Recovery of Neutrophil Count by Ganciclovir in Patients with Chronic Idiopathic Neutropenia Associated with Cytomegalovirus Infection in Bone Marrow Stromal Cells

Murine CMV induces type 1 IFN that impairs differentiation of MDSCs critical for transplantation tolerance

Clinical tolerance without immunosuppression has now been achieved for organ transplantation, and its scope will likely continue to expand. In this context, a previously understudied and now increasingly relevant area is how microbial infections might affect the efficacy of tolerance. A highly prevalent and clinically relevant posttransplant pathogen is cytomegalovirus (CMV). Its impact on transplantation tolerance and graft outcomes is not well defined. Employing a mouse model of CMV (MCMV) infection and allogeneic pancreatic islet transplantation in which donor-specific tolerance was induced by infusing donor splenocytes rendered apoptotic by treatment with ethylenecarbodiimide, we investigated the effect of CMV infection on transplantation tolerance induction. We found that acute MCMV infection abrogated tolerance induction and that this abrogation correlated with an alteration in the differentiation and function of myeloid-derived suppressor cells (MDSCs). These effects on MDSCs were mediated in part through MCMV induced type 1 interferon (IFN) production. During MCMV infection, the highly immunosuppressive Gr1^HI-granulocytic MDSCs were markedly reduced in numbers, and the accumulating Ly6C^HI-monocytic cells lost their MDSC-like function but instead acquired an immunostimulatory phenotype to cross-present alloantigens and prime alloreactive CD8 T cells. Consequently, the islet allograft exhibited an altered effector to regulatory T-cell ratio that correlated with the ultimate graft demise. Blocking type 1 IFN signaling during MCMV infection rescued MDSC populations and partially restored transplantation tolerance. Our mechanistic studies now provide a solid foundation for seeking effective therapies for promoting transplantation tolerance in settings of CMV infection.

Acute Progressive Visual Loss in a Case of Acute Myeloid Leukemia: Challenges in the Utility of Molecular Tests in Early Diagnose of Cytomegalovirus Retinitis

Cytomegalovirus (CMV) retinitis is one of the rare but debilitating presentations of the CMV infection in children with leukemia. Herein, we report a 12-year-old boy with acute myeloid leukemia complicated by rapid progressive visual loss during relapse of leukemia. The definite diagnosis of CMV retinitis was made after vitreous aspiration. Despite prompt treatment and ophthalmologic intervention, he died because of AML relapse. Viral infections, especially cytomegalovirus infection, may present with vague clinical pictures during any time of chemotherapy, which may not be easily distinguishable from bacterial or fungal retinitis and also chemotherapy-induced retinopathies. Clinician should consider CMV retinitis in seropositive patients especially those without detectable viremia.

Pathogenesis and prognosis of neutropenia in infants and children admitted in a university children hospital in Egypt

This study aimed to assess the prevalence, severity, and etiology of neutropenia in infants and children admitted to a children's hospital in Egypt. A total of 200 patients with neutropenia were recruited from April 1, 2010 to September 30, 2010. Patients with a known hematological or immunological disease were excluded. Patients were followed till recovery or an underlying cause was uncovered. Viral serological analysis was done for patients with moderate/severe neutropenia, including cytomegalovirus (CMV); Epstein-Barr virus (EBV); hepatitis A, B, and C viruses; and HIV. Antineutrophil cytoplasmic antibody (ANCA) tested by enzyme immunoassay and bone marrow aspirate were done for prolonged neutropenia. The results revealed that neutropenia was mild in 90 (45%), moderate in 56 (28%), and severe in 54 (27%). Clinical diagnosis at admission was bronchopneumonia (38%), pyrexia of undetermined etiology (17%), bronchiolitis (13%), urinary tract infection (9%), acute gastroenteritis (8%), hepatitis (6.5%), and septicemia (5%). Patients with mild neutropenia recovered within 1 week. Among 110 patients with moderate/severe neutropenia, 80 (73%) recovered in <3 weeks. Predictors of prolonged neutropenia were age younger than 18 months (P < .01), absolute neutrophils count (ANC) < 500/mm(3) (P < .05), hemoglobin < 10 gm/dL (P < .05), and positive CMV serology (P < .01). CMV and EBV serology were positive in 34.5% and 7.3% of patients, respectively. ANCA was positive in 42.8% of patients with prolonged severe neutropenia. In conclusion, neutropenia is a frequent finding in Egyptian infants and children, usually mild and transient, and mainly associated with infection. CMV and EBV are associated with prolonged neutropenia. Immune neutropenia is a common cause of moderate/severe neutropenia in the first two years of life.

Prolonged acquired neutropenia in children

BACKGROUND

Acquired neutropenia is not uncommon in childhood. This study investigated the risk factors associated with developing prolonged acquired neutropenia.

PROCEDURE

We reviewed 66,062 hospital admission medical records from the 5-year period January 1, 2002 to December 31, 2006 to identify neutropenic patients, with and without follow-up of their neutropenic course until December 31, 2007. After excluding patients with malignancy, collagen disease, bone marrow failure, prematurity, hereditary disease, congenital neutropenia, immunodeficiency, or status post-liver transplantation, 735 admissions with acquired neutropenia were included in our study.

RESULTS

A total of 474 patients with 735 admissions had moderate or severe neutropenia during the 5-year period. Among the 252 acquired neutropenia patients who had follow-up for at least 1 month, 226 patients recovered within 3 months, while 26 patients remained neutropenic after 3 months. Of these 26 patients, 14 recovered after 1 year. An absolute neutrophil count of <500/mm(3) (odds ratio [OR]: 13.66, 95% confidence interval [CI]: 2.90-64.41), thrombocytosis (OR: 5.76, 95% CI: 1.78-18.58), and age <1 year (OR: 4.93, 95% CI: 1.03-23.54) were associated with prolonged acquired neutropenia, as shown by multivariate logistic regression. Kaplan-Meier analysis showed that neutropenia associated with cytomegalovirus (CMV) was more prolonged than neutropenia associated with influenza or Epstein-Barr virus infection.

CONCLUSIONS

Prolonged acquired neutropenia was associated with younger age, thrombocytosis, and CMV infection. Neutropenic infants with CMV infection may require antiviral therapy to prevent prolonged acquired neutropenia.