Quantifying the Hydrological Effect of Permitted Water Abstractions across Spatial Scales.

Water abstraction from rivers and aquifers has considerable potential to alter flow regimes, thereby influencing the physical, chemical, and ecological well-being of freshwater ecosystems. The economic and social benefits of abstraction need to be balanced against its potentially deleterious consequences for hydrologically-driven ecological functions, ecosystem services, cultural values, and recreation. In New Zealand, recent legislation states that limits for the use of water resources should be set for all waterbodies to manage the potential cumulative impacts of abstraction and reduce allocation of the hydrological resource in over-allocated catchments. These limits must comprise at least a predefined minimum flow (the flow at which all abstraction must cease) and a total allocation (the maximum rate of abstraction summed across upstream abstractions). Over-allocation occurs when the sum of all upstream abstractions exceeds the total allocation. A national database describing consents to abstract water was collated. A replicable, transferable, and objective method was applied to calculate total allocation at the national, catchment, and reach scales across the entire country. Total allocation for each catchment was expressed by mapping Weighted Allocation Impact; an index that integrates magnitude and spread of water resource allocation across entire catchments. Results show that existing consents have caused over-allocation in several catchments, prompting questions about how to reduce abstraction in these locations.

Influence of hydrological regime and land cover on traits and potential export capacity of adult aquatic insects from river channels.

Despite many studies highlighting the widespread occurrence and effects of resource movement between ecosystems, comparatively little is known about how anthropogenic alterations to ecosystems affect the strength, direction and importance of such fluxes. Hydrological regime and riparian land use cause well-documented changes in riverine larval invertebrate communities. Using a dataset from 66 sites collected over 20 years, we showed that such effects led to spatial and temporal differences in the density and type of larvae with winged adults within a river reach, altering the size and composition of the source pool from which adult aquatic insects can emerge. Mean annual larval densities varied 33-fold and the temporal range varied more than 20-fold between sites, associated with the hydrological regime and land cover and antecedent high and low flows, respectively. Densities of larvae with winged adults were greater in sites that had more algal coverage, agricultural land use, seasonally predictable flow regimes and faster water velocities. More interestingly, by influencing larval communities, riparian land use and the magnitude and frequency of high and low flows affected the size structure, dispersal ability and longevity of adults available to emerge from river reaches, potentially influencing the spatial extent and type of terrestrial consumers supported by aquatic prey. This suggests that anthropogenic alterations to land use or river flows will have both spatial and temporal effects on the flux and potential availability of adult aquatic insects to terrestrial consumers in many rivers.

Recruitment of Anguilla spp. glass eels in the Waikato River, New Zealand. Evidence of declining migrations?

The timing of Anguilla spp. glass eel recruitment into the Waikato River, North Island, New Zealand, was studied over a 2 year period (2004-2005). While glass eels of both the shortfin eel Anguilla australis and the endemic longfin eel Anguilla dieffenbachii were caught, the former comprised >97% of the species composition. There was a positive correlation of glass eel migrations with spring tides, with peak migration periods typically occurring within a few hours of the peak of high tide, and between 2 and 4 days after the day of spring tide. Both water temperature and discharge had significant inverse relationships with glass eel catches, with temperature explaining >30% of the variance in catch periodicity. Comparison of catch data 30 years apart showed that main migration periods appear to occur several weeks earlier today than previously. Reduced catch per unit effort and duration of runs from recent years' sampling (compared with the 1970s) indicate that a reduction in recruitment may also have occurred during this period, something recorded in other temperate species of Anguilla.

IgG2 class red cell antibodies and autoimmune haemolysis.

AIM: To examine the role of IgG2 red cell autoantibodies in autoimmune haemolysis. METHODS: Study of immunohaematology case records. RESULTS: Six patients had only IgG2 autoantibodies detected by direct antiglobulin testing and in red cell eluates; two individuals, whose red cells were also coated with complement, suffered from autoimmune haemolytic anaemia. CONCLUSIONS: IgG2 antibodies are found alone in <1% of patients with warm autoantibodies and even more rarely cause red cell destruction. Several factors are important for inducing haemolysis. They include allele differences in the FCRIIA genes encoding for the FcyRII receptors--an allele with high affinity for IgG2 is needed for haemolysis. Topography of red cell antigens may also be significant; IgG2 is a relatively inflexible molecule and access of effector cell Fc receptors to the recognition sites on the IgG2 might be impossible unless the antigens are on, or proud to, the red cell surface. On rare occasions, IgG2 activates complement (as in our patients with active haemolysis); the synergistic effect between red cell bound immunoglobulins and C3 in causing haemolysis is well recognised.

Fatal cold anti-i autoimmune haemolytic anaemia complicating hairy cell leukaemia.

Hairy cell leukaemia (HCL) is a rare lymphoproliferative disorder associated with pancytopenia, splenomegaly and the presence of typical hairy B lymphocytes in the bone marrow and/or peripheral blood. The most significant complication relates to opportunistic infections that arise as a consequence of neutropenia and monocytopenia. HCL is occasionally associated with systemic autoimmune disorders including polyarteritis nodosa and rheumatoid disease. Secondary autoimmune haemolytic anaemia (AIHA) appears to be rare. We report on two cases of HCL complicated by fatal cold anti-i AIHA. Fulminant haemolysis causing death is rare in cold AIHA and only a few individual cases have been reported, none having anti-i specificity.

Cold haemagglutinin disease: clinical significance of serum haemolysins.

Two hundred and twenty-one patients with cold haemagglutinins of thermal amplitude > or = 30 degrees C (considered to be a reasonable indicator of clinical significance) were classified by in vitro haemolysin activity into three groups. Group 1 contained 116 individuals in whom haemolysins were never detected; the 74 patients in Group 2 had monophasic haemolysins alone; whereas both monophasic and biphasic haemolysins were detected in the 31 Group 3 patients. There was a significantly higher proportion of patients in Groups 2 and 3 with haptoglobin levels < 0.1 g/l compared with Groups 1 and 2, respectively (P < 0.005 and P < 0.001). Direct antiglobulin test results showed that the autoimmune response became more complex and IgM predominant through Groups 1-3, resulting in an increasing ability to activate complement which was reflected in increasing haemolysin activity and number of patients with active haemolysis. The 31 patients in Group 3 were mostly elderly (median age 71 years at presentation) and the majority had chronic cold haemagglutinin disease (CHAD), several in association with lymphoid neoplasms or carcinomas; only four had acute CHAD. The natural history of idiopathic chronic CHAD was of mild, well compensated haemolysis, punctuated by severe acute episodes necessitating intensive therapy. The condition often remained active for long periods and did not appear to affect natural lifespan. In some cases, no treatment (or just warmth) was needed; in others continuous or intermittent prednisolone and/or chlorambucil were effective; yet others required a greater variety and more intense therapy, or treatment of associated conditions. Blood transfusion support was frequently required when haemolysis was severe.

Paroxysmal cold haemoglobinuria caused by non-Hodgkin's lymphoma.

Paroxysmal cold haemoglobinuria is an autoimmune haemolytic anaemia characterized by a biphasic polyclonal IgG autoantibody, the Donath-Landsteiner (D-L) antibody. Although classically described in association with chronic syphilis, it is most commonly seen after acute viral infections in children. We describe a case of high-grade B-cell non-Hodgkin's lymphoma which presented with paroxysmal cold haemoglobinuria. The lymphoma responded promptly to combination chemotherapy whilst, at the same time, the haemolytic process rapidly resolved. Subsequent investigations showed that the D-L antibody originated from the lymphoma cells.

Erythropoiesis: Paroxysmal Cold Haemoglobinuria: A Clinico-Pathological Study of Patients with a Positive Donath-Landsteiner Test.

52 patients (30 male, 22 female) with paroxysmal cold haemoglobinuria (PCH) were identified by critically examining the records of all cases with Donath-Landsteiner antibodies seen over a 37 year period. Although ages ranged from 1-82 years, PCH was much commoner in young children; the median age at presentation was 5 and the peak incidence, 0.4 per year per 100,000 of the population at risk, was in the 4 years and under group. 44 patients had acute transient PCH, 3 chronic non-syphilitic PCH and 1 chronic syphilitic PCH; 4, in whom the positive Donath-Landsteiner tests were incidental findings, could not be classified. Acute PCH typically presented in young children as sudden onset of malaise, haemoglobinuria and pallor, often associated with mild jaundice - all 30 patients who were 13 or younger had this type. There was usually a history of a recent viral type infection, most commonly of the upper respiratory tract. The occurrence of acute PCH had no obvious relation to exposure to cold. Dramatic and rapid falls in haemoglobin level were common, often accompanied initially by relative or absolute reticulocytopenia. The illness was severe, but the prognosis was generally good and the majority of patients had completely recovered within one month, some requiring no treatment. In approximately 68% of patients, blood transfusion was needed; the P blood group was not taken into account, but the patients were kept warm throughout. Steroids (usually prednisolone) were given in many cases; but since there was no evidence to support their benefit, it was recommended that they were stopped as soon as the diagnosis was confirmed. Chronic non-syphilitic PCH was much rarer; the patients had a characteristic presentation of severe systemic symptoms (paroxysms) and haemoglobinuria brought on by exposure to cold. The clinical manifestations varied in intensity between individuals; at the extreme, severe debility was experienced over many years. Warmth and avoidance of cold were an effective treatment, though in a severely afflicted patient, an attack could be precipitated by relatively little exposure to cold. With chronic syphilitic PCH there was the added need to treat the specific infection. The direct antiglobulin test was almost always positive (50 out of 51 cases tested), with C3d coating the red cells. The Donath-Landsteiner antibodies were of IgG class, but this was rarely demonstrated unless direct antiglobulin tests were carried out at 4 degrees C. The antibodies showed the classical anti-P specificity in 27 of the 30 patients tested; other specificities were unusual. Although acting much better as haemolysins, Donath-Landsteiner antibodies could also cause weak agglutination at room temperature. This was paralleled in vivo by predominantly intravascular haemolysis with an extravascular component. Diagnosis was usually easy when PCH was suspected, though in some patients Donath-Landsteiner tests did not become positive until more sensitive techniques involving papainised red cells or two-stage procedures were employed. Of particular interest was the association in some cases with lymphoproliferative disorders, collagen disease, myelodysplastic syndrome, delayed haemolytic transfusion reaction and other types of autoimmune haemolytic anaemia. In one patient, an aetiological relationship was confirmed by a saline extract of lymphoma tissue behaving as a strong Donath-Landsteiner antibody with the same anti-P specificity as the serum. 4 patients had other types of autoimmune haemolysis concomitant with, but distinct from, the PCH; in 3 cases this was cold haemagglutinin disease and in one it was warm type autoimmune haemolytic anaemia.

Paroxysmal cold hemoglobinuria and the elusive Donath-Landsteiner antibody.

Four patients with paroxysmal cold hemoglobinuria (PCH) illustrate some of the difficulties in making the diagnosis. A 46-year-old male presented with anemia, a weakly positive direct antiglobulin test (DAT) with anti-IgG, a haptoglobin < 0.1 g/L, and a cold autoagglutinin showing anti-P specificity. A 9-year-old female had a 4-day coryzal illness, a 20 g/L fall in hemoglobin over 24 hours, and a haptoglobin < 0.1 g/L; the DAT was positive with anti-C3d. A 3-year-old female was referred following a rapid drop in hemoglobin of 30 g/L; the DAT was positive with anti-C3d. A 17-month-old female, unwell for 2 weeks, had a hemoglobin of 41 g/L; the DAT was strongly positive with anti-C3d and weakly positive with anti-IgG and -C3c. In all patients, PCH was confirmed by positive indirect Donath- Landsteiner tests, and the autoantibodies demonstrated P specificity. In two patients, the test was strongly positive; in the third patient, it was only positive using papainized red cells; and in the fourth patient, a two-stage papainized procedure was needed before a positive result was obtained. PCH must always be considered in a child with a rapid drop in hemoglobin, even if initial tests are negative.

Autoimmune hemolytic anemia caused by warm-reacting IgM-class antibodies.

Warm IgM autoantibodies occur in association with IgG-class and/or IgA-class immunoglobulins in approximately 30 percent of patients with warm-type autoimmune hemolysis. They may be classified as agglutinins or hemolysins, which may be incomplete or complete, depending on in vitro serology; they almost always bind complement. Autoimmune hemolytic anemia solely due to warm IgM autoantibodies is exceedingly rare. We report two cases of the incomplete agglutinin type. The autoantibodies were confirmed as IgM by their ability to rebind to normal red blood cells (RBCs) after elution; the absence of small increases in RBC-bound IgG and IgA was shown by a sensitive enzyme-linked antiglobulin test. Patient 1 was a 64-year-old female with non-Hodgkin's lymphoma, with a hemoglobin of 50 g/L and haptoglobin of < 0.1 g/L. Direct antiglobulin tests were positive for IgM, C3d, and C3c; only IgM was present in an eluate. The serum contained a weak autoantibody at 37 degrees C and tests for hemolysins were negative. The patient suffered chronic hemolysis and required intensive treatment, including splenectomy. Patient 2 was a 65-year-old female; the hemoglobin was 78 g/L and the haptoglobin was < 0.1 g/L. Direct antiglobulin tests were positive for IgM and C3d; an eluate contained only IgM. No free autoantibody was present in the serum and tests for hemolysins were negative. Two serious infections occurred and the hemolysis remained chronic, requiring continuous treatment during the 4 months she was followed.

IgA red cell autoantibodies and autoimmune hemolysis.

BACKGROUND: The objective of the study was to examine the interrelationships and clinical significance of IgA red cell antibodies in the autoimmune response. STUDY DESIGN AND METHODS: The records of 5235 patients referred to an immunohematology center over a 14-year period were critically examined for patients who had IgA autoantibodies, defined as elutable IgA immunoglobulins that would rebind to normal cells. RESULTS: One hundred twenty-four patients (61 male) aged 6 to 98 years had warm-reacting IgA autoantibodies. In 75 individuals, these were idiopathic; neoplasms were the most common associated conditions in the individuals with secondary IgA autoantibodies. IgA was the only immunoglobulin present in 6 patients; all others also had IgG and/or IgM coating their cells, and 102 individuals also had increased amounts of cell-bound complement. In a comparison by chi-square test of populations with haptoglobins of < 0.1 g per L, IgA was shown to act synergistically with IgG in producing hemolysis (p < 0.01). CONCLUSION: Autoimmune hemolysis due to IgA antibodies alone in rare, with red cell destruction occurring through mechanisms similar to those for IgG. Most commonly, IgA acts synergistically with other immunoglobulins (usually IgG) and complement; the hemolysis may be severe. Whether IgA autoantibodies alone can activate complement remains controversial, but increasing evidence suggests that they can, possibly via the alternative pathway, and that this activation may result in intravascular hemolysis.

Direct Coombs test-negative autoimmune hemolytic anemia and low-affinity IgG class antibodies.

Autoimmune hemolytic anemia, in which the direct antiglobulin test (DAT) is negative or weakly positive, may be due to low-affinity autoantibodies. We describe two such cases. An 8-year-old male presented with weight loss, jaundice, a hemoglobin of 33 g/L, reticulocytes of 306 x 10(9)/L, and haptoglobin of < 0.1 g/L. The DAT was negative. After washing the red blood cells (RBCs) with saline at 4 degrees C, the DAT was positive for IgG and an eluate contained an IgG3 autoantibody, thus confirming a diagnosis of autoimmune hemolytic anemia (AIHA). Red cell transfusions and corticosteroids were given with eventual complete recovery. A 73-year-old male had a hemoglobin of 89 g/L and haptoglobin of < 0.1 g/L. The DAT was initially negative but was positive for IgG using cold-washed (4 degrees C) RBCs; it was also positive with unwashed cells in the DiaMed system and an eluate contained IgG1 autoantibody. AIHA was therefore confirmed and prednisolone started but continued hemolysis necessitated splenectomy before full recovery occurred. Although RBCs may be strongly sensitized with low-affinity autoantibodies in vivo, the IgG is easily removed when RBCs are washed at room temperature for a DAT. The DiaMed system that uses unwashed RBCs overcomes this problem, but cold washing the RBCs at 4 degrees C must be used when preparing eluates.

Measurement of red blood cell-bound C3b and C3d using an enzyme-linked direct antiglobulin test.

Complement has a complex role in immune mediated red blood cell (RBC) destruction and usually induces extravascular hemolysis of C3b-coated RBCs by erythrophagocytosis and by acting synergistically with cell-bound immunoglobulins. A sensitive two-stage enzyme-linked direct antiglobulin test (ELDAT) was developed and used to measure RBC-bound C3b and C3d in 120 healthy adult individuals and in 60 patients suffering from a variety of conditions, including warm- and cold-type autoimmune hemolytic anemia, neoplasia, and collagen diseases. The results were compared with those of standard agglutination tests employing polyclonal and monoclonal antiglobulin reagents. Small amounts of C3b and C3d were detected on RBCs of the healthy individuals only by the ELDAT and probably reflected the continuing low-grade activation of complement necessary for the maintenance of homeostasis of a variety of physiological systems. The quantity did not vary with age or gender. In the patients, increased amounts of RBC-bound C3b and C3d were relatively common and probably resulted from autoantibody activity, immune-complexes, and nonspecific adsorption. There was no association between positive ELDAT results and the presence of active hemolysis. The ELDAT was far more sensitive than the agglutination tests for detecting RBC-bound C3b and also for C3d if the monoclonal reagent was employed.

Delayed hemolytic transfusion reaction and paroxysmal cold hemoglobinuria: an unusual association.

An 80-year-old female presented with melena and anemia due to bleeding from a benign gastric ulcer. Her blood group was O, D+. The serum contained anti-B and a weak anti-A (titer 2 at 18 degrees C). She was inadvertently transfused with approximately 3.5 units of group A red blood cells with no initial ill effects. One week later, the anti- A titer increased to 8 and the direct antiglobulin test (DAT) was weakly positive (IgG and C3d). The next day, intravascular hemolysis became evident. The DAT was still weakly positive and the serum contained a weak cold autoagglutinin, which did not correlate with the severity of the hemolysis. A Donath-Landsteiner test was performed and found to be strongly positive. The antibody showed P specificity, confirming a diagnosis of paroxysmal cold hemoglobinuria (PCH). Exchange transfusion was followed by rapid recovery even though the Donath-Landsteiner test remained positive for at least a month. The patient was well when last seen 11 months after presentation. It was thought that the original low titer of anti-A reflected compromised immune homeostasis in an elderly patient and that stimulation by incompatible blood in those circumstances resulted in a delayed hemolytic transfusion reaction that triggered, exacerbated, or was accompanied by an autoimmune response manifesting as PCH.

Immune hemolytic anemia due to diclofenac.

A 37-year-old male presented with severe anemia, mild jaundice, and hemoglobinuria during his second course of diclofenac for gout. The peripheral blood showed microspherocytes and nucleated red blood cells (RBCs). The reticulocyte count was 21 percent and haptoglobin was < 0.1 g/L. A presumptive diagnosis of diclofenac-induced immune hemolysis was made and blood, urine, and drug samples were referred for investigation. Direct antiglobulin testing showed the RBCs to be coated with IgG1, IgG4, and C3d, but an eluate only yielded weakly reacting IgG antibodies. In tests for drug-dependent antibodies, group O, R1R2 red cells were incubated with the patient's serum that had been mixed with either urine (which contained diclofenac metabolites) or diclofenac solution and then tested by an antiglobulin method. Strongly positive reactions with anti-IgG occurred in the tests using urine but only weak reactions in those tests employing diclofenac solution. All controls gave negative results. These findings support the role of diclofenac in causing hemolysis and the importance of employing urine as a source of drug metabolites. The findings also showed that an immune complex mechanism predominated and that the eluted IgG (detectable independently of the presence of the drug or its metabolites) confirmed a minor autoimmune component. Diclofenac was stopped and treatment with prednisolone and folic acid instituted; this resulted in complete recovery.

Autoimmune hemolytic anemia due to IgA class autoantibodies.

Autoimmune hemolytic anemia due to warm-reacting autoantibodies solely of the IgA class is very rare, and only five cases were identified among 5,177 patients referred during 13.5 years. All were females (ages 21-69 years) and all presented with idiopathic "Coombs negative" autoimmune hemolytic anemia, a diagnosis that was confirmed using monospecific anti-human IgA reagents. Red cell-bound IgG was reduced, but in two patients IgM was initially increased, an occurrence that was thought to reflect the developing autoimmune response. The autoantibodies had high affinity for red cells with very little free antibody detectable in the serum; in two instances Rh specificity was evident. Hemolysis was severe in four patients. Two of them had intravascular hemolysis, one of whom also had marked dyserythropoiesis and a transiently positive Ham's test. Although IgA autoantibodies caused hemolysis predominantly through immune adherence, on occasions they also seemed to be able to induce complement activation, possibly via the alternative pathway. Prednisolone was the mainstay of treatment, and was occasionally augmented with azathioprine and intravenous immunoglobulin. Blood transfusion was required in two patients, both of whom eventually required splenectomy that resulted in full remission. The one patient with mild hemolysis recovered without treatment.

The glycosylation of red cell autoantibodies affects their functional activity in vitro.

Factors governing the functional activity of red cell autoantibodies are poorly defined. Here we report the presence of qualitative differences in the glycosylation of IgG autoantibodies which affect in vitro interactions with Fc gamma RIII. The following antibodies were affinity-purified by adsorption and elution from normal red cells: IgG eluted from the red cells of 27 haemolysing or non-haemolysing patients, anti-D in sera from 11 pregnant women, and IgG1 and IgG3 human monoclonal anti-D. Monoclonal antibodies with differing levels of agalactosyl IgG were produced by culturing cell lines at high or low cell density. The % IgG with oligosaccharides lacking terminal galactose residues (agalactosyl IgG) of antibodies was designated as low, medium or high according to their reactivity with a monoclonal antibody to terminal N-acetylglucosamine. Fc gamma RIII-mediated functional activity was assessed by measuring the K-cell-mediated lysis of red cells in eluates diluted to achieve comparable levels of red cells sensitization. All eluates containing allo-anti-D were lytic (range 74-100%). In contrast, lysis by autoantibodies varied from 0 to 100%; 11/13 eluates from red cells of haemolysing patients promoted > 5% lysis compared to 2/7 eluates from red cells of non-haemolysing patients (P < 0.02). The ability of autoantibodies to promote K-cell-mediated red cell lysis correlated inversely with their level of agalactosyl IgG (r = -0.56, P < 0.01, n = 23). Further, monoclonal anti-D antibodies with very low levels of agalactosyl IgG were comparatively more lytic than the same antibodies containing more agalactosyl IgG. Analysis of the ratio of kappa:lambda light chains suggested that autoantibodies from 6/19 patients were monoclonal or oligoclonal in nature. The data indicate that IgG red cell autoantibodies from different patients are functionally heterogenous, and that this may be due, at least in part, to qualitative differences in the Fc region glycosylation reflected by differences in the proportion of agalactosyl IgG. This heterogeneity is consistent with the clonally-restricted nature of the autoantibodies in some patients.

Autoimmune haemolysis and red cell autoantibodies with ABO blood group specificity.

In order to study red cell autoantibodies with ABO specificity, the records of 4668 patients seen over 32 years were examined. Five group A patients had high thermal amplitude cold agglutinins showing anti-A, -A1 or -AI specificity; none had ever received blood or blood products. They presented as chronic cold haemagglutinin disease, autoimmune haemolytic anaemia or were discovered during investigation of pregnancy, carcinomatosis or anaemia. In vivo haemolysis was evident in all but the antenatal case; only the patient with autoimmune haemolytic anaemia required treatment, responding well to steroids. ABO-specific autoantibodies thus appear similar in reactions and clinical manifestations to autoantibodies in general.