Verapamil inhibition of lymphocyte proliferation and function in vitro

Management of Hypertension in Solid-Organ Transplantation

Posttransplant hypertension is a major risk factor for cardiovascular disease and chronic renal allograft dysfunction. A significant number of transplant recipients suffer from posttransplant hypertension in part because of corticosteroid and calcineurin inhibitor use. Although the optimal blood pressure range and the antihypertensive agents of choice in the transplant population have not been determined, the guidelines for blood pressure control in the general population can be extrapolated to the transplant population. The choice of an antihypertensive regimen should be tailored on the basis of the individual patient's risk factors and comorbidities.

New Verapamil Analogs Inhibit Intracellular Mycobacteria without Affecting the Functions of Mycobacterium-Specific T Cells

There is a growing interest in repurposing mycobacterial efflux pump inhibitors, such as verapamil, for tuberculosis (TB) treatment. To aid in the design of better analogs, we studied the effects of verapamil on macrophages and Mycobacterium tuberculosis-specific T cells. Macrophage activation was evaluated by measuring levels of nitric oxide, tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), and gamma interferon (IFN-γ). Since verapamil is a known autophagy inducer, the roles of autophagy induction in the antimycobacterial activities of verapamil and norverapamil were studied using bone marrow-derived macrophages from ATG5(flox/flox) (control) and ATG5(flox/flox) Lyz-Cre mice. Our results showed that despite the well-recognized effects of verapamil on calcium channels and autophagy, its action on intracellular M. tuberculosis does not involve macrophage activation or autophagy induction. Next, the effects of verapamil and norverapamil on M. tuberculosis-specific T cells were assessed using flow cytometry following the stimulation of peripheral blood mononuclear cells from TB-skin-test-positive donors with M. tuberculosis whole-cell lysate for 7 days in the presence or absence of drugs. We found that verapamil and norverapamil inhibit the expansion of M. tuberculosis-specific T cells. Additionally, three new verapamil analogs were found to inhibit intracellular Mycobacterium bovis BCG, and one of the three analogs (KSV21) inhibited intracellular M. tuberculosis replication at concentrations that did not inhibit M. tuberculosis-specific T cell expansion. KSV21 also inhibited mycobacterial efflux pumps to the same degree as verapamil. More interestingly, the new analog enhances the inhibitory activities of isoniazid and rifampin on intracellular M. tuberculosis. In conclusion, KSV21 is a promising verapamil analog on which to base structure-activity relationship studies aimed at identifying more effective analogs.

Calcium channel blockers for preventing acute tubular necrosis in kidney transplant recipients

BACKGROUND

The incidence of delayed graft function in cadaveric grafts has increased over the last few years due in part to the large demand for cadaveric kidneys necessitating the use of kidneys from marginal donors. Calcium channel blockers have the potential to reduce the incidence of post-transplant acute tubular necrosis (ATN) if given in the peri-operative period. However, there is controversy surrounding their use in this situation with no consensus as to their efficacy.

OBJECTIVES

To evaluate the benefits and harms of using calcium channel blockers in the peri-transplant period in patients at risk of ATN following cadaveric kidney transplantation.

SEARCH STRATEGY

We searched the Cochrane Renal Group's specialised register, the Cochrane Central Register of Controlled Trials (CENTRAL, in The Cochrane Library) MEDLINE (from 1966) and EMBASE (from 1980). The Trials Search Coordinator was contacted to develop the search strategy. Date of last search: January 2007

SELECTION CRITERIA

Randomised controlled trials comparing calcium channel blockers given in the peri-transplant period with controls were included. Quasi-randomised trials were excluded.

DATA COLLECTION AND ANALYSIS

Data was extracted and quality assessed independently by two reviewers, with differences resolved by discussion. Dichotomous outcomes are reported as relative risk (RR) and measurements on continuous scales are reported as mean differences (WMD) with 95% confidence intervals (CI).

MAIN RESULTS

Thirteen trials (724 participants) were suitable for inclusion. Treatment with calcium channel blockers in the peri-transplant period was associated with a significant decrease in the incidence of post-transplant ATN (RR 0.62, 95% CI 0.46 to 0.85) and delayed graft function (RR 0.55, 95% CI 0.42 to 0.73). There was no difference between control and treatment groups in graft loss, mortality, requirement for haemodialysis. There was insufficient information to comment on adverse events.

AUTHORS' CONCLUSIONS

These results suggest that calcium channel blockers given in the peri-operative period may reduce the incidence of ATN post-transplantation. The result should be treated with caution due to the heterogeneity of the trials which made comparison of studies and pooling of data difficult.

Calcium channel blockers for preventing acute tubular necrosis in kidney transplant recipients

BACKGROUND

The incidence of delayed graft function in cadaveric grafts has increased over the last few years due in part to the large demand for cadaveric kidneys necessitating the use of kidneys from marginal donors. Calcium channel blockers have the potential to reduce the incidence of post-transplant acute tubular necrosis (ATN) if given in the peri-operative period. However, there is controversy surrounding their use in this situation with no consensus as to their efficacy.

OBJECTIVES

To evaluate the benefits and harms of using calcium channel blockers in the peri-transplant period in patients at risk of ATN following cadaveric kidney transplantation.

SEARCH STRATEGY

We searched the Cochrane Renal Group's specialised register, the Cochrane Central Register of Controlled Trials (CENTRAL, in The Cochrane Library) MEDLINE (from 1966) and EMBASE (from 1980). The Trials Search Coordinator was contacted to develop the search strategy. Date of last database and register search: January 2005

SELECTION CRITERIA

Randomised controlled trials comparing calcium channel blockers given in the peri-transplant period with controls were included. Quasi-randomised trials were excluded.

DATA COLLECTION AND ANALYSIS

Data was extracted and quality assessed independently by two reviewers, with differences resolved by discussion. Dichotomous outcomes are reported as relative risk (RR) and measurements on continuous scales are reported as weighted mean differences (WMD) with 95% confidence intervals (CI).

MAIN RESULTS

Ten trials were suitable for inclusion. Treatment with calcium channel blockers in the peri-transplant period was associated with a significant decrease in the incidence of post transplant ATN (RR 0.57, 95%CI 0.40 to 0.82) and delayed graft function (RR 0.51, 95% CI 0.36 to 0.72). There was no difference between control and treatment groups in graft loss, mortality, requirement for haemodialysis. There was insufficient information to comment on adverse events.

AUTHORS' CONCLUSIONS

These results suggest that calcium channel blockers given in the peri-operative period may reduce the incidence of ATN post-transplantation. The result should be treated with caution due to the heterogeneity of the trials which made comparison of studies and pooling of data difficult.

Lupus erythematosus induced by medications, ultraviolet radiation, and other exogenous agents: A review, with special focus on the development of subacute cutaneous lupus erythematosus in a genetically predisposed individual

Exogenous agents implicated in or suspected of precipitating subacute cutaneous lupus erythematosus (SCLE) and lupus erythematosus (LE) are reviewed. An illustrative case of environmentally induced SCLE is presented. A previously healthy 30-year male homozygous for the tumor necrosis factor-alpha (TNF-alpha) 308. A promoter allele developed SCLE after spending several hours removing fertilizer- and pesticide-containing hay from an agricultural barn in the springtime. The cutaneous eruption soon resolved, only to reappear 3 weeks later on the day the patient re-entered the barn. An environmental agent present in the barn, coupled with springtime ultraviolet light, likely triggered the disease in this immunogenetically susceptible individual.

Verapamil (VP) improves the outcome after renal transplantation (CRT)

Calcium antagonists (CATs) have a role in the management of certain types of renal insufficiency. These include prophylaxis against post-transplant-associated acute renal failure and cyclosporine A (CsA)-induced renal dysfunction. For the transplanted kidney, CATs may be beneficial in several settings. First, a CAT during organ procurement protects the kidney during ischemic periods. Second, CATs given perioperatively protect the kidney during reperfusion and early after transplantation. Third, CATs also offer protection against CsA nephrotoxicity.

Lymphomatoid drug eruption mimicking digitate dermatosis: cross reactivity between two drugs that suppress angiotensin II function

A 75-year-old male presented with an eruption characteristic of digitate dermatosis. The eruption cleared completely after discontinuation of lisinopril (angiotensin converting enzyme inhibitor). Eighteen months later a similar eruption recurred after using valsartan (a competitive inhibitor of angiotensin II receptor). The eruption cleared after discontinuation of valsartan. Histologic findings in both eruptions were consistent with lymphomatoid drug eruption. This case is interesting in that the eruption occurred after the intake of two structurally unrelated drugs that interfere with angiotensin II function. This observation may shed light on the mechanisms that may be operative in provoking the lymphomatoid drug eruption.

Drug-induced reversible lymphoid dyscrasia: a clonal lymphomatoid dermatitis of memory and activated T cells

Certain systemic conditions predispose patients to excessive lymphocyte responses to immune-perturbing drugs, which may progress to malignant lymphoma. Many pathologists and clinicians believe that differentiation of pseudolymphoma from cutaneous T cell lymphoma (CTCL) can be reliably made through phenotypic and molecular analysis. We encountered 15 cases of atypical cutaneous T-cell lymphoid hyperplasia in the setting of drug therapy. We explored phenotypic anomalies using antibodies to CD2, 3, 4, 7, 8, 20, 30 and CD62 K and sought T-cell receptor gene rearrangements by a polymerase chain reaction methodology. The lymphoid infiltrates showed reproducible CD7 and/or CD62 K deletion in concert with T cell clonality and variable CD30 positivity-findings similar to those of CTCL-but the rashes resolved or improved substantially after drug modulation. We hypothesize that the infiltrates represent an unrepressed expansion of CD7- and CD62 K-negative activated memory T lymphocytes in response to antigenic triggers. We propose the term "drug-induced reversible lymphoid dyscrasia" to describe this entity.

The cutaneous pathology of lupus erythematosus: a review

The presentation of lupus erythematosus (LE) ranges from a skin rash unaccompanied by extracutaneous stigmata to a rapidly progressive lethal multiorgan disease. The diagnosis and subclassification is traditionally based on the correlation of serological and clinical findings. The latter include a photoinduced skin rash, arthralgia, arthritis, fever, Raynaud's phenomenon, anemia, leukopenia, serositis, nephritis and central nervous sysdtem disease. The conventional classification scheme includes systemic, subacute cutaneous and discoid LE. Recent advances in our understanding of the cutaneous histopathology which correlates with the traditional forms of LE, along with certain novel LE subtypes, are the focus of this review. In addition to the main subtypes of LE, we will discuss associated vasculopathic lesions and the contribution of immunofluorescence microscopy to the diagnosis of LE and related connective tissue disease syndromes. Consideration will be given to unusual variants of LE such as anti-Ro/SSA-positive systemic lupus erythematosus (SLE), bullous SLE, lymphomatoid LE, lupus erythematosus profundus, drug induced LE, linear cutaneous LE, chiblains LE and parvovirus B19-associated LE.

Glycine inhibits growth of T lymphocytes by an IL-2-independent mechanism

Previously, it was shown that glycine prevented increases in intracellular calcium ([Ca2+]i) in Kupffer cells. Since Kupffer cells and T lymphocytes are derived from the same pluripotent stem cell, it was hypothesized that glycine would prevent increases in [Ca2+]i in lymphocytes and inhibit cell proliferation. Lymphocyte proliferation was measured in one-way MLC with spleen cells from DA and Lewis rats and in enriched T lymphocyte preparations stimulated by immobilized anti-CD3 Ab. Glycine caused a dose-dependent decrease in cell proliferation to about 40% of control. Con A caused a dose-dependent increase in [Ca2+]i in Jurkat cells which was blunted maximally with 0.6 mM glycine. The effect of glycine was dependent on extracellular chloride and reversed by strychnine, an antagonist of the glycine-gated chloride channel. Similar results were obtained with rat T lymphocytes stimulated by anti-CD3 Ab. Surprisingly, glycine had no effect on IL-2 production in the mixed lymphocyte culture; therefore, the effect of glycine on IL-2-dependent proliferation was tested. Glycine and rapamycin caused dose-dependent decreases in IL-2-stimulated growth of Ctll-2 cells to about 60% and 40%, respectively, of control. Moreover, glycine also inhibited the IL-2-stimulated growth of rat splenic lymphocytes. It is concluded that glycine blunts proliferation in an IL-2-independent manner. This is consistent with the hypothesis that glycine activates a glycine-gated chloride channel and hyperpolarizes the cell membrane-blunting increases in [Ca2+]i that are required for transcription of factors necessary for cell proliferation.

Lichenoid and subacute cutaneous lupus erythematosus-like dermatitis associated with antihistamine therapy

The authors report the occurrence of lichenoid and/or subacute lupus erythematosus-like eruptions in a group of patients receiving agents with antihistaminic properties. In 1 of the patients the eruption clinically resembled lichen planus, while in 5 patients the eruption resembled subacute cutaneous lupus erythematosus (SCLE). At a light microscopic level all cases showed a lichenoid dermatitis and in 4 cases the lesions were interpreted as representing subacute lupus-like eruptions by virtue of the presence of alternating cell poor and lichenoid interface dermatitis, suprabasilar lymphocytosis around degenerating keratinocytes, and dermal mucinosis. Despite the resemblance at a clinical and light microscopic level to SCLE, anti-Ro seropositivity could not be established in any of the cases. One case, however, did demonstrate antihistone antibodies in concert with a high antinuclear antibody titer. A causal association was implicated by virtue of lesional resolution following drug withdrawal. The association of cutaneous eruptions resembling SCLE with antihistamine intake is seemingly a novel one. The possible pathogenetic basis of the eruptions is discussed.

Skin cancer in Australian heart transplant recipients

BACKGROUND

Cutaneous malignancy is a major cause of morbidity in organ transplant recipients.

OBJECTIVE

Our purpose was to report on skin cancer in Australian heart transplant recipients with analysis of HLA factors.

METHODS

We reviewed histologically proven skin cancers in the first 455 patients undergoing organ transplantation in Sydney, Australia.

RESULTS

The cumulative incidence of skin cancer was 31% at 5 years and 43% at 10 years with a squamous cell carcinoma/basal cell carcinoma ratio of 3:1. Caucasian origin, increasing age at transplantation, and duration of follow-up were significantly associated with skin cancer. Skin cancer accounted for 27% of 41 deaths occurring after the fourth year. Recipient HLA-DR homozygosity was associated with skin cancer overall, whereas HLA-DR7 was a protective factor in skin cancer overall, squamous cell carcinoma, and Bowen's disease. HLA-A1 and HLA-A11 were significant protective factors in Bowen's disease.

CONCLUSION

Skin cancer is a major cause of morbidity and long-term mortality in heart transplant patients.

Prolonged rat heart allograft survival after treatment with angiotensin converting enzyme inhibitor or a calcium antagonist

The effect in vivo of the angiotensin converting enzyme (ACE) inhibitors captopril and enalapril and the calcium antagonist verapamil was studied in an experimental model using rat heart allografts. Daily post-transplant treatment of recipient rats (DA strain) with verapamil (75 mg kg-1 day-1) or captopril (40 mg kg-1 day-1) significantly prolonged survival of allografts from donors (PVG/c strain) when compared with an untreated control group (p < 0.05). No synergistic effect was observed when the two drugs were used for combined treatment. An equipotent does of enalapril (12.5 mg kg-1 day-1) caused no change in allograft survival of statistical significance. The results support the hypothesis that verapamil and captopril have effects on the immune reactivity in vivo, and that this is not a characteristic shared by all ACE inhibitors.

Cutaneous pseudolymphomas

Cutaneous pseudolymphoma refers to a heterogeneous group of benign reactive T- or B-cell lymphoproliferative processes of diverse causes that simulate cutaneous lymphomas clinically and/or histologically. The inflammatory infiltrate is bandlike, nodular, or diffuse and is composed predominantly of lymphocytes with or without other inflammatory cells. Depending on the predominant cell type in the infiltrate, cutaneous pseudolymphomas are divided into T- and B-cell pseudolymphomas. Cutaneous T-cell pseudolymphomas include idiopathic cutaneous T-cell pseudolymphoma, lymphomatoid drug reactions, lymphomatoid contact dermatitis, persistent nodular arthropod-bite reactions, nodular scabies, actinic reticuloid, and lymphomatoid papulosis. Cutaneous B-cell pseudolymphomas include idiopathic lymphocytoma cutis, borrelial lymphocytoma cutis, tattoo-induced lymphocytoma cutis, post-zoster scar lymphocytoma cutis, and some persistent nodular arthropod-bite reactions. This review attempts to discuss current aspects of the classification, pathogenesis, clinical spectrum, histopathologic and immunohistochemical diagnosis, and laboratory investigations for clonality in the various types of cutaneous pseudolymphomas.

Protection against methoxyacetic-acid-induced spermatocyte apoptosis with calcium channel blockers in cultured rat seminiferous tubules: possible mechanisms

A calcium-mediated mechanism underlying spermatocyte apoptosis induced by 2-methoxyethanol (2-ME) has been previously proposed. This hypothesis was tested in vitro in the present study using cultured juvenile (25 days old) and adult rat seminiferous tubules (JRST and ARST, respectively) with methoxyacetic acid (MAA, the active metabolite of 2-ME). In JRST, spermatocyte degeneration was morphologically obvious 19 hr after a 5-hr exposure to 5 mM MAA. The lesion was unaffected by the presence or absence of extratubular Ca2+. However, MAA-induced cell death was significantly prevented by cotreatment with the dihydropyridines (DHP) nifedipine (50 microM) and nicardipine (20 microM), as well as verapamil (50 microM) and TMB-8 (50 microM), all of which are able to inhibit calcium movement through plasma membranes. However, neither ryanodine, dantrolene, nor cyclosporin A and ruthenium red, which inhibit Ca2+ mobilization from intracellular stores (endoplasmic reticulum and mitochondria), affected the MAA-induced cell death. Inhibition of calcium mobilization through IP3-sensitive pathways by blocking the product of IP3 with manoalide, neomycin, and U73122 did not block the MAA-induced lesion. The protective effects of 50 microM nifedipine and 50 microM TMB-8 were also observed in ARSTs treated with 10 mM MAA for 5 hr. However, when rat testicular sections were immunohistochemically stained with monoclonal antibodies specific for the alpha 1 (the DHP receptor) or the alpha 2 subunits of DHP-sensitive calcium channels, no positive staining was found. Finally, in an attempt to see whether the intracellular free calcium concentrations ([Ca2+]i) in germ cells were increased after the MAA treatment, intact seminiferous tubules were loaded with indo-1 and were measured using laser-scanning confocal microscopy. No detectable increase in the signal in MA A-sensitive spermatocytes was observed, while a 34-54% increase in the signal could be detected in the same cell types when tubules were exposed to 10 microM of the calcium ionophore 4-bromo-A23187 for 5 min. Collectively, these data suggest that the protective effect of calcium channel blockers against the MAA-induced spermatocyte apoptosis is probably not through their blocking effect on DHP-sensitive calcium channels. We postulate alternate mechanisms based on stabilization of cells membranes, or interactions with calmodulin or protein kinase C.

Subacute cutaneous lupus erythematosus arising in the setting of calcium channel blocker therapy

After 6 months to 5 years of calcium channel blocker (CCB) therapy for arterial hypertension, nine patients developed photoinduced annular or papulosquamous eruptions consonant clinically with subacute cutaneous lupus erythematosus (SCLE). Four patients were receiving diltiazem, four received verapamil, and one was taking nifedipine. Serology showed antinuclear antibodies (ANA) in seven of nine patients, anti-Ro antibodies in five, and anti-La antibodies in five, with three patients having only anti-La antibodies. Skin biopsy specimens in all nine patients were held to be characteristic of SCLE based on light microscopy, direct, and indirect immunofluorescence. The CCB was discontinued in all; in 8 patients in whom the CCB was stopped, the eruption resolved. A proposed mechanism by which the CCBs may have precipitated the eruptions is offered.

Drug-induced immune dysregulation as a cause of atypical cutaneous lymphoid infiltrates: a hypothesis

The authors encountered 22 patients in whom a skin biopsy showed atypical lymphoid hyperplasia and in whom a subsequent drug history showed indigestion of one or more agents before lesional onset. In 13 patients, the biopsy had been performed to rule out a diagnosis of malignant lymphoma, whereas the other nine the clinical impression was that of a drug eruption. Among the more frequently prescribed agents were calcium-channel blockers, angiotensin-converting enzyme (ACE) inhibitors, antidepressants, antihistamines, beta-blockers, benzodiazepines and lipid-lowering agents, all of which are either known to perturb lymphocyte function or have been implicated as a cause of pseudolymphomata. Twelve of the patients were on two or more of these drugs. The effect of drug modulation on the clinical course was assessed. The clinical presentations were as one or more erythematous plaques or multiple infiltrative papules, or as solitary nodules. The patient had been on one or more of the aforementioned drugs from 2 weeks to 5 years before developing the lesions. Resolution of the eruptions occurred in 17 patients within 1 to 32 weeks (mean, 7 weeks) of discontinuing the medication. Five additional patients had complete excision of solitary lesions without recurrence. A history of atopy, autoimmune disease, or previous carcinoma was elicited in five patients. All biopsy specimens showed atypical lymphoid infiltrates, which assumed one or more of the following patterns: mycosis fungoides (MF)-like, a lymphomatoid vascular reaction, lymphocytoma cutis and follicular mucinosis. Based on the histopathology of the biopsied lesions and the clinical course being one of lesional resolution after cessation of drug therapy or excision of a solitary lesion without subsequent recurrence, a diagnosis of drug-associated lymphomatoid hypersensitivity was established in all specimens. A diagnosis of drug-associated pseudolymphoma should be excluded before a diagnosis of cutaneous lymphoma is rendered, and should be considered if the patient is on a drug known to alter lymphocyte function, particularly in the setting of systemic immune dysregulation or multidrug therapy where agent may act synergistically or cumulatively to alter lymphoid function. The authors postulate that the drug may promote an aberrant immune response to an antigen that may be the drug itself or some other stimulus. A skin biopsy may be particularly helpful, as the lesions of drug-associated pseudolymphoma have a morphology distinctive from malignant lymphoma.

Clinically significant drug interactions with cyclosporin. An update

Since its approval in 1983 for immunosuppressive therapy in patients undergoing organ and bone marrow transplants, cyclosporin has had a major impact on organ transplantation. It has significantly improved 1-year and 2-year graft survival rates, and decreased morbidity in kidney, liver, heart, heart-lung and pancreas transplantation. Several studies have supported the efficacy of cyclosporin in preventing graft-versus-host disease in bone marrow transplantation. Cyclosporin is also possibly effective in treating diseases of autoimmune origin and as an antineoplastic agent. The introduction of therapeutic drug monitoring of cyclosporin was extremely useful because of the wide inter- and intraindividual variability in the pharmacokinetics of cyclosporin after oral or intravenous administration. Optimal long term use of cyclosporin requires careful monitoring of the blood (or plasma) concentrations. Sustained and clinically significant drug-drug interactions can occur during long term therapy with cyclosporin. The coadministration of multiple drugs with cyclosporin could result in graft rejection, renal dysfunction or other undesirable effects. Any interaction that leads to modified cyclosporin concentrations is of potential clinical importance. Cyclosporin itself may have significant effects on the pharmacokinetics and/or pharmacodynamics of coadministered drugs, such as digoxin, HMG-CoA reductase inhibitors and antineoplastic drugs affected by multidrug resistance. Many drugs have been shown to affect the pharmacokinetics and/or pharmacodynamics of cyclosporin. Interactions between cyclosporin and danazol, diltiazem, erythromycin, fluconazole, itraconazole, ketoconazole, metoclopramide, nicardipine, verapamil, carbamazepine, phenobarbital (phenobarbitone), phenytoin, rifampicin (rifampin) and cotrimoxazole (trimethoprim/sulfamethoxazole) are well documented in a large number of patients. Other interactions (such as those with aciclovir, estradiol and imipenem) are documented only in isolated case studies.

Drugs with antihistaminic properties as a cause of atypical cutaneous lymphoid hyperplasia

BACKGROUND

Although an association between antihistaminic drugs and atypical cutaneous lymphoid infiltrates has not been reported previously, in vitro evidence suggests that these agents perturb certain lymphoid functions through binding to histamine receptors, including a novel growth-promoting intracellular histamine receptor, designated HIC.

OBJECTIVE

We studied the clinical findings and histopathologic findings in 14 patients taking antihistaminic drugs in whom atypical cutaneous lymphoid infiltrates developed.

METHODS

We retrospectively reviewed the clinical and histologic features of these patients' skin lesions.

RESULTS

The clinical presentations included solitary or multiple nodules and plaques, and multiple papules. In some patients a temporal association between drug therapy and clinical course was observed, as the lesions improved or resolved after a decrease or discontinuation of the drug. Eleven patients were taking two or more medications that in vitro are associated with alterations in lymphocyte function, including agents without antihistaminic properties. A diagnosis of pseudolymphoma seemed clinically apposite in seven of the 14 patients on the basis of either resolution of the eruption or presentation of a solitary nodule that did not recur after excision. Histologic analysis showed four distinct morphologies: mycosis fungoides-like, nodular dermal infiltrates consistent with either lymphocytoma cutis or lymphoma cutis, lymphomatoid vascular reaction, and follicular mucinosis. Common to cases showing the first pattern were histologic features suggesting a delayed-type hypersensitivity reaction, thus enabling their distinction from mycosis fungoides. The infiltrates were predominantly of T-cell phenotype.

CONCLUSION

Antihistamines are associated with atypical lymphoid hyperplasia in some patients. The antihistaminic drug may not be the provocative agent per se; rather, a drug-induced immunodysregulatory state may render an abnormal immune response to some other exogenous antigen. Multidrug therapy with these and other agents known to exert immunomodulatory effects may increase susceptibility to the development of atypical lymphoid hyperplasia and malignant lymphoma.

Developments and dilemmas in renal transplantation

The number of patients waiting for a kidney transplant is about three times greater than the number of transplants performed each year. This article highlights current immunosuppression protocols and the newer immunosuppressive drugs under investigation in a number of multicenter trials. These hold out the promise of reducing the frequency of acute rejection and of prolonging graft survival. They are divided into three groups. The first, like cyclosporine, interferes with the action of interleukin 2. The second, like azathioprine, are antimetabolites; and the third, new monoclonal antibodies. The use of antibody-induction therapy is compared with standard regimens. There are risks related to prednisone withdrawal protocols and inadequate cyclosporine dosing that may lead to accelerated graft loss. Cardiovascular disease is a significant problem in older diabetic patients for whom coronary angiography is recommended. A defined set of risk factors is outlined that predicts which younger diabetic patients should have a cardiovascular evaluation. Chronic liver disease is a growing problem and rational strategies are emerging from studies of patients with biopsy-proven active hepatitis. The presence of hepatic inflammation is associated with progressive liver disease and patients must be made aware of this risk when seeking transplantation. A large number of studies of various prophylactic regimens are starting to provide data on the cost-effective reduction of cytomegalovirus disease in transplant recipients. It is recommended that patients receiving antibody therapy also receive preemptive gangciclovir. The issue of chronic allograft rejection is discussed briefly. The most important predictors of chronic allograft rejection are the frequency of acute rejection, inadequate immunosuppression, and infections.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of nifedipine on renal transplant rejection

The effect of early nifedipine therapy on acute renal allograft rejection was studied in 170 adult cadaveric transplant recipients. Acute rejection occurring in the first 3 months after transplantation was diagnosed by Tru-cut biopsy and the severity of each rejection episode assessed histologically. The incidence of acute rejection was significantly lower in patients treated with nifedipine (29 of 80; 36 per cent) than in controls (52 of 90; 58 per cent) (P < 0.01) and there was a higher proportion of histologically mild rejection episodes in the former group (P < 0.01). Multivariate analysis confirmed that nifedipine exerted a significant independent effect on the incidence of early acute rejection. Other factors identified in the multivariate model as influencing rejection were human leucocyte antigen (HLA) matching at the DR locus, blood level of cyclosporin during the first week, HLA matching at the B locus, donor age and donor sex. The 1-year graft survival rate was 88.6 per cent in patients given nifedipine and 63.8 per cent in controls (P < 0.02). These data suggest that nifedipine therapy has a useful role in human renal transplantation.

Hypertension after renal transplantation

In 212 cyclosporine-treated renal transplant recipients with stable graft function at 1 year and with potential follow-up of 5 years the prevalence of arterial hypertension was 81.6% at 1 year and 81.2% at 5 years. The logistic regression analysis showed that the presence of hypertension before transplantation (P = 0.0001; odds ratio 3.5), a plasma creatinine level higher than 2 mg/dL at 1 year (P = 0.0001; odds ratio 3.8), and a maintenance therapy with corticosteroids (P = 0.008; odds ratio 3.3) were positively associated with hypertension at 1 year after transplantation. The mean number of graft failures between 1 and 5 years was significantly higher and the mean reciprocal of plasma creatinine was significantly worse at 1 and 5 years in patients with noncontrolled hypertension than in normotensive patients or in patients with hypertension well controlled by drugs. We also investigated the potential protective role of nifedipine. The episodes of acute tubular necrosis (four versus three), of acute rejections (28 versus 29), the mean arterial pressure at 1 year (105 +/- 9 versus 104 +/- 9 mm Hg) and 5 years (105 +/- 10 versus 108 +/- 12 mm Hg), and the mean plasma creatinine level at 1 year (1.4 +/- 0.4 versus 1.6 +/- 0.4 mg/dL) and 5 years (1.8 +/- 1 versus 1.9 +/- 1 mg/dL) were similar in 52 patients who were given nifedipine for at least 4 years and 58 hypertensive patients who never took calcium channel blockers.(ABSTRACT TRUNCATED AT 250 WORDS)

A controlled, double-blind, randomized trial of verapamil and cyclosporine in cadaver renal transplant patients

Calcium channel blockers have immunomodulating effects in vitro and may be effective in preventing cyclosporine nephrotoxicity. We studied the effect of verapamil following renal transplantation on the incidence of rejection and cyclosporine nephrotoxicity in a double-blind, placebo-controlled trial. Patients were randomly assigned to placebo (n = 28) or verapamil (n = 32) at doses of 80 mg twice a day. There was no difference in the incidence of rejection or cyclosporine toxicity in the two study arms. Recipients randomized to verapamil had lower mean cyclosporine doses at all intervals during a 1-year follow-up. Although cyclosporine doses were lower in the placebo group, the mean cyclosporine levels were equivalent in the two groups. Recipients in the verapamil-treated group had a higher mean serum creatinine at the end of the study--1.7 mg/dL versus 1.4 mg/dL in the placebo group. Actual 1-year graft survival was 89% for the placebo recipients versus 91% in the verapamil-treatment group. When compared with placebo, the concomitant use of low-dose verapamil results in lower cyclosporine doses but equivalent cyclosporine blood levels. Reduction in the incidence of rejection or cyclosporine nephrotoxicity were not observed.

Calcium channel blockers inhibit cellular uptake of thymidine, uridine and leucine: the incorporation of these molecules into DNA, RNA and protein in the presence of calcium channel blockers is not a valid measure of lymphocyte activation

An important role of transmembrane flux of calcium in lymphocyte activation has been previously demonstrated. Herein, we demonstrate that the calcium channel blockers verapamil and isradipine are able to inhibit in a concentration-dependent manner 3H-thymidine incorporation into DNA in phytohemagglutinin (PHA)-stimulated human peripheral blood mononuclear cells (PBMC). However, verapamil and isradipine diminish PHA-stimulated thymidine incorporation into DNA to the same extent whether they are added at the beginning of culture or 4 h prior to completion of a 72-h culture. Thus, 3H-thymidine incorporation into DNA in the presence of verapamil or isradipine is not a valid measure of mitogen-induced lymphocyte proliferation. Similarly, verapamil and isradipine also inhibit PHA-stimulated incorporation of 3H-leucine into protein and 3H-uridine into RNA whether the drugs are added at the beginning of culture or 4 h prior to completion of 24-h cultures. There is no intracellular accumulation of 3H-thymidine, 3H-leucine, or 3H-uridine into 10% trichloroacetic acid-soluble molecules during inhibition with verapamil or isradipine, suggesting that these drugs impair the cellular uptake of these substances rather than directly inhibiting their incorporation into DNA, protein, or RNA, respectively. Since previous reports documenting the inhibitory effects of calcium channel blockers on lymphocyte proliferation have utilized 3H-thymidine incorporation into DNA to measure proliferation, we have re-examined the antiproliferative effects of these drugs by determining their effect on PHA-stimulated cell cycle progression, employing cytofluorometric analysis of propidium iodide-stained cells. When added at the initiation of culture, both verapamil and isradipine inhibited in a concentration-dependent manner PHA-stimulated cell cycle progression.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of calcium in biphasic immunomodulation by gamma-HCH (lindane) in mice

gamma-HCH (Lindane) is reported to cause a biphasic immunomodulation-stimulation followed by suppression-after oral administration in mice. Role of calcium in this biphasic immunomodulation was assessed after 4, 12 and 24 wks of gamma-HCH administration. 45Ca-uptake was enhanced during the initial immunostimulation followed by decrease concomitant with immunosuppression. Lymphocyte proliferation was inhibited during both the phases of immune response by verapamil, a calcium channel blocker, and by trifluoperazine, a calmodulin inhibitor. These findings show an impairment of calcium homeostasis in lymphocytes culminating into the biphasic immunomodulatory effects of gamma-HCH.

Therapeutic benefits of calcium channel blockers in cyclosporine-treated organ transplant recipients: blood pressure control and immunosuppression

Cyclosporine has dramatically improved the success rates for all forms of organ transplantation. However, its use is complicated by the frequent occurrence of hypertension and reversible nephrotoxicity. The iatrogenic hypertension induced by cyclosporine resembles a low-renin, salt-sensitive form of essential hypertension, which is often controlled with salt restriction and therapies counteracting renal salt acquisition, e.g., diuretics and calcium channel blockers (CCBs). CCBs may also counteract the direct vasoconstrictive effects of cyclosporine, as well as the effects of other vasoconstrictors, such as endothelin or thromboxane, that may be stimulated by cyclosporine. Additionally, CCBs may potentiate the immunosuppression of cyclosporine, yet minimize nephrotoxicity. We demonstrated that the in vitro combination of verapamil and cyclosporine had an additive inhibitory effect on the activation and function of human peripheral blood mononuclear cells in several assays of the afferent and efferent limbs of immunologic responses. This additive immunosuppression was not likely to have been related to these drugs' effects on interleukin-2 (IL-2) circuitry, since no additive inhibition of IL-2 production or IL-2 responsiveness was found. There was some additive inhibition of IL-2 receptor expression at the higher concentrations of verapamil and cyclosporine that were tested. Although the combination of verapamil and cyclosporine additively inhibited mitogen-induced 45Ca uptake, the inhibitory effect of cyclosporine appears to be due to an inhibition of lymphocyte activation rather than direct inhibition of calcium flux through the slow calcium channel, suggesting that the two drugs do not have additive effects in depressing the transmembrane flux of calcium. More recently, we have demonstrated that the inactive enantiomer of verapamil, which does not block the slow calcium channel, has identical immunosuppressive capabilities as the active enantiomer. Thus, the antiproliferative effect of verapamil is probably slow-calcium-channel independent and may represent the ability of the drug to interfere with muscarinic, alpha 1-adrenergic, or even opiate receptors on lymphocytes or to block lymphocyte potassium channels. An even better possibility is that verapamil may diminish necessary precursor molecule uptake into lymphocytes, since both the inactive and active isomeric forms of verapamil are capable of diminishing thymidine, uridine, and leucine incorporation into stimulated lymphocytes--necessary for DNA, RNA, and protein synthesis, respectively. These in vitro observations may have clinical applicability, as early studies demonstrate reduced rejection rates of cyclosporine-treated transplant patients receiving CCBs. Consequently, CCBs are important medications to be considered for use in cyclosporine-treated organ transplant recipients.

Modulation of murine in vitro immune response by verapamil (V)

Functionally distinct lymphocyte subsets differ with regard to necessary activation signals. In selected circumstances lymphocyte activation has been shown to be critically dependent upon transcellular calcium influx. Whether calcium plays a central role in the activation of all lymphocytes remains to be determined. The effect of the calcium channel blocker verapamil on the induction of murine cytotoxic T lymphocytes (CTL), suppressor cells, T helper cells, and B cells was investigated. Verapamil (V) was found to inhibit the induction of cytotoxic effector cells. V acted primarily on the afferent limb of this immune response, was synergistic with cyclosporin A (CsA), and its effects could be largely reversed by the addition of exogenous helper factors. V also inhibited B cell proliferation in response to anti-mouse IgM in the presence of 2-mercaptoethanol, but in the absence of cognate or non-cognate T cell help. In contrast to this, V did not inhibit the activation of cells capable of inducing B cell proliferation nor did it inhibit the induction of suppressor cells. The selective suppression of V is discussed in terms of activation requirements of CTL, suppressor cells and helper cell subsets.

Inhibition of macrophage- and neutrophil-mediated cytotoxicity by verapamil

Peripheral blood monocyte-derived macrophages and polymorphonuclear leukocytes (PMNs) obtained from normal donors kill tumor cells in vitro. However, if verapamil is added to the macrophages or neutrophil tumor cell suspensions in microgram concentrations (0.1 microgram to 0.1 mg), there is marked inhibition of tumor cell killing. The inhibitory effect for the macrophages resulted from an effect of verapamil on both the effector and target cells. When either the effector cells or target cells were preincubated with verapamil, they became resistant to the effects of the cytotoxic macrophages. Cytotoxicity was also inhibited when 0.1 mg of verapamil was added to the macrophages monolayers either at the time of addition of the tumor cells or 15-30 min after addition of the tumor cells, whereas no inhibition of cytotoxicity occurred when verapamil was added more than 30 min after the initiation of the cytotoxic reaction. For the neutrophils it was observed that the inhibitory activity resulted from an effect of verapamil on the effector cells rather than the target cells. When the effector cells were preincubated with verapamil they became incapable of killing the tumor cells, whereas preincubation of the target cells with verapamil had no effect on their ability to be killed by the neutrophils. Cytotoxicity was also inhibited when 0.1 mg of verapamil was added to the neutrophil monolayers either at the time of addition of the tumor cells or 15-60 min after addition of the tumor cells, whereas no inhibition of cytotoxicity occurred when verapamil was added more than 60 min after the initiation of the cytotoxic reaction.

Alleviation of cyclosporine nephrotoxicity with verapamil and ATP-MgCl2. Mitochondrial respiratory and calcium studies

Although recent studies have shown that combined treatment with verapamil and ATP-MgCl2 (ATP) prevents cyclosporine (CyA)-induced nephrotoxicity, the mechanism of these effects remains unknown. To study this, rat kidneys were perfused at 100 mmHg for 100 minutes with Krebs buffer containing 7.5 g/dL of albumin and substrates. After an equilibration period of 30 minutes, 500 ng/mL CyA was added. In some experiments 1 microgram/mL verapamil was added 10 minutes prior to CyA and in others 2 mM ATP was added to CyA. At the end of the perfusion, cortical mitochondria (mito) were isolated and mito Ca2+ and Mg2+ (mumoles/g protein) and respiratory control ratios (RCR) were measured. In addition, total tissue Ca2+ and Mg2+ levels were measured. The results indicate that CyA treatment leads to an accumulation of mito Ca2+ and a decrease in ADP/O ratio. Simultaneous administration of ATP with CyA led to an increased mito Ca2+ accumulation and depressed RCR, which were corrected by verapamil pretreatment. The combination of verapamil pretreatment and ATP cotreatment with CyA increased tissue ATP levels from 0.8 +/- 0.4 (control) to 1.4 +/- 0.1 mumol/g. This pharmacologic regimen may prevent CyA-induced nephrotoxicity by preventing mito Ca2+ accumulation and by preserving mitochondrial respiratory function. This allows a more efficient generation of ATP and consequently preservation of renal function.