A new syndrome of refractory sideroblastic anemia with vacuolization of marrow precursors and exocrine pancreatic dysfunction

976

December 1979 T/w Journal o f P E D I A T R I C S

A new syndrome of refractory sideroblastic anemia with vacuolization of marrow precursors and exocrine pancreatic dysfunction In the vast decade, we have studied four unrelated children with what we believe ts a previously unreported disorder affecting the bone marrow and exocrine pancreas. During in)Cancy these patients had the onset Of severe, cransfusi6n-dependent, macrocvtic anemia plus a variable degree of neutropenia and thrombocytopenia. Their bone marrows had normal cellularity but were characterized by remarkable vacuolization of erythroid and myeloid precursors, hemo'siderosis, and ringed sideroblasts. The vacuoles probably represented manifestations of cellular degeneration and death. In two patients, in vitro bone marrow eultltres showed abnormal erythroid and myeloid progenitor cell growth and, in one child. abnormal vacuolated erythroid colonies. Family histories were unrevealing, parents were hematologicallv normal, iTnd both sexes Were involved. There was no evidence of specific nutritional deficiencies or exposure w agents associated with marrow vacuolization. A number of therapeutic interventions produced no effect. One child had clinical malabsorption. This child and one other had extensive pancreatic fibrosis at. autopsy. The other two patients had findings indicating exocrine pancreatic dysfunction. Two children had splenic atrophy. This new syndrome, with assoc'ia~ed bone marrow and exocrine pancreatic dyshmctions, differs in several respects from the syndrome of pancreattc liposis and neutropenia described by Shwachman et al and Bodian et al, and from other conditions with vacuolization of the marrow or sideroblastosis.

Howard A. Pearson. Jeffrey S. Lobel, Samuel A. Kocoshis. J. Lawrence Naiman, Joan Windmiller. Ahti T. Lammi, Ronald Hoffman, and John C. Marsh, N e w H a v e n , Conn., P h i l a d e l p h i a , Pa., S y d n e y , A u s t r a l i a , a n d Fort Worth, T e x a s

DURING

THE PAST TEN YEARS we have s t u d i e d four

CASE REPORTS 2~

infants with a p r e v i o u s l y u n r e c o g n i z e d d i s o r d e r affecting

Patient 1. A 1.76 kg girl was born after an uneventful term

the hematolSoietic s y s t e m a n d e x o c r l n e p a n c r e a s . T h e

pregnancy to healthy unrelated parents. There were no siblings, family history was negative for hematologic disease, and blood counts of parents were normal. Pallor was noted during the

clinical a n d l a b o r a t o r y f e a t u r e s o~" these patients are t h e basis o f this r e p o r t From the Departments of Pediatrics and Medicine, Yale University School of Medicine," St. Christopher's" Children's Hospital." Royal Alexandra Hospital for Children: a~d Cook's Children's Hospital. Sappol"ted in part by National Institutes of Health giant RR125, GCRC. DRR: US~.I'IS grants HL07262, CA 08341: CA 18341: CA 22697.. and American Cancer Society grant CH 37. Presented in part at the Annual Meeting of the Society for Pediatric Research, New York, April 1978.

Vol. 95, No. 6, pp. 976-984

Abbreviations used ME: myeloid: erythroid rHgb F: fetal hemoglobin FEP: free erythroCyte protoporphyrin CFU-E: colony-forming unit=erythroid ADCPC: agar diffusion chamber progenitor cell neonatal period Hemoglobin level was 9.0 gm/dl, and reticulocyte count 9.2%. There were no blood group incompatibilities between mother and infant; Coombs test was negative in the child. White blood cell and platelet counts were initially normal.

0022-3476/79/120976+09500.90/0 9 1979 The C. V. Mosby Co.

Volume 95 Number 6

Sideroblastic anemia and vacuo[ization o f marrow precursors

At 6 weeks o f age, hemoglobin level had decreased to 5.0 gm/dl with 0.6% reticulocytes. A red blood cell transfi~sion was given. Extensive laboratory investigations did not reveal a cause for the anemia. At 3 months of age, recurrent anemia and reticulocytopenia necessitated another transfusion. Neutropenia (900/ram 3) and thrombocytopenia (100,000/mm 3) were found. Bone marrow aspirate was hypercellular. Striking vacuolization of both myeloid and erythroid precursors was observed. Myeloid/ erythroid ratio was 8:1 (normal 2 to 4:1). Megakaryocytes were present in normal numbers and no vacuolizations were noted. Various therapies had no effect, and regular monthly transfusions were given for recurrent severe anemia. Her growth was retarded but developmental milestones were normal. At 9 months of age, bone marrow aspiration showed normocellularity but markedly reduced numbers of erythroid precursors (ME ratio 14:1). Striking vacuolization was again noted. Increased hemosiderin and ringed sideroblasts were present. Circulating granulocyte level had decreased to 360/mm ~ and platelet count to 76,000/mm 3. Although fetal hemoglobin (Hgb F) level was 3.9%, acid elution (Kleihauer-Betke) preparations of peripheral blood showed red cells which contained large amounts of Hgb F. By one year of age she had marked growth failure; length and weight were well below the third percentiles. Steatorrhea and low serum carotene level were documented. Duodenal aspiration after secretin and pancreozymin stimulation showed reduced bicarbonate, amylase, and lipase activity. Sweat chloride levels were normal. Technetium 99m sulfur colloid scan showed normal hepatic activity but reduced splenic uptake by a small spleen. Conversion of pyridoxine to phyridoxal phosphate was normal (kindly measured by Dr. J. D. Hines, Cleveland). Bone roentgenograms revealed osteoporosis but no localized abnormalities. Pancytopenia became progressively more severe with granulocyte level below 300/mm 3 and platelets less than 10,000/mm ~. She required transfusions every three to four weeks. At 26 months of age she developed severe dehydration and metabolic acidosis. The liver was noted to be enlarged. She became jaundiced. Escherichia coli sepsis and meningitis were diagnosed shortly before death. At autopsy the marrow was moderately hypocellular. The pancreas showed marked fibrosis and acinar atrophy. Cystic dilatation of the ducts and liposis were not present. The islets were normal. Increased hemosiderin was deposited in liver, spleen, pancreas, and marrow. The liver was fatty but not cirrhotic. The spleen was atrophic; weighing 4.5 gm (normal 50 gin). Patient 2. A 2.89 kg boy was born after an uncomplicated term pregnancy to healthy unrelated parents. Two older siblings were healthy but an older sister had diabetes mellitus. Although the child was considered to be pale from birth by the parents, he developed normally until 14 months o f age. At this time anorexia, irritability, and increased pallor were observed. Blood studies at 16 months of age revealed a hemoglobin level of 3.5 gm/dl and reticulocytopenia. Platelets and white cells were normal. The bone marrow was normally cellular with adequate numbers of megakaryocytes. There were slightly reduced

977

numbers o f red cell precursors and increased hemosiderin. Iron stains were not performed. Many o f the marrow precursors were heavily vacuolated. Therapeutic trials with a number of agents were ineffective, and transfusions were required at six- and 8-week intervals during the next year. Several prolonged episodes of neutropenia (500-1000/mm 3) were documented. At t7 months of age stool and duodenal fluid had no demonstrable tryptic activity. Bone roentgenograms were normal. By 2 years of age severe pancytopenia had developed. He died at 29 months after a short illness characterized by fever, dehydration, metabolic acidosis, and hepatic decompensation. At autopsy the liver was fatty but not cirrhotic. The bone marrow was slightly hypocellular. The spleen was atrophic, weighing only 13 gm. The pancreas showed acinar atrophy and fibrosis without liposis. The ducts were not dilated or obstructed. The islets were normal. Moderate generalized hemosiderosis was present; this was out of proportion to the transfusional history. Patient 3. This 1.84 kg girl was born after an uncomplicated term pregnancy to healthy unrelated parents who had normal blood counts. Two older siblings were normal. There were no blood group incompatibilities and Coombs test was negative. At 3 weeks & a g e , hemoglobin level was 9.0 gm/dl, and by 10 weeks was 4.8 gm/dl with 2.6% reticulocytes. Mild leukopenia and thrombocytopenia were also present. A transfusion with packed red cells was administered at 2 months of age. Bone marrow aspirate at 3 months of age was normally cellular. The ME ratio was 4:1 and few red cell precursors were observed beyond the basophilic normoblast stage. Prominent vacuolization of both erythroid and myeloid precursors was present. Megakaryocytes were present in normal numbers and no vacuolizations were noted. Extensive metabolic and hematologic studies revealed no basis for the hematologic findings. Packed cell transfusions were required every five to six weeks to prevent severe anemia during the first 14 months o f life. Reticulocyte counts were consistently less than 1%. Absolute neutrophil counts were less than 1,000/mm '~. Weight was less than the third percentile and height was at the tenth percentile, but development was normal. At 18 months of age, unrelated to any specific therapy, her reticulocyte count increased to 5.4%. Transfusion requirements decreased. At 20 months o f age extensive re-evaluation was done. Bone marrow was of normal cellularity with ME ratio, 2:1. Many of the early erythroid and myeloid cells were vacuolated. Marrow hemosiderin was increased and many ringed sideroblasts were present. In vitro cultures of marrow and electron microscopic examination were performed. The liver and spleen were palpably enlarged and ~ sulfur colloid scan confirmed organ enlarge, ment and normal uptake. Liver function tests revealed hepatocellular dysfunction, with vitamin K refractory hypoprothrombinemia and SGOT 435 U, LDH 972 U, alkaline phosphatase 193 U. These abnormalities reverted to normal during the succeeding few months. Duodenal aspiration, with secretin-pancreozymin stimulation, revealed subnormal volume and bicarbonate response but normal pancreatic enzymes. At 33 months free erythrocyte protoporphyrin was elevated at 118 ~g/dl whole blood (normal < 30/~g/dl).

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The Journal of Pediatrics December 1979

Table I

I Blood Onset of Anemia (Hgb gm/dl) Reticulocytopenia (%) Granulocytopenia (granulocytes/mm 3) Thrombocytopenia (platelets/ mm 3) MCV (fl) Hemoglobin F (%)

Free erythrocyte protoprophyrin (/Lgm/dl whole blood) Serum Fe/TIBC (/~g/dl) Bone marrow Cellularity Vacuolization Hemosiderin Ringed sideroblasts

Patient 1

Patient 2

9.0 at birth

3.5 at 16 mo (pale since birth) < 1 at 16 mo

12.0 at birth <0.6 at 1 mo 300 at 6 m o 60,000 at 11 mo 92 at 11 mo 3.9 at 9 mo (increased numbers of Hgb F cells)

500-1,000 at 17 mo "Thrombocytopenia" at 17 mo "Markedly macrocytic" 20 at 16 mo

145/250 at 1 mo

Increased Yes Increased Yes

Normal Yes Increased

At 389 years o f age the child no longer requires regular transfusion. Hemoglobin level and neutrophil count are in the low normal range but platelet counts remain consistently low at 50 to 100,000/mm ~. FEP has decreased to 68 /~g/dl whole blood. Patient 4. This male child was born of a term pregnancy. There were no previous pregnancies and family history was negative for consanguinity or significant blood disorders; blood counts in the parents were normal. The mother experienced psychologic disturbances during the first trimester of pregnancy and was treated with a number o f medications, including tranquilizers and anti-depressants. Because of a urinary tract infection and asthma, she was treated with antibiotics and decongestants, but specifically not chloramphenicol. Ethanol was also consumed. Delivery was normal and birth weight was 3.2 kg. At about 4 weeks o f age he became irritable and pale, and had recurrent diarrhea. Hemoglobin was 8.4 gm/dl, reticulocytes 3.1%, and absolute neutrophil count 576/mm a. By ten weeks of age hemoglobin level had decreased to 5.8 gm/dl with 0.7% reticulocytes. A transfusion with packed red cells was given and repeated at approximately monthly intervals because of recurrent anemia. Neutropenia (500 to 750/mm 3) and mild thrombocytopenia (75,000/mm ~) were present. At 4 months o f age bone marrow aspirate was hypercellular. ME ratio was 2:1. Prominent cytoplasmic and nuclear vacuolization of both erythroid and myeloid precursors were present. Megakaryocytes were normal without vacuolization. Histochemical and electromicroscopic examinations and in vitro cultures of bone marrow were performed. Abnormal laboratory findings included a moderate elevation of serum uric acid (7.3 mg/dl) and

Patient 3

Patient 4

9.0 at 4 wk

8.4 at 4 wk

2.6 at 6 wk <1 a t S w k 700 at 8 wk

3.1 at 4 wk < 1 at 10wk 575 at 16 wk

110,000 at 11 wk

576 at 4 wk

95 at 20 mo 12.5 at 20 mo

100 at 11 mo 15 at 11 mo

118

109

250/299 at 2 0 m o

212/293 at 3 m o

Normal Yes Increased Yes

Increased Yes Increased Yes

SGOT (71 U), and a positive stool culture for Salmonella, group E. Skeletal roentgenograms were normal. Various therapies were given without evident improvement. During the next seven months, the transfusional requirement gradually decreased and at 11 months of age his hemoglobin level stabilized at 12 gm/dl. At 17 months of age growth and development were normal. Hemoglobin and platelets levels were normal, but leukopenia persisted. Blood FEP level was increased to 109/tg/dl. Duodenal aspiration with secretin-pancreozymin stimulation demonstrated normal amylase activity but significantly diminished lipase, volume and bicarbonate. 99mTcsulfur colloid scan showed normal size and action of liver and spleen. At 3 years of age the child has continued to grow and develop normally. Hemoglobin level is stable at 10 to 11 gm/dl, Platelet counts are normal. Neutropenia, with absolute neutrophil counts of 500-1000/mm ~, persists. METHODS B o n e m a r r o w aspirates w e r e s t a i n e d w i t h G i e m s a a n d hematoxylin-eosin.

Histochemical

examinations

with

p e r i o d i c a c i d - S c h i f f , m y e l o p e r o x i d a s e , S u d a n Black B, a l p h a n a p h t h y l a c e t a t e esterase, a n d P r u s s i a n b l u e - s t a i n ing p r o c e d u r e s w e r e used o n the m a r r o w s o f Patients 3 a n d 4. T r a n s m i s s i o n e l e c t r o n m i c r o s c o p y w a s p e r f o r m e d o n thin sections o f m a r r o w a s p i r a t e in P a t i e n t s 3 a n d 4. In Patients 3 a n d 4, g r o w t h o f e r y t h r o i d c o l o n i e s f r o m h u m a n m a r r o w was a s s a y e d using t h e in vitro p l a s m a clot culture t e c h n i q u e o f T e p p e r m a n

et al? F i v e h e m a t o -

Volume 95 Number 6

979

Sideroblastic anemia and vacuolization o f marrow precursors

logically normal adults served as controls. After seven days of culture, each clot was examined under 100x magnification and erythroid colonies of 8 to 49 benzidine positive cells were counted as colony-forming unit-erythroid derived colonies. Myeloid growth potential was measured in marrow and peripheral blood by the in vitro agar diffusion chamber progenitor cell technique of Gordon et al. 2 Patients 3 and 4 were studied and ten hematologically normal adults served as controls. After 14 days ofculture in an irradiated mouse preparation, clones of cells were counted under the dissecting microscope as ADCPC-derived clusters or colonies. A cluster was defined as a clone of 8 to 49 cells, and a colony as a clone of > 50 cells. Assessment of exocrine pancreatic function was performed in Patients 1, 3, and 4 with the secretinpancreozymin stimulation test described by Zoppi et al. 3 After an overnight fast and mild sedation, duodenal intubation was performed under flouroscopic visualization. Timed aliquots of duodenal juice were analyzed for determinations of volume, bicarbonate, amylase, and lipase. Because of the obscure nature of these children's problem, a large n u m b e r and variety of laboratory investigations were performed. These tests with normal results are summarized in Table IV. RESULTS Hematologic findings (Table 1). Anemia was present by 4 weeks of age in Patients 1, 3, and 4. It may have been present in early infancy in Patient 3 although not documented until 16 months of age. The anemia was macrocytic and aregenerative, with low levels of reticulocytes. Variable degrees of neutropenia and thrombocytopenia occurred concomitantly or shortly after the onset of anemia. Hgb F level was elevated in 3 patients. In Patient 1, transfusions with normal blood probably reduced the proportion of Hgb F, for acid elution studies indicated a population of red ceils with increased amounts of Hgb F. FEP values were increased in 2 patients studied. Bone marrow histology (Table I). At the time of diagnoses, the marrows were of normal or increased cellularity. Striking vacuolization of both erythroid and myeloid marrow precursors was present in all cases (Fig. 1, A and B). These vacuoles were not due to accumulations of fat, glycogen, or lysosomal material, for they were not stained by Giemsa, hematoxylin-eosin, Sudan black, PAS, myeloperoxidase, or alpha napthyl acetate esterase techniques. Increased marrow hemosiderin and ringed sideroblasts were present in Patients 1, 3, and 4, whose marrows were stained by the Prussian blue technique (Fig. 1, C).

Table II. In vitro hematopoietic precursor cell cultures

Erythroid CFU-E derived colonies/ 6 x 1@ marrow cells

Patient 3

Patient 4

Controls

33 • 6*

22 • 5

452 • 32

45.0

23.6

33.4 • 6.9

35.0

16.5

4.5 • 0.8

0.8

1.0

7.9 • 2.3

Myeloid ADCPC derived clusters + colonies/2 X 10:' marrow cells Ratio ADCPC derived clusters to colonies/2 x 10~ marrow cells ADCPC derived clusters + colonies/2 X 1@ peripheral blood leukocytes

Abbreviations u s e d : CFU-E= Colony-forming unit-erythroid; ADCPC = agar diffusionchamber progenitor cell. *Results expressed as the mean _+standard error of the mean.

Table i11. Secretin ~ancreozymin stimulation test Patients 1

3

Maximal response to secretin Volume (ml/kg/ 1.90 1.42 50 min) Bicarbonate 0.00 0.03 (mEq/Kg/50 rain) To pancreozymin Lipase (IU/kg/50 min) Amylase (IU/kg/ 50 min)

Normal* 4

X

Range

1.8-81

0.52

3.9

0.01

0.19 0.08-0.37

2.6

1270

218

1,464

t.0

859

502

655

3505,000 1602,150

*Prom uryboski j.a~

Electron microscopy in Patients 3 and 4 demonstrated no limiting m e m b r a n e of the vacuoles (Fig. 2, A). Ringed sideroblasts with iron-laden mitochondria were present (Fig. 2, B). Bone marrow culture (Table II). Hematopoietic stem cells were studied by in vitro culture techniques in Patients 3 and 4. Abnormalities were found in both erythroid and myeloid progenitors. Erythroid progenitors assayed as C F U - E derived colonies were decreased 13 to 20 times when compared to controls. The erythroid colonies of Patient 3 were also morphologically abnormal, with large clear vacuoles present within and between the cells making up the colony (Fig. 1, D).

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The Journal o f Pediatrics December 1979

Table IV Patient 1

Patient 2

Laboratory tests with normal resuits

Coombs, ANA, autohemolysis, G-6-PD, folate, B12 , serum and urine amino acids, urine orotic acid, serum copper and ceruloplasmin, serum electrolytes, BUN, creatinine glucose tolerance test, immunoglobulins, chromosomes, sweat chloride, serum and urine lysozyme

Coombs, folate, BI~, vitamin E, serum and urine amino acids, urine orotic acid, serum electrolytes, BUN, creatinine, immunoglobulins, chromosomes

Therapy

Prednisone, BI~, folate, thiamine, pyridoxine, pyridoxal-5 phosphate, riboflavin, plasma, growth hormone, oxymetholone, copper sulfate Died E. coli sepsis at 26 mo

Prednisone, B12, folate, pyridoxine, pyridoxal-5 phosphate, riboflavin plasma oxymetholone Died with acidosis and hepatic failure at 20 mo

Course

Myeloid progenitors, assayed as A D C P C derived clusters plus colonies, indicated normal total clonogenic potential. However, a significantly increased percentage of A D C P C clusters as opposed to larger colonies was found, suggesting a relative inability of individual clonogenic cells to form larger colonies. In addition, peripheral blood cultures revealed an eight- to tenfold reduction in A D C P C derived colonies plus clusters. Pancreatic studies (Table liD. Patient 1 had clinical evidence of pancreatic dysfunction with malabsorption and a markedly deficient response to secretin-pancreozyrain stimulation. Patient 2 had absent stool and duodenal tryptic activity, but stimulation studies were not performed. At autopsy the pancreases of Patients 1 and 2 were firm and fibrotic. Histologic examination showed acinar atrophy, fibrosis, and hemosiderosis. The islets of Langerhans were relatively normal (Fig. 3). In Patients 3 and 4, there was no steatorrhea, but exocrine pancreatic response to maximal stimulation by secretin and pancreozymin was suboptimal. Sweat chloride concentration was normal in the three patients studied. There were no endocrine pancreatic= abnormalities. Repeated blood glucose levels were normal in all children, and glucose tolerance tests with simultaneous determinations of serum insulin levels were normal in Patients 3 and 4. Clinical course and therapy (Table IV). Administration

Patient 3

Patient 4

Coombs, ANA, folate, BI~, vitamin E, serum and urine amino acids, urine orotic acid, serum copper, ceruloplasmin, serum electrolytes, BUN, creatine, uric acid, glucose tolerance test, immunogIobulins, chromosomes, sweat chloride, serum and urine lysozyme, thyroid functions, leukocyte NBT reduction Prednisone; vitamin E; riboflavin

Coombs, ANA, folate, BI_~,vitalatin E, serum and urine amino and organic acids, urine orotic acid, serum copper, ceruloplasrain, serum electrolytes, BUN, creatinine, glucose tolerance test, immunoglobulins, chromosomes, sweat chloride, serum and urine lysozyme, toxicology screen, thyroid functions

Spontaneous improvement beginning at 18 too; last transfusion at 20 mo; persistent moderate thrombopenia at 389 years

Prednisone; copper sulfate

Spontaneous improvement beginning at 7 mo; last transfusion at 11 mo; hemoglobin stable at 10-11 gm/dl; persistent, moderate neutropenia at 3yr

of m a n y hematinic agents and vitamins produced no specific responses. The clinical courses were variable. Patients I and 2 died at 26 and 29 months of age, respectively. In Patients 3 and 4, spontaneous improvement was manifested by decreasing transfusion requirements; discontinuation of transfusions was possible at 20 months in Patient 3 and by 11 months in Patient 4. Mild thrombocytopenia persists in Patient 3 and neutropenia in Patient 4 at 389 and 3 years, respectively. DISCUSSION Despite differenc~;s in the clinical courses of these four children, we believe that they represent the same disorder because of their similar hematologic and pancreatic abnormalities. The most consistent and characteristic feature was the striking vacuolization observed in myeloid and erythroid precursors in the bone marrow. Similar vacuolization has been noted in several deftciency states. Infants with copper deficiency have been described with severe neutropenia, sideroblastic anemia, vacuolaied myeloid precursors, and osseous changes resembling scurvy? ~ Copper deficiency was excluded in three patients by documentation of normal serum copper levels and ceruloplasmin, as well as by lack of response to oral copper sulfate therapy. Also, our patients did not have the osseous abnormalities described in copper deficiency. Induced riboflavin deficiency is associated with

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Sideroblastic anemia and vacuolization o f marrow precursors

aregenerative anemia and vacuolization of the marrow elements, 6 Therapy with large doses of riboflavin in three of our patients was ineffectual. Transient anemia with vacuolization of erythroid precursors has been described as a consequence of dietary phenylalanine deprivation. 7 Serum phenylalanine levels were normal in Patient 2, and all of the children were receiving diets with adequate protein content. Transient vacuolization of red cell precursors as well as sideroblastosis is produced by exposure to chloramphenicol? ~ None of our patients had received chloramphenicol. Sideroblastic anemia and vacuolated erythroid precursors may be noted in severe alcoholism? ~ ~ Vacuolated red cell precursors have also been seen in newborn infants whose mothers received intrapartum alcohol infusions. '-' In Patient 4, moderate ethanol ingestion occurred during pregnancy, but the mother was hematologically normal and marrow vacuolization was present in the child long after exposure was terminated. This child had none of the stigmata of the fetal alcohol syndrome? 3 The nature of marrow vacuolization in these various conditions has not been clearly defined. However, it is probable that the vacuoles are manifestations of cell degeneration and death due to direct injury, impaired protein synthesis, or abnormal cellular metabolism. Histochemical and electronmicroscopic findings in the marrows of our patients indicated that the vacuoles were hydropic rather than containing secreted or retained metabolic material, and they were not membrane limited. In vitro marrow culture studies revealed primary defects affecting the growth of both erythroid and myeloid series, suggesting a primary cellular abnormality rather than a secondary injury from an adverse in vivo condition. Abnormal iron metabolism was evident in all of our patients. Hyperferremia and hemosiderosis disproportionate to the amount of blood transfusions were observed. Ringed sideroblasts were easily demonstrated in the three patients in whom Prussian blue staining of the marrow was performed. Our patients differ significantly from other reported varieties of sideroblastic anemia. Hereditary sideroblastic anemia, an uncommon X-linked disorder, is characterized by hypochromic and microcytic red cells. In most cases anemia does not develop until adult life? ~ A defect in ALA synthetase and partial clinical responses to pharmacologic doses of pyridoxine have been observed? 5 In other patients, who did not respond to pyridoxine, a deficiency of coproporphyrin oxidase was likely.TM Although acquired sideroblastic microcytic anemia may occur in adults in association with malignancies, alcoholism, inflammatory diseases, and endocrinopathies, ~7 it has been noted rarely in children. Lead inhibits several of the enzymes which participate in heine synthe-

98 l

sis, and plumbism may be associated with hypochromic microcytic anemia and, occasionally, with ringed sideroblasts? 8 A child with severe acquired microcytic anemia with ringed sideroblasts due to a circulating gamma globulin inhibitor of red cell proliferation has been recently described. '9 It is possible that the sideroblastic changes seen in our patients represent a secondary effect on mitochondrial iron metabolism by an undefined underlying metabolic dysfunction or toxic process. The other consistent findings in these patients was dysfunction of the exocrine pancreas. Pancreatic atrophy and fibrosis has been demonstrated in children with kwashiorkor and protein malnutrition; pancreatic stimulation tests reveal diminished enzymes with normal volume and bicarbonate responses. .-'~ -'~ Except for the first patient, our children were adequately nourished and had impaired volume and bicarbonate responses. Dissociation between the degree of pancreatic abnormalities and clinical malabsorption may occur. Patients and animals with minimal pancreatic tissue have been described as having nearly normal digestion. ~-' '-'~ A primary metabolic or toxic abnormality could be responsible for both pancreatic and marrow changes in these children. Some patients with acquired aplastic anemia have been described with reduced trypic activity in their pancreatic secretions. -~ Another possibility is that a primary defect involves only hematopoietic precursors. The hemosiderosis which was induced postnatally by transfusions, increased iron absorption and ineffective erythroporesis might have caused secondary pancreatic injury. This does not seem likely, for in iron overload due to idiopathic hemochromatosis or multiple transfusions, the major effects on the pancreas involve the islets and are manifested clinically by diabetes mellitus. -~5 ~ Moreover, the degree of pancreatic fibrosis and acinar atrophy in the two autopsied patients was disproportional to the amount of iron deposition when compared to the pancreatic histology in thalassemia major or the congenital iron overload of the Zellweger syndrome. '-'7 _09 Finally, an intrauterine infection might have damaged both marrow and pancreas; however, we have no evidence to support this possibility. Splenic hypoplasia has been described in some cases of Fanconi asplastic anemia as well as in some patients with malabsorptive syndromes such as ulcerative colitis, celiac disease and sprue. ~9 3~ In Patients 1 and 2, splenic atrophy was found at autopsy, but in the other two children, splenic size and function were not reduced. Hepatic dysfunction was noted in three patients but no consistent pattern of liver abnormalities was noted. The children presented here have distinctly different features from the syndrome of pancreatic insufficiency and bone marrow dysfunction described by Shwachman

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Fig. 1. A, Vacuolated granulocyte precursors Patient 1 (magnification x 1,000). B, Vacuolated red cell precursors Patient 3 (magnification x 1,000). C, Ringed sideroblasts (arrow) and hemosiderin in marrow Patient 4 (magnification x 1,000). D, CFU-E derived colony in plasma clot culture Patient 3, Benzidine stain (magnification • Note the large clear vacuoles within and between the cells making up the colony.

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Sideroblastic anemia and vacuolization o f marrow precursors

Fig. 2. A, Electron micrograph (magnification x 15,000). Patient 4, A neutrophilic myelocyte demonstrates intense cytoplasmic vacuolization. The vacuoles have no limiting membrane. B, Electron micrograph (magnification x 15,000). Patient 3, A nucleated red cell demonstrates cytoplasmic vacuoles and hemosiderin-laden mitochondria in a perinuclear arrangement (ringed sideroblast).

Fig. 3. Pancreas from Patient 1. Note the marked increase in connective tissue. Masson trichrome stain (magnification X 450).

983

984

Pearson et al.

et al and Bodian et al. 3-~-~ The prominence of severe, aregenerative anemia in our patients contrasts with the predominant neutropenia of Shwachman-B0dian syndrome. N o r m a l cellularity of the marrow, the presence of striking hematopoietic cell vacuolization, and ringed sideroblasts are not reported findings in the ShwachmanBodian syndrome. The markedly hypoplastic pancreas with fatty replacement seen in Shwachman-Bodian syndrome contrasts with the normally sized but fibrotic pancreas found in our patients. Finally, m a n y of the reported cases of Shwachman-Bodian syndrome had epiphseal and metaphyseal dysostosis, but localized bone lesions were not present in our patients. We believe that these children have a previously undescribed syndrome whose basic defect or cause is undefined. The documentation of another example of concomitant dysfunction of the hematopoietic system and exocrine pancreas suggests that there may be fundamental interactions between these two apparently unrelated organ systems. We thank Drs. Joseph Zelson, Simeon Tsalbins, and Nancy L. Krejmas who participated in the care and investigation of these patients. REFERENCES

1. Tepperman AD, Curtis JE, and McCulloch EA: Erythropoietic colonies in cultures of human marrow, Blood 44:659, 1974. 2. Gordon MY, Blackett NM, and Douglas DC: Colony formation by human haemopoietic precursor cells cultured in semi-solid agar in diffusion chambers, Br J Haematol 31:103, 1975. 3. Zoppi G, Schmerling H, Gaburro D, and Prader A: The electrolyte and protein contents and outputs in duodenal juice after pancreozymin and secretin stimulation in normal children and children with cystic fibrosis, Acta Paediatr Scand 59:692, 1970. 4. A1-Rashid RA, and Spangler J: Neonatal copper deficiency, N EnglJ Med 285:841, 1971. 5. Ashkenazi A, Levin S, Djaldette M, Fishel E, and Benvenisti D: The syndrome of neonatal copper deficiency, Pediatrics 52:525, 1973. 6~ Lane M, and Alfrey CP: The anemia of human riboflavin deficiency, Blood 25:432, 1965. 7. Sherman JD, Greenfield JB, and Ingall D: Reversible bone marrow vacuolization in phenylketonuria, N Engl J Med 270:810, 1964. 8. Rosenback LM, Caviles AP, and Mitus WJ: Chloramphemicol toxicity: reversible vacuolization of erythroid cells, N Engl J Med 263:724, 1960. 9. Gussoff BD, and Lee SL: Chloramphenicol-induced hematopoietic depression a controlled CO~lSarison with tetracycline, Am J Med Sci 251:8, 1966. 10. McCurdy PR, Pierce LE, and Rath CE: Abnormal bone morphology .in acute alcoholism, N Engl J Med 266:505, 1962. ~" 11. Lindenbaum J, and Lieber CS: Hematologic effects of

The Journal of Pediatrics December 1979

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13.

14. 15. 16. 17.

18. 19.

20. 21. 22. 23.

24. 25. 26.

27. 28.

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