Giuseppe Luzi

Duodenal Pathology and Clinical-Immunological Implications in Common Variable Immunodeficiency Patients

OBJECTIVES:Common variable immunodeficiency (CVID) is an immunological disorder characterized by defective antibody production. An increased prevalence of celiac disease has been suggested in patients with this disorder. This study aimed to assess duodenal pathology and its clinical implications in these patients.METHODS:A total of 32 consecutive CVID patients with anemia or GI symptoms were enrolled. Patients underwent upper endoscopy, and biopsy specimens were taken in the descending duodenum for histological assessment. A blood sample was obtained to determine immunoglobulin and Hb levels and to evaluate the CD4+ T-lymphocyte count. Body mass index was calculated for all patients.RESULTS:Histological assessment of duodenal specimens revealed the presence of villous atrophy in 10 (31.2%) patients, a feature of nodular lymphoid hyperplasia in five (15.6%), and mild duodenitis in two (6.3%), whereas normal histology was observed in the remaining 15 (46.9%) patients. Patients with villous atrophy had anemia more frequently than those without, whereas the frequency of persistent diarrhea did not differ between these two groups. Moreover, both CD4 levels and body mass index were significantly lower in patients with atrophy than in controls.CONCLUSIONS:Duodenal villous atrophy is very frequent in symptomatic CVID patients, with relevant clinical and immunological implications. Specifically, this histological alteration is significantly associated with anemia, malnutrition, and low blood CD4+ lymphocyte levels.

Altered Clonogenic Capability and Stromal Cell Function Characterize Bone Marrow of HIV-Infected Subjects with Low CD4 + T Cell Counts Despite Viral Suppression during HAART

BACKGROUND Inflammatory cytokines in bone marrow may impair hematolymphopoiesis in human immunodeficiency virus (HIV)-infected subjects who do not experience reconstitution of CD4(+) T cells despite suppression of virus replication while receiving highly active antiretroviral therapy (HAART) (immunological nonresponders). METHODS Bone marrow samples from 12 immunological nonresponders receiving HAART were studied and compared with samples from 11 immunological responders. The mean CD4(+) T cell count (+/- standard deviation) was 174 +/- 68 cells/mm(3) and plasma HIV RNA levels had been <50 copies/mL for at least 1 year for individuals enrolled in the study. The clonogenic capability of bone marrow samples was evaluated using the colony forming cell assay and the long-term culture-initiating cell assay. CD34(+) cells from the colony forming cell assay were pooled for real-time polymerase chain reaction analysis of Fas and Fas ligand. Bone marrow cytokine production (interleukin-2 and tumor necrosis factor-alpha) and stromal interleukin-7 levels were analyzed by enzyme-linked immunosorbent assay in both groups. Flow cytometric analysis of CD4(+) and CD8(+) T cell subsets was performed. RESULTS A reduced clonogenic capability and a decrease in the level of more primitive progenitor cells were observed in parallel with lower production of interleukin-2 and increased tumor necrosis factor-alpha levels. A significant upregulation of Fas and Fas ligand on CD34(+) cells and a higher stromal interleukin-7 production were observed. Impairment of the naive T cell compartment and persistent T cell activation were observed in peripheral blood. CONCLUSIONS Samples from immunological nonresponders show reduced growth of in vitro colonies and an altered cytokine production in bone marrow. The cytokine pattern observed and the altered Fas and Fas ligand pathway may determine stem cell apoptosis and low CD4(+) cell recovery. These features, which are similar to those observed in HIV-infected subjects before starting therapy, persist despite treatment.

Bone Marrow Clonogenic Capability, Cytokine Production, and Thymic Output in Patients with Common Variable Immunodeficiency

In patients with primary Ab deficiencies, hematological and immunological abnormalities are frequently observed. A regenerative failure of hemopoietic stem/progenitor cells has been hypothesized. We evaluated in the bone marrow (BM) of 11 patients with common variable immunodeficiency, the phenotype of BM progenitors and their in vitro growth by colony-forming cell (CFC) and long-term culture (LTC) assays. A significant decrease in erythroid and mixed CFC and, to a greater extent, in primitive LTC-CFC progenitors was observed in patients compared with healthy controls. The frequency of BM pre-B and pro-B cells correlated directly with the absolute number of CD19+ lymphocytes. BM cells cultured in vitro produced spontaneously lower amounts of IL-2 and elevated levels of TNF-α compared with controls, indicating a skewing toward a proapoptotic cytokine pattern. In addition, stromal cells generated after BM LTC secreted less IL-7 and displayed by immunohistochemistry an altered phenotype. These findings were associated with a significant decrease in naive Th cells coexpressing CD31 in the peripheral blood. These results indicate an impaired growth and differentiation capacity of progenitor cells in patients with common variable immunodeficiency.

Division protein interaction web: identification of a phylogenetically conserved common interactome between Streptococcus pneumoniae and Escherichia coli

The ability of each of the 11 Streptococcus pneumoniae division proteins to interact with itself and with each of the remaining proteins was studied in 66 combinations of protein pairs, using a bacterial two-hybrid system. Interactions (homo- or hetero-dimerizations) were detected between 37 protein pairs, whereas 29 protein pairs did not interact. In some cases, positive interactions of the S. pneumoniae proteins were confirmed by co-immunoprecipitation experiments in Escherichia coli. Comparison between the S. pneumoniae division protein interaction web and that of E. coli, the only micro-organisms for which the whole division interactome has been described systematically, was also performed. At least nine division proteins, ZapA, FtsZ, FtsA, FtsK, FtsQ/DivIB, FtsB/DivIC, FtsL, FtsI and FtsW, are believed to have a conserved function between these bacteria and thus we may say that a significant part of the interactions are conserved. Out of 45 protein pairs tested in both bacteria, 30 showed the same behaviour: 23 interacted while seven did not. In agreement with these results, cross-interactions between S. pneumoniae proteins and the corresponding E. coli orthologues were observed. Taken together, these results suggest a phylogenetically conserved minimal common interactome of the division proteins.

HIV-1 infection and the developing nervous system: Lineage-specific regulation of viral gene expression and replication in distinct neuronal precursors

Neurologic abnormalities are common in HIV-1 infected patients and often represent the dominant clinical manifestation of pediatric AIDS. Although the neurological dysfunction has been directly related to CNS invasion by HIV-1, the pathogenesis of neurologic disorders remains unclear. Microglia and macrophages are major HIV-1 targets in the brain, whereas HIV-1 infected neurons or glial cells have been rarely reported. This suggests that indirect mechanisms may account for the severe neuronal damage observed in these patients. Nevertheless, immature, mitotically active neuronal and glial cells, which are present during fetal development, are susceptible to HIV-1 infection and replication in vitro, suggesting that HIV-1 infection during organ development may present unique features. To better characterize virus-host cells interactions in the developing CNS, we have examined the susceptibility of embryologically and biochemically distinct neuronal cell lines to HIV-1 infection. Here we show that mitotically active, immature neurons of distinct lineages, have different susceptibilities to HIV-1 infection and replication and different abilities to support viral gene expression. Mutational analysis of HIV-1 LTR reveals that a region of the viral promoter between nucleotide -255 to -166 is responsible for most quantitative and qualitative differences in viral transactivation among different neuroblasts. This suggests that specific regions of the viral promoter and cellular factors, either lineage- or differentiation-dependent, which bind to those regions, may contribute to control the levels of virus replication and possibly restrict the viral tropism in the developing brain. This may contribute to the establishment of a virus reservoir in the immature CNS and participate by either direct or indirect mechanisms to the severity of the AIDS-related pediatric neurological dysfunction.

The Escherichia coli FtsK functional domains involved in its interaction with its divisome protein partners

FtsK is a multifunctional protein involved in both cell division and chromosome segregation. As far as its role in cell division is concerned, FtsK is among the first divisome proteins that localizes at mid-cell, after FtsZ, FtsA and ZipA, and is required for the recruitment of the other divisome components. The ability of FtsK to interact with several cell division proteins, namely FtsZ, FtsQ, FtsL and FtsI, by the two-hybrid assay was already shown by our group. In this work, we describe the identification of the protein domain(s) involved in the interaction with the cell division partner proteins. The biological role of some interactions is also discussed.

Plasmacytoid Dendritic Cells Count in Antiretroviral-Treated Patients is Predictive of HIV Load Control Independent of CD4+ T-Cell Count

The depletion in circulating dendritic cells (DCs) and inverse correlation with viral load have been described in human immunodeficiency virus (HIV)-infected patients. The aim of this study was to investigate whether the DC blood count in antiretroviral-treated patients might be predictive of viral load control independent of CD4+ T cell count. Plasmacytoid DCs (pDCs) and myeloid DCs (mDCs) were enumerated using a newly developed flow cytometric assay based on TruCOUNT. A significant reduction of circulating pDCs and mDCs was detected both in untreated and -treated subjects. The probability of experiencing viral load increase according to pDC, and CD4 count at baseline was evaluated in 39 treated patients. Individuals with lower baseline pDCs were more likely to have an increase of HIV-RNA during the 30 month follow-up in comparison with patients with high pDCs (p <0.001). In particular, the pDC measurement may be useful in the context of a high CD4 count, to distinguish the patients who have virological failure despite high CD4 counts. These findings suggest that in treated patients the enumeration of circulating DCs, especially pDC count, can augment the predictive value of CD4 measurement in predicting virologic failure.

Plasma viraemia in seronegative HIV-1-infected individuals.

It has been reported that the period of latency between HIV-1 infection and the production of antibodies against the virus is sometimes prolonged for greater than 6 months. However, the data supporting this are still controversial and it is not known whether these individuals are actually infectious, especially through body fluids. We have performed a prospective study of 65 high-risk HIV-1-antibody-negative individuals who were followed-up for a period of at least 1 year. Twelve of these individuals were shown by polymerase chain reaction (PCR) to be carriers of HIV-1 proviral sequences. The virus was isolated from lymphocytes in five out of 10 PCR-positive subjects and from cell-free plasma in two. Our data indicate that in some cases delayed seroconversions may be associated with productive infection, suggesting that mechanism(s) other than viral latency may be responsible for the absence of antibody responses to HIV-1 proteins.

Correlative analysis of gene expression profile and prognosis in patients with gliomatosis cerebri

In modern clinical neuro‐oncology, the pathologic diagnoses are very challenging, creating significant clinical confusion and affecting therapeutic decisions and prognosis.

Parvovirus infection in children with AIDS : high prevalence of B19-specific immunoglobulin M and G antibodies

ObjectiveInvestigation of the prevalence and pathogenic role of parvovirus B19 infection in Italian and Rumanian children with AIDS, compared with age-matched HIV-negative children (controls) with various recurrent infections of unknown aetiology. DesignDetection of B19-specific immunoglobulin (Ig) M and IgG antibodies as the most indicative markers of past or current B19 infection. MethodsB19 antibodies were detected by two enzyme immunoassays using synthetic peptide or recombinant protein, which corresponded to different B19 epitopes, as coating antigens. ResultsB19 IgM and IgG were seen in 10 out of 20 (50%) Italian and in 20 out of 51 (39.2%) Rumanian children with AIDS, in contrast to none out of 17 Italian and one out of 22 Rumanian controls (P < 0.001). In addition, two Italian controls (11.8%), two Rumanian children with AIDS (3.9%), and two Rumanian controls (9.1%) had B19 IgM alone. Specific IgG alone was detected in eight (40%) Italian and 14 (27.5%) Rumanian children with AIDS, and in seven (41.2%) Italian and four (10.2%) Rumanian controls. ConclusionsWhile it is possible to attribute some B19 infections in Rumanian children to blood transfusion, the source was unknown for Italian children. However, in three of the Italian children who had B19 IgM and IgC persistently for 15–22 months, and in a 2-month-old Italian infant with B19 IgM and IgC, HIV might have activated a congenital or perinatally-acquired B19 infection.