Anti-Interleukin-23 Autoantibodies in Adult-Onset Immunodeficiency.

BACKGROUND: Autoantibodies against interleukin-12 (anti-interleukin-12) are often identified in patients with thymoma, but opportunistic infections develop in only some of these patients. Interleukin-12 (with subunits p40 and p35) shares a common subunit with interleukin-23 (subunits p40 and p19). In a patient with disseminated Burkholderia gladioli infection, the identification of both anti-interleukin-23 and anti-interleukin-12 prompted further investigation. METHODS: Among the patients (most of whom had thymoma) who were known to have anti-interleukin-12, we screened for autoantibodies against interleukin-23 (anti-interleukin-23). To validate the potential role of anti-interleukin-23 with respect to opportunistic infection, we tested a second cohort of patients with thymoma as well as patients without either thymoma or known anti-interleukin-12 who had unusual infections. RESULTS: Among 30 patients with anti-interleukin-12 who had severe mycobacterial, bacterial, or fungal infections, 15 (50%) also had autoantibodies that neutralized interleukin-23. The potency of such neutralization was correlated with the severity of these infections. The neutralizing activity of anti-interleukin-12 alone was not associated with infection. In the validation cohort of 91 patients with thymoma, the presence of anti-interleukin-23 was associated with infection status in 74 patients (81%). Overall, neutralizing anti-interleukin-23 was detected in 30 of 116 patients (26%) with thymoma and in 30 of 36 patients (83%) with disseminated, cerebral, or pulmonary infections. Anti-interleukin-23 was present in 6 of 32 patients (19%) with severe intracellular infections and in 2 of 16 patients (12%) with unusual intracranial infections, including Cladophialophora bantiana and Mycobacterium avium complex. CONCLUSIONS: Among patients with a variety of mycobacterial, bacterial, or fungal infections, the presence of neutralizing anti-interleukin-23 was associated with severe, persistent opportunistic infections. (Funded by the National Institute of Allergy and Infectious Diseases and others.).

Spinal Arachnoiditis as a Complication of Cryptococcal Meningoencephalitis in Non-HIV Previously Healthy Adults.

BACKGROUND: Cryptococcus can cause meningoencephalitis (CM) among previously healthy non-HIV adults. Spinal arachnoiditis is under-recognized, since diagnosis is difficult with concomitant central nervous system (CNS) pathology. METHODS: We describe 6 cases of spinal arachnoiditis among 26 consecutively recruited CM patients with normal CD4 counts who achieved microbiologic control. We performed detailed neurological exams, cerebrospinal fluid (CSF) immunophenotyping and biomarker analysis before and after adjunctive immunomodulatory intervention with high dose pulse corticosteroids, affording causal inference into pathophysiology. RESULTS: All 6 exhibited severe lower motor neuron involvement in addition to cognitive changes and gait disturbances from meningoencephalitis. Spinal involvement was associated with asymmetric weakness and urinary retention. Diagnostic specificity was improved by MRI imaging which demonstrated lumbar spinal nerve root enhancement and clumping or lesions. Despite negative fungal cultures, CSF inflammatory biomarkers, sCD27 and sCD21, as well as the neuronal damage biomarker, neurofilament light chain (NFL), were elevated compared to healthy donor (HD) controls. Elevations in these biomarkers were associated with clinical symptoms and showed improvement with adjunctive high dose pulse corticosteroids. CONCLUSIONS: These data suggest that a post-infectious spinal arachnoiditis is an important complication of CM in previously healthy individuals, requiring heightened clinician awareness. Despite microbiological control, this syndrome causes significant pathology likely due to increased inflammation and may be amenable to suppressive therapeutics.

Anti-cytokine autoantibodies in postherpetic neuralgia.

BACKGROUND: The mechanisms by which varicella zoster virus (VZV) reactivation causes postherpetic neuralgia (PHN), a debilitating chronic pain condition, have not been fully elucidated. Based on previous studies identifying a causative role for anti-cytokine autoantibodies in patients with opportunistic infections, we explored this possibility in PHN. METHODS: Sera from herpes zoster (HZ) patients without and with PHN (N = 115 and 83, respectively) were examined for the presence of autoantibodies against multiple cytokines, and other known autoantigens. In addition, a cohort of patients with complex regional pain syndrome or neuropathic pain was tested for autoantibodies against selected cytokines. Antibody levels against VZV, Epstein Barr virus, and herpes simplex virus-2 were also measured in the HZ and PHN patients. Patient sera with high levels of anti-cytokine autoantibodies were functionally tested for in vitro neutralizing activity. RESULTS: Six PHN subjects demonstrated markedly elevated levels of single, autoantibodies against interferon-α, interferon-γ, GM-CSF, or interleukin-6. In contrast, the HZ and the pain control group showed low or no autoantibodies, respectively, against these four cytokines. Further analysis revealed that one PHN patient with high levels of anti-interleukin-6 autoantibodies had a markedly depressed antibody level to VZV, potentially reflecting poor T cell immunity against VZV. In vitro functional testing revealed that three of the five anti-cytokine autoantibody positive PHN subjects had neutralizing autoantibodies against interferon-α, GM-CSF or interleukin-6. In contrast, none of the HZ patients without PHN had neutralizing autoantibodies. CONCLUSIONS: These results suggest the possibility that sporadic anti-cytokine autoantibodies in some subjects may cause an autoimmune immunodeficiency syndrome leading to uncontrolled VZV reactivation, nerve damage and subsequent PHN.

Pulmonary Nontuberculous Mycobacterial Infection. A Multisystem, Multigenic Disease.

RATIONALE: The clinical features of patients infected with pulmonary nontuberculous mycobacteria (PNTM) are well described, but the genetic components of infection susceptibility are not. OBJECTIVES: To examine genetic variants in patients with PNTM, their unaffected family members, and a control group. METHODS: Whole-exome sequencing was done on 69 white patients with PNTM and 18 of their white unaffected family members. We performed a candidate gene analysis using immune, cystic fibrosis transmembrance conductance regulator (CFTR), cilia, and connective tissue gene sets. The numbers of patients, family members, and control subjects with variants in each category were compared, as was the average number of variants per person. MEASUREMENTS AND MAIN RESULTS: A significantly higher number of patients with PNTM than the other subjects had low-frequency, protein-affecting variants in immune, CFTR, cilia, and connective tissue categories (35, 26, 90, and 90%, respectively). Patients with PNTM also had significantly more cilia and connective tissue variants per person than did control subjects (2.47 and 2.55 compared with 1.38 and 1.40, respectively; P = 1.4 × 10(-6) and P = 2.7 × 10(-8), respectively). Patients with PNTM had an average of 5.26 variants across all categories (1.98 in control subjects; P = 2.8 × 10(-17)), and they were more likely than control subjects to have variants in multiple categories. We observed similar results for family members without PNTM infection, with the exception of the immune category. CONCLUSIONS: Patients with PNTM have more low-frequency, protein-affecting variants in immune, CFTR, cilia, and connective tissue genes than their unaffected family members and control subjects. We propose that PNTM infection is a multigenic disease in which combinations of variants across gene categories, plus environmental exposures, increase susceptibility to the infection.

Paradoxical Immune Responses in Non-HIV Cryptococcal Meningitis.

The fungus Cryptococcus is a major cause of meningoencephalitis in HIV-infected as well as HIV-uninfected individuals with mortalities in developed countries of 20% and 30%, respectively. In HIV-related disease, defects in T-cell immunity are paramount, whereas there is little understanding of mechanisms of susceptibility in non-HIV related disease, especially that occurring in previously healthy adults. The present description is the first detailed immunological study of non-HIV-infected patients including those with severe central nervous system (s-CNS) disease to 1) identify mechanisms of susceptibility as well as 2) understand mechanisms underlying severe disease. Despite the expectation that, as in HIV, T-cell immunity would be deficient in such patients, cerebrospinal fluid (CSF) immunophenotyping, T-cell activation studies, soluble cytokine mapping and tissue cellular phenotyping demonstrated that patients with s-CNS disease had effective microbiological control, but displayed strong intrathecal expansion and activation of cells of both the innate and adaptive immunity including HLA-DR+ CD4+ and CD8+ cells and NK cells. These expanded CSF T cells were enriched for cryptococcal-antigen specific CD4+ cells and expressed high levels of IFN-γ as well as a lack of elevated CSF levels of typical T-cell specific Th2 cytokines -- IL-4 and IL-13. This inflammatory response was accompanied by elevated levels of CSF NFL, a marker of axonal damage, consistent with ongoing neurological damage. However, while tissue macrophage recruitment to the site of infection was intact, polarization studies of brain biopsy and autopsy specimens demonstrated an M2 macrophage polarization and poor phagocytosis of fungal cells. These studies thus expand the paradigm for cryptococcal disease susceptibility to include a prominent role for macrophage activation defects and suggest a spectrum of disease whereby severe neurological disease is characterized by immune-mediated host cell damage.

Nocardia-induced granulocyte macrophage colony-stimulating factor is neutralized by autoantibodies in disseminated/extrapulmonary nocardiosis.

BACKGROUND: Nocardia species cause infections in both immunocompromised and otherwise immunocompetent patients, although the mechanisms defining susceptibility in the latter group are elusive. Anticytokine autoantibodies are an emerging cause of pathogen-specific susceptibility in previously healthy human immunodeficiency virus-uninfected adults, including anti-granulocyte macrophage colony-stimulating factor (GM-CSF) autoantibodies with cryptococcal meningitis. METHODS: Plasma from patients with disseminated/extrapulmonary nocardiosis and healthy controls was screened for anticytokine autoantibodies using a particle-based approach. Autoantibody function was assessed by intranuclear staining for GM-CSF-induced STAT5 phosphorylation in normal cells incubated with either patient or normal plasma. GM-CSF-mediated cellular activation by Nocardia was assessed by staining for intracellular cytokine production and intranuclear STAT5 phosphorylation. RESULTS: We identified neutralizing anti-GM-CSF autoantibodies in 5 of 7 patients studied with central nervous system nocardiosis and in no healthy controls (n = 14). GM-CSF production was induced by Nocardia in vitro, suggesting a causative role for anti-GM-CSF autoantibodies in Nocardia susceptibility and dissemination. CONCLUSIONS: In previously healthy adults with otherwise unexplained disseminated/extrapulmonary Nocardia infections, anti-GM-CSF autoantibodies should be considered. Their presence may suggest that these patients may be at risk for later development of pulmonary alveolar proteinosis or other opportunistic infections, and that patients may benefit from therapeutic GM-CSF administration.

Mining the human autoantibody repertoire: isolation of potent IL17A-neutralizing monoclonal antibodies from a patient with thymoma.

Anti-cytokine autoantibodies have been widely reported to be present in human plasma, both in healthy subjects and in patients with underlying autoimmune conditions, such as autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED) or thymic epithelial neoplasms. While often asymptomatic, they can cause or facilitate a wide range of diseases including opportunistic infections. The potential therapeutic value of specific neutralizing anti-cytokine autoantibodies has not been thoroughly investigated. Here we used mammalian cell display to isolate IL17A-specific antibodies from a thymoma patient with proven high-titer autoantibodies against the same. We identified 3 distinct clonotypes that efficiently neutralized IL17A in a cell-based in vitro assay. Their potencies were comparable to those of known neutralizing antibodies, including 2, AIN457 (secukinumab) and ixekizumab that are currently in clinical development for the treatment of various inflammatory disorders. These data clearly demonstrate that the human autoantibody repertoire can be mined for antibodies with high therapeutic potential for clinical development.

The first US domestic report of disseminated Mycobacterium avium complex and anti-interferon-γ autoantibodies.

INTRODUCTION: Anti-interferon-γ (IFNγ) autoantibodies have been associated with disseminated mycobacterial infections, mostly in patients from Southeast Asia. PURPOSE: We studied an American-born, Caucasian female with M. avium complex infection of the subglottic mucosa and brain for underlying etiologies of infection. METHODS: Plasma was screened for anticytokine autoantibodies using a Luminex-based approach. The ability of patient plasma to block IFNγ-induced STAT1 phosphorylation in normal blood cells was evaluated by flow cytometry with intracellular staining. Plasma inhibition of IFNγ production and IFNγ-induced cytokines in normal and patient blood cells washed of autologous plasma was also evaluated. RESULTS: Patient plasma contained high-titer IgG anti-IFNγ autoantibodies, primarily of the IgG1 subclass. Patient but not control plasma prevented IFNγ-induced STAT1 phosphorylation and expression of the IFNγ-inducible cytokines tumor necrosis factor (TNF) α and interleukin (IL)-12 in normal blood cells. Patient blood cells washed free of autologous plasma demonstrated normal IFNγ production and response. CONCLUSIONS: Disseminated nontuberculous mycobacterial infections should always prompt immune evaluation. This first case of disseminated nontuberculous mycobacterial infection and anti-IFNγ autoantibodies in an American-born Caucasian suggests that anti-cytokine autoantibodies are not racially or regionally restricted.

Anti-granulocyte-macrophage colony-stimulating factor autoantibodies are a risk factor for central nervous system infection by Cryptococcus gattii in otherwise immunocompetent patients.

Cryptococcosis is caused by either Cryptococcus neoformans or C. gattii. While cryptococcal meningoencephalitis is caused mostly by C. neoformans in immunocompromised patients, the risk factors remain unclear for patients with no known immune defect. Recently, anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) autoantibodies were detected in the plasma of seven "immunocompetent" cryptococcosis patients, and the cryptococcal strains from these patients were reported as C. neoformans (three strains), C. gattii (one strain), and Cryptococcus (three strains not identified to the species level). We identified all three strains that had not been identified to the species level as C. gattii. Notably, the three strains that were reported as C. neoformans but were unavailable for species confirmation originated from Sothern California and Thailand where C. gattii is endemic. Most clinical laboratories designate C. neoformans without distinguishing between the two species; hence, these three strains could have been C. gattii. Since C. gattii infects more immunocompetent patients than C. neoformans, we pursued the possibility that this antibody may be more prevalent in patients infected with C. gattii than in those infected with C. neoformans. We screened the plasma of 20 healthy controls and 30 "immunocompetent" patients with cryptococcal meningoencephalitis from China and Australia (multiple ethnicities). Anti-GM-CSF autoantibodies were detected only in the plasma of seven patients infected by C. gattii and one healthy volunteer and in none infected by C. neoformans. While plasma from these C. gattii patients completely prevented GM-CSF-induced p-STAT5 in normal human peripheral blood mononuclear cells (PBMCs), plasma from one healthy volunteer positive for anti-GM-CSF autoantibodies caused only partial blockage. Our results suggest that anti-GM-CSF autoantibodies may predispose otherwise immunocompetent individuals to meningoencephalitis caused by C. gattii but not necessarily to that caused by C. neoformans. IMPORTANCE Cryptococcal meningoencephalitis is the most serious central nervous system (CNS) infection caused by Cryptococcus neoformans or C. gattii. Cryptococcus primarily infects immunocopromised patients but is also sporadically encountered in otherwise "immunocompetent" patients with no known risk. In a recent study, anti-GM-CSF autoantibodies were detected in the plasma of seven otherwise immunocompetent patients with cryptococcal meningoencephalitis. Four of seven (57%) cryptococcal isolates from these patients were identified as C. gattii, while three strains were unavailable for species confirmation. We collected plasma from 30 otherwise healthy patients with CNS cryptococcosis in China and Australia (multiethnic) and analyzed the samples for the presence of anti-GM-CSF autoantibodies. The results suggest that anti-GM-CSF autoantibodies are a risk factor for CNS infection by C. gattii but not C. neoformans. GM-CSF may have a specific role in host defense against C. gattii, thereby elevating the importance of determining the level of anti-GM-CSF autoantibodies which can impact clinical management.

Anticytokine autoantibody-associated immunodeficiency.

Anticytokine autoantibodies are an emerging mechanism of disease in previously healthy adults. Patients with these syndromes demonstrate a unique infectious phenotype associated with neutralizing autoantibodies that target a specific cytokine. Examples include anti-interferon (IFN)-γ autoantibodies and disseminated nontuberculous mycobacteria; anti-granulocyte macrophage colony-stimulating factor autoantibodies and cryptococcal meningitis; anti-interleukin (IL)-6 autoantibodies and staphylococcal skin infection; and anti-IL-17A, anti-IL-17F, or anti-IL-22 autoantibodies and mucocutaneous candidiasis in the setting of either APECED (autoimmune polyendocrinopathy, candidiasis, ectodermal dystrophy syndrome) or thymoma. Other anticytokine autoantibodies may contribute to an infectious phenotype such as anti-granulocyte colony stimulating factor and anti-IFN-α autoantibodies, although the strength of the association is less clear. Their identification not only affects disease management but also may uncover key mechanisms of host defense against specific organisms. Furthermore, it raises the possibility that currently idiopathic diseases will someday be explained by a yet unidentified anticytokine autoantibody. This review focuses on the current understanding, both clinical and mechanistic, of anticytokine autoantibody-associated immunodeficiency.

Cixutumumab for patients with recurrent or refractory advanced thymic epithelial tumours: a multicentre, open-label, phase 2 trial.

BACKGROUND: No standard treatment exists for refractory or relapsed advanced thymic epithelial tumours. We investigated the efficacy of cixutumumab, a fully human IgG1 monoclonal antibody targeting the insulin-like growth factor 1 receptor in thymic epithelial tumours after failure of previous chemotherapy. METHODS: Between Aug 25, 2009, and March 27, 2012, we did a multicentre, open-label, phase 2 trial in patients aged 18 years or older with histologically confirmed recurrent or refractory thymic epithelial tumours. We enrolled individuals who had progressed after at least one previous regimen of platinum-containing chemotherapy, had an Eastern Cooperative Oncology Group performance status of 0 or 1, and had measurable disease and adequate organ function. Eligible patients received intravenous cixutumumab (20 mg/kg) every 3 weeks until disease progression or development of intolerable toxic effects. The primary endpoint was the frequency of response, analysed on an intention-to-treat basis. We also did pharmacodynamic studies. This trial is registered with ClinicalTrials.gov, number NCT00965250. FINDINGS: 49 patients were enrolled (37 with thymomas and 12 with thymic carcinomas) who received a median of eight cycles of cixutumumab (range 1-46). At the final actuarial analysis when follow-up data were updated (Nov 30, 2012), median potential follow-up (from on-study date to most current follow-up date) was 24·0 months (IQR 17·3-36·9). In the thymoma cohort, five (14%) of 37 patients (95% CI 5-29) achieved a partial response, 28 had stable disease, and four had progressive disease. In the thymic carcinoma cohort, none of 12 patients (95% CI 0-26) had a partial response, five had stable disease, and seven had progressive disease. The most common grade 3-4 adverse events in both cohorts combined were hyperglycaemia (five [10%]), lipase elevation (three [6%]), and weight loss, tumour pain, and hyperuricaemia (two each [4%]). Nine (24%) of 37 patients with thymoma developed autoimmune conditions during treatment (five were new-onset disorders), the most common of which was pure red-cell aplasia. Two (4%) patients died; one was attributed to disease progression and the other to disease-related complications (respiratory failure, myositis, and an acute coronary event), which could have been precipitated by treatment with cixutumumab. INTERPRETATION: Cixutumumab monotherapy is well-tolerated and active in relapsed thymoma. Development of autoimmunity during treatment needs further investigation. FUNDING: Division of Cancer Treatment and Diagnosis at the National Cancer Institute (National Institutes of Health), ImClone Systems.

Protein microarray analysis reveals BAFF-binding autoantibodies in systemic lupus erythematosus.

Autoantibodies against cytokines, chemokines, and growth factors inhibit normal immunity and are implicated in inflammatory autoimmune disease and diseases of immune deficiency. In an effort to evaluate serum from autoimmune and immunodeficient patients for Abs against cytokines, chemokines, and growth factors in a high-throughput and unbiased manner, we constructed a multiplex protein microarray for detection of serum factor-binding Abs and used the microarray to detect autoantibody targets in SLE. We designed a nitrocellulose-surface microarray containing human cytokines, chemokines, and other circulating proteins and demonstrated that the array permitted specific detection of serum factor-binding probes. We used the arrays to detect previously described autoantibodies against cytokines in samples from individuals with autoimmune polyendocrine syndrome type 1 and chronic mycobacterial infection. Serum profiling from individuals with SLE revealed that among several targets, elevated IgG autoantibody reactivity to B cell-activating factor (BAFF) was associated with SLE compared with control samples. BAFF reactivity correlated with the severity of disease-associated features, including IFN-α-driven SLE pathology. Our results showed that serum factor protein microarrays facilitate detection of autoantibody reactivity to serum factors in human samples and that BAFF-reactive autoantibodies may be associated with an elevated inflammatory disease state within the spectrum of SLE.

Anti-GM-CSF autoantibodies in patients with cryptococcal meningitis.

Cryptococcal meningitis has been described in immunocompromised patients, as well as in those for whom no immune defect has been identified. GM-CSF regulates the function of phagocytes and pulmonary alveolar macrophages, critical elements in cryptococcal control. We performed clinical histories, immunological evaluation, and anticytokine autoantibody screening in four current patients with cryptococcal meningitis and identified and tested 103 archived plasma/cerebrospinal fluid samples from patients with cryptococcal meningitis. We assessed the ability of anti-GM-CSF autoantibody-containing plasmas to inhibit GM-CSF signaling. We recognized anti-GM-CSF autoantibodies in an otherwise healthy female with cryptococcal meningitis who later developed pulmonary alveolar proteinosis (PAP). Her diagnosis prompted screening of patients with cryptococcal meningitis for anticytokine autoantibodies. We identified seven HIV-negative patients with cryptococcal meningitis who tested positive for high-titer anti-GM-CSF autoantibodies. Two of the seven later developed evidence of PAP. Plasma from all patients prevented GM-CSF-induced STAT5 phosphorylation and MIP-1α production in normal PBMCs. This effect was limited to their IgG fraction. Anti-GM-CSF autoantibodies are associated with some cases of cryptococcal meningitis in otherwise immunocompetent patients. These cases need not have associated PAP.

Dominant gain-of-function STAT1 mutations in FOXP3 wild-type immune dysregulation-polyendocrinopathy-enteropathy-X-linked-like syndrome.

BACKGROUND: Mutations in signal transducer and activator of transcription (STAT) 1 cause a broad spectrum of disease, ranging from severe viral and bacterial infections (amorphic alleles) to mild disseminated mycobacterial disease (hypomorphic alleles) to chronic mucocutaneous candidiasis (CMC; hypermorphic alleles). The hypermorphic mutations are also associated with arterial aneurysms, autoimmunity, and squamous cell cancers. OBJECTIVE: We sought to investigate the role of STAT1 gain-of-function mutations in phenotypes other than CMC. METHODS: We initially screened patients with CMC and autoimmunity for STAT1 mutations. We functionally characterized mutations in vitro and studied immune profiles and regulatory T (Treg) cells. After our initial case identifications, we explored 2 large cohorts of patients with wild-type forkhead box protein 3 and an immune dysregulation-polyendocrinopathy-enteropathy-X-linked (IPEX)-like phenotype for STAT1 mutations. RESULTS: We identified 5 children with polyendocrinopathy, enteropathy, and dermatitis reminiscent of IPEX syndrome; all but 1 had a variety of mucosal and disseminated fungal infections. All patients lacked forkhead box protein 3 mutations but had uniallelic STAT1 mutations (c.629 G>T, p.R210I; c.1073 T>G, p.L358W, c.796G>A; p.V266I; c.1154C>T, T385M [2 patients]). STAT1 phosphorylation in response to IFN-γ, IL-6, and IL-21 was increased and prolonged. CD4(+) IL-17-producing T-cell numbers were diminished. All patients had normal Treg cell percentages in the CD4(+) T-cell compartment, and their function was intact in the 2 patients tested. Patients with cells available for study had normal levels of IL-2-induced STAT5 phosphorylation. CONCLUSIONS: Gain-of-function mutations in STAT1 can cause an IPEX-like phenotype with normal frequency and function of Treg cells.

Anticytokine autoantibodies in infectious diseases: pathogenesis and mechanisms.

Autoantibodies to cytokines occur in many different conditions and situations and can cause a wide range of disease, including pulmonary alveolar proteinosis, disseminated non-tuberculous mycobacterial disease, pure red-cell aplasia, and chronic mucocutaneous candidiasis. Anticytokine autoantibodies may also develop against exogenously administered cytokines, sometimes diminishing their effects or inhibiting the activity of the endogenous cytokine. Unlike primary congenital immunodeficiencies, autoantibodies may develop over time, wax and wane, and may change in titre or avidity. Naturally occurring autoantibodies to interferons α, ß, and γ, interleukins 1α, 2, 6, and 10, tumour necrosis factor, and granulocyte-macrophage colony-stimulating factor have been reported in healthy individuals and have been identified in rheumatological diseases, graft-versus-host disease, and cancer. Therapeutic antibodies, growth factors, other biological agents, and cytokines used to treat acute, chronic, malignant, and immune diseases may elicit or overcome autoantibodies, hence influencing the primary intended therapy. The increasing number of biologically active anticytokine autoantibodies being reported suggests that currently "idiopathic" diseases may someday be explained by neutralising or agonising autoantibodies. Their protean roles in causing, treating, preventing, and responding to disease, as well as simply maintaining normal homoeostasis, offer fascinating insights into the biology of immunity, inflammation, and infection.

Immunodeficiency secondary to anticytokine autoantibodies.

PURPOSE OF REVIEW: Anticytokine autoantibodies are an important and emerging mechanism of disease pathogenesis. We will review the clinical and laboratory features of syndromes in which immunodeficiency is caused by or associated with neutralizing anticytokine autoantibodies. RECENT FINDINGS: A growing number of patients have been described who demonstrate unique infectious phenotypes associated with neutralizing autoantibodies that target a particular cytokine known to participate in host defense against the offending organism. Examples include antigranulocyte macrophage-colony stimulating factor (GM-CSF) autoantibodies and pulmonary alveolar proteinosis; anti-interferon (IFN)-γ autoantibodies and disseminated nontuberculous mycobacteria (NTM); anti-interleukin-(IL)-6 autoantibodies and severe staphylococcal skin infection; anti-IL-17A, anti-IL-17F, or anti-IL-22 autoantibodies in patients with mucocutaneous candidiasis in the setting of both the autoimmune polyendocrinopathy, candidiasis, ectodermal dystrophy (APECED) syndrome and in cases of thymoma. SUMMARY: Anticytokine autoantibodies have manifestations that are diverse, ranging from asymptomatic to life-threatening. These emerging and fascinating causes of acquired immunodeficiency may explain some previously idiopathic syndromes.

Anti-cytokine autoantibodies are associated with opportunistic infection in patients with thymic neoplasia.

Patients with thymic malignancy have high rates of autoimmunity leading to a variety of autoimmune diseases, most commonly myasthenia gravis caused by anti-acetylcholine receptor autoantibodies. High rates of autoantibodies to cytokines have also been described, although prevalence, spectrum, and functionality of these anti-cytokine autoantibodies are poorly defined. To better understand the presence and function of anti-cytokine autoantibodies, we created a luciferase immunoprecipitation system panel to search for autoantibodies against 39 different cytokines and examined plasma from controls (n = 30) and patients with thymic neoplasia (n = 17). In this screen, our patients showed statistically elevated, but highly heterogeneous immunoreactivity against 16 of the 39 cytokines. Some patients showed autoantibodies to multiple cytokines. Functional testing proved that autoantibodies directed against interferon-α, interferon-ß, interleukin-1α (IL-1α), IL-12p35, IL-12p40, and IL-17A had biologic blocking activity in vitro. All patients with opportunistic infection showed multiple anti-cytokine autoantibodies (range 3-11), suggesting that anti-cytokine autoantibodies may be important in the pathogenesis of opportunistic infections in patients with thymic malignancy. This study was registered at http://clinicaltrials.gov as NCT00001355.

Sirolimus-based graft-versus-host disease prophylaxis protects against cytomegalovirus reactivation after allogeneic hematopoietic stem cell transplantation: a cohort analysis.

Sirolimus-based immunosuppressive regimens in organ transplantation have been associated with a lower than expected incidence of cytomegalovirus (CMV) disease. Whether sirolimus has a similar effect on CMV reactivation after allogeneic hematopoietic stem cell transplantation (HSCT) is not known. We evaluated 606 patients who underwent HSCT between April 2000 and June 2004 to identify risk factors for CMV reactivation 100 days after transplantation. The cohort included 252 patients who received sirolimus-tacrolimus for graft-versus-host disease (GVHD) prophylaxis; the rest received non-sirolimus-based regimens. An initial positive CMV DNA hybrid capture assay was observed in 225 patients (37.1%) at a median 39 days after HSCT for an incidence rate of 0.50 cases/100 patient-days (95% confidence interval [CI], 0.44-0.57). Multivariable Cox modeling adjusting for CMV donor-recipient serostatus pairs, incident acute GVHD, as well as other important covariates, confirmed a significant reduction in CMV reactivation associated with sirolimus-tacrolimus-based GVHD prophylaxis, with an adjusted HR of 0.46 (95% CI, 0.27-0.78; P = .004). The adjusted HR was 0.22 (95% CI, 0.09-0.55; P = .001) when persistent CMV viremia was modeled. Tacrolimus use without sirolimus was not significantly protective in either model (adjusted HR, 0.66; P = .14 and P = .35, respectively). The protective effect of sirolimus-containing GVHD prophylaxis regimens on CMV reactivation should be confirmed in randomized trials.