Ivano Mezzaroma

Long-term evaluation of T-cell subsets and T-cell function after HAART in advanced stage HIV-1 disease.

OBJECTIVES Evaluation of immunological reconstitution after 2 years of highly active antiretroviral therapy (HAART) in AIDS patients. DESIGN Previous data showed the effectiveness of HAART but conflicting evidence of immune reconstitution has been found in severely immunocompromised patients. Therefore, T-cell subsets and functions were analysed during 24 months of HAART in 21 AIDS patients (mean baseline CD4 cell count, 20 x 10(6)/l). METHODS Subjects were tested at baseline and after 4, 12 and 24 months of therapy for clinical symptoms and the following investigations were carried out: plasma HIV RNA, T-cell subsets and lymphoproliferative responses to mitogens (phytohaemagglutinin, anti-CD3), and recall antigens (Candida mannoprotein, tetanus toxoid and recombinant glycoprotein 160). RESULTS Increase in body weight, improvement of Karnofskys score and reduction of opportunistic infections were observed. All patients showed an initial increase in the CD4 memory subset, whereas naive CD4 cells consistently increased only after 1 year. The magnitude of immune recovery was stronger in patients showing a significant reduction in viral load. However seven out of 21 patients who did not reach a sustained suppression of viral load showed also an increase in T-cell subsets. The majority of patients recovered lymphoproliferative responses to mitogens, whereas only four subjects showed a functional response to Candida mannoprotein. No patients showed a response to HIV recombinant glycoprotein 160 or tetanus toxoid. CONCLUSIONS The immune recovery observed is slower and not complete in severely immunocompromised patients. Our data suggest that HAART may be continued also in the absence of a significant HIV RNA decrease if alternative drugs are not available.

Human Infection with Cryptosporidium felis: Case Report and Literature Review

An infection with Cryptosporidium felis in an HIV-positive man from Italy was successfully treated with paromomycin, despite the patient’s having a CD4+ cell count of 31/mL. Fourteen cases of human infection with C. felis have been described, all in the past 3 years, emphasizing the public health importance of Cryptosporidium parasites other than C. parvum.

Psychosocial factors and clinical evolution in HIV-1 infection : a longitudinal study

The aim of the study was to assess the relationship between the initial psychosocial situation and the probability of later symptom development in HIV-1 infection. One hundred HIV-1 seropositive subjects, 79 in Stage III (LAS) and 21 in Stage II (asymptomatic), were examined both immunologically (CD4+, Skin Test) and psychologically (test battery). Follow-up at 6 and 12 months involved clinical and immunological reassessment of subjects, who were then classified as fully symptomatic (S, Stage IV) or unchanged (U). The two groups were compared through ANOVA on initial psychosocial measures, while stepwise logistic multiple regression was employed to assess the predictive value of psychosocial measures on clinical and immunological evolution. Psychosocial measures most clearly showing an association with clinical evolution were Denial/Repression attitudes (negatively) and Fighting Spirit (positively), whereas aspects of Hardiness and Social Support showed an effect in interaction with initial CD4+ levels. No stable results were obtained on immunologic evolution. The two groups (U and S) did not show significant differences on other independent variables, with the exception of age.

T-cell homeostasis alteration in HIV-1 infected subjects with low CD4 T-cell count despite undetectable virus load during HAART.

Objective:To investigate the pathogenesis of low CD4 T-cell count in subjects who are immunological non responders (InR) to HAART. Design:Thirty-five HIV-positive subjects on HAART for at least 1 year, all with undetectable HIV-1 RNA, were studied. Patients were defined as InR according to a CD4 cell increase < 20% from CD4 cell baseline or CD4 cell count < 200/μl; subjects with a CD4 T-cell increase > 20% from baseline and a CD4 cell count > 200/μl were defined as immunological responders (IR). We performed a comprehensive study to characterize the immune response of InR. Methods:The immunological phenotype of peripheral blood mononuclear cells, thymic naive T cells, T-cell receptor Vβ repertoire, serum concentration of interleukin (IL)-7, the expression of IL-7Rα on naive and memory CD4 and CD8 T cells, and regulatory T cells (Treg) were studied. Results:In InR a significant reduction (P < 0.0001) of naive and thymic naive CD4 T cells was associated with a reduced expression of IL-7Rα in both cell subsets, with an increased serum concentration of IL-7 was observed. Furthermore, an increased immune activation with a reduced Treg frequency and increased number of expansions of Vβ families was observed. Conclusions:The reduced expression of IL-7Rα associated with the persistent immune activation and the alteration of Treg frequencies in part explains the low level of CD4 T cells observed in InR.

Clinical and Immunologic Response without Decrease in Virus Load in Patients with AIDS after 24 Months of Highly Active Antiretroviral Therapy

This study reports an analysis of clinical, virological, and immunologic outcomes in a cohort of 77 multidrug-experienced AIDS patients during 24 months of highly active antiretroviral therapy (HAART). Our results have shown a reduced risk of AIDS complications, prolonged survival, and immunologic benefit even in the absence of sustained virus suppression. The degree of immunodepression, the risk factors for HIV-1 infection, the use of 2 drugs instead of 3, and a change in protease inhibitor were independently correlated with virological failure. In the majority of studied patients, an increase in CD4+ T cells was observed after HAART. However, the increase was more pronounced in patients who showed a decrease in virus load than in those who did not. Moreover, we observed an absence of relapses among patients who permanently discontinued prophylaxis for Cytomegalovirus retinitis and atypical mycobacterial infections. Peripheral lipodystrophy developed in the majority of patients, regardless of treatment used and virological outcome.

Assessment of thymic output in common variable immunodeficiency patients by evaluation of T cell receptor excision circles

Common variable immunodeficiency (CVID) is a heterogeneous syndrome characterized by repeated infections and hypogammaglobulinaemia. Additionally, T‐cell abnormalities including lymphopenia, decreased proliferation to mitogens and antigens, and the reduced production and expression of cytokines, have also been observed. In this study we have investigated the expression of naive, memory and activation markers in T‐cell subpopulations in 17 CVID patients in comparison to age‐matched normal controls. The numbers of CD4+ T cells, including CD45RA+CD62L+ and, to a lesser extent, CD45RA–CD62L+/RA+CD62L– were significantly reduced in patients, whereas CD8+ T cells were within normal range. In contrast, HLA‐DR+ cells were increased both in CD4+ and CD8+ T cells. To assess the thymic output, we analysed the presence of T‐cell receptor excision circles (TRECs) in CD4+ and CD8+ T cells by quantitative PCR. TRECs were decreased significantly in patients and the rate of TREC loss was higher with increasing age. TRECs correlated with naive CD4+ T cells, whereas there was an inverse relationship between TRECs and CD8+HLA–DR+ and CD8+CD45RA–CD62L+/RA+CD62L– T cells. Our results suggest the presence of a defect in the naive T cell compartment with origin at the thymic level in CVID, and indicate that TREC may be a useful marker to monitor thymic function in this primary immunodeficiency.

Proliferative and cytotoxic responses to mannoproteins of Candida albicans by peripheral blood lymphocytes of HIV-infected subjects.

Mucosal candidiasis is one of the first opportunistic diseases in HIV‐infected subjects. In order to understand the relationship between this disease and immunodeficiency to chemically defined, immunodominant Candida antigens, a mannoprotein fraction from C. albicans cell wall (GMP) was used to analyse proliferative and non‐MHC‐restricted cytotoxic responses of peripheral blood mononuclear cells (PBMC) from normal and HIV‐infected subjects. In the former, GMP induced extensive blastogenesis, generation of powerful cytotoxicity against a tumour cell line (K562), and production of substantial amounts of interferon‐gamma (IFN‐γ). Cultured PBMC from HIV‐infected subjects manifested an early decreased ability for proliferative as well as differentia live cytotoxic responses to the candidal mannoproteins. This inability became clearly evident in subjects with stage III (CDC) of the disease, was total in CDC stage IV and occurred even in some subjects with a normal number of CD4+ cells. Low or absent response to GMP correlated with lack of response to tetanus toxoid. In contrast, both lymphoproliferative and cytotoxic responses to exogeneous IL‐2 was highly preserved at all stages of infection. The production of IFN‐γ in GMP‐stimulated PBMC cultures critically fell to negligible values in most of the subjects in CDC stages II and III. Thus, the lowered or absent cell‐mediated immune responses to candidal mannoprotein may be one factor to explain the early, elevated susceptibility of HIV‐infected subjects to mucosal candidiasis. This study also shows that our mannoprotein preparation may be used as a probe to detect the overall efficiency of T cell responses in the above subjects.

Immunologic aspects of hyperimmunoglobulinemia E–like syndrome in patients with AIDS

In this study we describe a series of nine patients affected by acquired immunodeficiency syndrome (AIDS) or AIDS-related complex who had hypereosinophilia and hyperimmunoglobulinemia E (hyper-IgE) with chronic dermatitis and recurrent staphylococcal infections. These patients had features similar to those present in hyper-IgE syndrome, a primary immunodeficiency disease. In addition, immunologic characterization of these patients with human immunodeficiency virus (HIV) infection, compared with 51 HIV-positive patients without hyper-IgE, both atopic and nonatopic, and three patients affected by the primary hyper-IgE syndrome, also revealed an increase in IgA and a severe decrease in B and CD4+ lymphocytes. Spontaneous in vitro synthesis of IgE by peripheral blood mononuclear cells was confirmed in both hyper-IgE conditions, together with increased levels of circulating eosinophil cationic protein. Serum-soluble CD23, usually increased in atopic conditions and hyper-IgE, was similar to that of normal control subjects in the HIV-positive patients with hyper-IgE. On the basis of our findings, we conclude that a hyper-IgE-like syndrome represents a distinct aspect of the clinical manifestations associated with HIV infection and that the immunologic mechanisms in this condition seem to differ from those known in primary hyper-IgE syndrome, because CD4+ TH2 type cells, which are currently believed to have a role in IgE production, are severely depleted in HIV-positive patients.

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.

Apoptosis-related mortality in vitro of mononuclear cells from patients with HIV infection correlates with disease severity and progression

Peripheral blood mononuclear cells (PBMC) from 103 HIV-infected patients were tested for their mortality rate (MR) when incubated in vitro for 3 days in a culture medium. MR was related to apoptosis as shown by DNA analysis and morphological evaluation of ethidium bromide-stained PBMC by flow cytometry. MR was significantly higher in patients in CDC stage IV as compared to patients in stage II or III (p = 0.017). MR was also higher in patients with low CD4 cells/mm3 (p = 0.014 for patients with < 400 cells; p = 0.001 for patients with < 200 CD4 cells/mm3) and with low percentage of CD4 cells (p = 0.001 for patients with < 10% of CD4 cells). A significant negative correlation was observed between MR and both absolute numbers or percentages of CD4 cells (p < 0.001). The addition of interleukin-2 (IL-2) and fibro-blast-conditioned medium (FCM) to the cultures significantly reduced MR. However, the ability of both IL-2 and FCM to preserve viability was significantly associated with p24 negativity. Clinical and immunological follow-up was available for 60 patients for a mean period of 26 months. MR at the beginning of the study was significantly higher in the group of patients who clinically progressed (according to the CDC classification) or died during the follow-up (p < 0.0001). Our data suggest that MR correlates with both disease severity and progression and that MR is directly related to the depletion of CD4 cells in cultures.(ABSTRACT TRUNCATED AT 250 WORDS)