Emmanuel N. Dessypris

The pathogenesis of anemia in rheumatoid arthritis: A clinical and laboratory analysis☆

Principal concepts concerning the anemia of RA are summarized in Tables 7 and 8. These concepts have been validated by our analysis of 93 anemic RA patients and by our review of the literature. The fact that anemia in RA may have one or more etiologies, occasionally in the same patient, mandates a reasoned approach to the analysis of anemia in every RA patient in whom it may occur. In particular, iron deficiency is common and determination of bone marrow iron content via an aspirate may be required for a definitive diagnosis. In those RA patients with anemia of chronic disease, the best therapy remains control of the underlying disease, most commonly with second line drugs and/or corticosteroids. The place for recombinant erythropoietin in the therapy of this anemia has not been defined; one specific role for erythropoietin may be in the preparation of RA patients for elective surgery, particularly hip arthroplasty, where correction of the anemia may either obviate the need for transfusion or may allow for donation of blood for purposes of autologous transfusion perioperatively. The pathogenesis of the anemia of chronic disease, as seen in RA anemia, is not completely understood. Inflammatory mediators, particularly the cytokines, appear to be important factors in the impairment of erythropoiesis. The mechanism by which these cytokines impair erythroid progenitor growth and hemoglobin production in developing erythrocytes is an important area for future study.

Effect of pure erythropoietin on DNA-synthesis by human marrow day 15 erythroid burst forming units in short-term liquid culture

Summary. The effect of pure erythropoietin (EP) on human marrow day 15 burst‐forming units‐erythroid (BFU‐E) was studied using a short‐term liquid culture system containing 30% human serum. Non‐adherent marrow cells were cultured in liquid medium for 0–48 h and then the number of BFU‐E was assayed by the use of the plasma clot method. The addition of 1 U/ml of EP into the liquid culture medium resulted in maintenance of the number of BFU‐E assayed after 24–48 h of incubation. The number of BFU‐E recovered after 24–48 h culture was directly proportional to the concentration of EP present in the liquid medium. In addition, the proliferative status of BFU‐E before and after exposure to EP was studied by 3H‐thymidine and hydroxyurea suicide. It was found that EP doubles the percentage of BFU‐E in DNA synthesis after 24–48 h of incubation in the liquid medium. This effect of EP on DNA synthesis by bone marrow day 15 BFU‐E is detectable as early as 6 h after the onset of incubation and at EP concentrations as low as 0.2 U/ml of medium, a concentration present in the serum of moderately anaemic patients. The human marrow day 15 BFU‐E is an EP‐responsive cell and pure EP can induce it into DNA synthesis.

Chronic lymphocytic leukemia with hyperleukocytosis the hyperviscosity syndrome

A 47‐year‐old man with hyperleukocytic chronic lymphocytic leukemia progressively developed retinal hemorrhages, headache, diplopia, dysequilibrium, slurred speech, nystagmus, ataxic gait, and hearing loss as his leukocyte count rose to a maximum of 968,000/mm3. All of these symptoms and signs resolved promptly after leukapheresis. The authors reviewed records of 210 patients with chronic lymphocytic leukemia seen at our institution over a 12‐year period, and found 16 patients with sustained hyperleukocytosis above 500,000/mm3, 3 of whom had features of the hyperviscosity syndrome. No laboratory values consistently predicted the occurrence or lack of occurrence of the hyperviscosity syndrome. The key to the management of hyperviscosity syndrome in the setting of hyperleukocytic chronic lymphocytic leukemia is to consider the diagnosis and to rapidly lower the lymphocyte count.

Rheumatoid arthritis and pure red cell aplasia.

Three patients with severe, deforming, and long-standing rheumatoid arthritis developed pure red cell aplasia that did not remit after withdrawal of medications, ran a chronic course, and in two patients remitted only after cytotoxic immunosuppressive treatment. An IgG inhibitor of autologous erythroid colony-forming and burst-forming unit growth in vitro was found in the serum of one patient. This specific erythropoietic inhibitor persisted in lower titer in the patients serum even after an azathioprine-induced remission of pure red cell aplasia, indicating the possible need for maintenance immunosuppressive therapy. Chronic pure red cell aplasia may be another extra-articular manifestation of rheumatoid arthritis and should be considered when severe anemia develops in the absence of blood loss or hemolysis.

Treatment of refractory pure red cell aplasia with cyclosporine A : disappearance of IgG inhibitor associated with clinical response

Summary Remissions were obtained in 6/9 evaluable patients with pure red cell asplasia (PRCA) refractory to other immunosuppresive agents who were treated with cyclosporine A (CsA). Four of these patients have remained in continuous remission off all treatment for 4–19 months. Another patient who stopped CsA abruptly relapsed, but responded to reinstitution of therapy. The sixth patient died of a cerebrovascular accident while in remission on a low dose of CsA. Acute side effects were minimal and were responsive to dose reduction. One patient developed a lymphoma while in an unmaintained remission, and one patient who did not respond to CsA was found to have a lymphoma approximately a year after stopping treatment.

Red Cell Aplasia and Chronic Granulocytic Leukaemia

Summary. Two patients with chronic granulocytic leukaemia developed red cell aplasia during the course of their disease. In one of them, cell culture studies demonstrated the presence in the patients serum of an IgG inhibitor of haemoglobin synthesis by his own mature erythroblasts and erythroblasts grown in vitro from his erythroid colony forming cells. The IgG fraction was also found to be cytotoxic for the patients’ marrow erythroblasts that were present after disappearance of the red cell aplasia. Treatment with corticosteroids resulted in reappearance of the erythroblasts in the marrow and decrease in the transfusion requirement. Red cell aplasia can occur before, at the same time or after the onset of chronic granulocytic leukaemia and may have the same immune pathogenesis as chronic idiopathic pure red cell aplasia. It occurs without busulphan treatment and seems to have no direct relation to the terminal metamorphosis. Treatment of the red cell aplasia with corticosteroids would appear worthwhile as it may reduce the transfusion requirement without affecting the course of the underlying leukaemia.

Granulocyte Colony-Stimulating Factor Overcomes Severe Neutropenia of Large Granular Lymphocytosis

Large granular lymphocytosis (LGL) is characterized by enhanced proliferation of T lymphocytes that have antibody-dependent cell-mediated cytotoxicity or natural killer cell activity and that often produce severe cytopenias, including neutropenia. When a 68-year-old man with seropositive rheumatoid arthritis and severe neutropenia was examined, he was found to have LGL with a T cell gene rearrangement, indicating the presence of a clonal population of T lymphocytes. The patient was admitted with a fever of 102 degrees F and a nonhealing ulcer over the right tibia. When the infection did not respond to intravenous antibiotics, granulocyte colony-stimulating factor (GCSF) therapy was started at 5 micrograms/kg subcutaneously each day. The neutrophil count promptly increased and the patient subsequently defervesced and was able to have a skin graft placed, which healed without difficulty. GCSF, which is known to be an effective therapeutic agent for neutropenia associated with chemotherapy and bone marrow transplantation, also was a very valuable treatment for the life-threatening neutropenia of LGL.

Deletion of the long arm of chromosome 5 (5q−) as a secondary event in the course of refractory anemia

A 54-year-old chemical plant worker developed mild pancytopenia, with normal bone marrow morphology. Normal bone marrow cytogenetics were documented. The patient developed worsening anemia 5 years into his course. The bone marrow morphology remained normal, but four of 30 bone marrow metaphases examined showed deletion of the long arm of chromosome #5. Eight years into his course, the patient developed severe thrombocytopenia, and his bone marrow became hypercellular, with dysplastic changes. Deletion of the long arm of chromosome #5 was seen in all of 21 bone marrow metaphases examined. There had been no new exposure to potential mutagens during the course of the patients illness. The occasional documentation of the late appearance of cytogenetic abnormalities during the course of clonal hematopoietic disorders implies that, in some cases at least, chromosomal abnormalities may not be primary pathogenetic events. The full expression of clonal disorders may require several pathogenetic events, which may occur in variable order.

Erythropoietin: regulation of erythropoiesis and clinical use.

Publisher Summary This chapter discusses the regulation of erythropoiesis (EPO) and clinical use. EPO is a glycoprotein that was purified from the urine of patients with aplastic anemia. The potency of EPO is expressed in units, with one unit defined as the amount of EPO present in one-tenth of one ampule of the International Reference Preparation. The density of EPO receptors on normal human erythroid progenitor cells appears to correlate with their responsiveness to and dependence on this hormone. Erythroid cells at the stage of the erythroid colony-forming unit (CFU-E) to the proerythroblast seem to have the highest density of receptors on their membrane. Production of an adequate number of erythrocytes depends on the continuous replenishment of the bone marrow with erythroblasts. Erythroblasts are derived from the proliferation and differentiation of morphologically unrecognizable erythroid progenitor cells. These cells have been functionally defined by their ability to form colonies of erythroblasts in semisolid culture medium.

Antibody-dependent cellular cytotoxicity to allogeneic but not autologous erythroblasts in vitro.

Antibody-dependent cellular cytotoxicity (ADCC) is a very sensitive mechanism for immune injury of target cells, which utilizes extremely low concentrations of antibody. We have developed a method for demonstrating this type of cytotoxicity to normal human erythroblasts. The latter were enriched 3- to 4-fold and were then labeled with59Fe. Blood lymphocytes from the same donor were enriched to 93% and were added as effector cells at a 60:1 ratio to the target cells. After 4 hr at 37°C, a 5- to 10-fold increase in the release of59Fe occurred when the plasma or IgG from patients with pure red-cell aplasia was present. This activity was not present when the effector cells were absent. However, this activity was found in the remission plasmas of patients and was not found when autologous erythroblasts were used. These studies demonstrate a method for detecting ADCC to allogeneic normal human erythroblasts. This ADCC does not appear to be related to the disease since a similar autoimmune activity to the patients own erythroid cells was not detected. Further studies are suggested using other effector cells in this system.