the combined detection of HIV antigen and antibody, were compared with a third-generation assay (HIV-1/HIV-2 3rd Generation Plus enzyme immunoassay [EIA]; Abbott) and a p24 antigen test (HIV-1 Ag monoclonal; Abbott). A total of 17 seroconversion panels, 15 cell culture supernatants infected with different HIV type 1 (HIV-1) subtypes, and 255 potentially cross-reactive serum samples were tested. Ten seroconversions were detected an average of 8.1 days earlier with HIV DUO and 7.5 days earlier with HIV Combi than with the third-generation ELISA. Overall, in the 17 seroconversion panels tested, HIV DUO detected HIV-1 infection an average of 4.8 days and HIV Combi detected infection an average of 4.4 days earlier than HIV-1/HIV-2 3rd Generation Plus EIA. HIV antigen was detected with HIV DUO and HIV Combi in all of the 15 cell culture supernatants infected with different HIV-1 subtypes, including subtype O. With fourth-generation assays, considerably fewer false-positive results (n = 4 to 6) were obtained, in comparison with the third-generation EIA (n = 18). Fourth-generation assays permit an earlier diagnosis of HIV infection than third-generation antibody screening assays through the detection of p24 antigen, which may be present in serum samples from individuals with recent HIV infection prior to seroconversion.     

Neurotropism of Human Immunodeficiency Virus

Three major characteristics of human immunodeficiency virus (HIV) infection define HIV as neurotropic. 1) Clinically, distinct neurological syndromes are associated with HIV infection and 2) presence of the virus as well as 3) pathological changes can be demonstrated in the central nervous system. Spread of HIV to the brain seems to be the general rule. Virus expression appears to be restricted during the asymptomatic period but increases with severity of HIV infection. Whether this reflects the emergence of virus variants with increased replicative capacity in brain cells has yet to be elucidated.     

Early Detection of Human Immunodeficiency Virus Infection Using Third- and Fourth-Generation Screening Assays

 Early detection of infection with human immunodeficiency virus (HIV) is critical for clinical diagnosis and treatment of patients, as well as for ensuring the safety of blood transfusion products. Recently, a number of fourth-generation HIV screening assays have been developed that offer increased sensitivity over earlier tests by combining detection of anti-HIV antibodies with detection of the p24 viral antigen. Previously, six different HIV assays were compared against a broad range of 30 seroconversion panels. In the present study, three of the newer fourth-generation assays were tested together with three of the third-generation HIV antibody-only assays. This extensive analysis highlights (i) the importance of p24 antigen detection for early diagnosis, (ii) the improved sensitivity of fourth-generation assays over antibody-only tests, and (iii) the superior performance of the Vidas Duo assay, which allows reduction of the diagnostic window by up to 2 weeks. Finally, the results emphasize the detection limitations of the different assays and suggest improvements for future HIV screening assays.     

Incidence of Human Immunodeficiency Virus Antibody in a Prenatal Population at a Community Hospital

Prenatal human immunodeficiency virus (HIV) screening may reduce vertical HIV transmission. We screened 4,419 prenatal sera and found 38 repeatedly reactive specimens with an HIV-1–HIV-2 enzyme-linked immunosorbent assay. Western blot analysis confirmed four of these specimens as positive for HIV-1 antibodies. Screening detects previously unidentified HIV infections, but false-positive results may also occur.     

Neuropathology of Human Immunodeficiency Virus Infection

Neuropathology has defined novel HIV-specific diseases at tissue level: HIV encephalitis and HIV leukoencephalopathy. Both occur usually in the later stages of the AIDS infection and consistently demonstrate large amounts of HIV products. In contrast to this HIV-specific neuropathology, HIV-associated neuropathology features unspecific syndromes with disputed relation to HIV infection: myelin pallor, vacuolar myelopathy, vacuolar leukoencephalopathy, lymphocytic meningitis, and diffuse poliodystrophy. All types of neuropathology may contribute to clinical manifestation according to severity, extent, and distribution of lesions, but clinico-pathologic correlation may be poor in the individual case. Neuropathologic and other data suggest two major pathogenetic pathways of HIV-associated CNS damage: First, systemic and local increase of the virus load leads to HIV encephalitis or HIV leukoencephalopathy; this is corroborated by prominent HIV production within such lesions. Second, neuronotoxicity by HIV proteins or factors secreted from infected cells is supported by histological changes of diffuse poliodystrophy and by morphometric loss of frontocortical neurons.     

Diagnosis of Human Immunodeficiency Virus Infection Using an Immunoglobulin E-Based Assay

Immunoglobulin assays that are sensitive and specific for detecting human immunodeficiency virus type 1 (HIV-1) infection are especially important in developing countries where PCR and viral culture may not be readily available. Immunoglobulin E (IgE), which is elevated in HIV-1 infection, is the only antibody that does not cross the placenta, making it potentially valuable for viral detection in both children and adults. This study developed an assay for detection of HIV specific IgE antibodies in adults. A total of 170 serum samples from 170 adults (116 HIV positive and 54 HIV negative) were analyzed. Serum or plasma samples were treated by using the protein G affinity method. The HIV status was determined by using two IgG enzyme-linked immunosorbent assays (ELISAs) and one Western blot evaluation. The IgE enzyme immunoassay test for HIV-1 correctly identified the HIV status in 98.8% of the samples (168 of 170). One false-positive and one false-negative test occurred with the IgE ELISA, as well as with the IgG ELISA test but were correctly identified by the IgE test. Analysis of the data demonstrated a high specificity (99%) and sensitivity (99%) of the IgE test, with 95% confidence intervals. The IgE assay appears to be sensitive and specific, suggesting that IgE-specific antibodies offer an effective method to detect HIV-1 infection in adults.     

Ultrastructural Pathology of Human Immunodeficiency Virus Infection

The electron microscope has been used with great skill in many aspects of the acquired immunodeficiency syndrome. It has played a critical role in classifying the human immunodeficiency virus, in characterizing the morphogenesis and gene products of the virus, and in elucidating the host cell targets and interactions. With the aid of the electron microscope, new opportunistic pathogens are being identified, and particularly difficult diagnoses are being made. Extrapolations from observations made at the ultrastructural level to the light microscopic level have provided criteria for the diagnosis of several infectious agents. As with any powerful scientific tool, observations must be interpreted with great care by scientists experienced in electron microscopy.     

Assessment of Antibody Response Elicited by a 7-valent Pneumococcal Conjugate Vaccine in Pediatric Human Immunodeficiency Virus Infection

We investigated antibody responses against pneumococci of serotypes 6B, 14, and 23F in 56 children and adolescents with perinatal human immunodeficiency virus (HIV) infection who were vaccinated with 7-valent pneumococcal conjugate vaccine. Overall immune responses differed greatly between serotypes. Correlation coefficients between immunoglobulin G (IgG) measured by enzyme-linked immunosorbent assay (ELISA) and functional antibodies measured by a flow cytometry opsonophagocytosis assay (OPA) varied with serotype and time points studied. After 3 months of administering a second PCV7 dose we got the highest correlation (with significant r values of 0.754, 0.414, and 0.593 for serotypes 6B, 14, and 23F, respectively) but no significant increase in IgG concentration and OPA titers compared to the first dose. We defined a responder to a serotype included in the vaccine with two criteria: frequency of at least twofold OPA and ELISA increases for each serotype and frequency of conversion from negative to positive OPA levels. Responders varied from 43.9% to 46.3%, 28.5% to 50.0%, and 38.0% to 50.0% for serotypes 6B, 14, and 23F, respectively, depending on the response criterion. The present research highlights the importance of demonstrating vaccine immunogenicity with suitable immunological endpoints in immunocompromised patients and also the need to define how much antibody is required for protection from different serotypes, since immunogenicity differed significantly between serotypes.     

Non-M Variants of Human Immunodeficiency Virus Type 1

SUMMARY

The AIDS pandemic that started in the early 1980s is due to human immunodeficiency virus type 1 (HIV-1) group M (HIV-M), but apart from this major group, many divergent variants have been described (HIV-1 groups N, O, and P and HIV-2). The four HIV-1 groups arose from independent cross-species transmission of the simian immunodeficiency viruses (SIVs) SIVcpz, infecting chimpanzees, and SIVgor, infecting gorillas. This, together with human adaptation, accounts for their genomic, phylogenetic, and virological specificities. Nevertheless, the natural course of non-M HIV infection seems similar to that of HIV-M. The virological monitoring of infected patients is now possible with commercial kits, but their therapeutic management remains complex. All non-M variants were principally described for patients linked to Cameroon, where HIV-O accounts for 1% of all HIV infections; only 15 cases of HIV-N infection and 2 HIV-P infections have been reported. Despite improvements in our knowledge, many fascinating questions remain concerning the origin, genetic evolution, and slow spread of these variants. Other variants may already exist or may arise in the future, calling for close surveillance. This review provides a comprehensive, up-to-date summary of the current knowledge on these pathogens, including the historical background of their discovery; the latest advances in the comprehension of their origin and spread; and clinical, therapeutic, and laboratory aspects that may be useful for the management and the treatment of patients infected with these divergent viruses.     

Rapid Method for Screening Dried Blood Samples on Filter Paper for Human Immunodeficiency Virus Type 1 DNA

PCR is a highly sensitive method for the detection of human immunodeficiency virus type 1 (HIV-1) nucleic acids in blood mononuclear cells and plasma. However, blood separation techniques require extensive laboratory support systems and are difficult when a limited volume of blood is available, which is often the case for infants. The use of blood samples stored on filter paper has many advantages for the detection of perinatal HIV-1 infection, but current methods require extraction and purification of target DNA prior to PCR amplification. We report a highly sensitive and rapid method for the extraction and detection of HIV-1 DNA in infant blood samples stored on filter papers. Because this rapid protocol does not involve steps for the removal of potential inhibitors of the PCR, the highest sensitivity is achieved by testing the filter paper lysate in quadruplicate. Assays for HIV-1 DNA were done by using nested PCR techniques that amplify HIV-1 gag DNA from blood spot samples on filter paper and from corresponding viably frozen mononuclear cells separated from venous blood samples obtained from 111 infants born to HIV-1-seropositive mothers. PCR results with blood from filter papers showed 100% specificity (95% confidence internal [CI] 93.1 to 100%) and 96% (95% CI, 88.65 to 98.9%) and 88% (95% CI, 79.2 to 94.5%) sensitivity (for quadruplicate and duplicate tests, respectively) compared to PCR results with blood mononuclear cells. Moreover, this method could detect HIV-1 sequences of multiple subtypes.     

Human Immunodeficiency Virus Type 1 Subtypes Prevalence in Central China

Purpose

To study the epidemic characteristics, transmission sources and routes of various subtypes of human immunodeficiency virus type 1 (HIV-1) and sequence variations in Henan, central China. To provide theoretical foundation for Acquired Immune Deficiency Syndrome (AIDS) prevention strategy in this region where the primary HIV transmission route was through former paid blood donation.

Materials and Methods

HIV-1 gene env and gag were amplified by nested polymerase chain reaction (PCR) from uncultured peripheral blood mononuclear cells (PBMCs) obtained from 1,287 HIV-1 confirmed samples in Henan.

Results

Among 1,287 samples, 5 HIV-1 strains were found including subtypes B'' (95.9%), C (0.47%) and recombinant subtypes CRF 07_BC (1.09%), CRF 08_BC (1.79%) and CRF 01_AE (0.78%). Phylogenetic tree analysis found that 1,234 Henan subtype B'' were closely related to those commonly found in Thailand, and were distantly related to other international subtypes. The dominant strain in former blood plasma donors (FPDs) was subtype B'', and the dominant strains in sexual transmission were subtype B'' and BC. Among HIV patients who were most likely infected through routes other than paid blood donation, the percentage of non-B'' subtypes was much higher than those of FPD.

Conclusion

These findings suggest that the prevailing strain of HIV-1 in Henan is subtype B'', similar to the B'' subtype found in Thailand. In addition, for the first time we found subtypes C and recombinant subtypes CRF07_BC, CRF08_BC and CRF01_AE in this region. Indicating that the subtype feature of HIV-1 became more complicated than before in central China.     

Human Immunodeficiency Virus and Leprosy Coinfection in Pune,India

We report eight cases and the incidence of leprosy in human immunodeficiency virus (HIV)-infected individuals after initiation of antiretroviral treatment (ART). The incidence of leprosy in patients on ART was 5.22 per 1,000 person-years (95% confidence interval, 2.25 to 10.28). This high incidence suggests that there should be regular examination of HIV-infected individuals for clinical signs of leprosy.Although there is a declining trend in the global burden of leprosy, there are 15 countries in Asia and Africa which account for 94% of the global total of the new-case detection rate. India is one of the countries where ≥1,000 new cases of leprosy were reported during 2006 (14). Human immunodeficiency virus (HIV) and leprosy both are feared due to the associated social stigma, and leprosy can manifest as immune reconstitution inflammatory syndrome (IRIS) in HIV-infected individuals (9). The first case of leprosy-associated immune reconstitution disease was reported in 2003 for a Ugandan living in London, United Kingdom (5). Later leprosy was described as a manifestation of IRIS in many instances (8, 10).Antiretroviral treatment (ART) for HIV infection is now available in resource-poor regions where leprosy is still endemic, such as South America, Africa, and Asia, including India. India accounts for half of the world''s leprosy cases due to its population of more than 1 billion, even though a nationwide prevalence of less than 1 case/10,000 population was reported in 2005 (4). In addition, India also has the third largest burden of HIV-infected individuals (12). In spite of having a large burden of both leprosy and HIV, there are very few published reports of HIV-leprosy coinfection from India. We report eight cases of incident leprosy in HIV-infected patients who were on ART and the incidence of leprosy in HIV-infected individuals on ART.This report is from the Amrita Clinic of PRAYAS, a nongovernmental organization working on HIV/AIDS in Pune, in the state of Maharashtra, India. We retrospectively analyzed data on HIV-infected patients who initiated ART between January 2003 and December 2006 and we studied their follow-up till December 2007 to evaluate the incident cases of leprosy. ART was provided following the national guidelines for treatment of HIV infection (7).Diagnosis of leprosy was based on the clinical signs and symptoms and demonstration of acid-fast bacilli in the slit skin smears by Ziehl-Neelsen staining. All patients with leprosy received multidrug treatment per the WHO guidelines (15).Several definitions of IRIS have been utilized, each incorporating the general concept that cases of IRIS need to have an inflammatory component occurring in the setting of immune reconstitution that cannot be explained by drug toxicity or a new opportunistic infection (1, 6). We have considered leprosy manifestation after starting ART with increase in CD4⁺ cell count, inflammatory response as seen by neuritis, type I or type II leprosy reaction, or need for the use of steroids for the control of inflammation as a criterion for defining leprosy manifestation as IRIS. Statistical analysis was done using STATA (version 8.0).Between January 2003 and December 2006, among the 1,002 HIV-infected patients who started ART for HIV infection and were followed up till December 2007, eight incident cases of leprosy were detected. None of them had clinical evidence of leprosy at the time of initiation of ART. Table ​Table11 describes the details of these eight patients. All the patients except for one were males, and the mean age of the patients with leprosy was 33.8 years (standard deviation [SD], 5.1 years; range, 27 to 42 years). Four patients had paucibacillary leprosy, and four patients had multibacillary leprosy. The mean CD4⁺ cell count of incident leprosy cases was 326 (median, 245; SD, 255.5; range, 99 to 892). Of these eight patients, three had other opportunistic infections such as pulmonary tuberculosis, abdominal tuberculosis, and herpes zoster. The mean number of months to develop leprosy after starting ART was 13.8 months (SD, 14.3 months; range, 2 to 43 months). All eight patients completed their leprosy treatment and recovered completely. Although eight patients developed incident leprosy, six of them developed leprosy within 2 years of starting ART and two patients had delayed manifestations, with one patient developing leprosy after 28 months and the other after 43 months. These 1,002 patients on ART contributed to 1,532.5 person-years, and hence, the overall incidence of leprosy after starting ART was 5.22 per 1,000 person-years (95% confidence interval, 2.25 to 10.28).

TABLE 1.

Details of HIV-infected patients on ART with incident leprosy^a