[Multicentric Castleman's disease accompanied with both lymphoid interstitial pneumonia and interstitial nephritis]

A 60-year old man admitted in November, 1991 because of hyperproteinemia. He had shown a gradual increase in serum levels of gamma-globulin since 1981, and idiopathic plasmacytic lymphadenopathy with hyperimmunoglobulinemia was diagnosed in 1989 when he was admitted to another hospital because of persistent swelling of bilateral inguinal lymph nodes since 1986. Multiple swelling of lymph nodes was observed in the right supraclavicle fossa, the left axillary and bilateral inguinal region, and diffuse reticulo-nodular shadows were observed on his chest roentogenogram. Other laboratory findings were as follows; erythrocyte sedimentation rate 143 mm/hr, CRP 3+, Hb 9.4 g/dl, TP 13.7 g/dl with 69.4% of beta-gamma bridge, BUN 21.1 mg/dl, creatinine 1.6 mg/dl, PaO2 77.6 mmHg, plasma cell count in bone marrow 6.4% and positive tests for autoantibodies such as rheumatoid factor, anti-DNA antibody, anti-smooth muscle antibody, and direct Coombs test. Serum interleukin-6 (IL-6) level increased to 259 pg/ml and IL-1 beta was 39.1 pg/ml. Specimens of both transbronchial lung biopsy and fine-needle kidney biopsy revealed a marked infiltration of lymphocytes and plasma cells into interstitial regions of lung and kidney. We reported here a case of multicentric Castleman's disease (MCD) who also demonstrated lymphoid interstitial pneumonia and interstitial nephritis. The present study suggests that some cytokines including IL-6 and IL-1 beta may be closely related to the pathophysiology of MCD.

Microsomal aldehyde dehydrogenase is localized to the endoplasmic reticulum via its carboxyl-terminal 35 amino acids

Rat microsomal aldehyde dehydrogenase (msALDH) has no amino-terminal signal sequence, but instead it has a characteristic hydrophobic domain at the carboxyl terminus (Miyauchi, K., R. Masaki, S. Taketani, A. Yamamoto, A. Akayama, and Y. Tashiro. 1991. J. Biol. Chem. 266:19536-19542). This membrane-bound enzyme is a useful model protein for studying posttranslational localization to its final destination. When expressed from cDNA in COS-1 cells, wild-type msALDH is localized exclusively in the well-developed ER. The removal of the hydrophobic domain results in the cytosolic localization of truncated proteins, thus suggesting that the portion is responsible for membrane anchoring. The last 35 amino acids of msALDH, including the hydrophobic domain, are sufficient for targeting of E. coli beta-galactosidase to the ER membrane. Further studies using chloramphenicol acetyltransferase fusion proteins suggest that two hydrophilic sequences on either side of the hydrophobic domain play an important role in ER targeting.

A patient with malignant paraganglioma that simultaneously produces adrenocorticotropic hormone and interleukin-6

BACKGROUND

To the authors' knowledge, there have been no reports describing a case of malignant paraganglioma that produces both adrenocorticotropic hormone (ACTH) and interleukin-6 (IL-6).

METHODS

The clinical course and pathophysiology of a patient with Cushing's syndrome induced by ectopic ACTH syndrome caused by a cervical malignant paraganglioma with elevated plasma levels of IL-6 was investigated.

RESULTS

Ultrasonography, computed tomography, and magnetic resonance imaging of the neck revealed the presence of a tumor around the area from which the blood sample that showed the highest levels of ACTH and IL-6 was obtained by selective catheterization. Immunohistochemical staining of the removed tissue demonstrated the presence of ACTH and IL-6 proteins in the tumor cells. Reverse transcriptase-polymerase chain reaction also revealed the existence of IL-6 mRNA in those cells.

CONCLUSION

The malignant paraganglioma of ectopic ACTH syndrome may produce IL-6. The present investigation provides new observations concerning ectopic ACTH syndrome.

Association of N-ethylmaleimide-sensitive factor with synaptic vesicles

N-Ethylmaleimide-sensitive factor (NSF) mediates docking and/or fusion of transport vesicles in the multi-pathways of vesicular transport. NSF was highly expressed in brain and adrenal gland. Immunostaining of cerebellum with an anti-NSF monoclonal antibody showed that NSF is predominantly localized in the molecular layers and the glomeruli of the granule cell layers. This distribution coincided well with that of synaptophysin, a marker protein of synaptic vesicles. Purification and immunoprecipitation revealed that NSF is associated with brain synaptic vesicles. The present results suggest that NSF is associated with synaptic vesicles without Ca2+ influx.

Serum gastrin levels following administration of omeprazole alone or in combination with pirenzepine

Serum gastrin levels in 44 peptic ulcer patients (26 gastric ulcer patients and 18 duodenal ulcer patients) were determined after they had been treated with omeprazole (OPZ) (20 mg/day) alone or in combination with pirenzepine (PZP) (100 mg/day). Serum gastrin levels were measured before, as well as 2, 4, and 6 weeks after administration, and the changes were compared. The levels were significantly elevated (twofold) at 2 weeks of treatment in both the OPZ and OPZ plus PZP groups. In patients taking OPZ alone, the levels rose up to 6 weeks, while in those taking OPZ plus PZP the levels decreased at 4 and 6 weeks. At 4 weeks, serum gastrin levels in the OPZ plus PZP group were lower (although not significantly) than those in patients taking OPZ alone. In gastric ulcer patients, serum gastrin levels in the OPZ group were significantly elevated, while in the OPZ plus PZP group, these levels were only slightly, but not significantly elevated. There was no significant difference between the two gastric ulcer groups at any time. In duodenal ulcer patients, serum gastrin levels increased significantly at 2 weeks of treatment in both groups. At 4 weeks and thereafter, the serum gastrin levels remained significantly high in patients taking OPZ alone, while they decreased at both 4 and 6 weeks in patients taking OPZ plus PZP. Thus, serum gastrin levels in duodenal ulcer patients were markedly decreased by the addition of PZP.(ABSTRACT TRUNCATED AT 250 WORDS)

Preferential localization of heat shock protein 47 in dilated endoplasmic reticulum of chicken chondrocytes

We investigated the distribution of heat shock protein 47 (hsp47) in cultured chicken embryonic chondrocytes and epiphyseal chondrocytes of tibial bones from 1-day-old to 6-week-old chickens. Northern blot and immunoblot analyses revealed that hsp47 exists in epiphyseal cartilage and cultured chondrocytes. Confocal laser immunofluorescence microscopy showed that hsp47 was localized mainly in the many granular structures found in the cytoplasm that contain Type II collagen. Epiphyseal cartilage and cultured chondrocytes were embedded in LR White resin and hsp47 was detected by protein A-immunogold electron microscopy. Gold particles were localized exclusively in the cisternal space of the endoplasmic reticulum (ER), and the labeling density of the cisternal space of the dilated ER was always higher than that of the non-dilated ER. In all the differentiating zones of epiphyseal cartilage, the labeling density was highest in the hypertrophic cells. These findings suggest that hsp47 plays an important role(s) in the synthesis, processing, and assembly of Type II collagen.

Sodium pump distribution is not reversed in the DBA/2FG-pcy, polycystic kidney disease model mouse

Recently, it has been reported that Na,K-ATPase in the renal epithelia of human autosomal dominant polycystic kidney disease and cpk mouse, a murine model of autosomal recessive polycystic kidney disease, mislocates to apical plasma membrane and that mislocated Na,K-ATPase causes the cyst formation. Whether the DBA/2FG-pcy mice, which are presumably a suitable model for autosomal dominant polycystic kidney disease, also exhibit the reversal polarity of Na,K-ATPase localization was examined. Kidneys of newborn DBA/2FG-pcy mice, and those at early and late stages of cyst development were examined by immunohistochemical techniques. At any stage, abnormal distribution of Na,K-ATPase on the apical membranes of tubular epithelial cells could not be detected. It is suggested that cysts can be formed without reversed polarity of Na,K-ATPase distribution in pcy mice.

Immunocytochemical localization of Na, K-ATPase in rat muscle spindles

In the muscle spindle, one of the major sensory receptors in the vertebrate skeletal muscle, it was demonstrated that stretching caused a conductance increase of the sensory terminal membrane mainly to Na+ (Hunt, Wilkinson and Fukami, 1978 (6)). Since the muscle spindle is a slowly adapting stretch receptor, and even at rest some spindles are active, a vigorous Na, K-pump activity is expected to counteract the incessant inflow of Na+ into the terminal. To test this assumption, rat muscle spindles were examined by immunofluorescence microscopy as well as by the electron microscopic immunogold technique using antibody against rat alpha-subunit of Na, K-ATPase. The results indicate that the sensory ending has the highest density of the enzyme among the other cellular components examined, and that the enzyme density appears to be higher in the plasma membrane of the sensory ending facing the intrafusal muscle fiber (synaptic membrane) than the rest of the membrane (extra-synaptic membrane). The functional significance of the above findings was discussed.

Immunohistochemical study of mucin carbohydrates and core proteins in human ovarian tumors

Many of the cancer-associated antigens recently have been identified as mucin antigens. However, there are no detailed studies describing the expression of carbohydrates and core proteins of mucin antigens in ovarian tumors. In this study we examined the expression of carbohydrate antigens, which are associated with the earliest steps in mucin glycosylation (Tn and sialosyl-Tn), and the expression of the mucin core protein antigens associated with the MUC1 gene product (mammary-type apomucin) and the MUC2 gene product (intestinal-type apomucin) in 123 ovarian epithelial (mucinous and serous) tumors. In normal ovarian tissues neither Tn, sialosyl-Tn, nor intestinal-MRP antigens (MUC2 gene product) were expressed, except for positive sialosyl-Tn staining of stromal capillaries, while the MUC1 gene product, DF3 antigen, was expressed in the cell apex of the germinal coelomic epithelium when it had plump, slightly elongated, or pseudostratified nuclei. In the benign adenomas Tn and sialosyl-Tn antigens were detected in a small number of mucinous adenomas and rarely in serous adenomas. In contrast, expression of both Tn and sialosyl-Tn antigens was observed in all the adenocarcinomas and in a considerable number of borderline malignancies. DF3 antigen was expressed in many benign serous tumors but not so frequently in benign mucinous tumors; however, it was frequently expressed in the adenocarcinomas and borderline malignancies of both mucinous and serous types. Intestinal-MRP antigen expression increased with the transition of the mucinous tumors from a benign to malignant state, although it was never detected in the serous tumors. Coexpression of DF3 and intestinal-MRP antigens was seen in borderline malignancies and carcinomas of the mucinous tumors. In conclusion, simultaneous expression of Tn and sialosyl-Tn antigens is a highly effective tumor marker in both mucinous and serous tumors of the ovary. Coexpression of DF3 and intestinal-MRP antigens may indicate the malignant potential of ovarian mucinous tumors.

Xanthogranulomatous cholecystitis masquerading as gallbladder carcinoma

We herein present a case of xanthogranulomatous cholecystitis which involved both the liver and transverse colon, clinically mimicking gallbladder carcinoma. Such cases may sometimes be judged inoperable due to extensive extra-gallbladder invasion, and thus it is necessary for physicians to take this lesion into consideration when making a diagnosis. An intraoperative biopsy is necessary, therefore, even when the features seem to clearly indicate inoperable carcinoma.

Transmembrane topology and sites of N-glycosylation of inositol 1,4,5-trisphosphate receptor

To define the transmembrane topology of the inositol 1,4,5-trisphosphate receptor (InsP3R), we determined the subcellular location of the hydrophilic segment (residues 2463-2529 of mouse type 1 InsP3R) believed to be located at the luminal side of the endoplasmic reticulum (ER) in the six-transmembrane model but at the cytoplasmic side in the eight-transmembrane model. This hydrophilic segment includes two consensus sites for N-glycosylation (Asn-2475 and Asn-2503). We prepared an anti-peptide antibody against residues 2504-2523. Electron microscope immunocytochemical studies of mouse cerebellar Purkinje cells showed that binding of this antibody frequently occurs in the intracisternal space of the ER. We constructed three mutant receptors by site-directed mutagenesis of Asn to Gln (N2475Q, N2503Q, and N2475Q/N2503Q). By concanavalin A column chromatography of these receptors, we found that both Asn-2475 and Asn-2503 are glycosylated. These results indicate that residues 2504-2523, Asn-2475, and Asn-2503 are exposed to the ER lumen. We therefore propose that InsP3R has six membrane-spanning segments. Based on the transmembrane topology and subunit organization, we suggest that InsP3R is a member of the superfamily that includes the voltage- and second messenger-gated ion channels on the plasma membrane.

Alpha- and beta-cell function in obese Zucker (fa/fa) rats: a study with the isolated perfused pancreas

1. The effects of various stimuli, including changes in glucose concentration, arginine, tyramine and noradrenaline, on insulin and glucagon secretion were investigated using isolated perfused pancreata of obese and lean male Zucker rats at 12 months of age. 2. In Zucker fatty rats, the insulin secretion rate was significantly (P < 0.01) higher than that of lean rats at all glucose concentrations tested (8.3, 16.7 and 1.4 mmol/l). However, the integrated insulin secretory response to raising the glucose concentration from 8.3 to 16.7 mmol/l was almost absent in these rats. The glucagon secretion rates were significantly lower at 8.3 and 1.4 mmol/l glucose (P < 0.001 for both), and in responses to 10 micrograms/ml tyramine and 0.1 mumol/l noradrenaline (P < 0.05 for both), in Zucker fatty rats. Integrated insulin and glucagon responses to 10 mmol/l arginine were identical in the two groups. 3. Histopathological and immunochemical studies revealed hyperplasia of beta-cells and scattered alpha-cells in the enlarged islets of Zucker fatty rats. 4. These results suggest that, in Zucker fatty rats, the decreased glucagon secretion in the isolated perfused pancreas is attributable to changes in the environment of alpha-cells and/or the inhibitory effects of hypersecreted insulin.

Immunocytochemical analyses of distributions of Na, K-ATPase and GLUT1, insulin and transferrin receptors in the developing retinal pigment epithelial cells

The retinal pigment epithelium (RPE) is unique in that Na,K-ATPase is predominantly localized on its apical surface. We studied the distributions of Na,K-ATPase and glucose transporter GLUT1, insulin and transferrin receptors in developing rat RPE cells immunocytochemically. Na,K-ATPase, first detected in 17-day-old embryonic eyes, was already distributed predominantly on the apical surface. This reversed distribution of Na,K-ATPase was maintained throughout their life. Insulin receptor and transferrin receptor were distributed exclusively on the basolateral surface. By quantitative immunogold electron microscopic technique we found that glucose transporter GLUT1 is distributed almost equal in amount on both the apical and basolateral surfaces of RPE cells, thus presumably constructing an efficient pathway for glucose transport from the choriocapillaries to the neural retina through the blood-retinal barrier. These results suggest that in the RPE cells the intrinsic basolateral plasma membrane proteins are sorted out at least in three different ways.

Acidification of phagosomes and degradation of rod outer segments in rat retinal pigment epithelium

PURPOSE

The authors investigated the phagocytic processes of the rod outer segments (ROS) in rat retinal pigment epithelium (RPE) cells, and the appearance of lysosomal enzymes, acidification, and degradation of the contents in the phagolysosomes. In particular, they examined the effect of bafilomycin A1, a specific inhibitor of vacuolar-type H(+)-ATPase, on the degradation of ROS in the RPE cells in vivo.

METHODS

A lysosomal enzyme (cathepsin D), a lysosomal membrane protein (LGP107), and opsin were localized in the RPE cells by the immunogold electron microscopic technique. Bafilomycin A1 was injected into the vitreous, and acidification of the phagosomes was measured in vivo by injecting 3-[2,4-dinitroanilino]3'amino-N-methyldipropylamine (DAMP) in the vitreous and detecting the accumulation of DAMP in the phagolysosomes using anti-dinitrophenol antibody.

RESULTS

Opsin was abundantly detected in phagosomes that did not contain cathepsin D, but the immunolabeling of opsin rapidly disappeared soon after the appearance of cathepsin D. By double staining with cathepsin D and DAMP, it was shown that the pH of the phagosomes dramatically decreased after fusion with lysosomes. When bafilomycin A1 was injected into the vitreous, many large phagolysosomes containing cathepsin D appeared in the RPE cells, in which the immunoreactivity of opsin was well preserved.

CONCLUSIONS

Degradation of opsin and acidification proceeded almost parallel with the appearance of cathepsin D in the phagolysosomes. Bafilomycin A1 did not inhibit the fusion of phagosomes with lysosomes, but it increased intraphagosomal pH and markedly inhibited the degradation of ROS in the phagolysosomes. This result indicates that vacuolar-type H(+)-ATPase is essential for acidifying the lumen of phagolysosomes and subsequent protein degradation of ROS in the RPE cells.

ATP-dependent uptake of anti-neoplastic agents by acidic organelles

Daunomycin, an anti-neoplastic agent, is known to be sequestered by acidic organelles in normal and multidrug-resistant cells [Willingham, M.C., Cornwell, M.M., Cardarelli, C.O., Gottesman, M.M., & Pastan, I. (1986) Cancer Res. 46, 5941-5946]. We studied the mechanism of accumulation of daunomycin into acidic organelles using chromaffin granule vesicles and proteoliposomes reconstituted with purified F-type H(+)-ATPase as model systems. Radiolabeled daunomycin was taken up by chromaffin vesicles upon addition of ATP. Its ATP-dependent uptake was stimulated about 1.4- to 1.8-fold by valinomycin plus K+, but was inhibited by ammonium chloride (10 mM) and nigericin plus K+. Quinidine (5 microM), verapamil (5 microM), or vanadate (0.5 mM), inhibitors of P-glycoprotein, had no effect on its uptake. Daunomycin was also taken up by liposomes reconstituted with F-type H(+)-ATPase. Furthermore, doxorubicin and vinblastine were taken up by these vesicles, whereas colchicine and rhodamine 123 were not. The accumulations of daunomycin and doxorubicin in acidic organelles of cultured cells were decreased by inhibiting vacuolar ATPase by addition of bafilomycin A1 or concanamycin A, or by increasing the internal pH by addition of nigericin. Melittin and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide dissipated the delta pH and inhibited accumulation of daunomycin in the membrane vesicles and acidic organelles in cultured cells. These results indicate that the delta pH established by vacuolar-type ATPase drives the uptake of daunomycin, doxorubicin or vinblastine into acidic organelles, and that no specific transporters are involved in their uptakes.

Inhibitors of vacuolar-type H(+)-ATPase suppresses proliferation of cultured cells

We investigated effects of bafilomycin A1, a specific inhibitor of vacuolar-type H(+)-ATPase (V-ATPase), and its analogues on proliferation of various cultured cells. The proliferation of the various cell lines was suppressed by adding bafilomycin A1 to the culture medium. This inhibitory effect appeared at a concentration of nanomolar order and was dose dependent. Although the suppression was reversible, the drug exerted not only suppression of the proliferation but also death to some cell lines. Drug concentration required for 50% inhibition of the cell proliferation during 48 h differed markedly depending on cell species and the sensitivity appears to increase by the transformation of the cells. Two derivatives of concanamycin A, an analogue of bafilomycin A1, also inhibited strongly V-ATPase in vitro and in vivo, and simultaneously cell proliferation. Two concanamycin A derivatives which have lost inhibitory effect on V-ATPase lost inhibitory effect on cell proliferation as well. These results suggest that V-ATPase is involved in the machinery maintaining the cell proliferation.

Microsomal aldehyde dehydrogenase or its cross-reacting protein exists in outer mitochondrial membranes and peroxisomal membranes in rat liver

We investigated the subcellular distribution of microsomal aldehyde dehydrogenase (msALDH) in rat liver and revealed by the immunoblotting method that msALDH or a cross-reacting 54-kDa protein(s) exists in the outer mitochondrial membranes and peroxisomes. Anti-msALDH antibody markedly inhibited the decanal aldehyde dehydrogenase activity of the outer mitochondrial membranes as well as that of the microsomes. Immunogold electron microscopic observations showed that gold particles are localized over the ER, outer mitochondrial membranes and peroxisomal membranes. These results suggest that msALDH or its cross-reacting related protein is distributed not only in the ER membranes but also in the mitochondrial outer membranes and peroxisomal membranes.

Immunoelectron microscopic localization of the HPC-1 antigen in rat cerebellum

HPC-1 antigen is a neuron-specific 34 kDa protein, identical to p35A (syntaxin), and is thought to play important roles in docking or fusion of synaptic vesicles to presynaptic active zones. In the present study we analyze the distribution of HPC-1 antigen in rat cerebellum by a cryoimmunogold technique using an antibody against the fusion protein of beta-galactosidase and the HPC-1 antigen. HPC-1 antigen was detected at high density on the plasma membranes and synaptic vesicles of presynaptic boutons which formed synapses with dendrites of Purkinje cells, and on the plasma membranes of parallel fibres in the cerebellar molecular layer. In the granule cell layer, gold particles were also detected on the endoplasmic reticulum, nuclear membranes and the plasma membranes of granule cells. Presynaptic membranes and synaptic vesicles in glomeruli were also labelled by gold particles. To determine the topology of HPC-1 antigen on the membranes, the synaptosome fraction prepared from rat cerebellum was embedded in agarose, and processed for the pre-embedding protein A-gold technique. Intact synaptosomes were not labelled by gold particles. However, when fixed in hypotonic fixative to rupture plasma membranes, or when ruptured after fixation in normotonic fixative, the cytoplasmic surfaces of presynaptic membranes and synaptic vesicles were labelled by gold particles. These results suggest that most of the epitopes of HPC-1 antigen are located on the cytoplasmic surface of plasma membranes and synaptic vesicle membranes.

Inhibition of intracellular transport of newly synthesized prolactin by bafilomycin A1 in a pituitary tumor cell line, GH3 cells

We have investigated the effects of bafilomycin A1, a specific inhibitor of vacuolar type H(+)-ATPase, on the secretion and intracellular distribution of prolactin in cultured rat pituitary tumor cells (GH3 cells). Pulse-labeling the cells with L-[35S]methionine for 5 min and subsequently incubating in chase medium containing 1 microM bafilomycin A1 showed inhibition of basal secretion of labeled prolactin. The inhibition of the secretion by the drug was clearly observed when it was added within 7.5 min after the pulse-labeling, whereas inhibition was barely observed when added at 22 min. When the pulse-labeled cells were chased with 1 microM bafilomycin A1 for 1 h and then washed and incubated in the presence of 10 micrograms/ml brefeldin A (BFA) for 2 h, BFA barely affected the secretion during the latter 2 h period. This result suggested that the labeled prolactin had passed through a BFA-sensitive step(s) in the intracellular transport during the treatment with 1 microM bafilomycin A1. Immunofluorescence microscopy and immunogold electron microscopy revealed that, when the cells were incubated with 0.1 to 1.0 microM bafilomycin A1, small, dense secretory granules containing prolactin decreased markedly, and numerous large vacuoles appeared, which also contained prolactin, and were partially coated with clathrin-like materials. The Golgi apparatus itself was preserved except for some dilatation of the trans-Golgi cisternae and trans-Golgi network (TGN) where these vacuoles were likely to be formed. These results suggest that acidification in immature secretory granules generated by a vacuolar type H(+)-ATPase is necessary for the intracellular transport of prolactin, maturation and concentration processes of the secretory granules.

Correlation between phospholipase A2 activity and intra-Golgi protein transport reconstituted in a cell-free system

A wide variety of phospholipase A2 inhibitors blocks intra-Golgi protein transport reconstituted in a cell-free system. Phospholipase A2 activity detectable under the protein transport assay conditions is actually inhibited by the inhibitors. There is a good correlation between the inhibition of protein transport and that of phospholipase A2 activity. Prolactin secretion from GH3 cells is also blocked by a membrane-permeable phospholipase A2 inhibitor, suggesting the physiological relevance to inhibition of protein transport in vitro by phospholipase A2 inhibitors.

[An adult case of acute lymphoblastic leukemia preceded by aplasia resembling aplastic anemia]

Although aplastic anemia (AA) is well known to precede acute leukemia, commonly acute myeloblastic leukemia, an adult case of acute lymphoblastic leukemia (ALL) preceded by aplasia similar to severe AA is very rare. An 18-year-old female was admitted to our hospital for scrutiny of pancytopenia in October 3, 1991. She was diagnosed as severe AA because of severe bone marrow hypoplasia and no abnormal or dysplastic cell. Recovery of hematopoiesis was achieved by pulse therapy of methylprednisolone combined with granulocyte colony stimulating factor (G-CSF). 3 months after AA onset, she was readmitted because of high fever and paralytic ileus. Then, she was diagnosed as ALL (L1; common ALL) and was successfully treated by remission induction chemotherapy. Retrospectively, this case was atypical AA with respect to serum iron and LDH level.

[Rapid aggravation of splenomegaly by administration of erythropoietin in a case of myelodysplastic syndrome]

In myeloproliferative disorders, aggravation of splenomegaly was reported as an adverse effect of erythropoietin (EPO). Recently, we experienced the adverse effect of EPO in myelodysplastic syndrome (MDS). A 65-year-old male was admitted to our hospital for scrutiny of pancytopenia in July 8, 1991. He was diagnosed as having MDS (refractory anemia: RA). After discharge, daily subcutaneous administration of EPO (3,000U) was started on August 1 because his Hb concentration had decreased to 9.2 g/dl. After the daily dose of EPO was increased up to 6,000U in August 15, left hypochondralgia gradually developed. EPO administration was haltedon August 22. His splenomegaly was aggravated from 2 finger breadths below the left costal margin before EPO administration to 4.5 finger breadths. Bone marrow examination revealed a change to extremely hypercellular marrow from slightly hypocellular marrow before EPO administration. The peripheral blood cell count was not altered. We concluded that he was a rare case of MDS in which aggravation of splenomegaly was observed, probably as a result of extramedullary hematopoiesis induced by administration of EPO.