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Electrostatic charges patterning along crystalline channels recognize CO2 with high selectivity and promote its fast screwing dynamics through the crystal at one million steps per second, strongly reminiscent of trans-membrane transport in biological channels., Porous molecular materials represent a new front in the endeavor to achieve high-performance sorptive properties and gas transport. Self-assembly of polyfunctional molecules containing multiple charges, namely, tetrahedral tetra-sulfonate anions and bifunctional linear cations, resulted in a permanently porous crystalline material exhibiting tailored sub-nanometer channels with double helices of electrostatic charges that governed the association and transport of CO2 molecules. The charged channels were consolidated by robust hydrogen bonds. Guest recognition by electrostatic interactions remind us of the role played by the dipolar helical channels in regulatory biological membranes. The systematic electrostatic sites provided the perfectly fitting loci of complementary charges in the channels that proved to be extremely selective with respect to N2 (S = 690), a benchmark in the field of porous molecular materials. The unique screwing dynamics of CO2 travelling along the ultramicropores with a step-wise reorientation mechanism was driven by specific host–guest interactions encountered along the helical track. The unusual dynamics with a single-file transport rate of more than 106 steps per second and an energy barrier for the jump to the next site as low as 2.9 kcal mol–1 was revealed unconventionally by complementing in situ13C NMR anisotropic line-shape analysis with DFT modelling of CO2 diffusing in the crystal channels. The peculiar sorption performances and the extraordinary thermal stability up to 450 °C, combined with the ease of preparation and regeneration, highlight the perspective of applying these materials for selective removal of CO2 from other gases.

Porous molecular materials represent a new front in the endeavor to achieve high-performance sorptive properties and gas transport. Self-assembly of polyfunctional molecules containing multiple charges, namely, tetrahedral tetra-sulfonate anions and bifunctional linear cations, resulted in a permanently porous crystalline material exhibiting tailored sub-nanometer channels with double helices of electrostatic charges that governed the association and transport of CO2 molecules. The charged channels were consolidated by robust hydrogen bonds. Guest recognition by electrostatic interactions remind us of the role played by the dipolar helical channels in regulatory biological membranes. The systematic electrostatic sites provided the perfectly fitting loci of complementary charges in the channels that proved to be extremely selective with respect to N2 (S = 690), a benchmark in the field of porous molecular materials. The unique screwing dynamics of CO2 travelling along the ultramicropores with a step-wise reorientation mechanism was driven by specific host–guest interactions encountered along the helical track. The unusual dynamics with a single-file transport rate of more than 106 steps per second and an energy barrier for the jump to the next site as low as 2.9 kcal mol−1 was revealed unconventionally by complementing in situ13C NMR anisotropic line-shape analysis with DFT modelling of CO2 diffusing in the crystal channels. The peculiar sorption performances and the extraordinary thermal stability up to 450 °C, combined with the ease of preparation and regeneration, highlight the perspective of applying these materials for selective removal of CO2 from other gases.

The sensitivity of 129Xe NMR to the size and shape of the cavities makes, both thermally-polarized and hyper-polarized techniques, invaluable for the characterization of porous materials, such as MOFs and molecular crystals [1-2]. In this presentation, the chemical shift anisotropy (CSA) pattern mirrors not only shape and symmetry of the explored rooms, but also the dynamics of xenon jumping from one site to the next. This study belongs to a program for generating ultra-fast molecular rotors and understanding dynamics in porous crystals [3-4]. Tetra-carboxylic molecules could be obtained in the permanently porous form for the stability imparted by 8 hydrogen bonds: the material was explored by xenon and the anisotropic 129Xe signal resonates in the 220-320 ppm range, indicating a tight fit of the gas atom in the adsorption sites [5]. The intriguing line-shape evolution (see figure) denotes a temperature dependent exchange dynamics (observed at 10 bar loading pressure) and was interpreted as the effect of thermally activated Xe jumps to adjacent vacant sites along the channels. Each site is marked by the relative orientations. Indeed, the explored cavities show elliptical cross-sections (e = 0.75), alternatively rotated by 90° about the channel axis, as CSA profile below 240 K depicts. At higher temperatures, xenon atoms dynamically explore the two orientations and, when the exchange rates exceed the frequency span of the tensor principal components, Xe perceives an averaged interaction. This interpretation allowed us to simulate the anisotropy and assign at each pattern a specific jump-rate and to measure, by an Arrhenius plot, the energy barrier for an individual jump of 1.8 kcal/mol. Ab initio calculations and molecular dynamics confirm the high mobility of xenon atoms inside the structure and evaluate a consistent energy barrier. The experimental single-jump frequency and energy were the basis to establish xenon diffusion rate in the narrow channels. Source of founding PRIN 2017-20 -NAZ-104, Cariplo Foundation 2017-19 BALANCE and INSTM-Lombardy 2017-18. References: [1] Porous Materials Explored by Hyperpolarized Xenon NMR; P. Sozzani, S. Bracco, A. Comotti in Hyperpolarized Xenon-129 Magnetic Resonance T. Meersman and E. Brunner (Eds.), 2015, 164. [2] A. Comotti, S. Bracco, P. Sozzani, S. Horike, R. Matsuda, S. Kitagawa JACS, 2008, 130,13664. [3] Review: Molecular rotors build in porous materials; S. Bracco, A. Comotti, P. Sozzani, Acc. Chem. Res., 2016, 49, 1701. [4] S. Bracco, F. Castiglioni, A. Comotti, S. Galli, M. Negroni, A. Maspero, P. Sozzani, Chem. Eur. J., 2017, 23, 11210. [5] I. Bassanetti, S. Bracco, A. Comotti, M. Negroni, C. Bezuidenhout, S. Canossa, P. P. Mazzeo, L. Marchio’, P. Sozzani J Mater. Chem A (in press).

A series of porous organic polymers were synthetized through extensive cross-linking of aromatic monomers containing multiple reactive sites. The inefficient packing of monomeric units determined the formation of highly porous frameworks with surface areas up to 4800 m2/g and broad pore size distributions. Besides, the formation of strong covalent bonds accounted for high chemical and thermal stability. In depth solid state NMR analysis allowed us to check the purity of samples and to determine the connectivity and the microstructure of porous frameworks. Due to their possible application in Adsorbed Natural Gas technology (ANG) methane uptake was measured up to 180 bar at room temperature. The methane uptake at high pressure was related to the surface area and the total pore volume obtained by nitrogen adsorption isotherms at 77K. For example, triptycene-based material (TRIP) with surface area as high as 1600 m2/g could adsorb more than 400 cm3/g of methane at 180 bar. We also evaluated the volumetric methane uptake (cm3 of adsorbate per cm3 of adsorbent) at high pressure which is a critical parameter in methane transportation by ships. Moreover, the volumetric uptake allowed us to compare the results directly with compressed natural gas technology (CNG). At 180 bar the methane adsorption of TRIP sample reached a considerable value of 220 cm3/cm3. Furthermore, we could evaluate the gain in methane storage due to the presence of the porous material by comparing the total volumetric uptake of CH4 in presence of TRIP with pure compressed methane: a gain above 100% could be achieved up to 65 bar (Figure1). The isosteric heat of adsorption, as measured by the Clausius-Clapeyron equation, provided an insight into the strength of interactions between the methane molecules and the pore walls. At low coverage it ranged from 19 to 21 KJ/mol and it was among the highest value reported in literature. Such high values were attributed to multiple CH-π interactions between the methane molecules and the electron-rich aromatic rings. Lastly, we investigated carbon dioxide uptake up to 10 bar. All samples showed high CO2 uptake, isosteric heat of adsorption up to 30 KJ/mol and an excellent CO2/N2 selectivity ranging from 20 to 25 at room temperature (estimated by the Ideal Adsorbed Solution Theory IAST). These adsorption properties combined with the high chemical and thermal resistance and low hydrophilicity made porous organic polymers attractive for post-combustion treatment of industrial emissions. [1] Bracco, S.; Piga, D.; Bassanetti, I.; Perego J.; Comotti A.; Sozzani P. J. Mater. Chem. A 2017, 5, 10328-10337.

Our approach is to design porosity in combination with switchable dynamics and flexibility in porous materials for gaining control over gas capture and selectivity. This approach was made possible by fabricating rotor-on-axel molecular struts and tetrahedral building blocks. Ultra-fast molecular rotors as fast as 1011 Hz were engineered in porous crystalline frameworks (molecular crystals, MOFs and mesoporous organosilicas) containing rod-like linkers as amphidynamic elements. The porous frameworks promise access to the control of rotary motion by chemical and physical stimuli. If a gas or a vapor is diffused to the cavities, such as CO 2, iodine and hydrocarbon vapors, rotor dynamics is hampered. In turn, on/off switching produces modulated physical responses. When C-F dipoles were mounted on the rotors, they induced fast oscillating dipoles that interact with an applied electric field. Direct evidence of hostguest interactions at the molecular level were established by 2D solid-state NMR. We achieved the fabrication of swellable porous adamantoid frameworks by the use of highly symmetrical tetrahedral elements and the co-operation of 8 surrounding hydrogen bonds mounted on conformationally flexible groups. The flexibility of the porous crystals manifests itself in response to stimuli of selected gases: CO2, Xe and hexane triggers the enlargement of channel cross-section. The accomodation of CO2 and Xe in the channel chambers was revealed by synchrotron-light XRD, combined with modelling. Xenon dynamics was gathered by 129Xe NMR chemical shift anisotropy profiles, which encode the shape and orientation of each visited cavity. Jump rate and activation energy experienced by exploring Xe atoms were uniquely established. Covalent connection of tetrahedral nodes results in expandable frameworks, especially if 3 instead of all 4 branches are cross-linked: the forth branch can be dedicated to bearing a functional group to catch the gas molecules (CO 2 is retained by –NH2 group by an energy as high as 54 kJ/mol). Moreover, photo-responsive molecular crystals were fabricated by tetrahedral azobenzene tetramers that form porous molecular crystals in their trans configuration. The efficient trans-to-cis photoisomerization converts the crystals into a non-porous phase but crystallinity and porosity are restored upon reverse isomerization promoted by heat. We demonstrated that the photo-isomerization enables reversible on/off switching of optical properties as well as CO2 capture from the gas phase. We thank Cariplo Foundation, Lombardy Region/INSTM Consortium and PRIN 2016. References 1. Acc.Chem.Res.2016,49,1701; 2. Chem.Eur.J. 2017,23,11210; 3. J.Am.Chem.Soc.2014,136,618; 4. Angew.Chem.Int.Ed. 2014,53,1043. 5. Chem.Comm.2017,53,7776; 6. J.Mater.Chem.A2018,6,14231; 7. Chem.Comm. DOI:10.1039/C8CC03951H; 8. NatureChem. 2015,7,634.

Two novel pillared Zn(II)-based Metal–Organic Frameworks were de novo synthesized exploiting N,N′-(1,1′-biphenyl)-4,4′-diylbis-4-pyridinecarboxamide (bpba) and its fluorinated analogous N,N′-(perfluoro-1,1′-biphenyl-4,4′-diyl)diisonicotinamide (F-bpba) as suitable pillar linkers and 2,6-naphthalene dicarboxylic acid as carboxylic ligand. The resulting heteroleptic MOFs, namely, PUM210, [Zn4(bpba)1.5·(ndc)4·(H2O)]n and PUM210F, [Zn3(F-bpba)1·(ndc)3·(DMF)]n, feature an uncommon truncation of the Zn(II) paddle-wheel nodes along the pillaring direction. PUM210 and PUM210F exhibit a polycatenated architecture, resulting in microporous channels decorated by amide moieties. The activated forms show a permanent porosity and a selective adsorption of CO2 over N2. Moreover, the partially transmetalated Cu-PUM210 and Cu-PUM210F were obtained by convenient transmetalation protocol and their adsorption propriety toward CO2 were subsequently investigated.

High surface area 3D polymers represent one of the most promising classes of porous materials because of their high gas uptake and stability to thermal and chemical degradation. A series of porous organic polymers with aromatic building units have been synthesized and compared to explore their high-pressure performance as adsorbents of gases of relevant importance for energy and the environment. Particular attention was paid to methane storage up to pressures as high as 180 bar at ambient temperature. Porous polymers were prepared starting from a wide choice of spatially expanded aromatic monomers: a systematic change in the number of rings, variable size and shape was taken under consideration. The high number of rings (up to 6), which act as multiple reactive sites and form a number of connections between the multi-dentate nodes, result in an extensive cross-linked framework. Condensation was obtained by two alternative synthetic routes, viz., Yamamoto cross-coupling and Friedel–Crafts alkylation reactions. The structural characteristics and high stability of the porous polymers, even to mechanical compression, were carefully determined by several methods, including 1D and 2D solid state NMR, FT IR and thermal analyses. The CH4 uptake in the porous polymers allowed an understanding of the incremental response to pressure, up to extremely high values, and the exploitation of the extensive pressure range to customize the gas adsorption/desorption cycles for storage and transportation. Owing to the notable presence of large mesopores and network flexibility, combined with high surface area, a remarkable gain at high pressure was achieved, ensuring a highly competitive uptake/delivery efficiency. At 180 bar, adsorption values up to 445 cm3 STP g−1 were measured for porous organic polymers such as carbazolyl- and triptycene-based materials. The benchmark of these materials PAF1 reaches the value of 916 cm3 STP g−1 of adsorbed CH4, exceeding the performance of most of the best performing MOFs, COFs and activated carbons. CO2 and N2 adsorption isotherms collected at room temperature enabled the assessment of the suitability of such polymer networks for CO2 selective separation and capture. In summary, the in-depth and extensive comparative screening within this class of materials up to high pressures provides the necessary parameters for further synthetic and applicative work.

A crystalline hydrogen-bonded framework with permanent porosity, built by rod-like struts and engineered to bear ultra-fast molecular rotors between two triple bonds, offers the possibility of controlling the rotational rates upon CO2 adsorption. CO2 enters the pores from the gas phase and reduces the rotational rates from the extremely fast regime of 107 Hz at 216 K to 105 Hz. The CO2–rotor interaction was evident from the 2H NMR response to the dynamics of the rotors in contact with CO2 in the crystal structure.

The development of solid materials that can be reversibly interconverted by light between forms with different physicochemical properties is of great interest for separation, catalysis, optoelectronics, holography, mechanical actuation and solar energy conversion. Here, we describe a series of shape-persistent azobenzene tetramers that form porous molecular crystals in their E-configuration, the porosity of which can be tuned by changing the peripheral substituents on the molecule. Efficient E -> Z photoisomerization of the azobenzene units takes place in the solid state and converts the crystals into a non-porous amorphous melt phase. Crystallinity and porosity are restored upon Z -> E isomerization promoted by visible light irradiation or heating. We demonstrate that the photoisomerization enables reversible on/off switching of optical properties such as birefringence as well as the capture of CO2 from the gas phase. The linear design, structural versatility and synthetic accessibility make this new family of materials potentially interesting for technological applications.

A family of bis(pyrazolato)-based metal-organic frameworks (MOFs) was isolated by reacting 1,4-bis(1H-pyrazol-4-ylethynyl)benzene (H2BPEB) with a number of transition metal ions. Special attention was dedicated to their structural features, their thermal and chemical stability, as well as their spectroscopic and adsorption properties. The rod-like ligands, connecting Zn(II), Ni(II) and Fe(III) nodes, fabricate 3-D networks containing 1-D pervious channels. The combination of thermal analysis and variable-temperature XRPD demonstrated the remarkable thermal robustness of the three materials, which are stable in air up to at least 410 °C, and showed their structural response to increasing temperature. Specific experiments permitted us to test the chemical stability of the three species toward water as well as moderately acidic and basic solutions, the Ni(II) derivative being stable and hydrophobic in all the conditions assayed. The electronic transitions of both the ligand and the MOFs were investigated by solid-state UV-Vis absorption as well as by steady-state and time-resolved fluorescence analysis, which showed that the high fluorescence of the linker is perturbed in the three MOFs, suggesting high sensitivity to environmental changes. N2 adsorption measurements at 77 K allowed to estimate promising Langmuir specific surface areas, peaking at 2378 m2 g−1 in the case of the Ni(II) derivative. The best CO2 and CH4 uptake performances were achieved with the Fe(III)-based MOF. Indeed, adsorption experiments with CO2 revealed that a considerable amount, up to 40% wt, is adsorbed by the Fe(III) derivative under the mild conditions of 298 K and 10 bar.

Weak interactions such as π-π, CH-π, H bonds and VdW forces, play a key role in the rational design of new fascinating supramolecular materials. In effect these interactions are able to drive the self-assembly of simple building blocks to create well defined molecular polyhedra. These materials have attracted much attention not only for their infinite range of application but also thanks to their very interesting supramolecular architectures. Here we present how 72 H-bonds guide the assembly of two kinds of hexagonal molecular tiles in a quasi-truncated octahedron q-TO (which corresponds to one of the 13 Archimedean solids)1 and how different counterions (BF4-, PF6- or NO3-, CF3SO3-) can largely modulate the structure of hexameric toroidal supramolecules h-SP which, at higher hierarchical level, can assembly in sphere2. Both q-TO and h-SP crystallize in high symmetric cubic space groups and both present a void volume inside the macrostructure: q-TO have a 2200Å3 of free total volume and it exhibits the remarkably ability of encapsulate a large assortment of molecular species as solvent molecules and organic guests; h-SP shows a permanent porosity with 18000 Å3 of void space and it is a good material for the adsorption of gases such as CO2 or solvent vapors. Porous dipeptide-based crystals held together by hydrogen bonds and showing selective adsorption of CO2 vs N2 are also presented.3

Two polymorphs of 2,7-dihydrobenzo[1,2,3-cd:4,5,6-c′d′] diindazole ("dipyrazoloanthracene"; α and β; DBDI) were isolated and fully characterized by means of structural X-ray powder diffraction methods, thermal, and extended spectroscopic analyses. Different interconversion paths between the two species were evidenced. UV-vis absorption, emission, and excitation spectra were measured, while time-resolved fluorescence studies allowed for the detection of multiple decay processes. In the two species, NH···N hydrogen bonds give rise to manifestly different structures, which, in the rhombohedral β phase, generate permanent porosity. This feature has been further characterized by CO2/N2/CH4 sorption isotherms at different temperatures, highlighting a significant selectivity favoring CO2 trapping. © 2013 American Chemical Society.

The complexation of a preorganized thioether-functionalized bis(pyrazolyl)methane ligand (L) with silver precursors produces supramolecular structures organized at two hierarchical levels: [AgL](6)(X)(6) metal-organic cyclic hexamers and their organization in 3D architectures. The cyclic toroidal hexamers of 22-26 Å external diameter are found to be stable already in solution before self-assembly into the crystalline state. In the 3D lattice, the hexameric building block are arranged in different highly symmetric space groups as a function of a variety of anions (cubic Fd3 with PF(6)(-) or BF(4)(-) and rhombohedral R3 with CF(3)SO(3)(-) or NO(3)(-)) and form cavities with the geometrical shapes of Platonic solids (tetrahedron and octahedron) that can be occupied by a variety of solvent molecules. Upon evacuation, cubic crystals can produce stable frameworks with permanent porosity, which can absorb reversibly several vapors, CO(2) and CH(4).

A family of bis(pyrazolato)-based metal-organic frameworks (MOFs) was isolated by reacting 1,4-bis(1H-pyrazol-4-ylethynyl)benzene (H2BPEB) with a number of transition metal ions. Special attention was dedicated to their structural features, their thermal and chemical stability, as well as their spectroscopic and adsorption properties. The rod-like ligands, connecting Zn(II), Ni(II) and Fe(III) nodes, fabricate 3-D networks containing 1-D pervious channels. The combination of thermal analysis and variable-temperature XRPD demonstrated the remarkable thermal robustness of the three materials, which are stable in air up to at least 410 °C, and showed their structural response to increasing temperature. Specific experiments permitted us to test the chemical stability of the three species toward water as well as moderately acidic and basic solutions, the Ni(II) derivative being stable and hydrophobic in all the conditions assayed. The electronic transitions of both the ligand and the MOFs were investigated by solid-state UV-Vis absorption as well as by steady-state and time-resolved fluorescence analysis, which showed that the high fluorescence of the linker is perturbed in the three MOFs, suggesting high sensitivity to environmental changes. N2 adsorption measurements at 77 K allowed to estimate promising Langmuir specific surface areas, peaking at 2378 m2 g−1 in the case of the Ni(II) derivative. The best CO2 and CH4 uptake performances were achieved with the Fe(III)-based MOF. Indeed, adsorption experiments with CO2 revealed that a considerable amount, up to 40% wt, is adsorbed by the Fe(III) derivative under the mild conditions of 298 K and 10 bar.

To evaluate the relation between elective cesarean section and vertical transmission of human immunodeficiency virus type 1 (HIV-1), we performed a meta-analysis using data on individual patients from 15 prospective cohort studies. North American and European studies of at least 100 mother-child pairs were included in the meta-analysis. Uniform definitions of modes of delivery were used. Elective cesarean sections were defined as those performed before onset of labor and rupture of membranes. Multivariate logistic-regression analysis was used to adjust for other factors known to be associated with vertical transmission. The primary analysis included data on 8533 mother-child pairs. After adjustment for receipt of antiretroviral therapy, maternal stage of disease, and infant birth weight, the likelihood of vertical transmission of HIV-1 was decreased by approximately 50 percent with elective cesarean section, as compared with other modes of delivery (adjusted odds ratio, 0.43; 95 percent confidence interval, 0.33 to 0.56). The results were similar when the study population was limited to those with rupture of membranes shortly before delivery. The likelihood of transmission was reduced by approximately 87 percent with both elective cesarean section and receipt of antiretroviral therapy during the prenatal, intrapartum, and neonatal periods, as compared with other modes of delivery and the absence of therapy (adjusted odds ratio, 0.13; 95 percent confidence interval, 0.09 to 0.19). Among mother-child pairs receiving antiretroviral therapy during the prenatal, intrapartum, and neonatal periods, rates of vertical transmission were 2.0 percent among the 196 mothers who underwent elective cesarean section and 7.3 percent among the 1255 mothers with other modes of delivery. The results of this meta-analysis suggest that elective cesarean section reduces the risk of transmission of HIV-1 from mother to child independently of the effects of treatment with zidovudine.

The paper analyses the recent supply side developments in France, Germany, and Italy by employing a non-parametric approach to estimate potential GDP. The analysis reveals marked heterogeneity among the three countries with regard to the contribution made by labour input. Where similarities can be found, however, are in the slowdown of accumulation activity and in the pronounced worsening of total factor productivity. The paper is rounded out by estimates of some measures of wage pressures and of profitability in order to assess the role played by the movements of relative input prices in the intensity of use of primary factors in the production process.

OBJECTIVE: To investigate the timing of onset of each clinical sign in infants and children with HIV-1 perinatal infection. DESIGN AND METHODS: A total of 200 HIV-1-infected children followed-up from birth were studied. Failure and conditional probabilities were estimated by the Kaplan-Meier product-limit method. Cox proportional hazard analysis was used to evaluate independently associated factors. Results of 934 seroreverters were used to calculate reference values of CD4+ cell counts and predictivity of early signs. RESULTS: Median age at the onset of any sign was 5.2 months (range, 0.03-56 months). The probability of remaining asymptomatic was 19% [95% confidence interval (CI), 14-25.1] at 12 months and 6.1% (95% CI, 2.6-11.7) at 5 years. Lymphadenopathy (69.5%), splenomegaly (62.4%) and hepatomegaly (58.4%) were the most common signs in the first year of life. Peculiar to the first year of life (compared with subsequent ages) was the onset of primary HIV-1 hepatitis and diarrhoea (rate ratios, 23.3 and 15.2, respectively). When CD4+ cell counts in the asymptomatic stage (age, 2 months; range, 0.03-5.9 months) were below rather than above the fifth percentile in seroreverters, onset of signs was earlier [3 range, 0.03-19) versus 5 (range, 0.03-56) months]. Children manifesting signs before the 5.2-month breakpoint had a lower survival rate [74% (range, 65.9-82%) at 12 months and 45% (range, 32.9-57%) at 5 years] than children manifesting signs later [98% (range, 92.2-100%) at 12 months and 74% (range, 60.3-87.7%) at 5 years]. Children whose birthweight was < or = 2400 g had an earlier onset (24 months; range, 1-57 months) of severe conditions than children with higher birthweight (71 months; range, 1-71 months). Development of lymphadenopathy or hepatosplenomegaly within 3 months of life were reliable indicators of infection. CONCLUSIONS: This study describes the sequence of onset of signs in perinatal HIV-1 infection. Infection is shown to progress faster than in adults and in a different manner. Low birthweight, early decreased CD4+ cell counts, and early onset of signs are predictive of rapid progression.

Children infected with HIV do not necessarily develop AIDS to a set pattern but can be divided into long-term and short-term survivors. We examined long-term survival in children perinatally infected with HIV-1. Out of a total of 624, we studied 182 children who survived longer than 5 years (long-term survivors [LTS]) and 120 children who died of HIV-1-related disease before 5 years (defined as short-term survivors [STS]). 28 (15%) LTS were symptomless (Centers for Disease Control [CDC] P-1 children). 154 (85%) had symptoms (CDC P-2). The proportion of LTS with less than 0.2 x 10(9)/CD4 cells per L was 24/116 (21%) at 61-72 months, rising to 11/26 (41%) at more than 96 months. On at least one occasion, p24 antigenaemia was observed in 112 (62%) LTS. Annual rate of CD4 cell loss was lower in LTS (25% [95% CI: 21-29]) than in STS (53% [45-60]) and in LTS symptomless or with solitary P-2A signs (17%; [13-21]) than in LTS with severe manifestations (30% [25-35]). A new outlook emerges. A substantial number of children do survive after early childhood; severe diseases; low CD4 cell numbers, and p24 antigenaemia do not necessarily preclude long-term survival. The study shows that a CD4 cell decrease early in life can be predictive of outcome.

info:eu-repo/semantics/published

info:eu-repo/semantics/published