The last 80 years in primary immunodeficiency: How far have we come, how far need we go?

Primary immunodeficiency diseases: relevant aspects for pulmonologists

Primary immunodeficiency diseases comprise a genetically heterogeneous group of disorders that affect distinct components of the innate and adaptive immune system, such as neutrophils, macrophages, dendritic cells, complement proteins and natural killer cells, as well as T and B lymphocytes. The study of these diseases has provided essential insights into the functioning of the immune system. Primary immunodeficiency diseases have been linked to over 120 different genes, abnormalities in which account for approximately 180 different forms of these diseases. Patients with primary immunodeficiency diseases are most often recognized because of their increased susceptibility to infections. However, these patients can also present with a variety of other manifestations, such as autoimmune diseases, inflammatory diseases and cancer. The purpose of this article is to update the main aspects of primary immunodeficiency diseases, especially regarding the clinical manifestations related to the diagnosis, emphasizing the need for the early recognition of warning signs for these diseases.

Children with frequent infections: a proposal for a stepwise assessment and investigation of the immune system

Although many children develop frequent infections, only a few have an underlying immune disorder. Children with dysfunction of the immune system develop frequent infections and/or recurrent, persistent, severe, and rare infections. The aim of this review is to provide to the clinician a valuable tool for recognizing any 'discords' of the 'immune-system symphonic orchestra'. By following a reverse route, it will be possible to brighten up the dark and winding road of immunodeficiencies and identify the exact point of immune dysfunction. This is fundamental and crucial to perceive etiologic management and subsequently achieve the best for these young patients and their families.

CD20 deficiency in humans results in impaired T cell-independent antibody responses

CD20 was the first B cell differentiation antigen identified, and CD20-specific mAbs are commonly used for the treatment of B cell malignancies and autoantibody-mediated autoimmune diseases. Despite this the role of CD20 in human B cell physiology has remained elusive. We describe here a juvenile patient with CD20 deficiency due to a homozygous mutation in a splice junction of the CD20 gene (also known as MS4A1) that results in "cryptic" splicing and nonfunctional mRNA species. Analysis of this patient has led us to conclude that CD20 has a central role in the generation of T cell-independent (TI) antibody responses. Key evidence to support this conclusion was provided by the observation that although antigen-independent B cells developed normally in the absence of CD20 expression, antibody formation, particularly after vaccination with TI antigens, was strongly impaired in the patient. Consistent with this, TI antipolysaccharide B cell responses were severely impeded in CD20-deficient mice. Our study therefore identifies what we believe to be a novel type of humoral immunodeficiency caused by CD20 deficiency and characterized by normal development of antigen-independent B cells, along with a reduced capacity to mount proper antibody responses.

Novel primary immunodeficiencies revealed by the investigation of paediatric infectious diseases

Human primary immunodeficiencies impairing myeloid and/or lymphoid cellular responses to activating receptors other than antigen receptors have recently been described in children with various infectious diseases. Germline mutations in NEMO and IKBA impair NF-kappaB-mediated signalling, at least in response to the stimulation of TLRs, IL-1Rs and TNFRs, and confer a broad predisposition to infections. Mutations in IRAK4 selectively impair TLRs other than TLR3 and most IL-1R responses, and confer a predisposition to pyogenic bacterial diseases, including invasive pneumococcal disease in particular. Mutations in TLR3 and UNC93B1 impair TLR3 responses and confer a predisposition to herpes simplex encephalitis. Mutations in STAT1 impair IFN-gamma and/or IFN-alpha/beta responses and predispose subjects to mycobacterial and viral diseases, respectively. Mutations in IFNGR1 and IFNGR2 impair IFN-gamma responses and confer a predisposition to mycobacterial diseases. Mutations in IL12B and IL12RB1 impair IL-12 and IL-23 responses and predispose subjects to infections caused by mycobacteria and Salmonella. Finally, mutations in TYK2 and STAT3 mostly impair IL-6R responses, conferring a predisposition to staphylococcal disease in particular. The infectious phenotypes associated with these novel leukocyte activation deficiencies are therefore collectively diverse, tightly dependent on the morbid gene and affected pathway, and individually narrow, often restricted to one or a few infectious diseases.

Spectrum of primary immune deficiency at a tertiary care hospital

OBJECTIVE

To report various primary immune deficiencies diagnosed in children at a tertiary care hospital, their clinical manifestations and laboratory profile.

METHODS

Case records of children diagnosed to have primary immunodeficiency disorders over a period of 24 months at a tertiary care hospital in northern India were evaluated.

RESULTS

Twenty-seven children (M: F=3.5: 1) with mean age of 5.4 +/- 4.6 yrs (2 mo-16 yr) were diagnosed to have primary immunodeficiency. Thirteen children had chronic granulomatous disease (CGD), 4 had severe combined immunodeficiency (SCID), 4 had hypogammaglobulinemia, 2 had Ataxia telangiectasia, and one each had DiGeorge syndrome, Wiskott Aldrich syndrome, hyper IgM syndrome and leukocyte adhesion defect. Common mode of presentation were recurrent/ persistent pneumonia in 19, recurrent/ persistent diarrhea in 10, deep seated abscesses in 8, allergy in 3, disseminated tuberculosis infection in 2, extensive fungal infections in 2 and 1 each of disseminated cytomegalovirus (CMV) infection, disseminated BCG disease, otitis media and meningitis. Family history of sibling deaths was elicited in 2 families. Infectious agents were isolated in 16 cases.

CONCLUSION

From a single center 27 patients with primary immune deficiency could be identified by chart review, suggesting need for high index of suspicion for diagnosis of primary immune deficiency in India. Though the exact prevalence is not known there is need to make a registry to document the magnitude of problem of these disorders.

Role of flow cytometry in the diagnosis and monitoring of primary immunodeficiency disease

This presentation is organized according to the recent classification of primary immunodeficiencies published by the International Union of Immunological Societies Primary Immunodeficiency meeting. The diseases have been classified into eight groups. After each list, individual diseases that are amenable to assessment by flow cytometry are reviewed with a brief clinical description and a discussion of the appropriate flow cytometry application.

The ESID Online Database network

Primary immunodeficiencies (PIDs) belong to the group of rare diseases. The European Society for Immunodeficiencies (ESID), is establishing an innovative European patient and research database network for continuous long-term documentation of patients, in order to improve the diagnosis, classification, prognosis and therapy of PIDs. The ESID Online Database is a web-based system aimed at data storage, data entry, reporting and the import of pre-existing data sources in an enterprise business-to-business integration (B2B). The online database is based on Java 2 Enterprise System (J2EE) with high-standard security features, which comply with data protection laws and the demands of a modern research platform.

AVAILABILITY

The ESID Online Database is accessible via the official website (http://www.esid.org/).

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.