Biomedical subjects

Daniele Moratto

Publications and source records attributed to Daniele Moratto.

5 recordsLinked to original sources

PubMed2006

Combined decrease of defined B and T cell subsets in a group of common variable immunodeficiency patients.

Common variable immunodeficiency disease (CVID) is a primary immune disorder affecting B cells and characterized by hypogammaglobulinemia and recurrent infections. To elucidate the clinical and immunological heterogeneity of this condition, we have studied B and T cell subsets in 25 CVID patients. In eleven of them, we observed a remarkable relative expansion of a B cell subpopulation (CD19(hi)/CD21(lo) cells) characterized by the absence of CD23 and the reduced expression of the chemokine receptors CXCR5 and CCR7. Our analyses demonstrated in these patients that the expansion of CD19(hi)/CD21(lo) cells correlates with a selective decrease of circulating naïve and CD21(hi) memory B lymphocytes. The same group of patients displayed a simultaneous severe reduction of naïve CD4+ T cells associated with decreased levels of T cell receptor excision circles. These observations suggest that a combined defect in generation of B and T subpopulations may account for the abnormal immunophenotype characterizing this subgroup of CVID patients.

Adolescent↗

PubMed2004

Altered leukocyte response to CXCL12 in patients with warts hypogammaglobulinemia, infections, myelokathexis (WHIM) syndrome.

The chemokine receptor CXCR4 and its functional ligand, CXCL12, are essential regulators of development and homeostasis of hematopoietic and lymphoid organs. Heterozygous truncating mutations in the CXCR4 intracellular tail cause a rare genetic disease known as WHIM syndrome (warts, hypogammaglobulinemia, infections, myelokathexis), whose pathophysiology remains unclear. We report CXCR4 function in 3 patients with WHIM syndrome carrying heterozygous truncating mutations of CXCR4. We show that CXCR4 gene mutations in WHIM patients do not affect cell surface expression of the chemokine receptor and its internalization upon stimulation with CXCL12. Moreover, no significant differences in calcium mobilization in response to CXCL12 are found. However, the chemotactic response of both polymorphonuclear cells and T lymphocytes in response to CXCL12 is increased. Furthermore, immunophenotypic analysis of circulating T and B lymphocytes reveals a decreased number of memory B cells and of naive T cells and an accumulation of effector memory T cells associated with a restricted T-cell repertoire. Based on our results, we suggest that the altered leukocyte response to CXCL12 may account for the pathologic retention of mature polymorphonuclear cells in the bone marrow (myelokathexis) and for an altered lymphocyte trafficking, which may cause the immunophenotyping abnormalities observed in WHIM patients.

Adolescent↗

PubMed2003

Functional defects of dendritic cells in patients with CD40 deficiency.

We have recently identified 2 patients with a rare autosomal recessive form of hyper IgM disease, known as HIGM3, caused by mutations in the CD40 gene. These patients had opportunistic infections observed on X-linked hyper IgM syndrome (HIGM), suggesting that the CD40-CD40 ligand interaction is important for promoting T-cell-mediated immunity. To evaluate whether innate immunity signals may substitute CD154 for inducing the maturation of dendritic cells (DCs), we analyzed monocyte-derived DCs in these patients. Monocyte-derived DCs of HIGM3 subjects on ex vivo stimulation with tumor necrosis factor-alpha (TNF-alpha) or lipopolysaccharide (LPS) combined with interferon-gamma (IFN-gamma) normally express all the markers of mature DCs, such as CD83 and DC-LAMP. However, cell surface levels of HLA-DR in mature DCs are reduced, as is costimulatory activity of these cells for allogeneic naive T cells. In addition, CD40-deficient DCs secrete lower amounts of interleukin-12 (IL-12) but larger quantities of IL-10 than control subjects. Finally, analysis of circulating plasmacytoid DCs demonstrates a normal percentage of this subset in CD40-deficient cells, but IFN-alpha secretion in response to herpes simplex virus 1 (HSV-1) infection is severely reduced in patients. These observations suggest that the severe impairment of DC maturation may contribute to the defect of T-cell-mediated immunity observed in HIGM3 patients.

CD40 Antigens↗

PubMed2003

Disseminated cryptosporidium infection in an infant with hyper-IgM syndrome caused by CD40 deficiency.

We report the case of an infant with severe respiratory infections, chronic diarrhea, failure to thrive, and disseminated Cryptosporidium parvum infection. Laboratory investigations disclosed a diagnosis of hyper-IgM syndrome caused by CD40 deficiency.

CD40 Antigens↗

PubMed2002

Defective migration of monocyte-derived dendritic cells in LAD-1 immunodeficiency.

beta2 Integrins (CD18) are required for leukocyte migration. In fact, the absence of CD18 results in type-1 leukocyte adhesion deficiency (LAD-1). We analyzed the distribution phenotype and function of dendritic cells (DCs) in three LAD-1 patients with homozygous mutations of CD18. Two of them did not express CD18 (Patients A and C), and the other subject (Patient B) displayed reduced expression of beta2 integrins because of a missense mutation. Analysis of DCs derived from Patients A and B showed an abnormal morphology and a severe impairment in transendothelial migration and chemotactic response to CCL19/macrophage inflammatory protein-3beta, suggesting that CD18 is required for migration of monocyte-derived DCs. Nevertheless, DCs displayed normal macropinocytosis and underwent normal maturation after addition of tumor necrosis factor alpha. Finally, immunohistochemical analysis of lymph nodes from subjects B and C revealed a significant reduction in the number of factor-XIIIa(+) interstitial DCs in the interfollicular area in both patients, suggesting that CD18 plays a role in the migration of these cells in vivo.

CD18 Antigens↗