[Infectious complications of immune deficiencies]

Infections constitute the most common and severe complication of immune deficiencies. The pattern of infections is strikingly dependent on the type of immune defect. Antibody deficiencies usually manifest with recurrent capsulated bacteria related-infections of the respiratory tract, due to pneumoccoci and Haemophilus influenza. The same bacteria are implicated in asplenic patients with frequent sepsis of devastating consequences. Complement deficiencies must be looked for in case of meningococcal infections. Neutropenia and defects in phagocytic cell functions favour bacteraemia and invasive fungal infections. Importantly, neutropenia can rapidly lead to septic shock. Cellular immune deficiencies are associated with opportunistic infections including viral infections due to Herpes viridae, fungal and parasitic infections (Pneumocystis jiroveci, Toxoplasma gondii) and mycobacterial infections. Most of the time, immune defects are combined, accounting for the variety and the complexity of clinical presentations and microbial investigations.

[How to diagnose a hereditary immunodeficiency?]

Efficient early identification of primary immunodeficiency is important for the patient prognosis and treatment. The first investigations need to be performed in case of severe, recurrent and/or unusual infections. Simple investigations like blood cell count, serum immunoglobulins level and postvaccination or post-infection serologies allow to direct the diagnosis. The medical history, the clinical examination and these laboratory investigations permit to realize more specific investigations according to the type of primary immunodeficiency suspected.

Drug-induced hypersensitivity syndrome due to cyanamide associated with multiple reactivation of human herpesviruses

Drug-induced hypersensitivity syndrome (DIHS), characterized by serious adverse systemic reactions in addition to skin rash, has unknown pathogenesis. Its association with human herpesvirus (HHV), mainly HHV-6, has been reported recently. A 46-year-old Japanese man is described in whom a generalized eruption developed about 1 month after taking cyanamide, a drug for alcoholism. This was associated with the following manifestations: high fever, lymphadenopathy, facial edema, marked leukocytosis with eosinophilia and atypical lymphocytes, lymphocytopenia, liver and renal dysfunction, and low IgG level. He was treated with 8 mg betamethasone daily and his condition improved, but he needed low-dose corticosteroid for almost 1 year because of several episodes of recurrence. HHV-6, HHV-7, herpes simplex virus (HSV), and cytomegalovirus (CMV) specific IgG titers showed more than a four-fold rise sequentially. Significant numbers of copies of HHV-6 and HHV-7 DNA were detected in the peripheral white blood cells by real-time polymerase chain reaction (PCR). HHV-6 and CMV DNA were detected in the serum by nested PCR. A patch test for cyanamide was positive. The diagnosis of DIHS due to cyanamide, which has never been reported as a causal drug of DIHS, accompanied by reactivation of not only HHV-6, but also HHV-7, CMV, and HSV, was made. Disturbance of the immune system was suggested by the persistent low level of IgG, and consecutive viral reactivation may have participated in the prolonged course in this case.

Patient-specific embryonic stem cells derived from human SCNT blastocysts

Patient-specific, immune-matched human embryonic stem cells (hESCs) are anticipated to be of great biomedical importance for studies of disease and development and to advance clinical deliberations regarding stem cell transplantation. Eleven hESC lines were established by somatic cell nuclear transfer (SCNT) of skin cells from patients with disease or injury into donated oocytes. These lines, nuclear transfer (NT)-hESCs, grown on human feeders from the same NT donor or from genetically unrelated individuals, were established at high rates, regardless of NT donor sex or age. NT-hESCs were pluripotent, chromosomally normal, and matched the NT patient's DNA. The major histocompatibility complex identity of each NT-hESC when compared to the patient's own showed immunological compatibility, which is important for eventual transplantation. With the generation of these NT-hESCs, evaluations of genetic and epigenetic stability can be made. Additional work remains to be done regarding the development of reliable directed differentiation and the elimination of remaining animal components. Before clinical use of these cells can occur, preclinical evidence is required to prove that transplantation of differentiated NT-hESCs can be safe, effective, and tolerated.

Enhanced function with decreased internalization of carboxy-terminus truncated CXCR4 responsible for WHIM syndrome

OBJECTIVE

WHIM (warts, hypogammaglobulinemia, recurrent bacterial infection, myelokathexis) syndrome is an autosomal dominant immune deficiency with severe chronic neutropenia and marrow neutrophil apoptosis. Carboxy-termini truncating mutations in the chemokine receptor CXCR4 have been identified in WHIM patients. We created a retrovirus encoding mutated CXCR4 (truncating point mutation 1000C-->T [R334X] inherited heterozygously in several WHIM patients) in order to transducer healthy human CD34 stem cells and K562 to overexpress mutated CXCR4 and determined its effect on receptor responses to stromal-derived factor-1 (SDF1).

METHODS

Retrovirus vector was engineered to coexpress WHIM-associated R334X mutated CXCR4 together with green fluorescent protein (GFP). Control vectors included similar constructs with wild-type CXCR4 (WT-CXCR4) or only GFP. CD34+ cells and K562 were transduced with these vectors. Populations of 100% transduced K562 were established by sorting GFP+ cells by flow cytometry. We performed migration and calcium flux assays of transduced CD34+ cells and transduced/sorted K562. We also examined receptor recycling in response to SDF1.

RESULTS

Healthy human CD34+ cells and/or human erythroleukemia K562 cells transduced to express mutated CXCR4, WT-CXCR4, or GFP alone demonstrated that mutated CXCR4 was associated with enhanced calcium flux and enhanced migration. There was also decreased receptor internalization and enhanced recovery of surface mutated CXCR4 in response to SDF1 compared with WT-CXCR4.

CONCLUSION

We propose that decreased internalization of WHIM-associated mutated CXCR4 leads to prolongation/enhancement of signaling in response to SDF1 and that this may provide the biochemical basis for the autosomal dominant abnormalities of cell trafficking and function associated with WHIM syndrome.

X-linked lymphoproliferative syndrome presenting with systemic lymphocytic vasculitis

X-linked lymphoproliferative syndrome (XLP) is a rare, often fatal, primary immunodeficiency disease characterized by an abnormal response to Epstein-Barr virus (EBV) infection. The gene responsible for XLP has been identified as SH2D1A/DSHP/SLAM-associated protein (SAP). The major clinical manifestations include fulminant infectious mononucleosis, lymphoproliferative disorder, and dysgammaglobulinemia. Affected males uncommonly present with lymphocytic vasculitis in addition to aplastic anemia. In this study, we describe a Japanese XLP patient who presented with hypogammaglobulinemia following acute EBV-induced infectious mononucleosis in the infancy and later had systemic lymphocytic vasculitis and hemophagocytic lymphohistiocytosis in the adulthood, which resolved by steroid pulse therapy. The patient's SAP gene was found to harbor a missense mutation (His8Asp), presumably resulting in defective expression of SAP in T cells. Biopsy specimens of lung and skin disclosed that CD8+ T cells predominantly infiltrated vascular vessels. However, immunohistochemical examination showed that EBV-infected cells were not identifiable in the vessels. We propose that T-cell-mediated immune dysregulation in XLP can cause vasculitis by EBV infection-unrelated mechanism.

Neutropenia associated with primary immunodeficiency syndromes

The primary immunodeficiency diseases are a heterogeneous group of more than 75 disorders characterized by intrinsic defects in the functions of the immune system. Many are associated with abnormalities of hematopoiesis as well. This article will review those primary immunodeficiency syndromes in which neutropenia is a prominent finding, including X-linked agammaglobulinemia (XLA), hyper IgM syndrome, common variable immunodeficiency (CVID), IgA deficiency, cartilage-hair hypoplasia (CHH), and reticular dysgenesis, with regards to pathophysiologic findings and treatment.

A preterm baby with Omenn syndrome

A preterm baby born with scaly skin who later developed recurrent infections and was subsequently diagnosed to have Omenn syndrome is presented.

CONCLUSION

Any baby with ichthyotic skin and recurrent infections should have immunodeficiency considered in the differential diagnosis.

The cytotoxic action of immune gamma globulin and complement on Krebs ascites tumor cells. I. Ultrastructural studies

Electron microscopic studies of Krebs ascites tumor cells treated in vitro with rabbit immune gamma globulin revealed a distinctive alteration in the structure of the cellular surface membrane. The subsequent addition of complement to this system severely damaged the cytoplasmic matrix, mitochondria, and endoplasmic reticulum. This sequence of events provides a structural basis for the cytotoxic action of antibody and complement.

The cytotoxic action of immune gamma globulin and complement on Krebs ascites tumor cells. II. Chemical studies

The in vitro exposure of Krebs ascites tumor cells to the action of rabbit immune gamma globulin alone does not result in any changes in the cell concentration of amino acids, ribonucleotides, RNA, DNA, or protein, nor in the rate of entry of potassium into the cell. The exposure of the cells to antibody + complement results in the following changes within a few minutes:— (a) Loss of about two-thirds of the free amino acids and ribonucleotides. (b) Loss of about 90 per cent of the intracellular potassium. (c) Loss of about three-quarters of the cell RNA to the medium, part appearing as TCA-soluble and the rest as TCA-insoluble products. There were no changes detectable in DNA. (d) A small increase in total free amino acid of the cell suspension. (e) Loss of from 30 to 60 per cent of the cell protein. The loss of these substances is believed to occur through a cell membrane which is still intact, as judged by phase and electron microscopy, and still able to discriminate to a small degree against passage of larger molecules.

X-linked mental retardation syndrome with seizures, hypogammaglobulinemia, and progressive gait disturbance is regionally mapped between xq21.33 and Xq23

We identified a family with three males in two generations with moderate mental retardation. The two oldest were first cousins whose mothers were sisters. The third affected was a grandson through a daughter of one of the sisters, strongly suggesting X- linked inheritance. The affected males had prominent glabella, synophrys, prognathism, generalized hirsutism, and bilateral single palmar creases. All developed seizures in childhood. The two oldest have had a slow deterioration in neurological status with poor gait and balance and progressive weakness. No deterioration in their mental status has been observed. The oldest had cerebellar atrophy confirmed on computed tomography and magnetic resonance imaging scans of the brain and prolonged nerve conduction velocity. Two of the males had hypogammaglobulinemia (IgA deficient). Two-point linkage analysis using 27 microsatellite markers on the X chromosome resulted in a maximum LOD score of 2.23 at straight theta = 0 for locus DSX101. Recombination was observed at locus DSX1170 in Xq21.33 and locus DXS8067 in Xq23. We conclude that this family represents an X-linked disorder associated with a recognizable phenotype, progressive neurological deterioration, and variable hypogammaglobulinemia. The gene appears to lie between Xq21.33 and Xq23.

A case of vaccinia necrosum (or progressive vaccinia), with severe hypogammaglobulinaemia, treated with n-methyl isatin beta-thiosemicarbazone (33T57)

A fatal case of vaccinia necrosum treated with antivaccinial gamma globulin and N-methyl isatin beta-thiosemicarbazone (33T57) is described. Histological abnormalities found at necropsy included intranuclear as well as cytoplasmic inclusion bodies, absence of lymphoid germinal centres, grey hepatization, and bronchiolar epithelial hyperplasia. Virus titres were highest in the original skin lesion; virus was also found in the lymph node draining it and in the kidney and the brain. No toxic effects could be clearly attributed to the drug used in treatment.