Dianzani autoimmune lymphoproliferative disease (DALD)

2006-07-01   Umberto Dianzani , Ugo Ramenghi , Annalisa Chiocchetti 

Interdisciplinary Research Center of Autoimmune Diseases (IRCAD) and Department of Medical Sciences, A. Avogadro University of Eastern Piedmont, via Solaroli 17, I-28100 Novara, Italy

Identity

Name

Dianzani autoimmune lymphoproliferative disease (DALD)

Note

Variant of the Autoimmune Lymphoproliferative Syndrome (ALPS)

Inheritance

Possibly, an oligogenic disease.

Omim

605233

Mesh

C535950

Orphanet

275523 Dianzani autoimmune lymphoproliferative disease

Umls

C2931071

Clinics

Phenotype and clinics

Paediatric onset with:
1) Autoimmunity, that is predominantly haematological, but any other autoimmunity can be displayed;
2) Enlargement of the spleen and\/or lymph nodes due to accumulation of polyclonal lymphocytes;
3) Decreased function of the Fas death receptor. These patients lack the peripheral blood expansion of T cells expressing the TCR alpha\/TCR beta but not CD4and CD8 (double-negative T cells), that are present in the typical form of ALPS.

Neoplastic risk

2.5 fold increased risk of cancer (both haematological and not haematological).

Treatment

Immune suppression.

Evolution

Autoimmunity may remit in adulthood but lymphoproliferation generally persists. Increased risk of lymphomas and other cancers in adulthood.

Prognosis

Good on survival, but the autoimmune haemolitic anemia may be occasionally lethal.

Genes involved and Proteins

Note

The disease is due to inherited defects decreasing function of the Fas (CD95) death receptor, involved in switching off the immune response by triggering apoptosis of activated lymphocytes. The mutation possibly hits unknown genes involved in Fas signalling. The Fas, Fas ligand, caspase-10, caspase-8 genes, that can be involved in ALPS are not mutated.
The genetic background may influence the disease onset. Variants of the gene of osteopontin or perforin (see above) can act as predisposition factors.

Alias

Osteopontin, early T lymphocyte activation (ETA-1), secreted phosphoprotein 1 (SPP1),bone sialoprotein, urinary stone protein.

Description

Encoded in 7 exons spanning 5.4-8.2 Kb.

Expression

Constitutively expressed by bone and several epithelial tissues, whereas in endothelial cells, macrophages and smooth muscle cells, it is mainly expressed upon activation in inflammatory contexts. Moreover, it is expressed by activated T-cells.

Localisation

Secreted cytokine.

Function

Functions as a free cytokine in body fluids or an immobilized extra-cellular matrix molecule in mineralized tissues. Plays a role in cell-to-cell and cell-to-extracellular matrix interaction by binding to several integrins and the CD44v6-7 isoforms, triggering signals involved in cell activation and migration. Involved in bone remodeling, tissue repair, and cell migration. It potentiates T-cell proliferation, IFN-gamma production, and CD40L expression, which in turn favor B-cell proliferation and antibody production.

Germinal

Polymorphic variants of the gene have been associated with increased susceptibility to develop DALD. Four polymorphisms, corresponding to position +282T\/C (exon VI), +750C\/T (exon VII, coding region), +1083A\/G and +1239A\/C (3 UTR) (ATG = +1), form 3 haplotypic combinations:
Haplotype-A (282T-750C-1083A-1239A),
Haplotype-B (282C-750T-1083A-1239C),
Haplotype-C (282C-750T-1083G-1239C).
Subjects carrying haplotype-B and\/or -C have a 8-fold higher risk of developing DALD than haplotype-A homozygotes. Haplotype-B and -C causes production of increased levels of osteopontin, possibly because of higher stability of its mRNA.

Alias

Perforin, PFN1, pore forming protein, PFP, HPLH2, FLH2.

Note

Biallelic mutations of PRF1 cause the familial hemophagocytic lymphohistiocytosis (HLH), an immune deficiency ascribed to decreased capacity of cytotoxic lymphocytes (CD8+ T cells and NK cells) to kill virus-infected cells.

Description

Encoded in 3 exons spanning 5.4 Kb.

Expression

Expressed by cytotoxic effector lymphocytes (activated cytototoxic T cells and NK cells).

Localisation

It is stored in the lytic granules and secreted against the target cell.

Function

It polymerizes on the membrane of target cells and forms pores.

Homology

High sequenze homology to the C9 complement component.

Germinal

Several PRF1 mutations have been associated with HLH and lymphomas. These mutations can inhibit either expression or function of perforin.
The A91V amino acid substitution decreases perforin function by altering its conformation, decreasing its cleavage to the active form, and increasing its degradation. Carriers of this variation show decreased NK activity. A91V is relatively frequent in control population (4.6%), but it has been associated with HLH, when combined with a second PRF1 variation. By contrast, it may favor DALD development when inherited defects hitting Fas function are also present. Its presence, in fact, increases the risk of DALD by 3 fold.

Bibliography

Pubmed IDLast YearTitleAuthors
165371202006The broad spectrum of autoimmune lymphoproliferative disease: molecular bases, clinical features and long-term follow-up in 31 patients.Campagnoli MF et al
145928382004High levels of osteopontin associated with polymorphisms in its gene are a risk factor for development of autoimmunity/lymphoproliferation.Chiocchetti A et al
167208362006Variations of the perforin gene in patients with autoimmunity/lymphoproliferation and defective Fas function.Clementi R et al
91084071997Deficiency of the Fas apoptosis pathway without Fas gene mutations in pediatric patients with autoimmunity/lymphoproliferation.Dianzani U et al
108077852000Deficiency of the Fas apoptosis pathway without Fas gene mutations is a familial trait predisposing to development of autoimmune diseases and cancer.Ramenghi U et al
105839591999Perforin gene defects in familial hemophagocytic lymphohistiocytosis.Stepp SE et al

External Links