Unusually High Prevalence of Stroke and Cerebral Vasculopathy in Hemoglobin SC Disease: A Retrospective Single Institution Study

INTRODUCTION

Unlike homozygous hemoglobin SS (HbSS) disease, stroke is a rare complication in hemoglobin SC (HbSC) disease. However, recent studies have demonstrated a high prevalence of silent stroke in HbSC disease. The factors associated with stroke and cerebral vasculopathy in the HbSC population are unknown.

METHODS

We conducted a retrospective study of all patients with sickle cell disease treated at the University of Missouri, Columbia, over an 18-year period (2000-2018). The goal of the study was to characterize the silent, overt stroke, and cerebral vasculopathy in HbSC patients and compare them to patients with HbSS and HbS/β thalassemia1 (thal) in this cohort. We also analyzed the laboratory and clinical factors associated with stroke and cerebral vasculopathy in the HbSC population.

RESULTS

Of the 34 HbSC individuals, we found that the overall prevalence of stroke and cerebral vasculopathy was 17.7%. Only females had evidence of stroke or cerebral vasculopathy in our HbSC cohort (33.3%, p = 0.019). Time-averaged means of maximum velocities were lower in the HbSC group than the HbSS group and did not correlate with stroke outcome. Among HbSC individuals, those with stroke and cerebral vasculopathy had a marginally higher serum creatinine than those without these complications (0.77 mg/dL vs. 0.88 mg/dL, p = 0.08). Stroke outcome was associated with recurrent vaso-occlusive pain crises (Rec VOCs) (75 vs. 25%, p = 0.003) in HbSC patients. The predominant cerebrovascular lesions in HbSC included microhemorrhages and leukoencephalopathy.

CONCLUSION

There is a distinct subset of individuals with HbSC who developed overt, silent stroke, and cerebral vasculopathy. A female predominance and association with Rec VOCs were identified in our cohort; however, larger clinical trials are needed to identify and confirm specific clinical and laboratory markers associated with stroke and vasculopathy in HbSC disease.

L-leucine improves anemia and growth in patients with transfusion-dependent Diamond-Blackfan anemia: Results from a multicenter pilot phase I/II study from the Diamond-Blackfan Anemia Registry

BACKGROUND

Diamond-Blackfan anemia (DBA) is an inherited bone marrow failure syndrome characterized by anemia, short stature, congenital anomalies, and cancer predisposition. Most cases are due to mutations in genes encoding ribosomal proteins (RP) leading to RP haploinsufficiency. Effective treatments for the anemia of DBA include chronic red cell transfusions, long-term corticosteroid therapy, or hematopoietic stem cell transplantation. In a small patient series and in animal models, there have been hematologic responses to L-leucine with amelioration of anemia. The study objectives of this clinical trial were to determine feasibility, safety, and efficacy of L-leucine in transfusion-dependent patients with DBA.

PROCEDURE

Patients ≥2 years of age received L-leucine 700 mg/m² orally three times daily for nine months to determine a hematologic response and any improvement in growth (NCT01362595).

RESULTS

This multicenter, phase I/II study enrolled 55 subjects; 43 were evaluable. There were 21 males; the median age at enrollment was 10.4 years (range, 2.5-46.1 years). No significant adverse events were attributable to L-leucine. Two subjects had a complete erythroid response and five had a partial response. Nine of 25, and 11 of 25, subjects experienced a positive weight and height percentile change, respectively, at the end of therapy.

CONCLUSIONS

L-leucine is safe, resulted in an erythroid response in 16% of subjects with DBA, and led to an increase in weight and linear growth velocity in 36% and 44% of evaluable subjects, respectively. Further studies will be critical to understand the role of L-leucine in the management of patients with DBA.

An Unusual Case of Fetal/Neonatal Alloimmune Thrombocytopenia

Objectives

Fetal/neonatal alloimmune thrombocytopenia (FNAIT) occurs when maternal IgG alloantibodies against paternal human platelet antigens (HPA) cross the placenta and cause the destruction of fetal platelets. The vast majority (up to 95%) of FNAIT cases are caused by antibodies against HPA-1a or HPA-5b antigens, while the remaining cases are usually due to antibodies against a variety of other HPA antigens. Cases of FNAIT due to anti-HLA antibodies are extremely uncommon and have only rarely been reported. We present a case of FNAIT suspected to be caused by anti-HLA class I alloantibodies.

Methods

The patient is a term infant boy born to a 32-year-old G2T2L2 mother. The mother had a previous diagnosis of Still disease (an adult form of systemic juvenile rheumatoid arthritis) but experienced complete resolution of symptoms and was off all treatment during the pregnancy. At birth, laboratory testing revealed isolated severe thrombocytopenia (platelet count 38,000/mcL) in an otherwise healthy-appearing infant.

Results

The infant had no evidence of bleeding, and testing for TORCH infection, sepsis, and DIC was negative. The maternal blood type was O positive. The maternal platelet count was normal. FNAIT was suspected and the infant was given two platelet transfusions from the same HPA 1a and 5b antigen-negative donor with no significant or sustained improvement in platelet count. Maternal platelet antibody testing subsequently revealed an absence of HPA antibodies, but anti-HLA class I alloantibodies were present. The infant was treated with three subsequent doses of IVIg with improvement in platelet count. No significant hemorrhage occurred.

Conclusion

HLA class I antibodies are commonly found in multiparous women but are not generally thought to cause significant fetal complications during subsequent pregnancies. This case suggests that, although rarely reported, HLA class I alloantibodies may be capable of causing FNAIT.

ZRSR2 mutation in a child with refractory macrocytic anemia and Down Syndrome

Here we report a case of refractory macrocytic anemia with a spliceosomal point mutation involving the ZRSR2 gene in a child with Down syndrome (DS). Such mutations have been shown to cause refractory macrocytic anemia and myelodysplastic syndrome (MDS) in elderly individuals. We report the hematological indices of a child with DS and a ZRSR2 spliceosomal mutation. DS is known to produce macrocytic anemia but does not lead to transfusion dependence. In this case, the ZRSR2 mutation was the likely implicating factor for severe transfusion-dependent anemia in a child with DS. The clinical implication of a ZRSR2 mutation in a child with DS has not been previously described and warrants close surveillance to detect potential insidious transformation to MDS.

Partial compensation of sexual receptivity deficits in female rats with bilateral lesions of the hypothalamic ventromedial nucleus by transplants of fetal mediobasal hypothalamic tissue

Bilateral aspiration as well as bilateral electrolytic lesions of the hypothalamic ventromedial nucleus (VMN) in ovariectomized, adult female rats treated with testosterone or estrogen resulted in a long-lasting decrease of sexual receptivity. Fetal mediobasal hypothalamic (MBH) tissue was grafted successfully to the site of VMN lesions. The following presuppositions for a sufficient rate of long-term survival of the grafts could be defined: (1) careful lesioning and minimalizing of damage to the surrounding tissues, (2) high vitality of the donor fetuses, (3) delay of transplantation after lesioning, and (4) testosterone treatment of the recipient animals at an early stage of graft development. In rats with surviving MBH grafts the receptivity deficits resulting from bilateral aspiration of the VMN were compensated partially.

Prevention of lesioning-induced precocious puberty in female rats by neonatal implantation of fetal preoptic tissue

Damage to the medial preoptic area (MPOA) was produced in one-day-old female rats by bilateral electrolytic lesions or by aspiration of preoptic tissue. Both procedures resulted in similar advancement of vaginal opening and the first ovulation. A further group of rats was lesioned or aspirated in the MPOA and immediately bilaterally implanted with medial preoptic tissue collected by the puncture method from 17-19-day-old female rat fetuses. After autopsy, tissue destruction and implants located in the MPOA could be identified in 5 females that showed significantly later onset of puberty than both the lesioned or aspirated and the untreated controls. The findings suggest that the elimination of neurones and not a stimulatory effect of electrolytic lesions on GnRH secretion is responsible for the acceleration of sexual maturation recorded after lesioning of the MPOA. Possible reasons for the failure to identify the grafts in most of the implanted females are discussed.