E. de Vries

Patient-centred screening for primary immunodeficiency, a multi-stage diagnostic protocol designed for non-immunologists: 2011 update

Efficient early identification of primary immunodeficiency disease (PID) is important for prognosis, but is not an easy task for non‐immunologists. The Clinical Working Party of the European Society for Immunodeficiencies (ESID) has composed a multi‐stage diagnostic protocol that is based on expert opinion, in order to increase the awareness of PID among doctors working in different fields. The protocol starts from the clinical presentation of the patient; immunological skills are not needed for its use. The multi‐stage design allows cost‐effective screening for PID within the large pool of potential cases in all hospitals in the early phases, while more expensive tests are reserved for definitive classification in collaboration with an immunologist at a later stage. Although many PIDs present in childhood, others may present at any age. The protocols presented here are therefore aimed at both adult physicians and paediatricians. While designed for use throughout Europe, there will be national differences which may make modification of this generic algorithm necessary.

Intrinsic defect of the immune system in children with Down syndrome: a review

Down syndrome (DS) is the most frequent cause of mental retardation in man. Immunological changes in DS have been observed since the 1970s. The neurological system appears to be ageing precociously, with early occurrence of Alzheimer disease; until now, the observed immunological differences have been interpreted in the same context. Looking back at past and present results of immunological studies in DS children in relation to the clinical consequences they suffer, we conclude that it is more likely that the DS immune system is intrinsically deficient from the very beginning.

B-cell replication history and somatic hypermutation status identify distinct pathophysiologic backgrounds in common variable immunodeficiency.

Common variable immunodeficiency disorder (CVID) is the most prevalent form of primary idiopathic hypogammaglobulinemia. Identification of genetic defects in CVID is hampered by clinical and immunologic heterogeneity. By flow cytometric immunophenotyping and cell sorting of peripheral B-cell subsets of 37 CVID patients, we studied the B-cell compartment at the B-cell subset level using the κ-deleting recombination excision circle assay to determine the replication history and the Igκ-restriction enzyme hot-spot mutation assay to assess the somatic hypermutation status. Using this approach, 5 B-cell patterns were identified, which delineated groups with unique replication and somatic hypermutation characteristics. Each B-cell pattern reflected an immunologically homogenous patient group for which we proposed a different pathophysiology: (1) a B-cell production defect (n = 8, 18%), (2) an early peripheral B-cell maturation or survival defect (n = 4, 11%), (3) a B-cell activation and proliferation defect (n = 12, 32%), (4) a germinal center defect (n = 7, 19%), and (5) a postgerminal center defect (n = 6, 16%). The results of the present study provide for the first time insight into the underlying pathophysiologic background in 5 immunologically homogenous groups of CVID patients. Moreover, this study forms the basis for larger cohort studies with the defined homogenous patient groups and will facilitate the identification of underlying genetic defects in CVID.

Development of Lymphocyte Subpopulations in Preterm Infants

In preterm neonates the immune system is thought to be less developed at birth, but very little is known about the actual size of lymphocyte subpopulations, and even less about the maturation of these subpopulations during the first months after a premature birth. To evaluate the development of lymphocyte subpopulations in preterm infants during the first 3 months after birth, we performed a prospective longitudinal study in two hospitals in the Netherlands. Preterm neonates (nu2003=u200338) of all post‐menstrual ages were included and blood samples were taken from cord blood, and at 1 week, 6 weeks, and 3 months. Lymphocyte subpopulations were measured by four‐colour flow cytometry. The data were compared with follow‐up data obtained in healthy term neonates (nu2003=u20038), and with single samples from school age children (nu2003=u20035) and adults (nu2003=u20035). Overall, we found a similar pattern of post‐natal development of lymphocyte subpopulations in the term and preterm infants. Both B lymphocytes and helper and cytotoxic T lymphocytes mainly consist of naive cells at birth and during the 3 months of follow‐up in all neonatal age groups. So, the preterm immune system seems to be able to generate an outburst of naive T and B lymphocytes from the thymus and bone marrow within the same time span after the start of post‐natal antigenic stimulation from the environment as the term immune system, but, with lower post‐menstrual age, the absolute counts of naive helper T lymphocytes are lower.

Common variable immunodeficiency (CVID) in a family: an autosomal dominant mode of inheritance

BACKGROUNDnCommon variable immunodeficiency (CVID) is characterised by a late onset deficiency of immunoglobulins resulting in recurrent infectious and non-infectious ailments. Most cases are sporadic but occasional familial clustering has been described. We present an extensively affected family with CVID in three consecutive generations.nnnMETHODSnWe conducted a study in this family to establish clinical phenotype, to clarify the mode of inheritance and to attempt to characterise the immune disturbance by determining immunoglobulin concentrations and B- and T-cell analysis.nnnRESULTSnWe describe six patients with CVID in three consecutive generations. In addition, we encountered 10 family members with dysimmunoglobulinemia. B-cell counts were normal, but T-cell analysis showed slightly abnormal results.nnnCONCLUSIONSnThe six cases of overt late onset hypogammaglobulinemia are compatible with an autosomal dominant mode of inheritance. The family members with dysimmunoglobulinemia may be at risk to develop overt CVID in the future, in view of the gradual course of progression of the disease in the clinically affected family members. B- and T-cell analysis are inconclusive though may support a possible defect in T-cell function to be involved. To further study this remarkable family and attempt to clarify pathogenesis, we are planning DNA linkage analysis in the near future.

Primary immunodeficiencies in the Netherlands : National patient data demonstrate the increased risk of malignancy

PURPOSEnTo analyze the data of the national registry of all Dutch primary immune deficiency (PID) patients, according to the European Society for Immunodeficiencies (ESID) definitions.nnnRESULTSnIn the Netherlands, 745 patients had been registered between 2009 and 2012. An overall prevalence of 4.0 per 100,000 inhabitants was calculated. The most prevalent PID was predominantly antibody disorder (PAD) (60.4%). In total, 118 transplantations were reported, mostly hematopoietic stem cell transplantations (HSCT). Almost 10% of the PID patients suffered from a malignancy, in particular lymphoma and skin cancer. Compared to the general Dutch population, the relative risk of developing any malignancy was 2.3-fold increased, with a >10-fold increase for some solid tumors (thymus, endocrine organs) and hematological disease (lymphoma, leukemia), varying per disease category.nnnCONCLUSIONSnThe incidence rate and characteristics of PID in the Netherlands are similar to those in other European countries. Compared to the general population, PID patients carry an increased risk to develop a malignancy.

HEMOLYTIC UREMIC SYNDROME IN A PATIENT ON CIS-PLATINUM, VINBLASTINE AND BLEOMYCIN

SummaryA 23-year-old woman with metastatic Sertoli-Leydig cell tumor was treated with cisplatin, vinblastine, and bleomycin. Hemolytic uremic syndrome appeared, while no evidence of residual tumor was found. Infusion of fresh frozen plasma together with aspirin and dipyridamole resulted in recovery of microangiopathic hemolytic anemia and thrombocytopenia. Renal insufficiency, however, persisted.

Augmentation of antigen‐specific lymphoproliferative responses in vitro by biological response modifiers

The detection of antigen‐specific T cell responsiveness, particularly of resting memory lymphocytes, in cultures of peripheral blood mononuclear cells (PBMC) may be hampered by a less than optimal antigen presentation in vitro. Augmented sensitivity of the test system may be achieved by the addition of reagents with a beneficial effect on lymphocyte and antigen‐presenting cell (APC) functions. In this study the effect of several biological response modifiers on antigen‐specific T cell proliferation was determined, using nickel sulphate and tetanus toxoid as lest antigens. IL‐lα (100 U/ml). interferon‐gamma (IFN‐γ) (10 U/ml), and indomethacin (2 μM) were found to significantly enhance nickel‐induced proliferation in PBMC cultures from nickel‐hypersensitive donors (n = 6). Tetanus‐induced proliferation (n = 5) was similarly enhanced, both by the above supplements and by the addition of polyethylene glycol (PEG) or a neuraminidase treatment of the PBMC before culture. The addition to PBMC cultures of a combination of IL‐lα (30 U/ml), IFN‐γ (10 U/ml), and indomethacin (2 μM) is recommended to specifically enhance antigen‐induced lymphoproliferative signals.

Characterization and classification of lymphoid cells after pokeweed mitogen stimulation

SummaryHuman peripheral blood mononuclear cells (PBMC) were stimulated with pokeweed mitogen (PWM) for 3 days and subsequently cultured in medium for another 3 days. It was shown that mononuclear phagocytes (MNP), although present initially in the PBMC cultures, disappeared shortly after the addition of PWM. It was concluded that MNP, although obligatory for stimulation, were no longer required for further transformation of cells after stimulation.At the ultrastructural level stimulation of PBMC with PWM resulted in the generation of 2 types of blast cells. The first type were characterized by the presence of polyribosomes throughout the cytoplasm, large and swollen mitochondria and a few short strands of rough endoplasmic reticulum. The second type of blast cell showed a dispersed pattern of ribosomes, a number of smaller mitochondria and some long strands of rough endoplasmic reticulum. In parallel with a decrease in the number of type I blast cells, plasma cells were found in the stimulated cell cultures. Labeling for surface-membrane immunoglobulins was positive only in type I blast cells and after a longer period in plasma cells. These observations suggest the transformation of type I blast cells into plasma cells, both being derived from the B-cell line. Type II blast cells probably represent transformed cells of the T-cell line.

Levels of somatic hypermutations in B cell receptors increase during childhood

Somatic hypermutation (SHM) is an important step in antigen‐driven B cell development creating B lymphocytes expressing high‐affinity antibody receptors. It is known that the peripheral B lymphocyte compartments of healthy children and adults differ considerably. However, the development of SHM with age has not been studied in detail previously. Therefore, we used the immunoglobulin (Ig)κ‐restriction enzyme hot‐spot mutation assay (Igκ‐REHMA) to gain an estimation of SHM levels in different age groups in order to relate this to the size of the memory B lymphocyte subpopulations. We show that the level of SHM increases rapidly during the first 2 years of life. This reflects the changes of the memory B cell subpopulations, but also changes in the SHM within memory B cell subsets, probably reflecting an increase of secondary memory B cell responses.