In vitro studies of complement function in sera of C4-deficient guinea pigs.

In vitro studies were performed utilizing sera from a strain of guinea pigs with a total absence of hemolytically active C4. Previous studies in these animals have demonstrated normal complement-dependent inflammatory reactions, suggesting that they are able to bypass their deficiency of C4. In vitro studies with C4-deficient serum also indicate normal activation of late-acting C components. Thus, endotoxin was capable of fixing normal amounts of the late components of complement (C3-9) in these sera, but did not fix C1 and C2. Antigen-antibody complexes fixed both early and late components of complement, although components beyond C4 were fixed less efficiently than in normal sera. Therefore, both in vivo and in vitro evidence indicates that the C4-deficient guinea pigs possess an alternate pathway for activation of late-acting complement components. Antigenic analysis of C4-deficient serum utilizing both guinea pig anti-C4 antibody and rabbit anti-C4 antibody suggests an absolute deficiency of C4-like molecules. Sera from animals with C4-deficiency were found to have one-half the normal level of C2. Sera from five of eight animals tested had 10-20% normal C1 activity. C3-9 assayed as a complex was normal.

Specific immune response genes of the guinea pig. 3. Linkage of the GA and GT immune response genes to histocompatibility genotypes in inbred guinea pigs.

The ability of guinea pigs to form immune responses specific for each of the random copolymers, L-glutamic acid and L-alanine (GA) and L-glutamic acid and L-tyrosine (GT), is under the control of distinct autosomal dominant genes. By testing for the ability to respond to these copolymers among the progeny from the reciprocal backcross mating of responder (2 x 13)F(1) animals with the appropriate nonresponder parental strain, we have demonstrated that different unigenic autosomal dominant traits control the ability to respond to GA and GT respectively. The data further shows that the GA gene is linked to the poly-L-lysine (PLL) gene and to the locus determining the major strain 2 histocompatibility specificities and that the GT gene is linked to the locus controlling the expression of major strain 13 histocompatibility specificities. Analysis of the inheritance of the GT and PLL genes among the offspring from a mating of responder (2 x 13)F(1) guinea pigs with random-bred guinea pigs unable to respond to GT or PLL demonstrate that these genes segregate away from each other. Thus, the PLL gene and the genes to which it is linked, the GA gene and the major strain 2 histocompatibility locus, behave as alleles or pseudoalleles to the GT gene and the major strain 13 histocompatibility locus.

Histocompatibility type and immune responsiveness in random bred Hartley strain guinea pigs.

Outbred Hartley strain guinea pigs capable of responding immunologically to 2,4-dinitrophenylated poly-L-lysine were shown to display a histocompatibility specificity in common with inbred strain 2 guinea pigs. This histocompatibility specificity was not detected in guinea pigs unable to respond immunologically to DNP-PLL. The result suggests that the poly-L-lysine specific immune response gene is very closely linked or even identical with a gene determining a major histocompatibility antigen in guinea pigs.

In vivo studies in C4-deficient guinea pigs.

Guinea pigs with a genetically determined total deficiency of the fourth component of complement have been studied for various in vivo immunological functions. Passive cutaneous anaphylaxsis, contact and delayed hypersensitivity, and the cellular exudative response to a foreign body were normal. These animals also have normal direct and reverse passive Arthus reactions which suggest that they possess a mechanism to bypass C4 and directly activate late-acting complement components. This would appear to be an unequivocal demonstration of an alternate pathway in the complement sequence. Immune clearance of guinea pig erythrocytes sensitized with rabbit antibody was impaired in the deficient animals. Antibody production in C4-deficient animals was impaired for two of the three antigens studied.

Genetically controlled total deficiency of the fourth component of complement in the guinea pig.

Guinea pigs with a total deficiency of the fourth component of complement (C4) have been discovered. There was no evidence for the presence of a C4 inhibitor in the serum of these animals. Mating studies indicate that C4 deficiency is transmitted as a simple autosomal recessive trait. A colony of these animals is being established at the National Institutes of Health. They will provide an opportunity to more precisely define the role of complement in immune phenomena and the defense against disease.

Coping as a mediator of stress and psychotic-like experiences.

BACKGROUND: There is evidence that individuals along the whole psychosis continuum have increased responsiveness to stress; however, coping responses to stressors have not been extensively explored in subthreshold psychotic symptoms. METHODS: In 454 undergraduates, psychotic-like experiences (PLEs) were evaluated using the positive items of the Prodromal Questionnaire. Perceived stress and traumatic life events were assessed using the Life Events Checklist and Perceived Stress Scale, and coping was measured using the Brief COPE. We also examined whether different coping styles mediated the relationship between perceived stress and PLEs, as well as whether different coping styles mediated the relationship between traumatic life events and PLEs. RESULTS: Both number of traumatic life events and current level of perceived stress were significantly associated with PLEs. These relationships were both mediated by higher levels of maladaptive coping. CONCLUSIONS: Results have the potential to inform treatment strategies, as well as inform targets for exploration in longitudinal studies of those at risk for psychosis.

Anemia in primary hyperparathyroidism.

Although anemia has not been widely appreciated as a complication of primary hyperparathyroidism, 5.1% of the individuals with this disorder seen at the Massachusetts General Hospital since 1962 had a normochromic, normocytic anemia that could not be related to blood loss,a deficiency state, or uremia. The anemic group had more advanced bone disease and higher levels of serum calcium, alkaline phosphatase, and parathyroid hormone than the nonanemic group. Results of bone marrow biopsies performed in five patients showed variable degrees of myelofibrosis. However, none of the patients had hepatosplenomegaly, a myelophthisic peripheral blood smear, leukopenia, or thrombocytopenia. Removal of the abnormal parathyroid glands led to improvement or correction of the anemia.

Treatment of plasma cell dyscrasias by antibody-mediated immunotherapy.

The use of serotherapy to treat patients with plasma cell dyscrasias (PCDs) has been sought by us and others. Candidate antigens that have been targeted or proposed for targeting in PCDs include the immunoglobulin idiotype, CD19, CD38, CD54, CD126, HM1.24, and Muc-1 core protein. Unfortunately, many of these antigens are not ideal for use in serotherapy since they are not selectively expressed, are either shed or secreted, or have not been fully characterized. Serotherapy with an anti-CD19 monoclonal antibody (B4) conjugated to a blocked ricin toxin had no significant activity in patients with multiple myeloma (MM). Circulating CD20+ clonotypic B cells have been detected in the circulation of most MM and Waldenstrom's macroglobulinemia (WM) patients. Plasma cells from most WM patients express CD20, but most MM patient plasma cells either lack CD20 or express it weakly. In view of recent successes with anti-CD20-directed serotherapy in other B-cell malignancies, we initiated a phase II trial to study the anti-CD20 monoclonal antibody rituximab (Rituxan; IDEC Pharmaceuticals, San Diego, CA, and Genentech, Inc, San Francisco, CA) in patients with MM. We describe two PCD patients (one with WM and one with MM) who responded to therapy. By flow cytometric analysis, CD20+ plasma cells and B cells present in the bone marrow and peripheral blood of a patient with MM disappeared with response to rituximab therapy. However, residual CD20- tumor cells remained in the bone marrow following rituximab therapy, and after 6 months this patient progressed with CD20- myeloma cells. As a potential strategy to overcome this limitation, we demonstrated that interferon-gamma at pharmacologically achievable levels induced CD20 expression on these CD20- plasma cells, consistent with our recent findings that interferon-gamma is a potent inducer of CD20 expression on MM patient plasma cells and B cells. We also characterize a response to rituximab with a decrease in paraprotein and resolution of anemia in a patient with WM whose response to rituximab is ongoing after 19+ months. This preliminary experience supports the potential use of serotherapy targeting CD20 in PCDs. Our studies further suggest that interferon-gamma may enhance CD20 expression on MM plasma cells, thereby increasing their susceptibility to anti-CD20 monoclonal antibody therapies.

Hereditary antithrombin III deficiency. Effect of antithrombin III deficiency on platelet function.

Antithrombin III (AT III) is the main physiologic inhibitor of thrombin, and activated factors X and IX as well. Normal levels of AT III appear to be necessary to maintain blood fluidity and to prevent thrombosis. Four families with AT III deficiency and recurrent venous thromboembolism have been reported on. We present an additional family with AT III deficiency and a high incidence of thromboembolism. AT III levels were determined by both a functional and an immunologic assay. Results of platelet function tests, not previously reported in persons with AT III deficiency, were found to be normal. Following gel filtration, the platelets were very sensitive to thrombin. Thrombin-induced platelet aggregation appears to be dependent on a balance between the amount of thrombin and AT III present.

Development of a histiocytic medullary reticulosis-like syndrome during the course of acute lymphocytic leukemia.

A 54 year old woman presented with acute lymphocytic leukemia. Following an initial response to chemotherapy with vincristine and prednisone, progressive pancytopenia developed coincident with intense bone marrow infiltration by abnormal histiocytes. At autopsy two months later, no evidence of leukemia was found, but the bone marrow was replaced by abnormal histiocytes showing active erythrophagocytosis, consistent with histiocytic medullary reticulosis. Detailed morphologic, ultrastructural and histochemical studies performed throughout the course of the patient's illness served to confirm the transition from leukemia to histiocytosis. Four similar cases of acute lymphocytic leukemia terminating in histiocytic medullary reticulosis have been reported. This association may represent a distinct clinicopathologic syndrome.

Plasma heparin neutralizing activity in coronary artery disease.

Platelets contain heparin neutralizing activity that is released into plasma after platelet aggregation. Increased amounts of plasma heparin neutralizing activity were found in patients with acute myocardial infarction, unstable angina pectoris and stable arteriographically confirmed coronary artery disease. Plasma heparin neutralizing activity levels provide additional evidence for a role of platelet aggregation in coronary artery disease.

Prevalence of intrinsic factor antibodies and vitamin B12 malabsorption in older patients admitted to a rehabilitation hospital.

It is possible that the commonly measured serum level of vitamin B12 may miss some cases when used to detect vitamin B12 malabsorption and deficiency in older persons. Serum levels of vitamin B12 and intrinsic factor antibody (IFAB) were determined on 250 consecutive patients over the age of 70 admitted to a rehabilitation hospital. Patients with abnormal results on either test were given the standard Schilling test when possible. Eight patients had documented B12 malabsorption. Of these, five had a low serum B12 level alone and one had a low serum B12 level and a positive IFAB level; however, two patients had positive IFAB and normal serum B12 levels. Serum IFAB level may serve as a useful adjunct to serum B12 level in detecting vitamin B12 malabsorption in older patients.

Kaolin-correctable prolongation of the activated partial thromboplastin time.

Seven patients who had normal prothrombin times but prolonged activated partial thromboplastin times (aPTT) are described. The prolonged aPTT, obtained with micronized silica as the contact activating agent in a semi-automated optical end-point system, a nonautomated optical end-point system, and a conductivity end-point system, corrected to normal when kaolin was used as the contact activating agent. Abnormal results were also obtained with celite and ellagic acid as contact activating agents. The activities of various clotting factors were within normal limits in all cases where they were assayed. The thromboplastin dilution test was uniformly negative, and mixtures of one patient's plasma with that of another patient failed to correct the abnormal aPTT. No patients had a personal or family history of bleeding, and all underwent surgery without bleeding difficulties. This pattern of a prolonged aPTT that corrects to normal when kaolin is used as the contact activator appears to represent a previously unrecognized laboratory phenomenon.

Plasma heparin neutralizing activity. Its use in the evaluation of thrombocytopenia and thrombocytosis.

Platelets contain heparin neutralizing activity, which is released into plasma following aggregation. This material is probably identical to platelet factor 4. We describe a technic to measure heparin neutralizing activity in platelet-poor plasma based on the serial heparin dilution technic of Harada and Zucker. Heparin neutralizing activity was depressed in thrombocytopenia due to immune thrombocytopenia and bone marrow depression, and elevated in thrombocytopenia due to disseminated intravascular coagulation. Secondary thrombocytosis is characterized by markedly elevated heparin neutralizing activity, while thrombocytosis associated with myeloproliferative disorders has normal heparin neutralizing activity.

Portal vein thrombosis after elective splenectomy. An underappreciated, potentially lethal syndrome.

We describe seven cases of thrombosis of the portal and splenic vein after elective splenectomy. The diagnosis was initially unrecognized in all patients and was confused with biliary sepsis (three cases), postoperative pancreatitis (three cases), or pulmonary emboli (one case). Two patients in whom the diagnosis of portal vein thrombosis was not made within 3 days of disease onset died. In the five survivors, the diagnosis was based on clinical suspicion, confirmed with color flow Doppler ultrasonography or computed tomography with intravenous contrast material, and treated with thrombolytic agents, anticoagulants, and antibiotics. In two patients, splenic vein thrombus was visualized on initial postoperative imaging studies and the thrombus subsequently extended into the portal vein. Portal vein thrombosis should be considered in patients with fever and abdominal complaints after splenectomy. Urgent treatment with thrombolysis and anticoagulants may preserve bowel integrity and be lifesaving.

Thromboembolic risk of postsplenectomy thrombocytosis.

Although thrombocytosis is a very common finding after splenectomy, the thromboembolic risk of postsplenectomy thrombocytosis has not been clarified. To our knowledge, this retrospective study of 318 patients without myeloproliferative disorders who underwent splenectomy is the largest of its type. Thrombocytosis developed in 75% of the patients. No substantial increase in the incidence of thromboembolism was detected in patients with thrombocytosis.

Physiologic responses to cognitive challenge during pregnancy: effects of task and repeat testing.

Physiological responses to stress during pregnancy are believed to influence birth outcomes. Researchers have studied pregnant women in laboratory stressor paradigms to investigate these associations, yet normative data on cardiovascular and respiratory responses to laboratory challenge during pregnancy are not yet established. To begin to establish such normative data, this study examined the effects of task and repeat stressor exposure on reactivity in third-trimester pregnant women. Thirty-one healthy pregnant women (mean age=27 years; range 18-36) between the 33rd and 39th week of pregnancy, were instrumented for continuous electrocardiography, blood pressure (BP), and respiration data. Subjects rested quietly for a 5-min baseline and then performed both a mental arithmetic stressor and a Stroop color-word-matching task, each 5 min in length and each followed by a 5-min recovery period. The order of the tasks was counterbalanced. After each 5-min period, subjects rated the period on a 10-point stress scale. Averaged across task type and challenge period, systolic and diastolic BP and respiration rate increased significantly in response to cognitive challenge, but heart rate (HR) did not. When data were examined for task and period effects, the following results emerged: the Stroop task elicited significantly greater systolic BP and HR reactivity than the arithmetic task, yet subjects rated the arithmetic task as more stressful. Averaged across task type, subjects showed greater systolic BP reactivity during the second challenge period compared to the first. Finally, women's BP tended to drift upward and did not return to baseline during the first recovery period. These findings indicate that averaging data across tasks and periods can obscure the time course of response patterns that may be important in the study of associations between maternal stress and perinatal development, as well as in other research on reactivity to repeat stress exposure.

The clinical correlates of IgM M-components: an analysis of thirty-four patients.

Thirty-four patients with an IgM M-component were evaluated for clinical presentation and course, laboratory data, and histologic findings. An attempt was made to ignore the presence of the IgM M-component and to assign each patient to one of the following categories: Waldenstrom's macroglobulinemia, IgM myeloma, Hodgkin's disease, lymphoma, chronic lymphocytic leukemia, chronic lymphosarcoma cell leukemia, and IgM M-components not associated with an identifiable lymphoproliferative disorder ("benign" M-component). Although transitional forms occasionally occurred, most patients could be readily categorized. The patients with lymphoma, Hodgkin's disease, chronic lymphocytic leukemia, and chronic lymphosarcoma cell leukemia did not appear to behave differently from patients with these disorders who did not have serum IgM M-component. Both for descriptive convenience and for clinical management, continued attempts should be made to separate patients with IgM M-components according to their underlying conditions.

Plasma heparin neutralizing activity in patients with valvular stenosis and prosthetic heart valves.

Patients with mitral and aortic valvular stenosis had plasma heparin neutralizing activity (HNA) which were comparable to the control group. In contrast, plasma HNA was elevated in patients with prosthetic valves, particularly in the group with prosthetic aortic valves. Neither the type nor the size of the valve appeared to influence the HNA level. No correlation was evident between plasma HNA levels and a history of systemic arterial embolism. It remains to be determined whether elevated plasma HNA levels result from platelet aggregation on the valve surface, or from platelet lysis due to turbulence around the prosthetic valve.