Large-amplitude internal waves benefit corals during thermal stress

Tropical scleractinian corals are particularly vulnerable to global warming as elevated sea surface temperatures (SSTs) disrupt the delicate balance between the coral host and their algal endosymbionts, leading to symbiont expulsion, mass bleaching and mortality. While satellite sensing of SST has proved a reliable predictor of coral bleaching at the regional scale, there are large deviations in bleaching severity and mortality on the local scale that are poorly understood. Here, we show that internal waves play a major role in explaining local coral bleaching and mortality patterns in the Andaman Sea. Despite a severe region-wide SST anomaly in May 2010, frequent upslope intrusions of cold sub-pycnocline waters due to breaking large-amplitude internal waves (LAIW) mitigated coral bleaching and mortality in shallow waters. In LAIW-sheltered waters, by contrast, bleaching-susceptible species suffered severe bleaching and total mortality. These findings suggest that LAIW benefit coral reefs during thermal stress and provide local refugia for bleaching-susceptible corals. LAIW are ubiquitous in tropical stratified waters and their swash zones may thus be important conservation areas for the maintenance of coral diversity in a warming climate. Taking LAIW into account can significantly improve coral bleaching predictions and provide a valuable tool for coral reef conservation and management.

Calibration of SeaWiFS. I. Direct techniques

We present an overview of the calibration of the Sea-viewing Wide Field-of View Sensor (SeaWiFS) from its performance verification at the manufacturer's facility to the completion of its third year of on-orbit measurements. These calibration procedures have three principal parts: a prelaunch radiometric calibration that is traceable to the National Institute of Standards and Technology; the Transfer-to-Orbit Experiment, a set of measurements that determine changes in the instrument's calibration from its manufacture to the start of on-orbit operations; and measurements of the sun and the moon to determine radiometric changes on orbit. To our knowledge, SeaWiFS is the only instrument that uses routine lunar measurements to determine changes in its radiometric sensitivity. On the basis of these methods, the overall uncertainty in the SeaWiFS top-of-the-atmosphere radiances is estimated to be 4-5%. We also show the results of comparison campaigns with aircraft- and ground-based measurements, plus the results of an experiment, called the Southern Ocean Band 8 Gain Study. These results are used to check the calibration of the SeaWiFS bands. To date, they have not been used to change the instrument's prelaunch calibration coefficients. In addition to these procedures, SeaWiFS is a vicariously calibrated instrument for ocean-color measurements. In the vicarious calibration of the SeaWiFS visible bands, the calibration coefficients are modified to force agreement with surface truth measurements from the Marine Optical Buoy, which is moored off the Hawaiian Island of Lanai. This vicarious calibration is described in a companion paper.

The efficacy of topical prophylactic antiglaucoma therapy in primary closed angle glaucoma in dogs: a multicenter clinical trial

The ability of either 0.5% betaxolol (1 drop topically, bid; n=31) or a combination of 0.25% demecarium bromide and a topical corticosteroid (gentamicin/betamethasone) (DB/GB; 1 drop of each topically, sid; n=55) to prevent glaucoma in the fellow eye of dogs with unilateral, primary closed angle glaucoma (PCAG) was investigated in a multicenter, open-label, clinical trial. Untreated control dogs (n=20) developed glaucoma significantly sooner (median, eight mos; p less than 0.001) than dogs treated either with DB/GB (median, 31 mos) or betaxolol (median, 30.7 mos). Although DB/GB and betaxolol equally delayed or prevented the onset of glaucoma in the second eye, a less frequent dosing schedule for DB/GB suggests demecarium bromide in combination with a topical corticosteroid may be preferable to betaxolol in preventing PCAG in dogs.

High-dose cytosine arabinoside and daunorubicin induction therapy for adult patients with de novo non M3 acute myelogenous leukemia: impact of cytogenetics on achieving a complete remission

Cytogenetic abnormalities are used to define prognostic subgroups of acute myelogenous leukemia (AML) with respect to achieving complete remission (CR) and remaining disease free. These prognostic groups for obtaining CR were based on an induction regimen mainly using standard dose cytosine arabinoside (Ara-C) + daunorubicin (DNR). We have reviewed our experience with 122 adult patients with de novo non-M3 AML who were treated with high-dose (HD) Ara-C 3 g/m2 given over 3 h every 12 h for a total of eight doses followed by DNR 60 mg/m2 daily for 2 days. CR was obtained in 80% while 16% had refractory disease and 4% died of sepsis during hypoplasia. CR rate for favorable, intermediate and unfavorable cytogenetic groups were 87%, 79% and 62%, respectively (P = 0.32). High white blood cell count, age, FAB subtype and LDH levels did not adversely affect CR rate. Eighty-five percent of patients achieved CR with one course of treatment and 87% of complete responders were able to receive post remission therapy. High-dose Ara-C/DNR appears to offer an excellent chance of achieving remission for patients with AML including those with poor risk cytogenetics, without an increase in early toxic deaths.

Cyclosporine, methotrexate, and prednisone compared with cyclosporine and prednisone for prevention of acute graft-vs.-host disease: effect on chronic graft-vs.-host disease and long-term survival

Graft-vs.-host disease (GVHD) is a major predictor of outcome following allogeneic bone marrow transplantation (BMT). For patients alive at day 100 after BMT, the presence or absence of chronic GVHD is one of the most important determinants of survival and quality of life. We wished to determine the effects on chronic GVHD of two regimens used for the prophylaxis of acute GVHD: cyclosporine, methotrexate, and prednisone (CSA/MTX/PSE) and cyclosporine and prednisone (CSA/PSE). One hundred forty-nine evaluable patients were entered into the acute GVHD study. As of 31 March 1997, 63 months after the last patient underwent BMT, the median survival time was 4.5 years (range 0.09-9.9). The incidence of chronic GVHD was independent of the prophylactic regimen (55 vs. 54%), and extensive chronic GVHD occurred in 25 and 24% of patients receiving CSA/MTX/PSE and CSA/PSE, respectively. Of note, the median Karnofsky performance status of both groups was 100% (range 70-100%), reflecting the low incidence of extensive chronic GVHD. Survival rates free of chronic GVHD were 52 vs. 42% (p = 0.29) for patients receiving CSA/MTX/PSE vs. CSA/PSE. The incidence of relapse was also similar in both groups of patients. These data suggest that the combinations of CSA/MTX/PSE and CSA/PSE result in comparable chronic GVHD-free survival without an increase in leukemic relapse.

Analyzing hospital readmissions using statewide discharge databases

Hospital readmissions are an important indicator of the outcomes of care as well as a source of unnecessary health care expenditures. This study focused on development of a uniform algorithm for identification of hospital readmission data. It involved development of a uniform definition of readmissions which could be applied to multiple statewide computer databases. Through this approach, comparable readmit data were generated for use in benchmarking and quality improvement activities.

Extracorporeal photochemotherapy for treatment of drug-resistant graft-vs.-host disease

Extracorporeal photochemotherapy (EP) is a therapeutic approach to the treatment of drug-resistant graft-vs.-host disease (GVHD) that uses the known immunosuppressive and immunomodulatory effects of ultraviolet light. In 1990, we initiated a pilot study to evaluate the efficacy and safety of EP in patients with refractory GVHD. Between 1991 and 1996, six patients with acute grade IV liver GVHD, 12 patients with chronic following acute GVHD, and six patients with de novo chronic GVHD were treated with EP. All patients had failed to respond to conventional GVHD immunosuppressive drug therapy of cyclosporine and prednisone. The six patients with acute liver GVHD had also received antithymocyte globulin (ATG); therapy for chronic GVHD included thalidomide in eight patients, psoralen plus ultraviolet A in five patients, and ATG in two patients. All patients with acute liver GVHD had progressive liver failure with short survival despite frequent EP. The response rate with EP treatment was 3 of 6 for patients with de novo chronic GVHD and 3 of 12 for patients with chronic following acute GVHD. Three patients with bronchiolitis obliterans had either no response or no documented disease progression while undergoing EP. Side effects of EP were minor and included gastrointestinal upset frequently, catheter-related sepsis in four patients, increased red blood cell and platelet transfusion requirements in one patient, and leukopenia in two patients. EP was discontinued in three patients because of side effects, including GI upset in one patient and bone marrow suppression in two patients. Side effects were reversible with the discontinuation of EP. We were unable to correlate response to EP with the level of methoxypsoralen, number of lymphocytes treated, or pattern of pre- and posttreatment CD4/CD8 ratio. We concluded that EP has some efficacy in the treatment of drug-resistant chronic GVHD, with minor overall toxicity.

In vivo purging with high-dose cytarabine followed by high-dose chemoradiotherapy and reinfusion of unpurged bone marrow for adult acute myelogenous leukemia in first complete remission

PURPOSE

To evaluate in a prospective study the efficacy of autologous bone marrow transplantation (BMT) in adult patients with acute myelogenous leukemia (AML) in first remission, using a single course of high-dose Cytarabine (HD Ara-C) consolidation therapy as in vivo purging.

PATIENTS AND METHODS

Sixty consecutive adult patients with AML in first complete remission (CR) were treated with HD Ara-C consolidation therapy as a method of in vivo purging before marrow collection. High-dose therapy consisted of fractionated total-body irradiation (FTBI) 12 Gy, intravenous etoposide 60 mg/kg, and cyclophosphamide 75 mg/kg, followed by reinfusion of cryopreserved marrow.

RESULTS

Sixty patients underwent consolidation treatment with HD Ara-C with the intent to treat with autologous BMT. Sixteen patients were unable to proceed to autologous BMT (10 patients relapsed, one died of sepsis, one developed cerebellar toxicity, two had inadequate blood counts, and two refused). Forty-four patients underwent autologous BMT and have a median follow-up time of 37 months (range, 14.7 to 68.7) for patients who are alive with no relapse. The cumulative probability of disease-free survival (DFS) at 24 months in the intent-to-treat group is 49% (95% confidence interval [CI], 37% to 62%) and in those who actually underwent autologous BMT is 61% (95% CI, 46% to 74%). The probability of relapse was 44% (95% CI, 31% to 58%) and 33% (95% CI, 20% to 49%) for the intent-to-treat and autologous BMT patients, respectively.

CONCLUSION

This approach offers a relatively high DFS rate to adult patients with AML in first CR. The results of this study are similar to those achieved with allogeneic BMT.

Preemptive ganciclovir administration based solely on asymptomatic pulmonary cytomegalovirus infection in allogeneic bone marrow transplant recipients: long-term follow-up

The use of ganciclovir at the time of cytomegalovirus (CMV) infection but before disease onset has been termed "preemptive" therapy. This preemptive ganciclovir administration has been shown to be an effective method for preventing severe CMV disease after allogeneic bone marrow transplantation (BMT), but the optimal method of CMV surveillance is not clear. The purpose of this study was to evaluate effectiveness, side effects, and long-term outcome of preemptive ganciclovir therapy in allogeneic BMT recipients when ganciclovir is prescribed solely on the basis of CMV detection in day +35 bronchoalveolar lavage (BAL). In a consecutive cohort of 202 HLA-matched recipients of sibling donor marrow transplantations, 163 received prospective BAL and were given preemptive ganciclovir if CMV-positive; 39 had disqualifying complications and were not eligible for BAL. Over the 36-month follow-up, CMV disease occurred in 21 (10%) of the 202 BMT recipients; there was one CMV-related death. In the 60 subjects (37% of the total 163) who received preemptive ganciclovir based on positive CMV-BAL, two (3%) developed CMV disease during the first 120 days post-BMT and two more developed late disease. Among the 103 BAL-negative subjects, CMV disease occurred in eight (8%) during the first 120 days and in three (3%) at > 120 days. Forty-three percent of all CMV disease occurred either before day +35 BAL (four cases) or at late times after BMT (five cases). The negative predictive value of BAL was 91%, allowing for the occurrence of 52% of all CMV disease in subjects considered CMV-BAL-negative. Nevertheless, using this treatment method, no significant differences in neutropenia rates or in 36-month survival were noted in the high-risk group having pulmonary CMV infection (compared with the group without pulmonary CMV). Thus, a strategy of preemptive ganciclovir based on a single BAL can reduce the complications caused by CMV; however, improved surveillance methods are necessary to eliminate all CMV disease.

Busulfan/cyclophosphamide as conditioning regimen for allogeneic bone marrow transplantation for myelodysplasia

PURPOSE

A non-radiation-containing regimen of busulfan and cyclophosphamide (BU/CY) was evaluated for toxicity, relapse, and long-term survival in patients who received allogeneic bone marrow transplantation (BMT) for myelodysplasia (MDS).

PATIENTS AND METHODS

Thirty-eight patients with MDS, including eight with therapy-related MDS, were prepared for BMT using BU/CY.

RESULTS

Fourteen patients remain in first remission 18 to 60 months posttransplant. Five patients relapsed after BMT, and four of these patients died. Eight additional patients died of acute or chronic graft-versus-host disease (GVHD), and 11 died of regimen-related toxicity, primarily systemic mycoses. Overall survival rate at 2 years was 45% (95% confidence interval [CI], 0.30 to 0.61), with a 24% probability of relapse (95% CI, 0.10 to 0.49). Regimen-related toxicity was manifested primarily as hepatic dysfunction in 72% of patients, with 16% developing overt venoocclusive disease (VOD).

CONCLUSION

Non-radiation-containing preparative regimens offer long-term survival in allogeneic BMT for MDS that is comparable to that of radiation-containing regimens, and are useful in patients with therapy-related MDS. Monitoring BU levels may reduce regimen-related mortality and improve survival.

Thalidomide as salvage therapy for chronic graft-versus-host disease

Thalidomide has been reported to be an effective agent for treatment of chronic graft-versus-host disease (CGVHD). To determine the efficacy of this agent in patients with refractory CGVHD a total of 80 patients who failed to respond to prednisone (PSE) or PSE and cyclosporine (CSA) were treated with thalidomide. Sixteen patients (20%) had a sustained response, 9 with a complete remission and 7 with a partial response. Twenty-nine patients (36%) had thalidomide discontinued because of side effects, which included sedation, constipation, neuritis, skin rash, and neutropenia. Side effects were reversible with drug discontinuation except for mild residual neuritis in one case. Rashes and neutropenia have not previously been reported as thalidomide side effects when used for CGVHD treatment. We conclude thalidomide is immunosuppressive and active in the treatment of CGVHD. A high incidence of reversible side effects limited dose intensity and reduced the number of patients who could benefit from treatment.

The outcome of matched unrelated donor bone marrow transplantation in patients with hematologic malignancies using molecular typing for donor selection and graft-versus-host disease prophylaxis regimen of cyclosporine, methotrexate, and prednisone

Graft-versus-host disease (GVHD) is a major obstacle to successful bone marrow transplantation (BMT) from matched unrelated donor (MUD). Currently available HLA-A, -B, and -DR serologic testing may not be sensitive enough to detect clinically relevant donor/recipient (D/R) nonidentity. Better HLA matching of D/R pairs using molecular typing for class II antigens in combination with intensive GVHD prophylaxis may potentially reduce the incidence of GVHD and lead to an improved outcome of MUD transplantation. Between July 1991 and August 1993, thirty consecutive patients with hematologic malignancies underwent MUD transplantation from donors who were identical for HLA -A, -B, and -DR by serologic typing. Twenty-five D/R pairs were matched for DRB and DQB by molecular typing (restriction fragment-length polymorphism and sequence-specific oligonucleotide probe hybridization analyses), whereas five were allele mismatched at either DRB or DQB. All patients also received GVHD prophylaxis with the combination of cyclosporine (CSA), methotrexate (MTX), and prednisone (PSE). The median age was 35 years (range, 15 to 50). The diagnoses were: chronic myelogenous leukemia (CML) in chronic phase (CP) (16), CML in more than CP (3), acute leukemia in more than first complete remission (CR) (8), acute leukemia in first CR (1), and advanced high-grade lymphoma (2). The preparative regimen consisted of 1,320 cGy fractionated total body irradiation (FTBI) and 60 mg/kg cyclophosphamide (CY) daily for 2 days in 17 good-risk patients (CML/CP and acute leukemia first CR); and 1,320 cGy FTBI in combination with 60 mg/kg etoposide and 20 to 60 mg/kg CY in 13 patients with advanced leukemia and lymphoma. All patients received CSA, PSE, and MTX on days 1, 3, 6 for GVHD prophylaxis, and 10 patients also received day +11 MTX. All patients engrafted except one who died early of regimen-related toxicity. The incidence of grade III or IV acute GVHD was 24% (95% confidence interval [CI], 10% to 44%) and that of extensive chronic GVHD was 65% (95% CI, 43% to 84%). At a median follow-up of 13.6 months, 57% of the patients are alive in remission with a median Karnofsky performance status of 90%. The cumulative probability of 2-year disease-free survival for all patients was 53% (95%) CI, 33% to 71%); for good-risk patients, 71% (95% CI, 46% to 87%) and for the poor-risk group, 34% (95% CI, 13% to 64%).(ABSTRACT TRUNCATED AT 400 WORDS)

High-dose chemotherapy with or without total body irradiation followed by autologous bone marrow and/or peripheral blood stem cell transplantation for patients with relapsed and refractory Hodgkin's disease: results in 85 patients with analysis of prognostic factors

Eight-five consecutive patients with relapsed or refractory Hodgkin's disease (HD) underwent high-dose chemotherapy or chemo/radiotherapy followed by autologous bone marrow (ABMT) and/or peripheral blood stem cell (PBSC) transplantation. Two preparative regimens were used. Twenty-two patients (26%) without prior radiation received fractionated total body irradiation (FTBI) 1,200 Gy in combination with high-dose etoposide (VP-16) 60 mg/kg and cyclophosphamide (CTX) 100 mg/kg. Sixty-three patients (74%) with prior radiotherapy received carmustine (BCNU) 450 mg/m2 instead of FTBI. The median age was 32 years (range, 16 to 56). The median number of prior chemotherapy regimens was three (range, 1 to 7). Forty-three patients (51%) received transplants in first relapse or second complete remission (CR), whereas 33 (39%) received transplants after second or subsequent relapse. All relapsed patients, except one, received conventional salvage chemotherapy and/or radiotherapy in an attempt to reduce tumor bulk before transplant. At the time of analysis in April 1994, fifty-seven patients (67%) are alive, including 44 (52%) in continuous CR, with a median follow-up for the surviving patients of 28 months (range, 7 to 66). Thirty patients (35%) relapsed at a median of 9 months (range, 1 to 43). Eleven patients (13%) died of transplant-related complications including veno-occlusive disease of the liver (VOD) in five, acute and late interstitial pneumonitis in three, graft failure in one, cerebral hemorrhage in one, and therapy-induced myelodysplasia (MDS)/acute leukemia in one patient. At a median follow-up of 25 months (range, 0.6 to 66), the cumulative probability of 2-year overall and disease-free survival (DFS) of all 85 patients is 75% (95% confidence interval [CI] 64% to 84%) and 58% (95% CI 47% to 69%), respectively. Three independent prognostic variables were identified by univariate analysis: number of prior chemotherapy regimens, prior radiotherapy, and extranodal disease at ABMT. Multivariate stepwise Cox regression identified the number of prior chemotherapy regimens as the only significant prognostic factor predicting for both relapse and DFS. There were no significant differences in the outcome of the treatment between the two preparative regimens. Our results confirm that high-dose therapy and ABMT is an effective therapy for patients with relapsed or refractory HD. Earlier transplantation is recommended before the development of drug resistance and end organ damage that results from repeated attempts of salvage therapy.

High-dose therapy followed by autologous peripheral-blood stem-cell transplantation for patients with Hodgkin's disease and non-Hodgkin's lymphoma using unprimed and granulocyte colony-stimulating factor-mobilized peripheral-blood stem cells

PURPOSE

To evaluate (1) the effect of granulocyte colony-stimulating factor (G-CSF) on peripheral-blood stem-cell (PBSC) mobilization; (2) the rate of hematopoietic recovery after G-CSF-mobilized PBSC transplantation; and (3) the outcome of high-dose myeloablative therapy and PBSC transplantation in patients with relapsed or refractory lymphoma.

PATIENTS AND METHODS

Ninety-five patients with lymphoma underwent high-dose therapy followed by PBSC transplant in three sequentially treated cohorts of patients in a nonrandomized study. The first 30 patients received nonmobilized PBSCs (unprimed) without G-CSF after transplant, the next 26 patients received PBSC that were mobilized with G-CSF 5 micrograms/kg/d (primed-5) plus G-CSF after transplant, and the last 39 patients received PBSC mobilized by G-CSF 10 micrograms/kg/d (primed-10) plus G-CSF after transplant. The conditioning regimen consisted of fractionated total-body irradiation (FTBI) 12 Gy in combination with etoposide 60 mg/kg and cyclophosphamide 100 mg/kg. Patients with prior radiotherapy received carmustine (BCNU) 450 mg/m2 instead of FTBI.

RESULTS

The use of G-CSF-mobilized PBSCs in combination with G-CSF posttransplant resulted in a significantly accelerated time to recovery of both granulocyte and platelet when compared with the unprimed group. The median number of days to an absolute granulocyte count (ANC) of greater than 0.5 x 10(9)/L was 10 days for G-CSF primed versus 20 days for the unprimed (P = .0001). The median days to platelet transfusion independence was 16 and 31 days (P = .0001) for the G-CSF primed and unprimed, respectively. There were also significant reductions in the number of platelet (P = .02) and RBC transfusions (P = .006) for the G-CSF primed. Multivariate analysis of prognostic factors identified CD34+ cell dose as the only additional factor predicting engraftment. Sixty-nine patients are alive at a median follow-up of 15.9 months (range, 7.4 to 63.7). The cumulative probability of 2-year disease-free survival is 59% (95% confidence interval [CI], 36% to 79%) and 39% (95% CI 25% to 55%) for patients with Hodgkin's disease and non-Hodgkin's lymphoma, respectively.

CONCLUSION

The use of G-CSF-mobilized PBSC after high-dose myeloablative therapy resulted in a rapid, complete, and sustained hematopoietic recovery. Disease-free survival over 2 years can be achieved in some patients with relapsed lymphoma after high-dose therapy and PBSC transplantation. However, longer follow-up is required to confirm the curability of this approach.

Comparison of plasma PCR and bronchoalveolar lavage fluid culture for detection of cytomegalovirus infection in adult bone marrow transplant recipients

Plasma PCR for human cytomegalovirus (CMV) DNA was compared with bronchoalveolar lavage (BAL) fluid culture as an indicator for disseminated CMV infection. Thirteen (32.5%) of 40 consecutive bone marrow transplant (BMT) recipients were BAL fluid culture positive for CMV on day 35 post-BMT, and 9 (69%) of the 13 had positive plasma PCRs between days 28 and 49. Of the 27 with negative BAL fluid cultures, 2 (7%) had positive plasma PCRs (P < 0.001). Plasma CMV DNA in BMT recipients is a useful clinical marker for serious infection.

Prediction of systemic fungal infection in allogeneic marrow recipients: impact of amphotericin prophylaxis in high-risk patients

PURPOSE

To identify risk factors that might predict for systemic fungal infections in marrow transplant recipients within the first 100 days and to assess the efficacy of low-dose amphotericin B used as prophylaxis for candidemia and infection with invasive Aspergillus species in patients at risk.

PATIENTS AND METHODS

A retrospective analysis of transplant outcomes for 331 allogeneic marrow recipients transplanted between 1983 and 1989 was performed to identify patients who might be at increased risk of fungal infection. Factors analyzed included disease, remission status, transplant regimen, graft-versus-host disease (GVHD) prophylaxis, duration of neutropenia, and development of GVHD. A trial of low-dose amphotericin (5 to 10 mg/d) begun on day +1 and continuing for 2 to 3 months posttransplant was begun in 1987 to evaluate its utility in reducing systemic mycoses.

RESULTS

There were 18 episodes of candidemia and 18 systemic mycoses documented by blood or tissue culture or by biopsy. The initiation of high-dose (0.5 to 1 mg/kg/d) corticosteroids early as a component of GVHD prophylaxis in 1986 was identified as the most important risk factor for fungal infections, with a sixfold increase in infections as compared with the previous GVHD regimen (P < .0001); this was despite a significant decrease in the incidence of grade II to IV GVHD (7% v 43%; P = .0001). Low-dose amphotericin B initiated before the start of high-dose corticosteroid GVHD prophylaxis reduced the incidence of fungal infections from 30% to 9% (P = .01) without renal toxicity. Cyclosporine levels were lower in the patients who received amphotericin, leading to an increase in the rate of GVHD to 19% (P = .02). Controlling for GVHD prophylaxis, prolonged neutropenia (P = .00), and grade II to IV GVHD (P = .01) were also identified as risk factors for fungal infection.

CONCLUSION

Amphotericin B can be used in low doses as prophylaxis for fungal infections early in the posttransplant course. However, cyclosporine doses need to be monitored to maintain target levels.

Fractionated total body irradiation and high-dose etoposide as a preparatory regimen for bone marrow transplantation for 99 patients with acute leukemia in first complete remission

Ninety-nine consecutive patients with acute leukemia in first complete remission under age 50 (median age 27 years; age range 1 to 47 years) with a histocompatible sibling donor were treated with fractionated total body irradiation (1,320 cGy) and high-dose etoposide (60 mg/kg) followed by allogeneic bone marrow transplantation. Sixty-one patients were diagnosed with acute myelogenous leukemia (AML), 34 patients with acute lymphoblastic leukemia (ALL), 3 patients with biphenotypic acute leukemia, and 1 patient with acute undifferentiated leukemia. Thirty of the 34 patients with ALL had at least one of the following high-risk factors: age greater than 30, white blood cell count at presentation > 25,000/microL, extramedullary disease, certain chromosomal translocations, or the need for greater than 4 weeks of induction chemotherapy to achieve first complete remission. Cumulative probabilities of disease-free survival and relapse at 3 years were 61% and 12%, respectively, for the 61 patients with AML and 64% and 12%, respectively, for the 34 patients with ALL. By stepwise Cox regression analysis, significant prognostic variables for patients with acute myelogenous leukemia were the presence of acute graft-versus-host disease and increasing age, whereas for patients with acute lymphoblastic leukemia, significant variables were age and the development of cytomegalovirus-associated interstitial pneumonia. Complications related to graft-versus-host disease and relapse of leukemia were the major causes of death.

Cyclosporine, methotrexate, and prednisone compared with cyclosporine and prednisone for prophylaxis of acute graft-versus-host disease

BACKGROUND

Acute graft-versus-host disease (GVHD) following allogeneic bone marrow transplantation remains a serious problem. In a clinical trial, we tested the combination of cyclosporine and prednisone with and without methotrexate for the prevention of GVHD.

METHODS

One hundred fifty patients with either acute leukemia in first complete remission, chronic myelogenous leukemia in first chronic phase, or lymphoblastic lymphoma in first complete remission were enrolled in the study. All the patients were given fractionated total-body irradiation (1320 cGy) and etoposide (60 mg per kilogram of body weight) in preparation for transplantation, and received bone marrow from genotypically histocompatible donors. To prevent GVHD, they were randomly assigned to prophylactic treatment with either cyclosporine, methotrexate, and prednisone or cyclosporine and prednisone without methotrexate. All the patients received standardized supportive care after transplantation, including intravenous gamma globulin.

RESULTS

Patients receiving cyclosporine, methotrexate, and prednisone had a significantly lower incidence of acute GVHD of grades II to IV (9 percent) than those receiving cyclosporine and prednisone (23 percent, P = 0.02). Multivariate regression analysis demonstrated that an increased risk of acute GVHD was associated with an elevated serum creatinine concentration (P = 0.006) and treatment with cyclosporine and prednisone alone (P = 0.02). The lower incidence of acute GVHD was not associated with a higher rate of relapse of leukemia or lymphoma. There was no significant difference in disease-free survival at three years between the two treatment groups (64 percent with the three-drug regimen vs. 59 percent with the two-drug regimen, P = 0.57).

CONCLUSIONS

The combination of cyclosporine, methotrexate, and prednisone was more effective in preventing acute GVHD of grades II to IV than was the combination of cyclosporine and prednisone without methotrexate.

Extended follow-up in 212 long-term allogeneic bone marrow transplant survivors. Issues of quality of life

A group of 235 allogeneic marrow recipients were contacted at least one year following their BMT to obtain information on their quality of life; 212 (90%) agreed to participate in this survey. A total of 162 adults and 50 pediatric survivors were interviewed during clinic visits (5%) or over the telephone (95%). Changes in productive activity and marital status at the time of interview were studied, as well as the presence of physical symptoms and perception of a general sense of well-being. Older transplant recipients were observed to have a significantly higher incidence of chronic graft-versus-host disease, common colds, and skin changes when compared with pediatric transplant recipients (P < 0.01). Older subjects were also more likely to require any type of regular medication. Younger survivors were rated with a higher Karnofsky performance status and global subjective score. There were no significant differences between patients who received TBI as part of the conditioning regimen and those who did not, with the exception of increased cataract development in pediatric patients receiving TBI (P < 0.008). We conclude that most allogeneic marrow transplant survivors, especially those individuals of younger age at the time of their transplants, are doing well in the domains tested.

Measurement of quality of life in bone marrow transplantation survivors

This study was designed to assess the reliability and validity of a Quality of Life (QOL) instrument on a sample of 179 allogeneic Bone Marrow Transplant (BMT) survivors. The QOL-BMT tool was developed specifically for this population and was based on the investigators' prior research and a conceptual model of Quality of Life. Patients who were at least 100 days post BMT completed the 30 item visual analogue questionnaire. The instrument measured physical symptoms (e.g., weight loss, frequent colds, skin changes, cataracts, sexual problems), psychological symptoms (e.g., worry about recurrence, adjustment to illness), social concerns (e.g., relationship adjustment, return to work), and spiritual well-being (e.g., sense of control, future goals). Psychometric analysis of the instrument included measures of reliability and validity. The study findings demonstrate the unique aspects of QOL dimensions in BMT survivors and the value of QOL assessment in clinical practice and research.

Pretransplant pulmonary function predicts cytomegalovirus-associated interstitial pneumonia following bone marrow transplantation

STUDY OBJECTIVE

To determine the value of pulmonary function tests (PFTs) in predicting the development of human cytomegalovirus (CMV)-associated interstitial pneumonia (IP) in allogeneic bone marrow transplant (BMT) recipients.

DESIGN

Nonrandomized, prospective, open-trial study.

SETTING

Tertiary referral medical center.

PATIENTS

66 evaluable CMV-seropositive patients with hematologic malignancies who were undergoing allogeneic BMT.

INTERVENTION

FEV1, FVC, FEV1/FVC, TLC, Dcoc/VA, PaO2, and P(A-a)O2 were measured on days -13, +33, and +44 following BMT. CMV-IP was diagnosed when typical roentgenographic findings developed with confirmatory positive bronchoalveolar lavage (BAL) using standard cytologic and/or rapid culture techniques.

MEASUREMENT AND MAIN RESULTS

Univariate logistic regression analysis to predict the development of CMV-IP revealed significant associations with the day -13 and +33 percent predicted FEV1, FVC, and TLC (p < 0.01) but no associations with other PFT parameters or with changes in these parameters. Stepwise logistic regression analysis demonstrated that only BAL positivity for CMV (odds ratio 14.8; p = 0.0002) and day -13 percent predicted FEV1 (odds ratio 0.92; p = 0.0004) were significant independent predictors of CMV-IP.

CONCLUSION

Pretransplant lung function is a previously unrecognized strong predictor and risk factor for the subsequent development of CMV-IP in BMT recipients.

High-dose chemoradiotherapy followed by autologous bone marrow transplantation as consolidation therapy during first complete remission in adult patients with poor-risk aggressive lymphoma: a pilot study

Twenty consecutive patients with poor-risk aggressive lymphoma who at presentation either had elevated serum lactic dehydrogenase level (LDH) and any one of the other poor-prognostic features: bulky mass greater than or equal to 10 cm, advanced stage III or IV, and greater than or equal to 2 extranodal sites, or normal LDH level and all other three features, underwent high-dose chemo/radiotherapy followed by unmanipulated autologous bone marrow transplantation (BMT) during their first complete remission. Eighteen had B-cell lymphoma and 2 had T-cell lymphoma. Eleven patients had high-grade (7 immunoblastic, 3 small noncleaved, non-Burkitt's, and 1 Burkitt's) and 9 had diffuse large cell lymphoma. All patients had achieved a complete remission following conventional chemotherapy. Four patients had also received involved field radiotherapy to areas of bulky disease. The preparative regimen consisted of high-dose etoposide 60 mg/kg and cyclophosphamide 100 mg/kg in combination with fractionated total body irradiation (FTBI) 1,200 cGy (15 patients), or single-dose TBI 750 cGy (2 patients), or carmustine 450 mg/m2 (3 patients). All patients tolerated the treatment well and achieved complete hematologic recovery. Three patients have relapsed at days 79, 196, and 401 after transplantation. Seventeen patients (84%) are alive and relapse-free with a median follow-up of 34 months (range 2 to 54). We conclude that high-dose chemo/radiotherapy followed by autologous BMT can be given as consolidation therapy during first remission in these patients with minimal transplant-related toxicity.

The meaning of quality of life for bone marrow transplant survivors. Part 2. Improving quality of life for bone marrow transplant survivors

Surviving bone marrow transplant (BMT) represents a major victory against malignant disease but also creates challenges of survivorship for patients and the professionals who care for them. Part 2 of this report presents the findings of a qualitative study (N = 119) related to improving quality of life (QOL) for BMT survivors. Results are shared based on BMT survivors' perceptions of (a) what makes QOL better, (b) what makes QOL worse, and (c) what doctors or nurses could do to enhance QOL. The findings of the study have been useful in constructing a quantitative instrument to measure QOL in BMT and in understanding the conceptual basis of QOL for the BMT population. Nursing interventions can improve the QOL for the BMT patient across all phases of the transplant process and long-term issues related to survival.

The meaning of quality of life for bone marrow transplant survivors. Part 1. The impact of bone marrow transplant on quality of life

Quality of life (QOL) is an important concept in cancer nursing and has particular significance for bone marrow transplant (BMT). BMT survivors are faced with the demands of acute transplant symptoms as well as chronic illness demands posttransplant. The purpose of this study was to explore the concept of QOL for BMT survivors and to gain understanding of nursing interventions that may improve QOL in this population. The conceptual framework for this study was derived from the model of QOL developed by Ferrell, Grant, and Padilla (1989) that depicts the QOL domains of physical well-being, psychological well-being, social concerns, and spiritual well-being. This qualitative study consisted of a one-time interview of 119 BMT survivors using six open-ended questions. The items were based on previous research of the authors and content validity was established by a panel of BMT experts. Content analysis was performed on verbatim written responses to six questions regarding BMT and QOL. Part one of this two-part report provides analysis based on the questions regarding the meaning of QOL to BMT survivors and the impact of BMT on QOL.

Prophylaxis of cytomegalovirus infection after bone marrow transplantation

Viral infections occur frequently during the reconvalescence phase of allogeneic bone marrow transplantation due to the persistence of severe immunodeficiency. Recent advances in the treatment of cytomegalovirus-associated interstitial pneumonia have resulted in the development of an effective strategy for the prevention of this disease. Cytomegalovirus infection as determined by rapid culture from prospective bronchoalveolar lavage specimens on day +35 has been identified as a formidable risk factor for the development of pneumonia. Preemptive therapy with ganciclovir alone prevents the evolution from infection to pneumonia in this subgroup while protecting most other patients from unnecessary drug exposure.

Allogeneic bone marrow transplantation for high-risk acute lymphoblastic leukemia during first complete remission

Fifty-three patients with high-risk acute lymphoblastic leukemia (ALL) under age 50 with a histocompatible sibling donor received high-dose radiochemotherapy followed by allogeneic bone marrow transplantation (BMT). The high-risk factors used to identify the patients were: white blood cell count at initial presentation, cytogenetic abnormalities, age, extramedullary leukemic infiltration, and time from initial therapy to complete remission. Patients with one or more of the above risk factors who received BMT have a disease-free survival of 61% with a median follow-up of 66 months (range 11 months to 10.6 years), and an actuarial relapse rate of 10%. This study demonstrates that patients with high-risk ALL achieve a significant disease-free survival and cure rate with the use of allogeneic fully matched sibling BMT. However, a properly designed prospective study comparing the outcome of BMT with the best currently available chemotherapy data is required to define the ultimate role of BMT in this group of patients.

Allogeneic bone marrow transplantation as therapy for primary induction failure for patients with acute leukemia

The survival of patients with acute leukemia who do not achieve a remission with primary therapy is very poor. High-dose chemoradiotherapy followed by allogeneic bone marrow transplantation (BMT) has been shown to be effective therapy for patients with acute and chronic leukemia. Therefore, we determined the long-term disease-free survival of patients who did not achieve a remission and were then treated with high-dose therapy and bone marrow allografting from matched sibling donors. Twenty-one patients (median age, 28 years) who did not achieve a remission with induction chemotherapy were subsequently treated with allogeneic BMT. After BMT, 90% achieved a complete remission. Six died of complications of the therapy, and six patients relapsed between 27 and 448 days after BMT. Nine patients (43%; median age, 25 years) are alive between 556 and 4,174 days after BMT. The cumulative probability of disease-free survival at 10 years is 43%. This study suggests that allogeneic BMT can be an effective therapy to achieve long-term control of acute leukemia, even in those patients who do not achieve a remission with primary therapy.

Importance of bone marrow cytogenetic evaluation before autologous bone marrow transplantation for Hodgkin's disease

Alkylating agents used either with or without radiation therapy have been associated with the development of myelodysplastic syndrome (MDS) and acute nonlymphoblastic leukemia (ANLL) after treatment of both malignant and nonmalignant disorders. This report describes seven patients with recurrent Hodgkin's disease (HD) evaluated for bone marrow transplantation (BMT) who developed chromosomal abnormalities, and emphasizes the importance of bone marrow cytogenetic studies before bone marrow harvest. Three patients with histologically normal bone marrow underwent autologous BMT and subsequently developed an MDS or ANLL. Four patients had the clonal abnormality detected before bone marrow harvest and did not proceed to BMT.

A randomized, controlled trial of prophylactic ganciclovir for cytomegalovirus pulmonary infection in recipients of allogeneic bone marrow transplants; The City of Hope-Stanford-Syntex CMV Study Group

BACKGROUND

Cytomegalovirus (CMV)-associated interstitial pneumonia is a major cause of death after allogeneic bone marrow transplantation. We conducted a controlled trial of ganciclovir in recipients of bone marrow transplants who had asymptomatic pulmonary CMV infection. We also sought to identify risk factors for the development of CMV interstitial pneumonia.

METHODS

After bone marrow transplantation, 104 patients who had no evidence of respiratory disease underwent routine bronchoalveolar lavage on day 35. The 40 patients who had positive cultures for CMV were randomly assigned to either prophylactic ganciclovir or observation alone. Ganciclovir (5 mg per kilogram of body weight intravenously) was given twice daily for two weeks and then five times per week until day 120.

RESULTS

Of the 20 culture-positive patients who received prophylactic ganciclovir, 5 (25 percent) died or had CMV pneumonia before day 120, as compared with 14 of the 20 culture-positive control patients (70 percent) who were not treated prophylactically (relative risk, 0.36; P = 0.01). No patient who received the full course of ganciclovir prophylaxis went on to have CMV interstitial pneumonia. Four patients treated with ganciclovir had maximal serum creatinine levels greater than or equal to 221 mumol per liter (2.5 mg per deciliter), as compared with none of the controls (P = 0.029). Of the 55 CMV-negative patients who could be evaluated, 12 (22 percent) had CMV pneumonia--a significantly lower rate than in the untreated CMV-positive control patients (relative risk, 0.33; P = 0.003). The strongest predictors of CMV pneumonia were a lavage-fluid culture that was positive for CMV and a CMV-positive blood culture, both from specimens obtained on day 35.

CONCLUSION

In recipients of allogeneic bone marrow, asymptomatic CMV infection of the lung is a major risk factor for subsequent CMV interstitial pneumonia. Prophylactic ganciclovir is effective in preventing the development of CMV interstitial pneumonia in patients with asymptomatic infection.

Inheritance of associated ocular and skeletal dysplasia in Labrador retrievers

A breeding colony was established to investigate the inheritance of associated ocular and skeletal dysplasia in Labrador Retrievers; 124 pups were produced. These pups were evaluated for the presence of ocular lesions, including cataracts, vitreous strands, persistent hyaloid remnants, retinal folds, retinal dysplasia, peripapillary hyperreflectivity, and rhegmatogenous retinal detachments, and skeletal abnormality, which was recognized by shorter than normal forelimbs and an abnormal morphologic appearance of the radius and ulna. Analysis of the distribution of lesions in pups indicated that the syndrome is caused by one abnormal gene, which has recessive effects on the skeleton and incompletely dominant effects on the eye. This would suggest that suspect carrier dogs could be identified by test matings with a known homozygote.

Fractionated total body irradiation and high dose cyclophosphamide: a preparative regimen for bone marrow transplantation for patients with hematologic malignancies in first complete remission

We treated 73 patients with hematologic malignancies in first complete remission (acute lymphoblastic leukemia = 23 patients; acute non-lymphoblastic leukemia = 25 patients; chronic myelogenous leukemia in first chronic phase = 20 patients, and high grade lymphoma = five patients) with a uniform preparative regimen consisting of fractionated total body irradiation (1,320 cGy) and high dose cyclophosphamide (100 mg/kg), followed by allogeneic bone marrow transplantation. By radiation dosimetry we demonstrated that the calculated doses were delivered accurately and reproducibly. Actuarial survival rates (+/- SEM) in complete remission were as follows: Acute lymphoblastic leukemia = 74 +/- 9%; acute nonlymphoblastic leukemia = 50 +/- 11%; and chronic myelogenous leukemia = 55 +/- 11%. Actuarial relapse rates for these three diagnoses were 19 +/- 9%, 17 +/- 11%, and 0% respectively. Three of the five lymphoma patients are alive in complete remission at 22+, 28+, and 54+ months. Overall probability of survival for the 73 patients was 59 +/- 7%. Interstitial pneumonia, usually associated with cytomegalovirus infection and graft-versus-host disease, and relapse of the underlying malignancy were the major causes of death.

Bone marrow transplantation for myelodysplastic and myeloproliferative syndromes

Twenty patients (age range, 4 to 48 years; median age, 36 years) with de novo or drug-induced myelodysplastic syndromes or myeloproliferative disorders were treated with myeloablative immunosuppressive therapy followed by bone marrow transplantation (BMT). Four preparative regimens were used; three regimens consisted of combined total body irradiation (TBI) and chemotherapy and one of combination chemotherapy only. One patient received marrow from his identical twin brother, whereas the other 19 patients were grafted with marrow from histocompatible siblings. In 19 patients the abnormal clone was at least temporarily ablated, while in one patient the congenital myelodysplasia persisted. Eight patients are alive and well for +108 to +3,359 days post-transplantation. Nine patients died of transplant-related complications (six of interstitial pneumonia, two of gastrointestinal bleeding, and one of fungal sepsis) and three patients died with persisting or recurring disease. One patient with a late recurrence has undergone a second successful bone marrow transplant procedure. Outcome of BMT was not related to French-American-British (FAB) type, marrow fibrosis, cytogenetic abnormalities, or preparation regimen. Marrow transplantation as a means of providing long-term disease-free survival and possible cure should be considered in patients if a suitable donor is available.

Bone marrow transplantation for patients with Philadelphia chromosome-positive acute lymphoblastic leukemia

We report the treatment outcome of allogeneic bone marrow transplantation in ten patients with Philadelphia chromosome-positive acute lymphoblastic leukemia. Six patients are alive and well for 6 to 30 months (median 19 months) after transplantation. Four patients died with transplant related complications. In view of the poor prognosis associated with this disease, marrow ablation followed by allogeneic or syngeneic marrow grafting may be the preferred treatment modality if a suitable marrow donor is available.

Allogeneic bone marrow transplantation for high risk non-Hodgkin's lymphoma during first complete remission

Allogeneic bone marrow transplantation from histocompatible sibling donors was performed in six patients with extranodal involvement of high grade lymphoma during first complete remission. Five patients had lymphoblastic lymphoma and one had diffuse undifferentiated lymphoma. The cytoreductive/immunosuppressive regimen consisted of total body irradiation and high dose cyclophosphamide. Four patients are alive in complete remission at 8 months, 14 months, 21 months and 47 months post transplantation. One patient who relapsed 7 months after his initial transplantation underwent a second transplantation but another relapse 17 months later led to his death. One patient died of chronic graft-versus-host disease and at autopsy there was no evidence of lymphoma. These data demonstrate that allogeneic bone marrow transplantation can produce durable remissions in patients with high grade lymphoma who present with bone marrow, central nervous system and/or skin involvement.

Bone marrow transplantation for acute nonlymphoblastic leukemia during first complete remission. An analysis of prognostic factors

Sixty-nine patients with acute nonlymphocytic leukemia in first remission received total-body irradiation and chemotherapy followed by allogeneic bone marrow transplantation from histocompatible sibling donors. Patient age was between 1 and 41 years: 20 patients 1-19 years (group 1); 27 patients 20-29 years (group 2); and 22 patients 30-41 years (group 3). Two pretransplant radiochemotherapy regimens were employed: The first 45 patients received total-body irradiation (in a single dose) with cytosine arabinoside and cyclophosphamide; the next 24 patients received total-body irradiation (in a fractionated schedule) with cyclophosphamide alone. For all patients, actuarial disease-free survival is 51% (37 of 69 patients are alive and in continuous remission between 5 months and 9.3 years, median 3.7 years). For group 1 actuarial survival is 56%, group 2 48%, and group 3 48%. When analyzed for pretransplant factors that might predict disease-free survival after bone marrow transplantation neither patient age, white cell count at the time of diagnosis, FAB leukemic subtype, length of time before achieving remission, nor length of time between remission and bone marrow transplantation were established as prognostic.

Total body irradiation and high-dose etoposide: a new preparatory regimen for bone marrow transplantation in patients with advanced hematologic malignancies

In a phase I/II study, 47 patients (median age, 24 years) with hematologic malignancies (33 patients with acute leukemia not in first remission and 14 patients with other advanced malignant hematologic disorders) were treated with total body irradiation and high doses of etoposide (VP16-213) followed by bone marrow transplantation. At the time of analysis, 21 patients were alive, and 19 of them were in continued complete remission for 101 days to greater than 40 months (median, 12 months). The actuarial disease-free survival rate of the 33 acute leukemia patients is 43% (2 SEM, 18%) and the actuarial relapse rate is 32% (2 SEM, 20%). Five of the 14 patients with the other hematologic malignancies are alive, and four of them continue to be free of disease for 8 to 27 months. Pharmacokinetic studies established a strong correlation between the administered drug doses and their plasma levels and also demonstrated complete drug clearance prior to marrow grafting. An etoposide dose of 60 mg/kg body weight was found to be the maximum tolerated dose. This new preparatory regimen was well tolerated and was not associated with specific acute or long-term regimen-related toxicities. Our data suggest that total body irradiation with high-dose etoposide presents a viable alternative to other preparatory regimens. The role of this novel combination remains to be defined by future prospective randomized trials.

Rhegmatogenous retinal detachment in Labrador retrievers. II. Proliferative vitreoretinopathy

We observed proliferative vitreoretinopathy in Labrador retrievers with spontaneous rhegmatogenous retinal detachment. Cellular membranes and their associated connective tissue matrix were prominent on the surfaces of the detached formed vitreous and on the retina. Membrane contraction folded the underlying vitreous and retina and exerted traction on the structures to which they attached. Proliferation occurred in the retinal pigment epithelium under the detached retina and in the nonpigmented ciliary epithelium when it became detached. Retinal pigment epithelial cells, nonpigmented ciliary epithelial cells, macrophages, and glial cells appeared to contribute to the membranes. Our findings suggested a sequence that began with vitreous abnormalities and ended with fibrocellular membranes on the surfaces of the vitreous and the totally detached retina. Because a similar sequence can develop in humans, these dogs may be useful in future studies of proliferative vitreoretinopathy.

Rhegmatogenous retinal detachment in Labrador retrievers. I. Development of retinal tears and detachment

We used clinical and pathologic methods to examine ten Labrador retrievers with ocular and skeletal abnormalities. The major ocular findings were axial myopia; cataract; vitreous abnormalities, including liquefaction, detachment, and vitreoretinal traction; retinal tears; rhegmatogenous retinal detachment; and proliferative vitreoretinopathy. The appendicular skeleton showed retarded bone growth, bone dysplasia, and degenerative arthropathy. Vitreoretinal traction appeared to be the cause of the retinal tears because (1) formed vitreous was always attached near the anterior edge of the tear, and (2) vitreous traction caused a retinal ridge adjacent to a retinal tear in a dog that had not yet developed retinal detachment. The pathogenetic sequence of spontaneous vitreous abnormalities, retinal tears, and retinal detachment observed in these dogs has not previously been described in animals, to the best of our knowledge, and mimicked human rhegmatogenous retinal detachment, particularly those associated with giant retinal tears.

Unsuccessful treatment of disseminated protothecosis in a dog

Systemic protothecosis was diagnosed in a 7-year-old dog that had only ocular manifestations. During the 3-month course of disease, a variety of drugs was administered, including amphotericin B, gentamicin, and ketoconazole. The ocular signs initially abated, but subsequently worsened during this period. The dog was found dead 3 months after initial examination, and systemic protothecosis was confirmed at necropsy.

Onchocerca cervicalis in horses: dermal histopathology

A histopathological study of ventral midline skin from midwestern U.S. horses with and without onchocerciasis due to Onchocerca cervicalis found perivascular mononuclear dermatitis as the most consistent difference between the two groups. Seasonal variation in parasite numbers or cellular influxes was not observed. Eosinophilic dermatitis was observed in horses with onchocerciasis and dermatitides of unknown etiology.