Primary/de novo paroxysmal nocturnal hemoglobinuria in a child from north India: a case report with review of literature

Frequency of Paroxysmal Nocturnal Hemoglobinuria Clones by Multiparametric Flow Cytometry in Pediatric Aplastic Anemia Patients of Indian Ethnic Origin

BACKGROUND

The literature on paroxysmal nocturnal hemoglobinuria (PNH) in aplastic anemia (AA) is largely focused on adults with few studies in children. Moreover, large studies are conspicuously absent from developing countries. Knowledge of the prevalence and utility of their detection is required before widespread use of PNH screening in pediatric AA in resource-limited settings.

METHODS

We performed a retrospective audit over a period of 9 years to study the prevalence of PNH clones by flow cytometry (FCM) in children ≤12 years of age presenting with AA, and analyzed their response to immunosuppressant therapy.

RESULTS

Nine (12.9%) out of 70 patients had PNH clones comprising >1% of the target cell population, including five patients (7.14%) with PNH clone size >10%. The clone size in monocytes ranged from 3.7% to 95.2% (median 21.1%) and in neutrophils from 1.6% to 87.6% (median 19.5%). Fluorescent aerolysin (FLAER)-based FCM screening significantly improved the detection of PNH clones compared to non-FLAER based screening techniques (18.4% vs. 6.25%). One child showed chronic intravascular hemolysis and another developed arterial stroke during the course of illness. None of our PNH-positive AA patients tested for chromosome breakage studies (n = 8) showed increased clastrogen-induced breakage.

CONCLUSIONS

A lower frequency but moderate/large-sized PNH clones were seen in our pediatric AA population, compared to western data. FLAER-based FCM screening significantly improved the detection of PNH clones. We recommend routine FLAER-based screening of PNH in pediatric AA patients.

Pediatric myelodysplastic syndromes: they do exist!

One of the most common hematologic malignancies in adults, myelodysplastic syndrome (MDS) is a heterogenous group of clonal disorders characterized by peripheral cytopenia(s) and normal or hypercellular bone marrow with dysplasia in ≥1 blood cell lineages. MDS frequently evolves to secondary acute myeloid leukemia with poor prognosis. Although uncommon among pediatric hematologic malignancies, both de novo and secondary MDS occur in children and may be the first presentation of an inherited bone marrow failure syndrome. Unlike its adult counterpart, pediatric MDS is more frequently associated with hypocellular bone marrow and monosomy 7. Refractory cytopenia is more typical than refractory anemia, as seen in the elderly. Its recognition and management can be quite challenging and requires the expertise of an experienced hematopathologist. In this review, we describe the epidemiology, genetics, and clinical spectrum of pediatric MDS along with its diagnostic and therapeutic challenges. We also compare and contrast pediatric and adult MDS.

Paroxysmal nocturnal haemoglobinuria. Experience over a 10 years period

INTRODUCTION

Paroxysmal nocturnal hemoglobinuria (PNH) is a hemolytic, clonal and acquired disorder of the hematopoietic stem cell with a deficiency of all glycophosphatidyl-inositol (GPI) linked proteins. The aim of this retrospective study was to analyse haematological and biochemical data from 152 patients referred to our laboratory for diagnosis of PNH by flow cytometry (FC).

METHODS

Patients and healthy donor (152 and 99 respectively) were studied. Ham, sucrose, lactate dehydrogenase (LDH), Iron, haptoglobin (Hp), blood cell morphology and Kaplow cytochemical stain for leukocyte alkaline phosphatase (LAP) were carried out. GPI-proteins anti-CD55 and CD59 in erythrocytes and the former, plus anti CD16b and CD66b on neutrophils were evaluated by FC.

RESULTS

Anemia and/or leukopenia and/or thrombocytopenia, increased reticulocyte count and LDH were observed in patients with PNH clone. Some of them had dacriocytes, schistocytes. LAP was low. On average, we detected 50% CD59 (-) erythrocytes and 29, 83, 78% CD55/59 (-), CD16b (-), CD66b (-) neutrophils, respectively.

CONCLUSION

Paroxysmal nocturnal hemoglobinuria clone was detected in 20/152 patients. Negative population's percentages were high in patients with classic PNH, Hematimetry, LAP and adequate use of CF contribute to PNH clone detection in the laboratory.