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Mutations of the IL2RG gene, which encodes for the interleukin-2 receptor common gamma chain (γ C , CD132), can lead to X-linked severe combined immunodeficiency (X-SCID) associated with a T - B + NK - phenotype as a result of dysfunctional γ C -JAK3-STAT5 signaling. Lately, hypomorphic mutations of the IL2RG gene have been described causing atypical SCID with a milder phenotype. Here, we report three brothers with low-normal lymphocyte counts and susceptibility to recurrent respiratory infections and cutaneous warts. The clinical presentation combined with dysgammaglobulinemia suspected an inherited immunity disorder, which has been proven by Next Generation Sequencing as a novel c.458T > C; p.Ile153Thr IL2RG missense-mutation. Subsequent functional characterization revealed impaired T-cell proliferation, low TREC levels and a skewed TCR Vβ repertoire in all three patients. Interestingly, investigation of various subpopulations showed normal expression of CD132 but with partially impaired STAT5 phosphorylation compared to healthy controls. Additionally, we performed precise genetic analysis of subpopulations revealing spontaneous somatic reversion, predominately in lymphoid derived CD3 + , CD4 + and CD8 + T cells. Our data demonstrate that the atypical SCID phenotype noticed in these three brothers is due to the combination of hypomorphic IL-2RG function and somatic reversion.

A new human neuroblastoma cell line (LS) that originated from an abdominal tumor of a 16-month-old girl is presented; it was classified, according to Evans, as being stage III. Morphological (dense-core particles) and biochemical characteristics (dopamine-beta-hydroxylase, acetylcholinesterase, neuron-specific-enolase) confirmed the diagnosis. In addition to a slightly variable modal chromosome number of 48 or 49 (because of marker-chromosomes and autosomal trisomies), cytogenetic analysis revealed two constantly appearing chromosomes with homogeneously stained regions (HSR's). The karyotype remained constant over 50 passages in vitro [49,XX, -12, +der5, + 17, + mar1, + mar2]. Double minutes were a rare phenomenon and appeared only in a few metaphases. In situ hybridization showed that some of the HSR's consisted of amplified N-myc copies. The distribution of the N-myc copies according to in situ hybridization signals along the HSR's was compared with the data of Southern and Northern blotting analyses.

Antiproliferative effects of interferon alpha, beta and gamma were investigated on several human neuroblastoma cell lines using the soft agar colony forming assay and the MTT-test. Investigations were carried out in order to prove whether there is any relationship between antiproliferative effects, inhibition of N-myc expression and the 2-5A system. Growth of neuroblastoma cells was inhibited by all three kinds of interferons in a concentration-dependent manner, however, rather high concentrations were necessary in some cell lines. Expression of N-myc oncogen was not inhibited by interferon-beta and no relationship between antiproliferative effects and the 2-5A system was observed. A vector containing a small N-myc fragment in antisense direction was constructed and transferred into the interferon insensitive human neuroblastoma cell line LS. After transformation, LS cells became sensitive to interferon beta: Proliferation as well as N-myc expression were inhibited and these processes are most probably associated with activation of the 2-5A system.

The determination of 2'-5'-oligoadenylate synthetase in peripheral blood mononuclear cells is used as a biological response parameter during therapy with interferon and in the diagnosis of diseases related to the interferon system. In this communication, some general aspects concerning the preparation of 2'-5'-oligoadenylate synthetase from peripheral blood mononuclear cells and the incubation conditions of the 2'-5'-oligoadenylate synthetase reaction are reported. Four analytical procedures for the determination of the products formed during the 2'-5'-oligoadenylate synthetase reaction were comparatively investigated and the advantages and limitations of the assays are discussed. As an example of possible clinical application, the levels of 2'-5'-oligoadenylate synthetase were determined in the mononuclear cell fraction of peripheral blood from healthy persons as well as from children with chronic myelogenous leukaemia.