Low Penetrance, Broad Resistance, and Favorable Outcome of Interleukin 12 Receptor β1 Deficiency: Medical and Immunological Implications

The clinical phenotype of interleukin 12 receptor β1 chain (IL-12Rβ1) deficiency and the function of human IL-12 in host defense remain largely unknown, due to the small number of patients reported. We now report 41 patients with complete IL-12Rβ1 deficiency from 17 countries. The only opportunistic infections observed, in 34 patients, were of childhood onset and caused by weakly virulent Salmonella or Mycobacteria (Bacille Calmette-Guérin -BCG- and environmental Mycobacteria). Three patients had clinical tuberculosis, one of whom also had salmonellosis. Unlike salmonellosis, mycobacterial infections did not recur. BCG inoculation and BCG disease were both effective against subsequent environmental mycobacteriosis, but not against salmonellosis. Excluding the probands, seven of the 12 affected siblings have remained free of case-definition opportunistic infection. Finally, only five deaths occurred in childhood, and the remaining 36 patients are alive and well. Thus, a diagnosis of IL-12Rβ1 deficiency should be considered in children with opportunistic mycobacteriosis or salmonellosis; healthy siblings of probands and selected cases of tuberculosis should also be investigated. The overall prognosis is good due to broad resistance to infection and the low penetrance and favorable outcome of infections. Unexpectedly, human IL-12 is redundant in protective immunity against most microorganisms other than Mycobacteria and Salmonella. Moreover, IL-12 is redundant for primary immunity to Mycobacteria and Salmonella in many individuals and for secondary immunity to Mycobacteria but not to Salmonella in most

Cytomegalovirus infections in unrelated cord blood transplantation in pediatric patients: incidence, risk factors, and outcomes

BACKGROUND AND OBJECTIVES: Stem cells from umbilical cord blood (CB) have increasingly become a viable alternate source of progenitor cells for hematopoietic cell transplantation (HSCT). Cytomegalovirus (CMV) is thought to contribute significantly to HSCT morbidity and mortality. DESIGN AND SETTING: Retrospective case-control study in patients at tertiary care center. PATIENTS AND METHODS: We determined the incidence, risk factors and outcomes for CMV infection and disease after unrelated cord blood transplantation (UCBT) in children. RESULTS: Between 2003 and 2007, 73 pediatric patients underwent UCBT and 68% of recipients were CMV seropositive. The overall incidence of CMV infection, early and late CMV infection was 58.9% (43/73), 62.8% (27/43), and 37.4% (16/43), respectively. In patients with early CMV infection, 6 of 27 (22%) patients progressed to develop CMV end-organ disease including pneumonitis and retinitis. High levels CMV antigenemia ≥70 infected cells by pp65 antigenemia assay+PMNs, P=.237) were associated with a higher risk of progression to CMV disease. The development of CMV infections was higher in CMV-seropositive recipients (P<.001) and in those who developed graft-versus-host-diseases (GVHD) (P<.001). Other risk factors for CMV infection include the use of high-dose corticosteroids (P<.001) and older age of the recipient at the time of transplant (P<.002). Late CMV infection was strongly associated with a previous history of early CMV infection (P<.001). CONCLUSION: CMV infection is a significant complication in UCBT recipients in pediatric patients and is associated with an increase in transplant-related morbidity and mortality. Risk factors for CMV infections after UCBT include GVHD, use of corticosteroids, underlying diseases (hematologic malignancies) and older age. Late CMV infection was strongly associated with a previous history of CMV infection

A role for interleukin-12/23 in the maturation of human natural killer and CD56+ T cells in vivo.

International audienceNatural killer (NK) cells have been originally defined by their "naturally occurring" effector function. However, only a fraction of human NK cells is reactive toward a panel of prototypical tumor cell targets in vitro, both for the production of interferon-gamma (IFN-gamma) and for their cytotoxic response. In patients with IL12RB1 mutations that lead to a complete IL-12Rbeta1 deficiency, the size of this naturally reactive NK cell subset is diminished, in particular for the IFN-gamma production. Similar data were obtained from a patient with a complete deficit in IL-12p40. In addition, the size of the subset of effector memory T cells expressing CD56 was severely decreased in IL-12Rbeta1- and IL-12p40-deficient patients. Human NK cells thus require in vivo priming with IL-12/23 to acquire their full spectrum of functional reactivity, while T cells are dependent upon IL-12/23 signals for the differentiation and/or the maintenance of CD56(+) effector memory T cells. The susceptibility of IL-12/23 axis-deficient patients to Mycobacterium and Salmonella infections in combination with the absence of mycobacteriosis or salmonellosis in the rare cases of human NK cell deficiencies point to a role for CD56(+) T cells in the control of these infections in humans

Revisiting human IL-12Rβ1 deficiency: a survey of 141 patients from 30 countries

Interleukin-12 receptor β1 (IL-12Rβ1) deficiency is the most common form of Mendelian susceptibility to mycobacterial disease (MSMD). We undertook an international survey of 141 patients from 102 kindreds in 30 countries. Among 102 probands, the first infection occurred at a mean age of 2.4 years. In 78 patients, this infection was caused by Bacille Calmette-Guérin (BCG; n = 65), environmental mycobacteria (EM; also known as atypical or nontuberculous mycobacteria) (n = 9) or Mycobacterium tuberculosis (n = 4). Twenty-two of the remaining 24 probands initially presented with nontyphoidal, extraintestinal salmonellosis. Twenty of the 29 genetically affected sibs displayed clinical signs (69%); however 8 remained asymptomatic (27%). Nine nongenotyped sibs with symptoms died. Recurrent BCG infection was diagnosed in 15 cases, recurrent EM in 3 cases, recurrent salmonellosis in 22 patients. Ninety of the 132 symptomatic patients had infections with a single microorganism. Multiple infections were diagnosed in 40 cases, with combined mycobacteriosis and salmonellosis in 36 individuals. BCG disease strongly protected against subsequent EM disease (p = 0.00008). Various other infectious diseases occurred, albeit each rarely, yet candidiasis was reported in 33 of the patients (23%). Ninety-nine patients (70%) survived, with a mean age at last follow-up visit of 12.7 years ± 9.8 years (range, 0.5-46.4 yr). IL-12Rβ1 deficiency is characterized by childhood-onset mycobacteriosis and salmonellosis, rare recurrences of mycobacterial disease, and more frequent recurrence of salmonellosis. The condition has higher clinical penetrance, broader susceptibility to infections, and less favorable outcome than previously thought