Immunoproliferative small intestinal disease and primary small intestinal lymphoma. Relation to alpha chain protein.

Forty-three patients with immunoproliferative small intestinal disease and primary small intestinal lymphoma were studied prospectively. Eighteen patients in whom alpha-chain protein was detected in the serum had significantly more features of malabsorption, and disease was localized more commonly in the jejunum. In all of these patients, a diffuse lymphoplasmacytic infiltrate was found in the intestine; in three patients lymphoma was found only in mesenteric lymph nodes. Twenty-five patients with lymphoma in whom alpha-chain protein failed to be detected had significantly more features of intestinal obstruction, and disease was found more commonly in the ileum. Five of these patients had lymphoma associated with a diffuse mucosal infiltrate that was indistinguishable from the first group. In patients available for follow-up, no difference was found in cumulative survival over 30 months in the two groups, with approximately 40% mortality at 6 months.

In vitro suppression of erythropoiesis by bone marrow adherent cells from some patients with fungal infection.

We present evidence that alterations in marrow adherent cell (M phi) function may play a role in the suppression of erythropoiesis in some patients with fungal infection. Bone marrow (BM) cells from 12 normals and 10 patients with histoplasmosis were cultured in plasma clots before and after removal of M phi. BM from five patients (Group A) produced normal numbers of erythroid colonies (EC). In the remaining patients (Group B), smaller numbers of EC were detected (P less than 0.01). Removal of M phi from BM of normals and Group A patients resulted in decreased growth of EC. In contrast, M phi depletion of BM from patients in Group B resulted in greater EC formation (P less than 0.01). When normal M phi were admixed with normal or patients' BM-M phi, enhanced EC formation resulted. Whereas, at similar concentrations, M phi from group B patients caused inhibition of EC formation (P less than 0.005). The erythro-regulatory function of M phi, including the inhibitory action of patients' M phi, was mediated via a soluble agent(s) since media conditioned by M phi mimicked the action of these cells. Three patients in Group B were restudied 14 months after treatment with amphotericin B, when blood parameters had returned to normal. At this time, normal patterns of EC formation and M phi activity were observed.

Cell-cell interaction in human granulopoiesis: role of T lymphocytes.

T lymphocytes have been implicated in the pathogenesis of granulocytopenias. We studied the effects of unstimulated and pokeweed mitogen (PWM) activated intact (Ti) and partially purified T cell subpopulations (T gamma and Tnon gamma, i.e., T mu plus T0) on in vitro granulocyte-macrophage colony formation (CFUGM) by autologous normal human bone marrow (BM). Coculture of BM and Ti, T gamma, or Tnon gamma caused only a slight decrease in the numbers of colonies and clusters; however, when cultured with a mixture of T gamma and Tnon gamma, the inhibition was significant. In contrast, activation of T cells or T cell subsets with PWM resulted in a marked decrease in colony formation. These results demonstrate that: 1) PWM-activated T cells or its subpopulations will inhibit autologous BM colony formation in vitro. The suppression seen with admixes of unstimulated T gamma and Tnon gamma is presumptive evidence that prior cell-cell interaction(s) may be required for the generation of inhibitory cells in this system; and 2) this model may represent an in vitro counterpart of immune-mediated cytopenias in man.

Studies on the liver to kidney switch of erythropoietin production.

Although the liver is the major site of erythropoietin (Ep) production in the fetus, this function is assumed by kidneys in the adult. The mechanisms underlying the liver to kidney switch of Ep formation are not understood. We studied the natural progression of this transition in sheep by measuring Ep production in response to anemia in normal and bilaterally nephrectomized fetal and newborn sheep beginning at about 80 d gestation (normal gestation: 140 d). Removal of both kidneys before induction of anemia did not affect Ep formation up to about 120 d of gestation. A significant reduction (29%, P < 0.02) in Ep synthesis was first noted at about 130 d of gestation (initiation of switch). This level of nephrectomy-induced reduction of Ep formation persisted until about 15 d after birth. Thereafter, bilateral nephrectomy caused further significant decreases (P < 0.05) in Ep production, gradually resulting in near total absence of Ep production at about day 40 postpartum (completion of switch). Chronic administration of testosterone (12 mg/wk) or estradiole benzoate (1.5 mg/d, 5 d/wk) to the fetus/newborn beginning at 85-90 d of gestation enhanced or suppressed erythropoiesis, respectively, but failed to affect the time at which the liver to kidney switch was initiated and/or completed. By contrast, a significant delay (P < 0.001) in the onset, but not completion of the switch occurred in animals that were either thyroidectomized or rendered chronically anemic beginning in the second third of the gestation period. Administration of thyroxin (1.2 mg/d, 5 d/wk) to thyroidectomized fetus/newborns not only prevented the delay in the initiation of the switch, but also accelerated the rate at which the switch was completed. These results demonstrate that in sheep (a) the liver to kidney switch of Ep production is initiated in utero during the last third of the gestation period, but is completed after birth, (b) this transition occurs gradually; the assumption of Ep producing capacity by the kidney is not preceded by an abrupt loss of hepatic Ep formation; and (c) the switch is not affected by changes in sex hormone levels during the prenatal-postnatal growth periods, but is profoundly influenced by alterations in thyroid hormone and oxygen supply-demand levels.

Autoimmune pancytopenia. Lymphocyte inhibition of autologous but not allogenic bone marrow growth in vitro.

A patient with autoimmune renal failure, cavitary lung lesions and arthritis experienced pancytopenia while prednisone therapy was being tapered. Utilizing semisolid culture techniques, a population of nonadherent peripheral blood mononuclear cells was demonstrated, which inhibited autologous but not allogeneic bone marrow erythroid colony-forming units (CFU-E) and myeloid colony-forming units (CFU-c) in vitro. No inhibition of CFU-E or CFU-c colony formation was seen when patient's serum or immunoglobulin G (IgG) was added to cultures. Reinstitution of prednisone therapy resulted in normalization of peripheral blood counts, which was accompanied by the loss of the hemopoietic inhibitor cell activity in the patient's peripheral blood. These results demonstrate the need for testing autologous marrow samples when looking for possible immune-mediated inhibition of hematopoiesis.

Human peripheral blood erythroid burst forming unit (BFU(E)): evidence against T-lymphocyte requirement for proliferation in vitro.

Erythroid burst-forming units (BFU(E)) are proliferative cells which may be precursors of the erythroid colony-forming unit (CFU(E)). To examine the role of T lymphocytes in the proliferation and/or differentiation of human blood BFU(E), the effect of purified T lymphocytes on erythroid colony (EC) formation by purified null cells was examined in vitro. Lymphocyte subpopulations were prepared by Ficoll-Hypaque centrifugation, immunoadsorbent chromatography, and sheep red blood cell rosetting after removal of monocytes by adherence to plastic. Cultures of isolated B, T, or null lymphocytes alone revealed that BFU(E) were present in the null cell fraction. Addition of isolated B and/or T lymphocytes in various ratios to null cells failed to influence the number or size of EC formed. These results indicate that normal human circulating BFU(E) are contained in the null cell fraction of peripheral blood lymphocytes and do not require T lymphocytes for normal growth and differentiation in vitro.

Hormonal stimulation of erythropoietin production and erythropoiesis in anephric sheep fetuses.

The effect of testosterone (DT) and thyroxin (L-T4) on erythropoiesis and erythropoietin (Ep) production was studied in control and nephrectomized sheep fetuses beginning at about 100 d of gestation. Fetuses were given injections of either 1.2 mg/d x 13 of L-T4, 12 mg, once every 5 d x 3 of DT or the vehicle alone. Fetal plasma samples for Ep determinations were obtained before and at intervals after the start of the treatment. Reticulocyte and hematocrit levels, and the percent erythrocyte-59Fe uptake values were used to assess erythropoiesis in each fetus. No Ep was detected in plasmas of control fetuses, while significant amounts of Ep were present in plasma obtained from DT- and L-T4-treated intact fetuses. Bilateral nephrectomy did not diminish the Ep response to DT and L-T4. In both intact and nephrectomized fetuses, treatment with DT resulted in the production of significantly greater amounts of Ep than L-T4. The rise in Ep in all groups was accompanied by increases in reticulocytes (2.2 +/- 0.2% vs L-T4:8.1 +/- 0.4% and DT:7.6 +/- 0.7%), percent erythrocyte-59Fe uptake (20.5 +/- 2.9% vs. L-T4:36.7 +/- 3.8% and DT:39.1 +/- 4.0%) and hematocrit (31.2 +/- 2% vs. L-T4:41.8 +/- 3% and DT:48.6 +/- 4.2%). The enhanced erythropoiesis in all groups of nephrectomized fetuses was dependent upon the presence of Ep, because the administration of anti-Ep to these fetuses resulted in the suppression of erythropoiesis in all three groups. These data demonstrate that (a) DT and L-T4 are effective promoters of extrarenal Ep production, thereby enhancing erythropoiesis in intact and nephrectomized fetuses; (b) DT is a stronger stimulus of extrarenal Ep formation than L-T4; and (c) Ep is required for the expression of the erythropoietic effects of L-T4 and DT.

HLA AW19, B12 in immunoproliferative small intestinal disease.

A group of 21 patients with immunoproliferative small intestinal disease (IPSID), 10 with alpha heavy chain paraproteinaemia and 11 without it, were HLA typed. The results were compared with 35 disease controls and 120 normal controls. A significant increase of Aw19 and B12 antigens was noted among the patients compared with the control subjects. The high rate of association of both AW19 and B12 antigens in patients as compared with controls suggests a possible haplotype (Aw19, B12) association with IPSID.