Background

Recent advances in genomics have enabled the successful identification of a number of rare pathogenic mutations. Uncovering these mutations is essential as the first step towards devising a cure for the often debilitating and life-limiting diseases arising from them. For many of these mutations targeted agents do not yet exist. Here, we describe the case of a patient who has a novel pathogenic mutation in the erythropoietin (EPO) gene, which is essential for normal erythropoiesis, and who presented with a profound hypoplastic anemia.

Methods

The patient aged 5 months, was started on recombinant erythropoietin, at a standard dose of 500 units (50 U/kg) and subsequently 800 units three time weekly and her blood counts were monitored over 4 years.

Findings

A prompt response to the recombinant erythropoietin was found with an increase in hemoglobin levels to 12.8 g/dL and increase in red cell count to 4.89×10⁶/uL. The patient became transfusion independent. The therapy enabled the patient to maintain a hemoglobin level in the normal range without any adverse effects and with no requirement for further blood transfusions.

Conclusions

Patient-customized therapies can be highly effective in the treatment of rare genetic disorders and for many of these disorders effective treatment may already exist in the clinical domain, as described for the patient in this report.

Funding

This work was supported by the New York Stem Cell Foundation (V.G.S.), a gift from the Lodish Family to Boston Children's Hospital (V.G.S.), and National Institutes of Health Grants R01 DK103794 and R01 HL146500 (V.G.S.).

Background

Dedicator of cytokinesis 8 (DOCK8) deficiency is the main cause of the autosomal recessive hyper-IgE syndrome (HIES). We previously reported the selective loss of group 3 innate lymphoid cell (ILC) number and function in a Dock8-deficient mouse model. In this study, we sought to test whether DOCK8 is required for the function and maintenance of ILC subsets in humans.

Methods

Peripheral blood ILC1-3 subsets of 16 DOCK8-deficient patients recruited at the pretransplant stage, and seven patients with autosomal dominant (AD) HIES due to STAT3 mutations, were compared with those of healthy controls or post-transplant DOCK8-deficient patients (n = 12) by flow cytometry and real-time qPCR. Sorted total ILCs from DOCK8- or STAT3-mutant patients and healthy controls were assayed for survival, apoptosis, proliferation, and activation by IL-7, IL-23, and IL-12 by cell culture, flow cytometry, and phospho-flow assays.

Results

DOCK8-deficient but not STAT3-mutant patients exhibited a profound depletion of ILC3s, and to a lesser extent ILC2s, in their peripheral blood. DOCK8-deficient ILC1-3 subsets had defective proliferation, expressed lower levels of IL-7R, responded less to IL-7, IL-12, or IL-23 cytokines, and were more prone to apoptosis compared with those of healthy controls.

Conclusion

DOCK8 regulates human ILC3 expansion and survival, and more globally ILC cytokine signaling and proliferation. DOCK8 deficiency leads to loss of ILC3 from peripheral blood. ILC3 deficiency may contribute to the susceptibility of DOCK8-deficient patients to infections.