Autoantibodies against type I IFNs in humans with alternative NF-κB pathway deficiency

Patients with autoimmune polyendocrinopathy syndrome type 1 (APS-1) caused by autosomal recessive AIRE deficiency produce autoantibodies that neutralize type I interferons (IFNs)1,2, conferring a predisposition to life-threatening COVID-19 pneumonia3. Here we report that patients with autosomal recessive NIK or RELB deficiency, or a specific type of autosomal-dominant NF-κB2 deficiency, also have neutralizing autoantibodies against type I IFNs and are at higher risk of getting life-threatening COVID-19 pneumonia. In patients with autosomal-dominant NF-κB2 deficiency, these autoantibodies are found only in individuals who are heterozygous for variants associated with both transcription (p52 activity) loss of function (LOF) due to impaired p100 processing to generate p52, and regulatory (IκBδ activity) gain of function (GOF) due to the accumulation of unprocessed p100, therefore increasing the inhibitory activity of IκBδ (hereafter, p52LOF/IκBδGOF). By contrast, neutralizing autoantibodies against type I IFNs are not found in individuals who are heterozygous for NFKB2 variants causing haploinsufficiency of p100 and p52 (hereafter, p52LOF/IκBδLOF) or gain-of-function of p52 (hereafter, p52GOF/IκBδLOF). In contrast to patients with APS-1, patients with disorders of NIK, RELB or NF-κB2 have very few tissue-specific autoantibodies. However, their thymuses have an abnormal structure, with few AIRE-expressing medullary thymic epithelial cells. Human inborn errors of the alternative NF-κB pathway impair the development of AIRE-expressing medullary thymic epithelial cells, thereby underlying the production of autoantibodies against type I IFNs and predisposition to viral diseases.

Hematopoietic stem cell transplantation for CD40 ligand deficiency: Results from an EBMT/ESID-IEWP-SCETIDE-PIDTC study

BACKGROUND

CD40 ligand (CD40L) deficiency, an X-linked primary immunodeficiency, causes recurrent sinopulmonary, Pneumocystis and Cryptosporidium species infections. Long-term survival with supportive therapy is poor. Currently, the only curative treatment is hematopoietic stem cell transplantation (HSCT).

OBJECTIVE

We performed an international collaborative study to improve patients' management, aiming to individualize risk factors and determine optimal HSCT characteristics.

METHODS

We retrospectively collected data on 130 patients who underwent HSCT for CD40L deficiency between 1993-2015. We analyzed outcome and variables' relevance with respect to survival and cure.

RESULTS

Overall survival (OS), event-free survival (EFS), and disease-free survival (DFS) were 78.2%, 58.1%, and 72.3% 5 years after HSCT. Results were better in transplantations performed in 2000 or later and in children less than 10 years old at the time of HSCT. Pre-existing organ damage negatively influenced outcome. Sclerosing cholangitis was the most important risk factor. After 2000, superior OS was achieved with matched donors. Use of myeloablative regimens and HSCT at 2 years or less from diagnosis associated with higher OS and DFS. EFS was best with matched sibling donors, myeloablative conditioning (MAC), and bone marrow-derived stem cells. Most rejections occurred after reduced-intensity or nonmyeloablative conditioning, which associated with poor donor cell engraftment. Mortality occurred mainly early after HSCT, predominantly from infections. Among survivors who ceased immunoglobulin replacement, T-lymphocyte chimerism was 50% or greater donor in 85.2%.

CONCLUSION

HSCT is curative in patients with CD40L deficiency, with improved outcome if performed before organ damage development. MAC is associated with better OS, EFS, and DFS. Prospective studies are required to compare the risks of HSCT with those of lifelong supportive therapy.

AUTOIMMUNE DISEASE. Patients with LRBA deficiency show CTLA4 loss and immune dysregulation responsive to abatacept therapy

Mutations in the LRBA gene (encoding the lipopolysaccharide-responsive and beige-like anchor protein) cause a syndrome of autoimmunity, lymphoproliferation, and humoral immune deficiency. The biological role of LRBA in immunologic disease is unknown. We found that patients with LRBA deficiency manifested a dramatic and sustained improvement in response to abatacept, a CTLA4 (cytotoxic T lymphocyte antigen-4)-immunoglobulin fusion drug. Clinical responses and homology of LRBA to proteins controlling intracellular trafficking led us to hypothesize that it regulates CTLA4, a potent inhibitory immune receptor. We found that LRBA colocalized with CTLA4 in endosomal vesicles and that LRBA deficiency or knockdown increased CTLA4 turnover, which resulted in reduced levels of CTLA4 protein in FoxP3(+) regulatory and activated conventional T cells. In LRBA-deficient cells, inhibition of lysosome degradation with chloroquine prevented CTLA4 loss. These findings elucidate a mechanism for CTLA4 trafficking and control of immune responses and suggest therapies for diseases involving the CTLA4 pathway.

Tumor immune surveillance defect of X-linked severe combined immunodeficiency is not Epstein-Barr virus specific

Immunodeficient patients are at an increased risk of developing Epstein-Barr virus (EBV) associated lymphomas. We report a patient with X-linked severe combined immunodeficiency (X-SCID), who presented with an EBV-negative, B-cell non-Hodgkin lymphoma. The tumor did not resolve with chemotherapy or rituximab, but only after recovery of functional donor T-cells cell following hematopoietic stem cell transplantation (HSCT). This case illustrates that the cancer predilection associated with immunodeficient hosts may not be a specific immune defect in the recognition of viral specific antigens, and it could be a defect in immune surveillance necessary for elimination of cells with abnormalities in proliferation, function and/or apoptosis.

Anisotropies in global stereoscopic orientation discrimination

Human orientation discrimination of long rectangular targets formed from dynamic random-element stereograms was assessed at four orientations (horizontal, vertical, left, and right oblique) as a function of width, disparity direction and magnitude using a temporal two-alternative, forced-choice paradigm. The results revealed the presence of an oblique effect in cyclopean orientation discrimination. In addition, observers discriminated targets with crossed disparity better than targets with uncrossed disparity, and had lower discrimination thresholds when the targets were oriented horizontally than vertically. These results demonstrate the existence of the oblique effect in the hypercyclopean domain comparable in magnitude to that present in the luminance domain.

Monitoring demyelination in multiple sclerosis with multi-flash campimetry

Multi-flash campimetry is a computer-implemented psychophysical technique that allows a rapid and extensive assessment of visual flicker sensitivity. Multi-flash field maps generated from the data typically reveal the presence of 'islands' of degraded temporal resolution in multiple sclerosis (MS) patients, but not in normal control observers. These distinct 'islands' presumably reflect the influence of demyelination as well as a variety of other possible transient factors, such as edema and inflammation of the optic nerve. The question addressed in the present study concerned a means of distinguishing among such influences. The strategy employed was to test MS patients more than once over a period of several months. Under the assumption that there is little or no significant remyelination in the central nervous system, it was argued that 'islands' that remain present over time should be those that principally reflect demyelination. Transient changes that appear in the fields of MS patients probably reflect the influence of other mediating factors. Examples of multi-flash field maps are presented to illustrate this point and to serve as an initial assessment of the reliability of the technique. It is concluded that multi-flash campimetry may prove to be an effective aid in documenting the degree of progressive visual involvement in MS, and provide a means of monitoring the clinical course of demyelination in the visual system.

Auditory deficits in multiple sclerosis: a review

This article reviews available clinical and psychophysical data concerning the effects of multiple sclerosis (MS) on basic auditory processes. On the basis of the data, it is suggested that the presence of auditory deficits should be sought in MS patients. This is especially important in light of recent psychophysical evidence suggesting that subtle auditory problems present in affected individuals may not always be detectable via conventional clinical testing. These data also provide an alternate means of interpreting various aspects of impaired auditory functioning in MS patients, and aid in generating new hypotheses regarding the possible consequences of demyelination on normal auditory perception. Finally, new ways of testing such hypotheses are proposed, and possible directions for future research are suggested.

Multi-flash campimetry in multiple sclerosis

Data are reported from the initial stage of development of a psychophysical technique that allows temporal resolution to be sampled in 120 retinal locations per eye in half an hour. This computer generated test consists of systematically increasing the off period of a small spot of light, temporally modulated at 5 Hz, until the light is perceived as flickering. Visual field plots based on the data from control observers reveal good temporal resolution in the central visual field with a fall-off in resolving power in peripheral regions. Data from multiple sclerosis patients are characterized by "islands" of poor temporal resolution that presumably reflect demyelination along the optic nerve.