Kathleen Gutierrez

Impaired Accumulation and Function of Memory CD4 T Cells in Human IL-12 Receptor β1 Deficiency

Defects in IL-12 production or IL-12 responsiveness result in a vulnerability to infection with non-viral intracellular organisms, but the immunological mechanisms responsible for this susceptibility remain poorly understood. We present an immunological analysis of a patient with disseminated Salmonella enteritidis and a homozygous splice acceptor mutation in the IL-12Rβ1-chain gene. This mutation resulted in the absence of IL-12Rβ1 protein on PBMC and an inability of T cells to specifically bind IL-12 or produce IFN-γ in response to either IL-12 or IL-23. The accumulation of memory (CD45R0high) CD4 T cells that were CCR7high (putative central memory cells) was normal or increased for age. Central memory CD4 T cells of the patient and age-matched controls were similar in having a low to undetectable capacity to produce IFN-γ after polyclonal stimulation. In contrast, the patient had a substantial decrease in the number of CCR7neg/dull CD45R0high memory CD4 T cells (putative effector memory cells), and these differed from control cells in having a minimal ability to produce IFN-γ after polyclonal stimulation. Importantly, tetanus toxoid-specific IFN-γ production by PBMC from the patient was also significantly reduced compared with that in age-matched controls, indicating that signaling via the IL-12Rβ1-chain is generally necessary for the in vivo accumulation of human memory CD4 T cells with Th1 function. These results are also consistent with a model in which the IL-12Rβ1 subunit is necessary for the conversion of central memory CD4 T cells into effector memory cells.

Comparison of conventional viral cultures with direct fluorescent antibody stains for diagnosis of community-acquired respiratory virus infections in hospitalized children.

Objective. Because of the widespread availability of rapid viral antigen testing, many institutions never adopted a routine practice of ordering viral cultures to detect community-acquired respiratory viruses (CRVs). The ease of performing complete viral studies in our on site laboratory allowed us to assess the clinical implications of the absence of conventional culture results in previously healthy hospitalized children with CRV infections. Methods. From June 1997 through May 2000, the results of direct immunofluorescence assay (DFA) of 1069 nasopharyngeal swab (NP) specimens were compared with simultaneously inoculated conventional tube cell cultures for detection of CRVs. In addition the medical records of 140 previously healthy infants and children hospitalized for management of lower respiratory tract infections caused by culture-proved CRVs were reviewed. Results. Viruses were isolated or detected by DFA or viral culture or both in 468 (30%) of the 1557 NP samples evaluated. The most common CRV isolated was respiratory syncytial virus (49%), followed by parainfluenza viruses (15%), influenza A viruses (14%), rhinoviruses (8%), adenoviruses (4%), enteroviruses (4%) and influenza B viruses (1%). Of the 1069 NP specimens for which both viral culture and rapid antigen testing were performed, 190 specimens were DFA-positive and culture-positive, 7 specimens were DFA-positive and culture-negative, 35 specimens were DFA-negative and culture-positive and 837 specimens were DFA-negative and culture-negative. The overall sensitivity, specificity, positive predictive value and negative predictive value of DFA were 84, 99, 96 and 96%, respectively. Of the 140 hospitalized patients with culture-proved viral cultures (89 respiratory syncytial virus, 22 influenza A, 20 parainfluenza virus and 9 adenovirus), the mean duration of hospital stay was 3.6 days, and the mean time for viral cultures to become positive was 7.7 days (P < 0.001, signed rank test). One hundred twenty (86%) viral cultures did not become positive until after the patient had been discharged from the hospital. In no case was the clinical decision regarding the patient’s treatment or discharge from the hospital based on the results of viral culture. Conclusions. We conclude that positive viral cultures have no impact on clinical decision making and management of healthy children during hospitalization for illness attributable to community-acquired respiratory viruses.

The Epidemiology of Neonatal Herpes Simplex Virus Infections in California from 1985 to 1995

Comprehensive hospital discharge data completed by the California Office of Statewide Health Planning and Development was used to determine whether the proportion of infants </=6 weeks of age who were hospitalized with a diagnosis of herpes simplex virus (HSV) infection changed between 1985 and 1995. During 1985, 1990, and 1995, respectively, 11.7, 11.3, and 11.4 infants per 100,000 live births had a diagnosis of HSV (P=.98). The proportion of infants 1-42 days of age who were discharged from the hospital with a diagnosis of HSV infection did not change over this time period despite a decrease in deliveries by cesarean section and an increase in the proportion of women with a diagnosis of genital HSV infection who gave birth to infants by vaginal delivery. From 1985 to 1995 there was no decrease in the rate of secondary diagnosis of genital HSV in delivering women.

Intravenous ribavirin therapy for adenovirus pneumonia

We report on the effectiveness of intravenous ribavirin for severe adenoviral pneumonia in a 10‐month‐old male following orthotopic liver transplantation. On day 20 post‐transplantation, he developed high fever, marked respiratory compromise, and hypoxemia. The chest radiograph showed bilateral pulmonary infiltrates. Samples of bronchoalveolar lavage fluid grew adenovirus, serotype 1. Marked clinical and radiological improvement was noted after intravenous ribavirin therapy. A prospective clinical trial is needed to determine the efficacy of ribavirin therapy for severe adenovirus disease. Pediatr Pulmonol. 2000; 29:69–73.

Severe cryptosporidiosis in a seven-year-old renal transplant recipient – Case report and review of the literature

Abstract:  Cryptosporidium is an intracellular protozoa that can cause gastroenteritis in humans. In immunocompromised hosts, infection can be severe, leading to life‐threatening persistent diarrhea. There is limited experience in treating this infection in solid organ transplants. Although newer drugs active against Cryptosporidium exist, they are only licensed in the USA for treatment of immunocompetent hosts. Here we describe a seven‐year‐old renal transplant recipient with severe cryptosporidiosis. He had a protracted course of diarrhea of up to 2 L/day. He was successfully managed with combination antimicrobial therapy including nitazoxanide, paromomycin, and azithromycin. In conjunction with this regimen, he had a reduction in immunosuppression and complete bowel rest. His stool pattern normalized in four weeks and he has had no recurrence after six months of follow up.

Staphylococcal infections in children, California, USA, 1985-2009.

Young children, Black children, and those without private insurance were at higher risk for hospitalization.

Nocardia farcinica Pneumonia in Chronic Granulomatous Disease

Infection with Nocardiaposes a diagnostic challenge in patients with chronic granulomatous disease (CGD) because the signs and symptoms are often nonspecific, delay in diagnosis is common, and invasive procedures are frequently required to obtain appropriate tissue specimens. We present the first reported case of N farcinica pneumonia in an adolescent with X-linked CGD. Differentiation of N farcinica from other members of N asteroidescomplex is important because of its propensity for causing disseminated infection and antimicrobial resistance. Physicians caring for patients with CGD should maintain a high index of suspicion for nocardiosis, especially in those receiving chronic steroid therapy. Early diagnosis remains critical for decreased morbidity and occasional mortality.

Nontuberculous mycobacteria infections in immunocompromised patients: single institution experience.

Disseminated infection due to nontuberculous Mycobacterium (NTM) species is rare in pediatrics. Here we report 6 infections affecting 5 patients at a single institution in an immunocompromised population of pediatric oncology and stem cell transplant recipients. The patients presented within a 1-year period with catheter-associated bacteremia. New pulmonary nodules were noted in 4 of the 5 patients. All of the infections were due to rapidly growing NTM. Patients were successfully treated with removal of the infected catheter and combination antibiotic therapy. There are currently no consensus guidelines for treatment of NTM infections in this population, and a therapeutic approach is presented here.

Continuation of Antibiotic Therapy for Serious Bacterial Infections Outside of the Hospital

Many children hospitalized with serious bacterial infections are candidates for either home oral antibiotic therapy or outpatient parenteral antibiotic therapy. Outpatient antibiotic therapy offers the potential for excellent medical treatment, reduced costs, and improved quality of life for ill children. However, cost considerations must not override good medical judgment. Certain children simply are not candidates for outpatient therapy because of the seriousness of their infection, poor compliance, lack of intravenous access, or poor social situation. In addition, although the few published studies to date all show that outpatient antibiotic therapy is effective, there is further need for properly designed clinical trials to evaluate the efficacy and safety of outpatient antibiotic therapy for serious bacterial infections in children.

Fatal West Nile Virus Encephalitis in a Heart Transplant Recipient.

ABSTRACT The diagnosis of encephalitis is particularly challenging in immunocompromised patients. We report here a case of fatal West Nile virus encephalitis confounded by the presence of budding yeast in the cerebrospinal fluid (CSF) from a patient who had undergone heart transplantation for dilated cardiomyopathy 11 months prior to presentation of neurologic symptoms.