Disseminated cryptococcosis in two boys with novel mutation of CD40 Ligand-Associated X-linked hyper-IgM syndrome.

X-linked hyper-IgM syndrome (XHIM) caused by CD40L mutations is a primary immunodeficiency condition that increases susceptibility to opportunistic infections. Disseminated cryptococcosis in XHIM is rarely reported in children. Here, we report two related boys who have a novel hemizygous frameshift c.208delC mutation of CD40L. They live in the western region of Thailand and developed disseminated cryptococcosis while receiving regular intravenous immunoglobulin supplementation.

Bell's palsy in a pediatric patient with hyper IgM syndrome and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Bell's palsy is an acute facial paralysis with known association to viral infections. We describe a medically complex 6-year-old male with hyper IgM syndrome who presented with unilateral facial droop and positive SARS-CoV-2 RT-PCR. This is the first reported pediatric case of Bell's palsy in the setting of SARS-CoV-2 infection.

A tetrameric form of CD40 ligand with potent biological activities in both mouse and human primary B cells.

CD40 ligand (CD40 L) expressed by activated T cells interacts with CD40 on B cells and triggers B cell survival, proliferation and differentiation. Deficiency in CD40 L or CD40 in humans causes hyper IgM syndrome due to a defect in T-B interaction that is essential for Ig gene class switch recombination (CSR). CD40 L belongs to the tumor necrosis factor family and normally forms a homotrimer on the cell surface, which is important for its biological activity. To generate a multimeric CD40 L that can be used to stimulate both mouse and human B cells, we fused the extracellular domain of mouse CD40 L, which is known to also bind human CD40, with streptavidin (SA) that forms a stable tetramer under physiological conditions. As expected, 293 T cells transiently transfected with an SA-CD40 L expression vector secreted tetrameric SA-CD40 L in the culture supernatant. The secreted SA-CD40 L exhibited > 25-fold stronger activities in inducing the survival, activation and proliferation of both mouse and human primary B cells than did an agonistic anti-mouse or anti-human CD40 antibody. In the presence of IL-4, SA-CD40 L also induced efficient CSR and plasma cell differentiation in both mouse and human B cells. Moreover, administration of SA-CD40 L in mice induced activation and proliferation of spleen B cells in vivo. These results demonstrate that the SA-CD40 L fusion protein generated in the present study recapitulates the function of membrane-bound trimeric CD40 L and has potent biological activities in both mouse and human primary B cells.

Ataxia-telangiectasia in a patient presenting with hyper-immunoglobulin M syndrome.

Ataxia-telangiectasia (AT) and hyper-immunoglobulin M (HIGM) syndrome are both primary immunodeficiency diseases caused by different genetic defects. While a small proportion of AT patients have increased serum immunoglobulin (Ig) M concentrations during the course of a disease, a high level of IgM at onset is rare. We report the case of an 8-year-old girl who had experienced recurrent respiratory infection, cutaneous abscesses, and hepatosplenomegaly since the age of 2 years. She was diagnosed with HIGM based on the results of immunological studies, including low IgG and IgA levels and raised serum IgM concentrations. However, at the age of 4 years, a neurological examination revealed gait disturbance and telangiectatic lesions on the conjunctiva; therefore, a diagnosis of AT was suggested. In spite of regular intravenous immunoglobulin infusions and antimicrobial prophylaxis, the patient experienced several episodes of respiratory infection and eventually died of respiratory failure at the age of 8 years. Further molecular analysis revealed a novel homozygous missense mutation in exon 53 (c.8250C>T, p.2622Ala>Val) of the ATM gene. Patients with AT and the HIGM phenotype may not develop clinical characteristics of AT for some time. While patients with AT and increased serum IgM levels could have a considerably more severe disease course and a shorter survival, IgM levels could be considered a prognostic factor.

Successful treatment of autoimmune and lymphoproliferative complications of patients with intrinsic B-cell immunodeficiencies with Rituximab.

The heterogeneous group of primary immunodeficiencies requires personalized diagnosis and therapy to acheive an optimal outcome for each patient. This was exemplified by two patients with intrinsic B-cell class-switch defects (subclass of Hyper-IgM syndromes), where lymphoproliferation and autoimmunity determined the clinical course for many years due to lack of exact diagnosis. Based on genetics or a novel functional diagnostic approach, a definite individual diagnosis was established for each patient and they started Rituximab therapy. Autoimmune phenomena and generalized lymphadenopathy disappeared and remained well controlled during the observation period (3-4 years) without adverse effects. Quality of life increased remarkably in both patients.

Hyper-IgM syndrome--a case report and a clinical perspective.

The authors describe the case of a 28-year-old woman, with a history of recurrent bacterial infections since childhood and multiple hospitalizations for pneumonia, with important pulmonary sequelae, including bronchiectasis which warranted the need to perform a left lobectomy and lingulectomia at age 13. After diagnostic work up, the diagnosis of hypogammaglobulinemia with hyper-IgM was established, and she began regular replacement i.v. immunoglobulin treatment, with good tolerance and no side effects. A sequencing of the entire coding region (exons 1-5) of the AICDA gene was performed, and a homozygous c.260G > C mutation was identified, confirming the diagnosis of type 2 hyper-IgM syndrome. This case illustrates the negative impact that a delay in diagnosis and hence delay in treatment has in patients with primary immunodeficiency since early therapy is the only way to reduce the incidence and severity of complications.

Isolated growth hormone deficiency in a patient with immunoglobulin class switch recombination deficiency.

Growth hormone deficiency (GHD) may be associated with a number of immunodeficiency diseases, but its association with immunoglobulin class switch recombination (Ig CSR) deficiencies is very rare. We report the case of a patient with a history of recurrent diarrhea and respiratory infections diagnosed with hyper IgM syndrome on the basis of immunological findings (low serum levels of IgG and IgA and an elevated serum level of IgM). In view of the patient's short stature, growth hormone evaluation was performed and growth hormone deficiency confirmed. The patient received growth hormone therapy in addition to Ig replacement therapy and antibiotics and responded well. As the coding regions of the genes known to be responsible for Ig CSR (CD40L, CD40, AICDA, and UNG) were intact in our patient, this might be a new form of Ig CSR deficiency.

Vesical varices and telangiectasias in a patient with ataxia telangiectasia.

A Japanese boy with ataxia telangiectasia (AT) developed severe gross hematuria and recurrent bladder tamponade, requiring an extensive blood transfusion. He had received intermittent intravenous cyclophosphamide pulse therapy (cumulative dose of 1.3 g) for refractory steroid-resistant and intravenous immunoglobulin-resistant severe autoimmune thrombocytopenia 3 years previously. A cystoscopy revealed multiple varices and severe telangiectasias in the bladder wall. The intensive treatment, such as repeatedly selective embolization of the vesical arteries, proved to be partially effective. Finally, a surgical cystotomy resulted in a gradual improvement in clinical symptoms. To the best of our knowledge, this is the first report of a patient with AT who developed refractory bladder hemorrhage caused by widespread vesical telangiectasias.