The cellular and environmental regulation of hematopoiesis has been generally conserved throughout vertebrate evolution, although subtle species differences exist. The factors that regulate hematopoietic stem cell homeostasis may closely resemble the inducers of embryonic patterning, rather than the factors that stimulate hematopoietic cell proliferation and differentiation. Comparative study of embryonic hematopoiesis in lower vertebrates can generate testable hypotheses that similar mechanisms occur during hematopoiesis in higher species.

We studied 25 T-cell chronic lymphocytic leukemia (T-CLL) cases collected over a 15-year period. Immunophenotypic analysis was performed in each case; 12 cases were evaluated by cytogenetics, and gene rearrangement studies were performed in 14 cases. The median age was 57 years with a male predominance (M:F, 15:10). The median presenting lymphocyte count was 36.3 x 10(9)/L (range, 3.9 to 438 x 10(9)/L). Fourteen patients (56%) had shotty adenopathy and ten (40%) had mild-to-moderate splenomegaly at presentation; four (16%) had erythematous skin lesions. The lymphocytes were predominantly small; some cases had a minor component of medium-sized cells (< 10%). The nuclear: cytoplasmic ratios were uniformly high with round to oval nuclei; however, a wide spectrum of nuclear outlines could be found, ranging from minimally to markedly convoluted. Nucleoli were either absent or small and inconspicuous. These lymphocytes did not have the morphology of prolymphocytes and did not contain cytoplasmic granules. Bone marrow infiltration was generally in an interstitial pattern; the degree of involvement ranged from 15% to 90%. Immunophenotyping showed that the lymphocytes were mature T-cells with a predominant CD4+ immunophenotype. Three cases displayed a CD8+ immunophenotype. The patients were treated with a variety of chemotherapeutic regimens with only a minimal response observed in two of 20 patients. We conclude that T-CLL is an uncommon chronic lymphoproliferative disorder (CLPD) that can be morphologically similar to B-CLL, is distinct from T-prolymphocytic leukemia, and has an aggressive clinical course that is refractory to therapy. It may also be difficult to distinguish T-CLL from other T-CLPD, especially the leukemic phase of peripheral T-cell lymphoma and some cases of Sézary syndrome.

Acute graft-versus-host disease (aGVHD) has been classified according to the Seattle criteria as grades 0, I, II, III, and IV for 20 years. The predictive value of such detailed grading is a matter of debate; publications usually report GVHD as present or absent or as absent, moderate, or severe. The Working Party Chronic Leukemia of the European Group for Bone Marrow Transplantation analyzed data of 1,294 patients transplanted from an allogeneic donor for chronic myelogenous leukemia (CML) in first chronic phase and tested the predictive value of aGVHD grading for the following end-points: day 100 mortality (D100M), transplant-related mortality (TRM), relapse incidence (RI), leukemia-free survival (LFS), and survival (SURV). aGVHD was absent in 462 patients (35.7%), grade I occurred in 335 (25.8%), grade II in 264 (20.5%), grade III in 110 (8.5%), and grade IV in 123 patients (9.5%). A total of 297 patients (23%) died within 100 days, 495 patients (38%) died of any TRM, and 100 patients (8%) died of relapse. D100M according to grades 0, I, II, III, and IV was 17%, 13%, 19%, 38%, and 70%, respectively, with significant difference between 0-II versus III-IV. TRM was 28%, 27%, 43%, 68%, and 92%, respectively, with a distinct separation between 0-I versus II-IV. RI showed a continuous decrease of 37%, 30%, 23%, 18%, and 8%, respectively, with increasing aGVHD. LFS was 45%, 51%, 44%, 26%, and 7%, respectively, and was best for patients with grade I aGVHD. This finding was also reflected in a better overall survival (60%, 64%, 53%, 30%, and 8%, respectively). The better LFS for grade I aGVHD patients compared with patients with grade 0 or II aGVHD was confirmed (P = .05) in a multivariate analysis. These data document the value of the present 5-point grading of aGVHD, ie, different outcome is observed depending on endpoint analyzed. Restricting information about aGVHD to presence or absence is not warranted.

Within the Cooperative Study of Sickle Cell Disease, 694 infants with confirmed sickle cell disease were enrolled at less than 6 months of age. Information about the nature and frequency of complications was collected prospectively over a 10-year period. Painful crises and acute chest syndrome were the most common sickle cell-related events in homozygous sickle cell anemia (SS), hemoglobin SC disease (SC), and S beta thalassemia patients (overall incidence in SS patients of 32.4 and 24.5 cases per 100 person-years, respectively). Bacteremia occurred most frequently in SS children under 4 years of age and in SC patients less than 2 years of age. The mortality rate was low in this cohort compared with that found in previous reports. Twenty children, all with Hb SS, died (1.1 deaths per 100 person-years among SS patients). Infection, most commonly with Streptococcus pneumoniae and Hemophilus influenzae, caused 11 deaths. Two children died of splenic sequestration, 1 of cerebrovascular accident, and 6 of unclear causes. Two patients underwent cholecystectomies, and 17 underwent splenectomies after one or more splenic sequestration crises. The experience of this cohort should reflect closely the true clinical course of those children with Hb SS and Hb SC disease who are observed in sickle cell centers in the United States.

The TNF receptor superfamily members are all type I membrane glycoproteins with typical homology in the extracellular domain of variable numbers of cysteine-rich repeats (overall homologies, 25% to 30%). In contrast, the TNF ligand superfamily members (with the exception of LT alpha) are type II membrane glycoproteins with homology to TNF in the extracellular domain (overall homologies, 20%). TNF and LT alpha are trimeric proteins and are composed of beta-strands forming a beta-jellyroll. The homology of the beta-strand regions for the TNF ligand superfamily members suggest a similar beta-sandwich structure and possible trimeric or multimeric complex formation for most or all members. A genetic linkage, as evidence for evolutionary relatedness, is found by chromosomal cluster of TNFR p80, CD30, 4-1BB, and OX40 for 1p36; TNFR p60, TNFR-RP, and CD27 for 12p13; TNF, LT alpha, and LT beta for 6 (MHC locus); CD27L and 4-1BBL for 19p13; and FASL and OX40L for 1q25. Of the TNF ligand superfamily, TNF, LT alpha, and LT beta and their receptors (TNFR p60, TNFR p80, and TNFR-RP) interact in a complex fashion of cross-binding. However, the other family members presently have a one ligand/one receptor binding principle (CD27/CD27L, CD30/CD30L, CD40/CD40L, 4-1BB/4-1BBL, OX40/gp34, and FAS/FASL). In general, the members of the TNF ligand superfamily mediate interaction between different hematopoietic cells, such as T cell/B cell, T cell/monocyte, and T cell/T cell. Signals can be transduced not only through the receptors but also through at least some of the ligands. The transduced signals can be stimulatory or inhibitory depending on the target cell or the activation state. Taken together, TNF superfamily ligands show for the immune response an involvement in the induction of cytokine secretion and the upregulation of adhesion molecules, activation antigens, and costimulatory proteins, all known to amplify stimulatory and regulatory signals. On the other hand, differences in the distribution, kinetics of induction, and requirements for induction support a defined role for each of the ligands for T-cell-mediated immune responses. The shedding of members of the TNF receptor superfamily could limit the signals mediated by the corresponding ligands as a functional regulatory mechanism. Induction of cytotoxic cell death, observed for TNF, LT alpha, CD30L, CD95L, and 4-1BBL, is another common functional feature of this cytokine family. Further studies have to identify unique versus redundant biologic and physiologic functions for each of the TNF superfamily ligands.(ABSTRACT TRUNCATED AT 400 WORDS)

Chediak-Higashi syndrome is a rare condition characterized by susceptibility to bacterial infections, defective natural killer activity, and episodes of macrophage activation known as accelerated phases. Chemotherapy can induce transient remission of the accelerated phase, but relapses become less and less sensitive to treatment and ultimately lead to death. Allogenic bone marrow transplantation (BMT) has been proposed as a curative treatment for Chediak-Higashi syndrome. We report the outcome of BMT in 10 such children. Seven received marrow from an HLA-identical related donor and three from an HLA-nonidentical related donor. Three patients died, two from a new accelerated phase after rejection of transplanted bone marrow and one from cytomegalovirus (CMV) pneumonia. Six of seven recipients of HLA-identical marrow and one of three recipients of HLA-nonidentical marrow are alive and well without treatment 1.5 to 13 years after transplantation (median, 6.5 years). No manifestations of accelerated phases have occurred in these seven patients, and significant natural killer activity is detectable. Interestingly, BMT prevented recurrence of accelerated phases in patients with limited numbers of donor-type leukocytes after transplantation. Ocular and cutaneous albinism were not corrected after transplantation. None of the patients developed serious toxic reactions to the BMT conditioning regimen or have long-term sequelae. These results show that HLA-identical BMT is an acceptable curative treatment for Chediak-Higashi syndrome, whereas HLA-nonidentical BMT remains an experimental approach.

Between December 1990 and January 1994, bone marrow (BM) samples from 151 patients with multiple myeloma (MM), including 117 patients evaluated at diagnosis, were collected for cytogenetic analysis. A total of 129 patients had assessable metaphases (100 patients at diagnosis). Cytogenetic studies were performed on BM cells after longterm cultures (6 days) with stimulation of cultures by granulocyte-macrophage colony-stimulating factor (GM-CSF), GM-CSF plus interleukin (IL)-6, IL-3 plus IL-6, or GM-CSF plus IL-3 plus IL-6 to improve myeloma cell growth, and 91 patients had an additional unstimulated culture. Sixty-six patients (51%) had cytogenetic abnormalities, including 47 of 100 patients at diagnosis (47%) and 17 of 24 patients at relapse (71%; P = .04). The aberration rate increased with stage (P = .007), BM plasmacytosis (P = .003), beta 2 microglobulin level (P = .001), C-reactive protein (CRP) level (P = .001), and Ki-67 (P = .007). The abnormality detection rate was higher in stimulated than unstimulated cultures, and the difference was statistically significant (P < .01). Hyperdiploidy was observed in 39 patients (30% of patients with an assessable karyotype) and hypodiploidy in 19 patients (15%). Among numeric changes, gains predominantly involved chromosomes 3, 5, 7, 9, 11, 15, 19 and losses, chromosomes 8, 13, 14, and X. The most frequent loss was loss of chromosome 13, observed in 22 patients (15%), including 18 patients at diagnosis (12%). We observed frequent structural changes of chromosomes 1 (15%) and 14 (10%) but also a 5% incidence of 19q13 abnormality and two patients with translocation t(1;16)(p11;p11). By using the proportional hazard univariate model, patients with abnormal karyotypes were demonstrated to have 2.5-fold greater chance of death than patients with normal karyotypes (P < .014). Despite a multivariate approach with the same model, the respective roles of karyotype abnormality, age, stage, and beta 2 microglobulin level could not be clearly ascertained. From these results we conclude that cytogenetic analysis using stimulation of cultures by cytokine(s) may be a promising method to identify about 50% of cytogenetic abnormalities in patients with newly diagnosed MM. Cytogenetic analysis may help to define a high-risk population that would benefit from intensive therapeutic approaches.