Horizontal transmission of human immunodeficiency virus type 1 from father to child

Accidental Father-to-Son HIV-1 Transmission During the Seroconversion Period

A 4-year-old child born to an HIV-1 seronegative mother was diagnosed with HIV-1, the main risk factor being transmission from the child's father who was seroconverting at the time of the child's birth. In the context of a forensic investigation, we aimed to identify the source of infection of the child and date of the transmission event. Samples were collected from the father and child at two time points about 4 years after the child's birth. Partial segments of three HIV-1 genes (gag, pol, and env) were sequenced and maximum likelihood (ML) and Bayesian methods were used to determine direction and estimate date of transmission. Neutralizing antibodies were determined using a single cycle assay. Bayesian trees displayed a paraphyletic-monophyletic topology in all three genomic regions, with the father's host label at the root, which is consistent with father-to-son transmission. ML trees found similar topologies in gag and pol and a monophyletic-monophyletic topology in env. Analysis of the time of the most recent common ancestor of each HIV-1 gene population indicated that the child was infected shortly after the father. Consistent with the infection history, both father and son developed broad and potent HIV-specific neutralizing antibody responses. In conclusion, the direction of transmission implicated the father as the source of transmission. Transmission occurred during the seroconversion period when the father was unaware of the infection and was likely accidental. This case shows how genetic, phylogenetic, and serological data can contribute for the forensic investigation of HIV transmission.

Genetic relatedness of human immunodeficiency virus-1 (HIV-1) strains in a 12-year-old daughter and her father in a household setting

Modalities of intra-familial transmission of HIV-1 are not always clear. Here we describe an uncommon case of HIV transmission in a family setting, analyzed using clinical, epidemiological and nucleic-acid-based methods, and assess risk factors for intrafamilial transmission of HIV-1 infection. All sequences from the father and the daughter were grouped in the same cluster with a 100 % bootstrap value, which means that the father and his daughter were infected with highly homologous CRF01_AE. The diversity of genetic clones between env and pol genes was insignificant (p > 0.05). Moreover, the results of analysis of drug-resistance-associated mutation positions of the two viral isolates were almost identical, indicating that both were susceptible to the first-line anti-HIV drugs prior to the initiation of antiretroviral treatment (ART), and this presented additional evidence of a high similarity between the two family members' HIV-1 quasispecies. In this family, HIV-1 isolates from a father and his daughter had very highly genetic relatedness. By combining their clinical histories, we could draw the conclusion that the daughter was probably infected via contact with her father's blood or other body fluids, but no obvious transmission route was found, suggesting that HIV-1 infection in similar household settings should be taken into consideration whenever the origin of HIV-1 infection cannot be identified.

Identification of human immunodeficiency virus-1 (HIV-1) transmission from a 29-year-old daughter to her mother in Shanghai, China

BACKGROUND AND METHODS

Routes of intrafamilial transmission of HIV-1 are not always clear. Here, we describe transmission to a mother from her 29-year-old daughter within a family setting through clinical, epidemiological and molecular evidence. We evaluated the risk factors for intrafamilial transmission of HIV-1 infection through qualitative epidemiology following pol and env gene sequencing and phylogenetic analysis.

RESULT

The nucleotide sequences of the pol and env genes of the two strains from the two patients in the family were 99 % and 100 % identical, respectively, and they clustered with CRF07_BC, which includes the main recombinant strains in Shanghai, China. The diversity of genetic clones between the env and pol genes was insignificant (p > 0.05). The drug-resistance-associated mutation positions of the two viral strains were basically similar and indicated that both were susceptible to the first-line anti-retroviral drugs including zidovudine (AZT), lamivudine (3TC), efavirenz (EFV) and nevirapine (NVP) prior to the initiation of highly active antiretroviral treatment (HAART), providing additional evidence of a close similarity between the quasispecies of the two family members.

CONCLUSION

In this family, the two strains of the virus, isolated from the mother and her adult daughter, had very high homology. In the context of their clinical histories, we can make a conclusion that the mother was infected by the virus in her daughter's blood or other body fluids, but no overt transmission route has been clarified. This investigation also suggested that intimate personal exposure in the same household can contribute to HIV-1 transmission and underscores the need to educate persons who care for or are in contact with HIV-infected persons in household settings where such exposures may occur.

In vitro human immunodeficiency virus and sperm cell interaction mediated by the mannose receptor

Leukocytes are considered to be the main source of HIV-1 infection in semen. However, HIV-1 interaction with spermatozoa has also been demonstrated, suggesting that both spermatozoa and leukocytes might play a role during sexual transmission of HIV-1. The purpose of the present study was to evaluate if HIV-1 particles interact with sperm cells through the mannose receptor (MR), and then to determine the ability of "infected" sperm cells to transmit the virus to susceptible targets. The expression of classical HIV-1 receptor and co-receptors and the MR by sperm cells was determined by flow cytometry; the interaction in vitro between sperm and HIV-1 was evaluated by fluorescence microscopy. Additionally, the in vitro interaction of sperm cells and HIV-1 was determined detecting viral nucleic acids by PCR. D-Mannose was used to block HIV-1-sperm cell interaction. Sperm cells preincubated with HIV-1 particles and activated mononuclear cells were co-cultured to determine viral transmission. The presence of viral RNA was detected in 28% of the samples in which sperm cells were preincubated with HIV-1 particles. Mannose was able to block interaction in 75% of the cases. Finally, we demonstrated that "infected" sperm cells were able to transmit the HIV-1 infection to susceptible targets. In conclusion, these results indicate that the MR is involved in sperm cell-HIV-1 interaction. Our results also suggest that sperm cells could be an important source of infection.

Late postnatal HIV infection in children born to HIV-1-infected mothers in a high-income country

OBJECTIVE

To evaluate the risk of late postnatal HIV-1 infection in nonbreastfed children enrolled in the French ANRS Cohort CO01 (EPF).

METHODS

The EPF cohort has prospectively enrolled HIV-infected mother/child pairs with a low proportion of known breastfeeding (<0.2%). Children were followed until they were 24 months old, with HIV-1 DNA/RNA PCR tests performed at birth, M1, M3 and M6 and a late serology at 18-24 months. This substudy included 4539 children who were uninfected at the age of 6 months in 1984-2005.

RESULTS

Five children were late diagnosed with HIV-1 infection despite negative PCR tests until 6 months. In three cases, the infection was diagnosed between 14 and 18 months. The other infections were diagnosed at 10 and 12 years of age because of AIDS-defining symptoms; their last (negative) serologies were performed at 19 and 9 months, respectively. A phylogenetic study performed in the latest case revealed a strong homology between the mother and child strains. No known mode of viral transmission (including breastfeeding or use of premasticated food) could be found. However, we observed previously reported risk factors for intrafamilial HIV-1 transmission: poor socioeconomic backgrounds and sustained HIV-1 viremia in the mothers during the follow-up of their children.

CONCLUSION

Late postnatal HIV-1 infection can rarely be diagnosed in the absence of known breastfeeding in high-income countries. Our results highlight the need for a maintained close follow-up of the noninfected children even after 6 months, especially when there are risk factors for intrafamilial viral transmission.

Oral complications of HIV disease

Oral lesions are among the early signs of HIV infection and can predict its progression to acquired immunodeficiency syndrome (AIDS). A better understanding of the oral manifestations of AIDS in both adults and children has implications for all health care professionals. The knowledge of such alterations would allow for early recognition of HIV-infected patients. The present paper reviews epidemiology, relevant aspects of HIV infection related to the mouth in both adults and children, as well as current trends in antiretroviral therapy and its connection with orofacial manifestations related to AIDS.

Current trends of HIV disease of the mouth

HIV infection affects residents of all countries of the world, but the greater majority of affected individuals reside in the developing world. In the past decade there have been substantial changes in the management of HIV disease, particularly the introduction of highly active antiretroviral therapy (HAART). Such agents have reduced significantly the morbidity and mortality associated with HIV disease, however, they are not available for most HIV-infected individuals in the developing world. There is now considerable understanding of the molecular epidemiology, transmission and therapy of the common opportunistic oral infections of HIV disease, and as a consequence of improved anti-HIV strategies, the frequency and severity of oral disease associated with HIV infection have reduced considerably, although HAART may predispose to human papilloma virus infection of the mouth and potentially increase the risk of later oral squamous cell carcinoma. Despite advances in clinical care the majority of individuals with HIV disease worldwide will continue to develop oral disease, as they are resident in the developing world and do not have ready access to even simple therapies.

Epidemiological and molecular evidence of two events of father-to-child HIV type 1 horizontal transmission

HIV-1 infection in children less than 15 years of age is mainly due to mother-to-child transmission. The aim of this work was to investigate molecular evidence to prove father-to-be horizontal transmission in two possible events of transmission. In the first event a boy was identified as HIV infected at 2-3 years of age. At the same time infection was confirmed in the father, while mother and siblings were negative. In the second event a girl was negative for HIV at age 1 and identified as HIV-1 infected at age 6. The father's HIV infection was diagnosed in the same period while the mother was repeatedly negative. No evidence of sexual assault or transfusion was recorded in any case. Peripheral blood mononuclear cells were obtained from both fathers and children. After PCR amplification, the C2V3 region of the envelope gene and the region coding for amino acid 132 of p24 up to amino acid 40 of p7 of the gag gene were sequenced. Genetic distance measurements and phylogenetic tree analysis showed that in both cases the father's and child's viral sequences were closely related. They were distinct when compared to Argentina sequences including sequences from the same geographic region. Epidemiological and molecular data strongly suggest that horizontal transmission had occurred, probably related to the close father-to-child contact.

Intrafamilial transmission of HIV-1 infection from individuals with unrecognized HIV-1 infection

OBJECTIVE

To describe the clinical, epidemiological and molecular evidence for transmission of HIV-1 infection from a person with unrecognized HIV infection to a family member in two unconnected families where the route of transmission could not be conclusively determined.

DESIGN

Case studies, molecular analysis of viral strains and a clinical and laboratory investigation of risk factors for transmission.

SETTING

State referral centres for HIV/AIDS in two Australian teaching hospitals.

RESULTS

Previously unrecognized HIV-1 infection was diagnosed in two unconnected females following blood donation in different Australian cities. Initially, no source of infection was identified but subsequently HIV-1 infection was diagnosed in the sister of one case and the adult son of the other. Using nucleic acid-based methods, it was demonstrated that one index case and her sister were infected with highly homologous 'Russian-type' HIV-1 subtype A, and the other index case and her son were infected with highly homologous HIV-1 subtype E (CRF01_AE). Sexual history taking from the sister and the son of the respective index cases revealed prior sexual partners from geographical areas in which the corresponding subtypes are known to be prevalent. Extensive history taking, cross-validated by independent reviewers, found no evidence whatsoever that any form of sexual contact or known blood contact could explain the HIV-1 infection in the two index cases. However, there was evidence that some form of domestic contact involving unperceived blood transfer may have occurred.

CONCLUSION

Intra-familial transmission of HIV-1 infection should be considered when a source of HIV-1 infection cannot be determined.

Co-receptor usage of HIV-1 primary isolates, viral burden, and CCR5 genotype in mother-to-child HIV-1 transmission

OBJECTIVE

To investigate the relationship between CC chemokine receptor 5 (CCR5) genotype, viral load and co-receptor usage of maternal HIV-1 isolates in perinatal HIV-1 transmission.

PATIENTS AND METHODS

A total of 181 mothers and infants were studied at the time of delivery. Wild-type (wt) and delta32 CCR5 alleles were determined by means of polymerase chain reaction (PCR). The viral load in maternal plasma samples was determined by a quantitative reverse transcriptase-PCR assay; co-receptor usage of maternal isolates was determined by viral infection in cells stably expressing CCR5 or CXC chemokine receptor 4 (CXCR4) co-receptors.

RESULTS

HIV-1 transmission rates in wt/wt and wt/delta32 mothers (14.7 versus 15.8%), and in wt/wt and wt/delta32 infants (14.6 versus 14.3%) were similar. Mothers transmitting infection to wt/delta32 infants had significantly higher HIV-1-RNA levels than those who transmitted infection to wt/wt infants (5.4 versus 4.1 log10 copies/ml, P = 0.03). In wt/wt children there was a positive relationship between transmission rate and maternal viral load over the entire range of HIV-1 values, whereas in wt/delta32 children transmission occurred only at viral loads greater than 4.0 log10 copies/ml. Logistic regression analysis confirmed that the relationship between viral load and transmission varied according to the child's CCR5 genotype (P = 0.035; adjusted for zidovudine prophylaxis and mode of delivery, P = 0.090). Moreover, the majority of wt/wt transmitting mothers had R5-type isolates, whereas none of the wt/delta32 mothers with an R5-type virus transmitted HIV-1 to their wt/delta32 infants.

CONCLUSION

Taken together, these findings suggest that CCR5 delta32 heterozygosity exerts a protective effect against perinatal transmission in children exposed to a low maternal viral burden of an R5-type isolate.

Restriction of HIV type 1 infection in macrophages heterozygous for a deletion in the CC-chemokine receptor 5 gene

Homozygosity for a 32-base pair deletion (delta32) within the CC-chemokine receptor 5 (CCR5) gene confers resistance to infection by R5-type HIV-1 isolates. To ascertain how CCR5delta32 heterozygosity influences the susceptibility of lymphocytes and macrophages to HIV-1 infection, peripheral blood lymphocytes (PBLs) and monocyte-derived macrophages (MDMs) from three HIV-1-uninfected CCR5delta32 heterozygous infants and three HIV-1-uninfected CCR5 wild-type homozygous infants were exposed to two R5-type primary isolates. HIV-1 infection was monitored by DNA-PCR and p24 antigen determination; CCR5 and CCR5delta32 transcripts were quantified by competitive reverse transcription-PCR. Wild-type homozygous MDMs and PBLs and heterozygous PBLs were infected by both viral isolates, albeit with different efficiencies, but heterozygous MDMs showed restriction to HIV-1 infection. Lower levels of CCR5 mRNA and protein expression were found in heterozygous versus wild-type homozygous MDMs and PBLs. Interestingly, wild-type homozygous MDMs showed higher levels of CCR5 mRNA expression compared with wild-type homozygous PBLs, while heterozygous MDMs had lower levels of CCR5 wild-type mRNA and a higher CCR5delta32/CCR5 mRNA ratio compared with heterozygous PBLs. These findings suggest that CCR5delta32 heterozygosity confers a different degree of protection against HIV-1 in PBLs and MDMs, depending on the ratio of wild-type and mutant CCR5 mRNA in the two cell types, and may delay virus spread in the host by preventing infection of monocytes and macrophages.