Clinical and Immunological Characterization of ICF Syndrome in Japan

OBJECTIVE

Immunodeficiency, centromeric instability, and facial anomalies (ICF) syndrome is a rare autosomal recessive primary immunodeficiency. Hypogammaglobulinemia is a major manifestation of ICF syndrome, but immunoglobulin replacement therapy does not seem to be effective for some ICF patients. Therefore, we aimed to reassess the immunological characteristics of this syndrome.

METHODS

Eleven Japanese patients with ICF syndrome were enrolled. We performed whole-exome sequencing in four cases and homozygosity mapping using SNP analysis in two. We evaluated their clinical manifestations and immunological status.

RESULTS

We newly diagnosed six ICF patients who had tentatively been diagnosed with common variable immunodeficiency. We identified two novel mutations in the DNMT3B gene and one novel mutation in the ZBTB24 gene. All patients showed low serum IgG and/or IgG2 levels and were treated by periodic immunoglobulin replacement therapy. Three of the six patients showed worse results of the mitogen-induced lymphocyte proliferation test. Analyses of lymphocyte subpopulations revealed that CD19+CD27+ memory B cells were low in seven of nine patients, CD3+ T cells were low in three patients, CD4/8 ratio was inverted in five patients, CD31+ recent thymic emigrant cells were low in two patients, and CD19+ B cells were low in four patients compared with those in the normal controls. ICF2 patients showed lower proportions of CD19+ B cells and CD16+56+ NK cells and significantly higher proportions of CD3+ T cells than ICF1 patients. T cell receptor excision circles were undetectable in two patients. Despite being treated by immunoglobulin replacement therapy, three patients died of influenza virus, fatal viral infection with persistent Epstein-Barr virus infection, or JC virus infection. One of three dead patients showed normal intelligence with mild facial anomaly. Two patients presented with autoimmune or inflammatory manifestations. Infectious episodes decreased in three patients who were started on trimethoprim-sulfamethoxazole and/or antifungal drugs in addition to immunoglobulin replacement therapy. These patients might have suffered from T cell immunodeficiency.

CONCLUSION

These results indicate that patients with ICF syndrome have a phenotype of combined immunodeficiency. Thus, to achieve a better prognosis, these patients should be treated as having combined immunodeficiency in addition to receiving immunoglobulin replacement therapy.

Type I and III Interferon Productions Are Impaired in X-Linked Agammaglobulinemia Patients Toward Poliovirus but Not Influenza Virus

Background

X-linked agammaglobulinemia (XLA) is a primary immunodeficiency caused by Bruton's tyrosine kinase (BTK) mutation. Patients are susceptible to severe enterovirus infections. The underlying mechanism remains unknown. BTK is involved in toll-like receptors pathway, which initiates antiviral responses including interferon (IFN) productions.

Objective

To demonstrate type I and III IFN productions in dendritic cells of XLA patients is decreased in response to oral poliovirus vaccine (OPV) but not H1N1 virus.

Methods

Monocyte-derived dendritic cells (MoDCs) were derived from nine XLA patients aged 22-32 years old and 23 buffy coats from Hong Kong Red Cross blood donors. LFM-A13 was used to inhibit BTK. OPV Sabin type 1 and H1N1 influenza virus were used to stimulate MoDCs with RPMI as mock stimulation. The antiviral cytokine productions and phenotypic maturation of MoDCs were determined 24 h post-stimulation. OPV RNA was determined at 0, 6, 12, and 24 h post-stimulation.

Results

Upon OPV stimulation, IFN-α2, IFN-β, and IFN-λ1 productions in MoDCs from XLA patients and BTK-inhibited MoDCs of healthy controls were significantly lower than that from healthy controls. Whereas upon H1N1 stimulation, the IFN-α2, IFN-β, and IFN-λ1 productions were similar in MoDCs from XLA patients, BTK-inhibited MoDCs of healthy controls and healthy controls. The mean fluorescent intensities (MFI) of CD83, CD86, and MHC-II in MoDCs from XLA patients in response to OPV was similar to that in response to mock stimulation, while the MFI of CD83, CD86, and MHC-II were significantly higher in response to H1N1 stimulation than that in response to mock stimulation. Whereas, the MFI of CD83, CD86, and MHC-II in MoDCs of healthy controls were significantly higher in response to both OPV and H1N1 stimulation compared to that in response to mock stimulation.

Conclusion

Production of type I and III IFN in response to OPV was deficient in MoDCs from XLA patients, but was normal in response to H1N1 due to deficient BTK function. Moreover, phenotypic maturation of MoDCs from XLA patients was impaired in response to OPV but not to H1N1. These selective impairments may account for the unique susceptibility of XLA patients toward severe enterovirus infections.

Emergence of Carbapenem Non-susceptible Campylobacter coli after Long-term Treatment against Recurrent Bacteremia in a Patient with X-linked Agammaglobulinemia

We herein report a case of recurrent Campylobacter coli bacteremia in a 37-year-old Japanese man with X-linked agammaglobulinemia (XLA). The patient experienced seven episodes of C. coli bacteremia over one year, with an erythematous rash intermittently emerged on the lower limbs. Although hospitalization for intravenous treatment was repeatedly recommended, he obstinately declined it. Following long-term oral antibiotic treatment with tebipenem and faropenem for the persistent infection, C. coli showed elevated minimum inhibitory concentrations to meropenem, a key drug for severe campylobacteriosis. Physicians should note that the overuse of antibiotics can lead to the emergence of carbapenem-non-susceptible Campylobacter strains.

Enhancement of stem cell engraftment on a WHIM

WHIM (warts, hypogammaglobulinemia, infections, and myelokathexis) syndrome is a genetic autoimmune disorder that results from gain-of-function mutations in the gene encoding chemokine receptor CXCR4. A previous study characterized a patient with WHIM who underwent a chromothriptic event that resulted in spontaneous deletion of the WHIM allele in a single hematopoietic stem cell and subsequent cure of the disease. In this issue of the JCI, Gao et al. extend this work and show that Cxcl4-haplosufficient bone marrow has a selective advantage for long-term engraftment in murine WHIM models. Moreover, successful engraftment occurred without prior conditioning of recipients. Together, these results have important implications for improving hematopoietic stem/progenitor cell transplant not only for patients with WHIM but also for all patients who may require the procedure.

[Successful cord blood transplantation in a patient with adult-onset common variable immunodeficiency]

Common variable immunodeficiency (CVID) is the most frequently diagnosed congenital immunodeficiency and is characterized by dysfunctional antibody production. It often occurs at the age of ≥10 years. Here we reported a case of a 46-year-old man confirmed with adult-onset CVID. He was effectively treated with cord blood transplant (CBT). The patient was observed with repeated upper respiratory infection a few years back and was referred to our department owing to a marked decrease in neutrophil counts and progression of anemia. Laboratory tests confirmed hypogammaglobulinemia, but no autoantibodies were detected. Bone marrow aspiration showed a hypocellular marrow with predominantly mature lymphocytes. T-cell receptor excision circle assay revealed a reduction in T-cell neogenesis. Further, multicolor flow cytometry analysis revealed a low differentiation of B cells; subsequently, CVID was confirmed in the patient. The patient had a severe clinical course and therefore, received CBT for the treatment. After the transplantation, the hematopoiesis was restored and the serum immunoglobulin levels returned to normal. The patient exhibited a favorable clinical course. Nevertheless, there is no precise definition to establish the disease concept of CVID. Also, most of the potential cases are predominantly reported in adults. Therefore, further data on cases with CVID should be accumulated to establish the diagnostic criteria as well as treatment modalities.