Apoptosis and JNK activation are differentially regulated by Fas expression level in renal tubular epithelial cells.

BACKGROUND: In chronic renal disease, renal tubular epithelial cell (RTC) Fas expression is up-regulated, leading to apoptotic RTC deletion and tubular atrophy. In vitro, cytokine- or hypoxia-induced up-regulation of Fas expression is associated with RTC apoptosis. In contrast, constitutively expressed, low level RTC Fas does not mediate apoptosis, suggesting that Fas may be coupled to expression level-dependent RTC signaling pathways. Fas is known to signal through JNK in many systems, but the requirement of JNK activation for apoptosis remains controversial. METHODS: To determine if RTC Fas regulates JNK activity and apoptosis, human RTC were transfected with graded concentrations of a eukaryotic expression vector for murine Fas. Apoptosis was measured by annexin V, TUNEL and PARP cleavage assays. JNK activity was determined by immune complex kinase assay and/or immunoblots with phospho-specific JNK antibodies, in the presence or absence of co-expressed dominant negative JNK constructs. RESULTS: Fas antibody stimulation of RTC with high Fas expression levels (to model RTC phenotype in renal disease) caused a tenfold increase in apoptosis, while RTC with low level Fas expression (to model normal RTC phenotype) were apoptosis-resistant. Fas ligation activated JNK in RTC expressing low levels of Fas, but not in apoptosis-sensitive RTC with increased Fas expression. Dominant negative JNK co-expression failed to inhibit apoptosis in RTC expressing high levels of Fas, suggesting that JNK is neither necessary, nor sufficient, for Fas-dependent apoptosis. CONCLUSIONS: At high levels of expression, RTC Fas promotes apoptosis in a JNK-independent manner. At low basal expression, Fas induces JNK activation, but not apoptosis, consistent with novel roles for RTC Fas as a mediator of cell stress or chronic inflammation.

Decreased CD10-positive mature granulocytes in bone marrow from patients with myelodysplastic syndrome.

OBJECTIVE: We retrospectively examined the maturation of the granulocytic cell lineage in bone marrow specimens from patients with myelodysplastic syndrome (MDS) by flow cytometry using both light scatter and surface marker characteristics, including CD10 and myeloid lineage-associated antigens. PATIENTS: The 7 MDS cases we studied included 2 patients with refractory anemia (RA), 3 with RA with ringed sideroblasts, 1 with RA with excess of blasts, and 1 unclassified case. Another 7 patients matched for age and sex who received bone marrow aspirates for lymphoma staging (all negative for lymphoma involvement or any other hematologic abnormalities) were selected as the control group. RESULTS: The percentage of CD10(+) mature granulocytes was significantly lower in patients with MDS than in control patients. Additionally, all patients with MDS had less than 50% CD10(+) cells in the granulocytic lineage. In contrast, only 1 of the 7 control patients had less than 50% CD10(+) cells (P <.01). CONCLUSIONS: These results suggest that flow cytometry might be a useful adjunct in the assessment of patients with suspected MDS. Further studies to correlate CD10(+) mature granulocytes from MDS cases with other benign hematologic disorders are indicated to confirm our evaluation.

Expression of c-Myc and p53 correlates with clinical outcome in diffuse large B-cell lymphomas.

We performed a retrospective immunohistochemical study of the relationships between clinical manifestations and outcomes of diffuse large B-cell lymphoma (DLBCL) and expression of oncogenic proteins in 21 cases of DLBCL at various clinical stages. Cases of nodal origin expressed p53 more often and presented with high clinical stage more frequently than those of extranodal origin. Expression of c-Myc or p53, but not Bcl-6, Bcl-2, or Bcl-1, showed a statistically significant positive correlation with high clinical stage at presentation and with high or high-intermediate risk. Coexpression of c-Myc and p53 occurred in 7 of 12 patients with high clinical stage but was absent in patients with low clinical stage; coexpression was more frequent in patients with high or high-intermediate risk than in patients with low or low-intermediate risk. Four patients with this coexpression pattern demonstrated an unusually aggressive clinical course (median survival, 7 months). Coexpression of c-Myc and p53 seems to be a better indicator than the MIB1 proliferative index for identification of a cohort of aggressive disease in patients with DLBCL.

Involvement of Fas-dependent apoptosis in renal tubular epithelial cell deletion in chronic renal failure.

Renal tubular atrophy predicts a poor prognosis in chronic renal failure, but the molecular mechanisms that regulate tubular atrophy are unknown. Because the Fas apoptosis pathway has been implicated in disease pathogenesis and Fas is expressed in kidney, we hypothesized that Fas-mediated renal tubule epithelial cell (RTC) apoptosis contributes to tubular atrophy in chronic renal failure. Immunohistochemical analyses of renal sections from two murine models of progressive renal disease revealed increases in RTC Fas expression and apoptosis compared with tissue sections from age-matched control kidneys. Increased RTC apoptosis was not accompanied by compensatory hyperplasia, suggesting that RTCs targeted for Fas-dependent apoptotic deletion contribute to tubular atrophy. These data are supported by in vitro studies that showed that interleukin-1alpha or tumor necrosis factor-alpha, cytokines that are secreted in chronic renal failure, stimulated increases in Fas expression in cultured RTCs. Both murine kidney cortex and RTCs in culture demonstrated constitutive expression of Fas ligand, a feature that is characteristically restricted to lymphocytes and immune-privileged tissues and previously unrecognized in RTCs. Functional studies revealed that interleukin-1alpha-stimulated RTC Fas expression was accompanied by increased apoptosis, which was inhibited by blocking anti-Fas ligand antibodies. The data suggest that up-regulated RTC Fas binds to Fas ligand on adjacent RTCs, which then leads to RTC death by fratricide. We propose this pathway as an initiating mechanism of tubular atrophy.

Hypoxia induces renal tubular epithelial cell apoptosis in chronic renal disease.

Renal tubular atrophy characterizes chronic progressive renal disease, but the molecular mechanisms of renal tubular cell (RTC) deletion are unclear. Because glomerular sclerosis leads to impaired peritubular blood flow, we tested the hypothesis that chronic hypoxia contributes to RTC apoptosis. Tubule hypoxia in mice with progressive renal disease (Os/+) was assessed by injecting EF5, a nitroimidazole compound that preferentially binds to cells undergoing anaerobic metabolism. Hypoxic tubules, as determined by direct immunofluorescence with anti-EF5 antibodies, were identified in kidneys from Os/+ mice, but not in age-matched controls (+/+) at 12 weeks, coincident with the onset of glomerular pathology. Hypoxia can cause apoptosis, but apoptotic RTCs were rare and equivalent in number in 12 week Os/+ and +/+ kidneys. However, by 16 weeks apoptotic RTCs were significantly more frequent in Os/+ versus +/+ mice, demonstrating that tubule hypoxia preceded RTC apoptosis. Importantly, apoptotic RTCs co-localized to hypoxic, but not normoxic tubules, indicating that tubular atrophy may result from hypoxic stimulation of RTC apoptosis. We have previously demonstrated enhanced, diffuse expression of the Fas apoptosis receptor in Os/+ tubules, providing a potential intermediary between hypoxia and apoptosis. To determine whether hypoxia stimulates Fas-dependent apoptosis, RTCs were cultured within a hypoxia chamber or in the presence of the cyanide analog, sodium azide. Both in vitro hypoxic conditions stimulated RTC plasma membrane Fas expression, and caused RTC apoptosis upon ligation with agonistic Fas antibodies. The data suggest that in the context of progressive renal disease, chronic hypoxia stimulates Fas-dependent RTC apoptosis, which represents the first definitive link between hypoxia and tubular atrophy. We believe that hypoxic induction of RTC apoptosis provides a unifying mechanism for the pathogenesis of tubular atrophy, and this paradigm identifies novel targets for chronic renal failure therapy.

Coinfusion of irradiated splenocytes with low titer tumor-infiltrating lymphocytes augments antitumor efficacy in adoptive immunotherapy.

We hypothesized that adoptively increasing the density of antigen-presenting cells (APCs) at a tumor site would improve tumor-infiltrating lymphocyte (TIL) in vivo antitumor efficacy. Irradiated splenocytes were used as crude APCs. Alone, they did not have in vitro antitumor activity nor did they augment TIL efficacy in vitro. Pulmonary metastases were established by intravenous (i.v.) injection of 5 x 10(5) MC-38 tumor into irradiated C57B1/6 mice (500 cGy). After 3 days, MC-38 TIL (0.1, 0.5, and 1 x 10(6) cells) +/- irradiated splenocytes (5,000 cGy) as APCs were administered intravenously (0.25, 0.5, and 1 x 10(6) cells) to each group (n = 5/group). Interleukin-2 (60,000 IU) was injected intraperitoneally three times daily for 3 days. Mice were sacrificed 9 days later and metastases elaborated in blinded fashion. A titer of 1 x 10(6) TIL, completely eradicated pulmonary metastases. In two consecutive experiments, when increasing titers of irradiated splenocytes were coinfused with a constant titer of TIL that did not completely eradicate pulmonary metastases, a moderate reduction in pulmonary metastases was observed. The contribution of splenocytes to an improvement in TIL antitumor efficacy was not altered when irradiated splenocytes derived from mice bearing 10-day subcutaneous MC-38 tumors were used. The coinfusion of nonirradiated splenocytes did not improve TIL antitumor in vivo activity. Activated B cells (expressing ICAM-1, B7.1, and B7.2) had no effect on in vitro tumor lysis and did not augment in vivo TIL efficacy. The results show a modest but statistically significant improvement in adoptive immunotherapy antitumor efficacy with fewer TIL by coinfusion of irradiated splenocytes. Further studies to characterize the active potential APC cell subpopulation and to clarify the mechanism(s) responsible for in vivo augmentation of TIL antitumor efficacy are in progress.

Fas-dependent fratricidal apoptosis is a mechanism of tubular epithelial cell deletion in chronic renal failure.

Renal tubular atrophy predicts a poor prognosis in chronic renal failure, but the molecular mechanisms regulating this process remain unknown. Because the Fas apoptosis pathway has recently been implicated in disease pathogenesis and Fas is expressed in the kidney, we hypothesized that Fas-mediated apoptosis of renal tubule epithelial cells (RTC) contributes to tubular atrophy in chronic renal failure. In vivo, immunohistochemical analyses of renal sections from two murine models of progressive renal disease revealed coordinate increases in RTC Fas expression and apoptosis compared with tissue sections from age-matched control kidneys. Increased RTC apoptosis was not accompanied by compensatory hyperplasia, suggesting that RTC targeted for Fas-dependent apoptotic deletion contribute to tubular atrophy. These data are supported by in vitro studies showing that interleukin-1alpha and tumor necrosis factor-alpha, cytokines secreted in chronic renal failure, stimulated increases in Fas expression in cultured RTC. Both murine kidney cortex and RTC in culture demonstrated constitutive expression of transmembrane and soluble forms of RTC Fas ligand, features that are primarily restricted to lymphocytes and immune-privileged tissues and that have been previously unrecognized in RTC. Functional studies revealed that interleukin-1alpha-stimulated RTC Fas expression was accompanied by increased apoptosis, which was inhibited by blocking anti-Fas ligand antibodies. In contrast to the conventional paradigm, which holds that Fas-dependent apoptosis is initiated by the binding of lymphocyte Fas ligand to target cell Fas, our data suggest that up-regulated RTC Fas binds to Fas ligand on adjacent RTC, which then leads to RTC death by fratricide. We propose this pathway as an initiating mechanism of tubular atrophy.

Reduced CD4 and HLA-DR expression in neonatal monocytes.

Three-color flow cytometry was used to assess the immunophenotypic characteristics of normal cord blood monocytes after labeling with a variety of antibodies against myeloid/monocyte-specific markers. Monocytes both in cord blood and in peripheral blood from normal adults were defined in a backgating procedure as cells with the light-scattering characteristics of monocytes that also expressed CD14. The percentage of monocytes, defined in this fashion, that also displayed CD4 receptors was significantly lower in cord blood (mean +/- SD = 29.3 +/- 13.9%) than in peripheral blood from normal adult controls (mean +/- SD = 68.9 +/- 13%) (P < 0.005). Similarly, HLA-DR expression was found on only 86 +/- 6.6% of monocytes in cord blood but on 99 +/- 1% of monocytes in adults (P < 0.005). The percentage of monocytes displaying CD16 receptors in cord blood did not show any significant difference in comparison with adult monocytes. When coexpression of CD14, CD16, and CD4 was assessed, cord blood showed a predominant population of monocytes bearing the phenotype CD14+/CD16-/CD4-. Similarly, approximately 10% of CD14+ monocytes in cord blood expressed neither CD4 nor HLA-DR. Cytochemically, monocytes from cord blood revealed intense granular staining for PAS and marginal or absent staining for nonspecific esterase (NSE). These results raise the possibility that reduced expression of CD4 and HLA-DR receptors on cord blood monocytes may contribute to their impaired immune response. Additionally, the high percentage of CD14+/CD16-/CD4- cells in cord blood suggests that these cells may represent a phenotypically immature population of monocytes. Likewise, the unusual cytochemical staining patterns suggest that these cells are biochemically immature as well.

Gonadotropin-releasing hormone agonist influences absolute levels of lymphocyte subsets in vivo in male mice.

Our earlier studies have demonstrated that gonadotropin-releasing hormone (GnRH) agonists suppress immune system function in female mice. No systematic studies regarding the effect of gender on immune system function following GnRH agonist treatment, however, have been reported. This study, therefore, investigated sequential changes in lymphocyte subsets in 3- and 10-week-old male mice following agonist or placebo administration. Changes in immunophenotypic expression of lymphocytes from thymus, bone marrow, spleen, and blood were analysed at periodic intervals. Upon agonist administration, plasma testosterone levels were significantly increased in pre-pubertal mice, but were significantly decreased in post-pubertal males. Absolute thymic weights, thymocytes and T subsets were significantly increased from the third week regardless of gonadal status. Blood lymphocyte subsets showed a decreasing trend after agonist administration in pre-pubertal males, whereas no differences were observed in post-pubertal males. No significant differences were observed in spleen cells after agonist administration. These studies, together with earlier observations in female mice indicate that GnRH agonist effects on the immune system, are independent of steroid hormone levels. In contrast to suppressive effects in females, GnRH agonist induce no change or ultimately enhanced lymphocyte counts in males, indicating differential effects on the immune system between males and females. This may have important implications for the treatment of various diseases.

CD4 Expression by erythroid precursor cells in human bone marrow.

Flow cytometry was used to assess CD4 expression in 62 consecutive bone marrow specimens from patients with a variety of clinical conditions. Using a lysed-whole-blood technique for labeling with monoclonal antibodies, two populations of CD4+ cells were identified within the lymphocyte/blast-cell fraction in 58 (94%) of these specimens. These consisted of (1) a population of T helper cells with high density expression of CD4 and (2) a second population of cells with low-density expression of CD4, which ranged from 1% to 36% of the gated cells. This latter population was present regardless of age, sex, or clinical condition including 21 of 21 specimens (100%) categorized as unremarkable bone marrows both morphologically and by flow cytometry and in four of four patients (100%) with human immunodeficiency virus-type 1 (HIV-1) infection. Coexpression of the erythroid lineage marker, glycophorin A, with the majority of cells in this second population was demonstrated in all 11 randomly selected samples using two-color flow cytometric analysis. These cells also expressed low levels of the myeloid markers, CD13 and CD33, but CD34 expression could not be demonstrated. These results provide evidence for expression of CD4 on cells of erythroid lineage in human marrow, and offer a potential mechanism for direct infection of erythroid precursor cells and deranged erythropoiesis in patients with HIV-1 infection.

Hematopoietic stem cell antigen-1 (Sca-1) expression in different lymphoid tissues of female mice treated with GnRH agonist.

PROBLEM: Our earlier studies have demonstrated a general suppression of leukocyte maturation upon GnRH agonist treatment in mice and suggested a potential effect at an early stem cell stage of leukocyte development. METHOD: Three-week old Balb/c and C57BL/6 female mice received 50 micrograms injections of Lupron depot or placebo. Sequential changes in Sca-1+ cells in the bone marrow, thymus, blood and spleen were studied by flow cytometry. RESULTS: In bone marrow, the absolute numbers of Sca-1+ cells were significantly decreased at 2 weeks in C57BL/6 mice whereas a decreasing trend was noted in Balb/c mice following agonist administration. Concomitantly, thymocytes expressing Sca-1+ cells were significantly increased at 2 weeks in C57BL/6 mice, but were significantly decreased in Balb/c mice. Significant decreases in Sca-1+ cells were also observed in spleen and blood in Balb/c mice whereas no significant differences were observed in C57BL/6 mice. CONCLUSIONS: These data suggest GnRH agonists affect hematopoietic stem cell development in mice. The effects observed vary with different genetic backgrounds. In Balb/c mice these effects are more pronounced, and appear to result in the inhibition of stem cell maturation. In contrast, GnRH agonist enhances stem cell maturation in C57BL/6 mice.

B-cell prolymphocytic leukemia expressing discordant myeloid-associated antigens in simultaneous specimens from bone marrow and peripheral blood.

The case of a 73-year-old man with B-cell prolymphocytic leukemia (PLL) and rapid clinical demise is reported. Flow cytometric immunophenotyping results of specimens obtained from the patient demonstrated a monoclonal CD5 positive B-cell population with myeloid-associated marker expression, which was discordant: CD15 and CD11b were expressed in bone marrow leukemic cells, whereas peripheral blood leukemic cells showed virtually no expression of these markers. Discordant immunophenotyping results between bone marrow and peripheral blood cells have been reported recently. Additionally, investigators have associated expression of CD13 and CD11b by chronic B-cell lymphoid leukemias with a more aggressive clinical course and shorter survival. Expression of these myeloid-associated antigens by B-cell prolymphocytes in PLL has not been widely reported. Cytogenetic analysis revealed a karyotype of 46,XY/?44,XYdel(1q),del (3p), whereas molecular genetic studies demonstrated immunoglobulin gene rearrangements in both heavy and light chain regions. Cytochemical staining for PAS (periodic acid-Schiff), nonspecific esterase and methyl-green-pyronin was positive in leukemic cells.

Discordant immunophenotype of chronic B-cell lymphoproliferative disorders in simultaneous specimens from bone marrow and peripheral sites.

This study consisted of 10 cases of chronic B-cell lymphoproliferative disorders that had simultaneous specimens obtained from both bone marrow and peripheral sites for flow cytometric immunophenotyping. The immunophenotyping results of peripheral sites from all 10 cases showed a monoclonal B-cell proliferation expressing monoclonal surface immunoglobulin, CD19, CD20, HLA-DR, and CD5 (except 1 case). Eight (80%) of the 10 cases, however, demonstrated discordant immunophenotypes with myeloid-associated marker expression (CD13, CD11b, and/or CD15) found only in the bone marrow. Patients with CD13 or CD11b marker expression in the bone marrow followed an aggressive clinical course with advanced Rai's stage and a diffuse or mixed bone marrow infiltration pattern or disease transformation. These results indicate that discordant immunophenotypes of malignant cells from different body sites occur in chronic B-cell lymphoproliferative disorders and are not uncommon. Additionally; myeloid-associated markers, which some investigators have described as being associated with an unfavorable clinical course, may be expressed only in bone marrow specimens in these disorders. Thus, bone marrow specimens may be preferential in determining myeloid-associated marker expression in chronic B-cell lymphoproliferative disorders.

Effects of GnRH antagonist on lymphocyte subpopulations in primary and secondary lymphoid tissues of female mice.

PROBLEM: GnRH analogs are playing an increasing role in the treatment of many clinical disorders. Recent studies have indicated that GnRH agonists suppress immune function in mice in vivo. The present study investigated the effects of GnRH antagonist of functional lymphocyte subsets of mice in vivo. METHOD: Three- and 10-wk old female mice received 10 micrograms of Nal-Glu daily for 15 and 30 days; changes in the immunophenotypic expression of lymphocytes from thymus, bone marrow, spleen and blood were analyzed by flow cytometry. RESULTS: The administration of GnRH antagonist to pre- and postpubertal female mice induced slight increases in lymphocyte subpopulations in primary and secondary lymphoid tissues. These effects are opposite those obtained with GnRH agonist in our earlier studies in mice. CONCLUSIONS: Assuming similar effects in humans and rodents, the gonadal steroid suppression achieved by GnRH antagonist treatment has no apparent suppressive effects on the immune system.

Composite cutaneous T-cell lymphoma and small B-cell lymphocytic lymphoma: morphologic, immunologic, and molecular genetic documentation of concurrent lymph node involvement.

Synchronous cutaneous T-cell lymphoma and low-grade B-cell lymphoproliferative disorders have rarely been reported in the same patient. Coexpression of each phenotype in the same lymph node has not, to our knowledge, been previously documented. We describe an 86-year-old man with chronic pruritus and erythroderma and recent-onset peripheral lymphadenopathy and lymphocytosis. Lymph node biopsy provided morphological and immunohistochemical evidence of concurrent small B lymphocytic lymphoma and small pleomorphic T-cell lymphoma. Immunophenotyping of nodal lymphocytes demonstrated two distinct clones: IgM-kappa B-cells with CD5 positivity and CD7 negative T-helper cells. Both immunoglobulin (heavy and light chains) and T-cell receptor (beta I and beta II) gene rearrangements were detected by Southern blot analysis of the lymph node. In contrast, the immunophenotype of lymphocytes from peripheral blood and bone marrow was exclusively that of T-helper cells with atypical CD7 deletion. Electron microscopic examination of circulating lymphocytes revealed small cerebriform Sezary cells. This case demonstrates that small lymphocytic lymphoma may coexist intranodally with cutaneous T-cell lymphoma as a unique form of composite T- and B-cell lymphoma.

Alterations in thymic and bone marrow lymphocyte subpopulations in GnRH agonist treated prepubertal female mice.

Complex endocrine relationships exist among the hypothalamus, pituitary, ovaries and thymus. There is also considerable evidence showing gonadotropin releasing hormone (GnRH) involvement in modulating immune system functions. The present study investigated the sequential changes in functional lymphocyte subsets in primary lymphoid tissues of prepubertal female mice in vivo following GnRH agonist treatment in slow release microcapsule formulation. A direct two color immunofluorescence staining followed by flow cytometry was employed. Single i.m injection of agonist significantly decreased both absolute and relative thymic weights and absolute thymocyte counts. No differences, however, were observed in the percentage of thymocytes expressing Thy 1.2, CD4 and CD8. Absolute levels of thymic T cells, CD8 positive cells, immature cells expressing both CD4 and CD8, and immature subsets differentiating toward CD4 were significantly reduced two weeks after agonist treatment. The percentage of bone marrow B cells was also significantly decreased at the second and third weeks following agonist administration. Functional studies to determine in vivo cell-mediated immune function also indicated a significant suppression following agonist administration. These data, together with our earlier observations on secondary lymphoid tissues, suggest a general suppression of lymphocyte maturation at an early stem cell stage of development in prepubertal female mice in vivo.

GnRH agonist induces suppression of lymphocyte subpopulations in secondary lymphoid tissues of prepubertal female mice.

PROBLEM: Gonadotropin-releasing hormone (GnRH) agonists are playing an increasing role in the medical management of a variety of diseases. Recent evidence also indicates GnRH immune system interactions. METHOD: The present study investigated the sequential changes in lymphocyte subpopulations in secondary lymphoid tissues of prepubertal female mice in vivo following Lupron depot administration. A direct two-color immunofluorescence staining followed by flow cytometric analysis was employed. RESULTS: Following agonist administration, white blood cell counts decreased significantly with decreases in both granulocyte and lymphocyte counts. Blood T-cell and B-cell subsets were also reduced although B cells decreased more markedly. In the spleen, B cells were again reduced more than T cells. There was no selective loss of either CD4 or CD8 subpopulations at any time point, in both spleen and blood. There were no differences in the percentage of lymph node subsets except that B cells decreased in the second week. CONCLUSIONS: These data indicate that GnRH agonist alters specific lymphocyte subpopulations and, therefore, have the potential for affecting immune system function in vivo.

Binding of human C-reactive protein to monocytes: analysis by flow cytometry.

An opsonic role has been proposed as a major function of C-reactive protein (CRP) in humans. In support of this hypothesis, recent radiolabelled ligand binding studies have provided evidence for the presence of specific receptors for soluble human CRP on human phagocytic cells, including neutrophils and monocytes. In order to confirm specific binding of CRP to monocytes and to quantify the percentage of such cells capable of expressing binding sites, we employed a sensitive biotin-avidin fluorescence assay to study the CRP-monocyte interaction. It was observed that 67% of monocytes bound biotinylated CRP in a dose-dependent manner, that the binding was calcium dependent, and that it could be inhibited by 60% in the presence of a greater than 20-fold excess of competing native CRP. In other experiments, neither IgG nor heat-aggregated IgG inhibited the binding of CRP to monocytes; and no significant binding to lymphocyte population could be detected. These studies confirm the ability of human CRP to bind to a majority of human monocytes in a calcium-dependent and specific manner, and provide further support for a biologically important interaction of this acute-phase protein with phagocytic cells.

Differences in HLA-B27 positive and negative patients with ankylosing spondylitis: study of clinical disease activity and concentrations of serum IgA, C reactive protein, and haptoglobin.

To find out whether disease activity and B27 status were associated with serum concentrations of IgA, C reactive protein (CRP), and haptoglobin in ankylosing spondylitis (AS) multivariate analysis of variance was used to study 101 patients with AS whose disease was clinically classified as active or inactive, and who were HLA-B27 typed. It was found that B27 and disease activity do interact significantly to affect the serum concentrations of IgA, CRP, and haptoglobin. When the 77 B27+ patients were examined, however, it was found that disease activity was significantly associated with serum concentrations IgA. In contrast, in the 24 B27- patients concentrations of serum IgA were significantly associated with disease activity, but not. These results emphasise the known difference between B27+ and B27- AS and suggest different pathogenic mechanisms in the two forms of AS.

Immunodeficiency in patients with hemophilia: an underlying deficiency and lack of correlation with factor replacement therapy or exposure to human immunodeficiency virus.

Nineteen patients with hemophilia, five of whom were classified as untreated, were immunologically evaluated by the measurement of cell surface markers, natural killer cell activity, mitogenic responses, polyclonal immunoglobulin production, and serologic evidence of human immunodeficiency virus infection. No correlations were found between human immunodeficiency virus infection and immune abnormalities, or between patients who did or did not receive factor therapy, although the abnormalities were more profound in those who received treatment. An intrinsic B cell abnormality in patients with hemophilia is suggested.