Wayne Borcherding

Lymphocyte dysfunction in congenital hypoplastic anemia.

Congenital hypoplastic anemia (Diamond-Blackfan syndrome) is thought to involve the erythropoietic cell line alone. In this study, the evaluation of lymphocyte function in five patients with this syndrome revealed a number of abnormalities. Peripheral blood T lymphocyte percentages as assessed by monoclonal antibodies were decreased in three patients. T-helper/T-suppressor cell (OKT4:OKT8) ratios were almost unity in four of the five patients. We usually find a ratio of 2:1 in normal populations. Studies of lymphocyte-mediated suppression of lymphoproliferation demonstrated an inability to generate concanavalin A-induced suppressor cells in the same four patients and impaired prostaglandin-mediated suppression in two patients. Co-culture studies revealed a T lymphocyte-mediated suppression of erythropoiesis in a single patient, who also showed suppression of the mixed lymphocyte reaction. The four remaining patients showed no excessive suppressor effects either upon erythropoiesis or lymphoproliferation. These studies demonstrate that in congenital hypoplastic anemia, the cellular defect is not restricted to the erythroid progenitor cells, but extends to the lymphocytes.

Elevated serum 1,25-dihydroxyvitamin D concentrations in the hypercalcemia of sarcoidosis: Correction by glucocorticoid therapy

AN EVALUATION of hypercalcemia in a 9-year-old girl revealed a low normal immunoreactive PTH level, cutaneous anergy, and abnormal macrophage suppressor activity. Numerous noncaseating granulomata were seen in a liver biopsy specimen confiming diagnosis of sarcoidosis. The patient had hypercalcemia (serum calcium of 14.8 mg/dl), hypercalcuria ( > 300 mg daily), an abnormal urinary calcium/creatinine ration, and a reduced creatinine clearance. An assay of vitamin D metabolites revealed normal 25(OH)-vitamin D~ and D3 levels, normal 24,25(OH)~-vitamin D, and supranormal 1,25(OH)~-vitamin D (calcitriol) concentrations of 91 and 75 pg/ml (normal 42 + 12 pg/ml; SD). Oral prednisone therapy resulted in lower serum calcitriol concentrations and normalized the abnormalities of calcium metabolism. This is the first case in a child supporting the hypothesis that abnormalities of calcium metabolism in sarcoidosis are related to elevated calcitriol concentrations. Sarcoidosis is infrequent during childhood, but abnormalities of calcium metabolism are found in 30 to 50% of childhood cases? These abnormalities of calcium metabolism are similar to those found in vitamin D intoxication. 2 Subjects with sarcoidosis have increased sensitivity

B cell lymphoproliferative disorders following T cell depleted allogeneic bone marrow transplantation

The recipients of organ allografts are at increased risk for developing post-transplant lymphoproliferative disorders (LPDs), reflecting malignant B cell lymphomas. These have been particularly noted in the recipients of cardiac and renal allografts, with occasional de novo LPDs reported following allogeneic bone marrow transplantation. Recently, a number of transplant centers have been testing in vitro elimination of donor T cells from the marrow suspension as a means for potentially reducing the incidence and severity of graft versus host disease. We have used monoclonal anti-T ceil antibody and complement to deplete T cells from 74 allogeneic marrow transplant donations. Eight of these recipients have developed malignant lymphomas. During this same time period, 36 patients received whole (untreated) marrow infusions, and none developed LPDs. We report here the clinical details for these eight patients, and the histologic characterization of their malignant lymphomas.

Autoimmune hemolytic anemia as a manifestation of T-suppressor-cell deficiency

This report describes two children in whom autoimmune hemolytic anemia was the initial clinical manifestation of an underlying T-cell deficiency. Further investigation revealed a profound deficiency of T suppressor cells in both children as detected by monoclonal T-cell antibody (OKT8) and/or functional assays. In vitro incubation of their lymphocytes with cultured thymus epithelium or thymic factors induced T suppressor cells. In vivo treatment with cultured thymus epithelium or calf thymosin fraction 5 resulted in increased T-suppressor-cell numbers and/or function in both and possibly decreased hemolytic activity in one. These results suggest that the autoimmune process in some patients with autoimmune hemolytic anemia is associated with T-suppressor-cell deficiency and that in vivo therapy with agents that modulate T-cell function may be of therapeutic value.

Immunologic studies of lymph node lymphocytes in the generalized lymphadenopathy syndrome

A generalized lymphadenopathy syndrome (GLS) occurs in persons at high risk for development of acquired immunodeficiency syndrome (AIDS). The natural history and immunologic status of patients with GLS are not fully known, although in some persons GLS may progress to full AIDS. We present the clinical and immunologic findings in two children with severe hemophilia A with nonprogressive GLS for 18-24 months. The functional activity in vitro of lymphocytes from both peripheral blood and biopsied lymph nodes were compared. The peripheral blood lymphocytes responded normally to both mitogens and antigens; lymph node lymphocytes failed to respond to antigens, but did respond to mitogens. The implications of these abnormalities for understanding the pathogenesis of GLS are discussed.

T-Lymphoblasts with Erythropoietic Helper Function in Acute T-Cell Leukemia

A patient with acute T-lymphoblastic leukemia was found to maintain a normal hemoglobin concentration both at presentation and preterminally several months later, despite a replaced bone marrow and over 80% circulating lymphoblasts on both occasions. Cell surface marker analysis demonstrated the T-lymphoblasts both at presentation and preterminally to belong to the T-helper subpopulation. In vitro culture studies demonstrated that the patients T-lymphoblasts, as well as conditioned medium derived from these lymphoblasts, significantly stimulated normal bone marrow erythroid colony growth (CFU-E). These findings suggest that in this patient the preservation of erythropoiesis resulted from a helper effect exerted by his T-lymphoblasts.

878 RECATEGORIZING CHILDHOOD ACUTE LYMPHOBLASTIC LEUKEMIA WITH MONOCLONAL ANTIBODIES TO HUMAN T CELLS

The immunologic surface markers of lymphoblasts from three patients with childhood acute lymphoblastic leukemia (ALL) were analyzed. Blasts from two of these patients did not form rosettes with sheep erythrocytes and the third did so marginally, suggesting these patients had non-T cell leukemia. These blasts were also tested with commercially available monoclonal antibodies (OKT 3, 4, 6, 8,) that detect thymocyte differentiation markers, and all three patients were highly reactive with at least 2 of these reagents.We anticipate the availability of multiple standardized monoclonal reagents will necessitate a recategorization of ALL phenotypes. Furthermore, some of these leukemic phenotypes may not correspond to normal stages of lymphoid differentiation. Therefore, it may be inappropriate to attempt to identify and categorize leukemic cells by the pathways of normal differentiation. We suggest that leukemic cells be identified by the presence or absence of standardized immunologic and enzymatic markers without attempting to classify them by prior labels of “T, null, B, pre-B or pre T.”

864 SUPPRESSOR T CELL FUNCTION IN DIABETES MELLITUS

Autoaggression against pancreatic islet cells has been described in patients with diabetes mellitus. Based on the hypothesis that a loss of immune regulatory suppressor T cells could be important in the development of these autoaggressive reactions, we examined suppressor T cell function in 14 children with insulin-dependent diabetes mellitus. Suppressor cell activity was determined by assessing the effect of concanavalin A-treated lymphocytes on the one-way mixed leukocyte culture reaction. Suppressor cell activity was demonstrated in 15 of 15 normal controls. However, 11 of 14 patients with insulin-dependent diabetes mellitus lacked suppressor T cell function. In our sample, age, sex, duration of diabetes mellitus and control of the disease did not correlate with the presence or absence of suppressor cell activity. Our data suggest that decreased suppressor T cell function may be important in the pathogenesis of some forms of diabetes mellitus. The relationship of HLA (HLA-A,B,C,D) and suppressor T cell function in diabetes mellitus is being investigated.