L. Chieco-Bianchi

Replication and tropism of human immunodeficiency virus type 1 as predictors of disease outcome in infants with vertically acquired infection

In a series of 97 infants born to mothers who were seropositive for human immunodeficiency virus type 1 (HIV-1), 18 were identified as infected within the first 60 days of life on the basis of viral culture and polymerase chain reaction findings. We studied viral burden in vivo by quantitative polymerase chain reaction and the in vitro replication pattern of the HIV-1 infecting strain by culturing patient cells with normal phytohemagglutinin-stimulated peripheral blood mononuclear cells. According to the lag phase before p24 antigen detection and the level of p24 production on peripheral blood mononuclear cells, HIV-1 isolates from these patients were classified as rapid/high (R/H), slow/high (S/H), and slow/low (S/L). The pattern of HIV-1 replication in vitro was significantly associated with the viral burden in vivo; the range of HIV-1 copies per 10(5) peripheral blood mononuclear cells was 10 to 38, 44 to 314, and 360 to 947 in children with isolates of the S/L, S/H, and R/H types, respectively. Viral tropism was assessed by culturing patient cells under end-point dilution conditions with either CD4+ T-lymphocytes or monocyte-derived macrophages. We found that children with S/L isolates harbored mainly monocytotropic variants; all infants with S/H or R/H isolates had T-lymphotropic variants and, in 7 of 11 cases, monocytotropic or amphitropic variants. All children with R/H isolates had HIV-related symptoms by the age of 4 months, and five had acquired immunodeficiency syndrome by the age of 1 year. At 1 year of age, four and no infants with S/H or S/L isolates, respectively, had HIV-1-related symptoms (p < 0.001), and none had acquired immunodeficiency syndrome (p = 0.006).

Immunological markers in the cerebrospinal fluid of HIV-1-infected children.

ABSTRACT. Several immunological abnormalities were detected in the cerebrospinal fluid (CSF) of human immunodeficiency virus type 1 (HIV‐1)‐infected children. Intrathecal synthesis of immunoglobulins, free light chains (FLC), IL‐1β, IL‐6, and M‐CSF were demonstrated both in asymptomatic children and children with subacute encephalopathy. Our findings further support the hypothesis that an immunopathological subclinical process within the central nervous system (CNS) may be an early manifestation of acquired immunodeficiency syndrome (AIDS). Cytokine detection in the CSF may represent a useful diagnostic tool in evaluating the outcome of HIV‐1‐infected patients.

The e19a2 BCR/ABL fusion transcript with additional chromosomal aberrations on a new case of chronic myeloid leukemia (CML) of mild type.

The e19a2 BCR/ABL fusion transcript with additional chromosomal aberrations on a new case of chronic myeloid leukemia (CML) of mild type

p53 gene alterations and protein accumulation in colorectal cancer

Aim—To correlate immunohistochemical staining with single strand conformation polymorphism (SSCP) analysis of the p53 gene in colorectal cancer in order to understand how the findings provided by the two techniques complement each other in defining p53 functional status. Methods—Frozen tumour tissue from 94 patients with colorectal cancer was studied for p53 protein accumulation and gene mutations. Accumulation of p53 protein was detected by immunohistochemistry using PAb1801 and BP53-12-1 monoclonal antibodies. The findings were then compared with SSCP analysis of exons 5 to 8 of the p53 gene. All cases with a positive result by SSCP analysis were confirmed by sequencing. Results—Nuclear staining was observed in 51 (54.2%) cases. SSCP analysis of the DNA amplified by PCR revealed that the electrophoretic pattern had shifted in 30 cases; sequence analysis confirmed the occurrence of a mutation in 29 cases and of a polymorphism in one. In 27 cases both assays gave a positive result, and in 40 both were negative; therefore, concordance between PCR-SSCP and immunohistochemistry was seen in 72% of cases. Conclusion—The data indicate that positive immunostaining corresponds with the presence of a mutation in most, but not all, cases studied; other mechanisms could be responsible for stabilisation and accumulation of p53 protein in the nucleus. Nonsense mutations which do not confer stability on the protein will not be detected by immunohistochemistry and false negative results can also occur with SSCP analysis.

Risk factors for mother-to-child transmission of HIV-1

Researchers analyzed data on 721 infants enrolled in the European Collaborative Study during 1985-1991 to examine risk factors of vertical transmission of HIV-1 infection. No differences in transmission rates existed between the collaborative centers. The risk of vertical transmission HIV was lower in women with history of IV drug use than those with no such history (odds ration [OR] for no history of IV drug use=1.45). This was due to a high rate of former IV drug users (8%). Overall vertical transmission rate was 14.4%. Further vertical transmission increased greatly for women with a low CD4 count ( 34 weeks gestation (33% vs. 14%; OR=3.80; p=.002). The mechanism may be insufficient passive or active immunity at <34 weeks gestation and increased transmission during labor or delivery. In addition the vaginal delivery procedures of episiotomy (OR=1.66; p=.02) scalp electrodes (OR=0.91; p=.05) and instrumental vaginal deliveries (OR=1.68; p=.07) were strongly related to vertical transmission but only in those centers where these procedures were not routine. Further cesarean section delivery appeared to have a protective effect against vertical transmission of HIV (OR=0.56). Moreover children who were breast fed were more likely to be HIV positive than those not breast fed (31% vs. 14%; p<.05; OR=2.25). No association existed for duration of breast feeding however. Thus based on immunological finding p24-antigenemia status and low CD4 count counselors should inform HIV infected women who are considering pregnancy of an increased risk of HIV transmission.

Intrathecal Synthesis of Anti‐HIV Oligoclonal IgG in HIV‐Seropositive Patients Having No Signs of HIV‐Induced Neurologic Diseases

The peculiar neurotropism of human immunodeficiency virus (HIV) has been proved by (a) the isolation of HIV from the brain, spinal cord, and cerebrospinal fluid (CSF) of patients with acquired immunodeficiency syndrome (AIDS) and encephalopathy, and (b) the evidence that the AIDS dementia complex can be the presenting or sole manifestation of HIV infection, suggesting that a direct brain infection may occur early in the course of systemic virus spread. Few data have so far been produced on CSF antibodies of HIV-seropositive patients having no signs of HIV-induced neurologic diseases (i.e., AIDS dementia complex, vacuolar myelopathy, and inflammatory demyelinating peripheral neuropathy ). Therefore, a study was undertaken to identify an early CSF marker that could reflect a latent infection of the nervous system in such patients.

Immunological Findings in the CSF of HIV-1 Infected Patients

Both peripheral and central nervous system disorders have been described in patients with the acquired immunodeficiency syndrome (AIDS).1–8 Increasing evidence indicates that the human immunodeficiency virus type 1 (HIV-1) is neurotropic and infects the nervous system early in the course of systemic virus spread.9–14 Ultrastructural and hybridization analyses of brain tissue from AIDS patients have revealed that HIV-1 replication occurs predominantly in cells of macrophage/microglial lineage.15–16 However, the relationship between the neurological/psychiatric symptoms associated with HIV-1 infections of the central nervous system (CNS) and the HIV-1-induced immunological abnormalities at the cellular level is still unclear.

IL-10 is intrathecally synthesized in HIV-induced/related CNS diseases, but it is not produced by HIV-infected mononuclear cells

INTRODUCTION: Intracembrst transplantation of lymphocytes from patients with MS into severe combined immunodeflcienoy (SCID) mice has been reported to reproduce demyelinating lesions typical of MS. The validity of these studies has been disputed. MATERIALS AND METHODS: PBLs from 7 patients with MS were transplanted by I.P. injection into 28 SCID mice (MSSCID). Seven animals transplanted with PBLs from 2 healthy subjects (huSCID) were used as controls. Animals were sacnficed between 2 and 8 weeks alter transplantation. RESULTS: PCR analysis aimed to the HLA-DQ region showed presence of human cells in neural tissues of MS-SCID mice. Immunocytochemical analysis showed that the majority of cells present in the brain of MS-SCID were T-cells and resided in the meningeal spaces or choroid plexuses. Isolated human cells were tound in the immediate submeningeal cerebral parenchyma. However, human lymphocytes were also found in brains of 2/7 hu-SCID mice. No signs or symptoms of neurological impairment were observed in MS-SCID. CONCLUSIONS: Our results indicate that T-calls from MS patients can reach the central nervous system of SCID mice when I.P. injected. However, no immuno-pathological signs of neurological impairment can be observed in this model. In our hands the I.P. MS-SCID mouse is not a valid tool for studies on MS immunopathology.

No evidence of HIV-2 infection in subjects at risk for aids living in North-East Italy

Sera samples from 1134 individuals (824 HIV-1 seropositive and 310 HIV-1 seronegative), collected from January 1988 to April 1990, were tested for HIV-2 antibodies by whole virus assays and synthetic peptide-based assays to determine the prevalence of HIV-2 infection in populations at risk for AIDS in North-East Italy (Veneto Region). Partial reactivities on HIV-2 Western Blot were a common finding in HIV-1 seropositive samples. None of the sera fulfilled the criteria for HIV-2 seropositivity, since only low-level reactivity was observed with an HIV-2 competitive ELISA test, and no reactivity occurred with an HIV-2 specific peptide.Therefore, there is no evidence of HIV-2 infection in this geographical area, to date.

Natural history of M-MSV tumors in mice carrying endogenized Moloney leukemia virus.

The conservation of endogenous type CDNA provirus sequences throughout evolution has raised the question of whether or not they exert normal physiological functions. Among the different hypotheses advanced has been suggested that a genetically transmitted virus could serve to protect the host, possibly via immune reactions, against related, more virulent viruses that may be acquired from the outside [14]. No substantial evidence for this hypothesis has been provided, however. Years ago during studies aimed at investigating in vivo interaction between endogenous and exogenous type C murine retroviruses, we noticed that AKR mice which had been injected with Moloney murine sarcoma virus (M-MSV) developed tumors with a longer latent period than that observed in mice of conventional strains. Furthermore, these late appearing tumors showed an unusual growth pattern, which was characterized by a slow but continuous progression until the host’s death [2]. Subsequently, these findings were confirmed in larger studies using different mouse strains [4, 7, 8]. Figure 1 depicts the general pattern of tumor behavior that has emerged; mice characterized by early endogenous ecotropic virus activation are resistant to early M-MSV oncogenesis, but late appearing progressive tumors are observed in the majority of strains. While late tumor progression is probably due to immunological tolerance of cytotoxic T-lymphocytes (CTL) toward virus-coded antigens [6], the mechanism underlying resistance to early tumor induction is still poorly understood. BALB/Mo mice, which carry the exogenous Moloney leukemia virus (M-MuLV) as an endogenous virus integrated at a single locus (Mov-1) on chromosome 6 [1, 11], offer the unique opportunity of studying whether the full expression of genetically transmitted M-MuLV confers resistance against the antigenically related (M-MuLV) M-MSV complex. Indeed, in a first series of experiments [9], it was found that the natural history of induced tumors in these mice is quite similar to that observed in AKR type mice. In addition, resistance to early tumors appears related to the time course of M-MuLV activation as well as to the presence in the serum of normal mice of antibodies possessing specific binding capacity to M-MuLV surface determinants. The possibility that this particular tumor pattern might be influenced by these antibodies, or by virus-specific CTL activity, is discussed in this study.