Flow cytometry-detected changes in megaloblastic anemia secondary to cobalamin deficiency

Introduction: Megaloblastic anemias secondary to Vitamin B12 deficiency are a group of pathologies produced by defective nuclear DNA synthesis. Objective: To describe the maturation alterations found in hematopoietic precursors of the bone marrow in a series of patients with megaloblastic anemia. Methods: Were included patients attended at the Regional Hospital of Concepción with bone marrow samples sent for the study of cytopenia by flow cytometry whose final diagnosis was megaloblastic anemia. The immunophenotype was performed with CD45, CD34, CD117, HLA-DR, markers of neutrophil (CD13, CD11b, CD10, CD16) and/or erythroblast (CD105, CD71, CD36) maturation. Results: From the flow cytometry laboratory database, 8 patients with megaloblastic anemia were identified, and myelodysplastic syndromes (n=9) and normal or reactive bone marrow (n=10) were used as controls. 44% were men, with a median age of 58 years. Megaloblastic anemia was associated with a higher proportion of size and complexity of erythroid and myeloid progenitors compared to lymphocytes compared to controls. The total percentage of erythroblasts and the proportion of CD34+ myeloid cells associated with erythroid lineage was higher in megaloblastic anemia, associated with a maturation arrest in the CD105+ precursor stage (69% vs 19% and 23%, p<0.001). The heterogeneity of CD36 and CD71 in megaloblastic anemia was similar to myelodysplastic syndromes. Conclusions: Megaloblastic anemia produces a heterogeneous involvement of hematopoiesis, characterized by a greater size and cellular complexity of precursors of the neutrophil and erythroid series and a maturation arrest of the erythroblasts.

Introducción: Anemias megaloblásticas secundarias a la deficiencia de vitamina B12 son patologías producidas por una síntesis defectuosa del ADN nuclear. Objetivo: Describir las alteraciones madurativas encontradas en precursores hematopoyéticos de la médula ósea de una serie de pacientes con anemia megaloblástica. Métodos: Se incluyeron pacientes atendidos en el Hospital Regional de Concepción con muestras de médula ósea enviadas para estudio de citopenias por citometría de flujo cuyo diagnóstico fue anemia megaloblástica. El inmunofenotipo se realizó con CD45, CD34, CD117, HLA-DR, marcadores de maduración de serie de neutrófilo (CD13, CD11b, CD10, CD16) y/o eritroblasto (CD105, CD71, CD36). Resultados: Se identificaron 8 pacientes con anemia megaloblástica y como controles se utilizaron síndromes mielodisplásicos (n=9) y médula ósea normal o reactiva (n=10). El 44% eran hombres, con una mediana de edad de 58 años. La anemia megaloblástica se asoció con una mayor proporción de tamaño y complejidad de progenitores eritroides y mieloides con respecto de los linfocitos en comparación a los controles. El porcentaje total de eritroblastos y la proporción de células mieloides CD34+ comprometidas con el linaje eritroide fue mayor en anemia megaloblástica, asociado a una parada madurativa en la etapa de precursor CD105+ (69% vs 19% y 23%, p <0.001). La heterogeneidad de CD36 y CD71 en anemia megaloblástica fue similar a los síndromes mielodisplásicos. Conclusiones: la anemia megaloblástica produce una afectación heterogénea de la hematopoyesis, caracterizada por un mayor tamaño y complejidad celulares de precursores de la serie neutrófilo y eritroide y una detención madurativa de los eritroblastos.

Deficiencia de cobalamina C de inicio temprano: presentación de caso clínico / Early onset cobalamin C deficiency: clinical case presentation

Cobalamin C (CblC) deficiency is an autosomal recessive disorder caused by mutations of the MMACHC gene that results in impaired synthesis of the methylcobalamin and adenosylcobalamin co-factors. This brings an impaired conversion of dietary cobalamin and therefore dysfunction of two key enzymes generating hyperhomocysteinemia, hypometionimemia and methylmalonic aciduria. It is the most common intracellular metabolism disorder of cobalamin. The early clinical form is the most frequent disorder and appears as a multisystemic disease with developmental delay, failure to thrive, and ocular, renal and hematological involvement during the first year of life. The thromboembolic events are associated with small vessel involvement, generating thrombotic microangiopathy responsible for renal involvement and pulmonary thromboembolism. The late-onset form is characterized by leukoencephalopathy, psychiatric disorders, subacute degeneration of the spinal cord, and thromboembolic events of medium to large vessels. The treatment currently available increases the survival of the patient and improves growth, neurological manifestations, biochemical, hematological profile and hydrocephalus. We present the neonatal debut of a case of CblC deficiency that appeared as a multisystem disease with initial neurological, ocular and hematological manifestations. The onset of symptoms was acute, a characteristic that is not frequent in CblC. The patient started treatment early, but in an unsatisfactory fashion, which led to increased neurological deterioration. Due to MRI images performed during the evolution of his condition, a superior and transverse sagittal sinus thrombosis, a rare manifestation of the disease, was observed.

La deficiencia de cobalamina C (CblC) es un defecto autosómico recesivo causado por la mutación del gen MMACHC, que resulta en la síntesis alterada de los cofactores metilcobalamina y adenosilcobalamina. Esto trae aparejado una disfunción de dos enzimas claves, lo cual genera hiperhomocisteinemia, hipometionimemia y aciduria metilmalónica. La presentación clínica de la deficiencia de CblC es heterogénea, y varía desde las formas de inicio temprano graves y potencialmente mortales, hasta los fenotipos más leves de inicio tardío. La forma clínica temprana es la más frecuente y se manifiesta como una enfermedad multisistémica, con restricción del desarrollo, restricción del crecimiento y alteraciones oculares, renales y hematológicas durante el primer año de vida. Las manifestaciones tromboembólicas están asociadas con el compromiso de pequeños vasos, lo que causa microangiopatía trombótica, responsable de compromiso renal y de tromboembolismo pulmonar. La forma tardía se caracteriza por leucoencefalopatía, trastornos psiquiátricos, degeneración subaguda de la médula espinal y eventos tromboembólicos de medianos o grandes vasos. El tratamiento disponible actualmente aumenta la supervivencia de la enfermedad y mejora el crecimiento, las manifestaciones neurológicas, el perfil bioquímico y hematológico y la hidrocefalia. Presentamos el debut neonatal de un caso de deficiencia de CblC que se manifestó con compromiso inicial neurológico, ocular y hematológico. El comienzo de los síntomas fue agudo, característica que no es frecuente en la deficiencia de CblC. El tratamiento se inició tempranamente, pero en forma insatisfactoria, con evolución de deterioro neurológico. En la evolución de su enfermedad en las imágenes de resonancia magnética, se puso de manifiesto trombosis de los senos sagital superior y transversos, una rara manifestación de la deficiencia de CblC.

Mielopatia por deficiência de cobalamina: resolução clínica e de imagem / Cobalamin deficiency myelopathy: clinical and imaging resolution

Embora o quadro clássico de mielopatia por deficiência de vitaminaB12 seja a degeneração subaguda combinada da medula, a manifestaçãoclínica pode ser variável. Homem branco de 36 anos de idade com hipotireoidismo e vitiligo apresentou dormência nas mãos de início súbito. Exame físico: sinal de Lhermitte e hipoestesia nas palmas. Evidenciada alteração de sinal na ressonância magnética (RM) da medula cervical. Foram evidenciados nível sérico de vitamina B12 de 150 pg/mL, gastrite atrófica e hemograma normal. Paciente foi tratado com reposição intramuscular de vitamina B12. Após seis meses, houve remissão completa dos sintomas com normalização do exame de imagem em um ano. O presente caso ilustra discreta alteração clínica e lesão extensa na RM (dissociação entre a clínica e o exame de imagem) na deficiência de B12. A melhora dos sintomas precedeu a resolução da alteração no exame de imagem, no presente caso.

Although the classic manifestation of myelopathy due to vitamin B12deficiency is a subacute combined degeneration of the spinal cord, the clinical manifestation may be varied. A 36-year-old white man with hypothyroidism and vitiligo presented sudden onset of numbness in hands. Physical examination: Lhermitte's sign and hypoesthesia in palms. Signal change on magnetic resonance image (MRI) of the cervical spinal cord was evidenced. Serum vitamin B12 of 150 pg/mL, gastric atrophy and normal hemogram were shown. The patient was treated with intramuscular vitamin B12 replacement. After six months there was complete remission of the symptoms, and within one year the MRI was normal. This case illustrates mild clinical signs and extensive changes on MRI (dissociation between clinic and image) in B12 deficiency. Resolution of MRI was observed after the clinical signs, in the present case.