Diphenylhydantoin interstitial nephritis. Roles of cellular and humoral immunologic injury

Managing the patient with epilepsy and renal impairment

PURPOSE

Epilepsy affects more than 50 million people worldwide and its management can be complicated by comorbidities such as impaired renal function. To optimize epilepsy control in patients with kidney disease, clinicians need to be aware of how antiepileptic drugs (AEDs) are affected by impaired renal function and how the kidneys are affected by epilepsy management strategies. Herein we present a narrative review with systematic literature search to discuss the use of AEDs in patients with renal impairment, including those undergoing dialysis, as well as the nephrotoxic effects of some AEDs. We finally conclude the article by providing practical tips about our approach to using AEDs in the setting of renal disease.

METHODS

A literature search targeting epilepsy management in patients with kidney disease was performed in MEDLINE database (1946 to 7th Jan 2019).

RESULTS

A total of 1193 articles were found. After duplicate removal, title and abstract screening followed by full text screening, a total of 110 references were included in this review. Additional information was included from drug product monographs.

CONCLUSION

The disposition of AEDs can be altered in patients with impaired renal function, leading to a higher risk of AED toxicity or therapy failure. Renal dosage adjustment and close monitoring is recommended. Although AED-induced nephrotoxicity is rare, it is unpredictable and clinicians need to vigilant about this possibility. In addition, AEDs renal adverse reactions and renal drug interactions should be considered when selecting an AED.

The effect of antiepileptic drugs on the kidney function and structure

INTRODUCTION

Long-term use of antiepileptic drugs (AEDs) is associated with number of somatic conditions. Data from experimental, cross-sectional and prospective studies have evidence for the deleterious effect of some AEDs on the kidney. Areas covered: This review summarized the current knowledge of the effect of AEDs on the kidney including evidence and mechanisms. Fanconi syndrome was reported with valproate (VPA) therapy in severely disabled children with epilepsy. Renal tubular acidosis and urolithiasis were reported with acetazolamide, topirmate and zonisamide, drugs with carbonic anhydrase inhibition properties. Increased levels of urinary N-acetyl-beta-D-glucosaminidase (NAG) to urinary creatinine (U-NAG/UCr), urinary excretion of α1-micrglobulin, β-galactosidase activity; and urinary malondialdehyde to creatinine (MDA/Cr), markers of renal glomerular and tubular injury, were reported with chronic use of some AEDs (VPA, carbamazepine and phenytoin). The mechanism(s) of kidney dysfunction/injury induced by AEDs is unknown. Experimental and clinical studies have shown that VPA induces oxidative stress, mitochondrial deficits, carnitine deficiency and inflammation and fibrosis in renal tissue in mice and in vitro studies. Expert commentary: It seems reasonable to monitor kidney function during treating patients with epilepsy at high risk of kidney injury (e.g. on combined therapy with more than one AED, severely disabled children, etc).

Prevalence, Severity, and Impact of Renal Dysfunction in Acute Liver Failure on the US Liver Transplant Waiting List

BACKGROUND AND AIMS

Although renal dysfunction is a known complication of acute liver failure (ALF), its frequency, severity, and impact among patients with ALF on the US liver transplant list are not well defined.

METHODS

Organ Procurement and Transplantation data for ALF patients listed as status 1/1A from 2002 to 2012 were analyzed. The frequency and severity of renal dysfunction at the time of listing [the latter was categorized in 5 stages using estimated GFR (eGFR) according to Chronic Kidney Disease Epidemiology Collaboration creatinine 2009 equation] were determined and the association between renal dysfunction and waiting list mortality was assessed using Cox proportional hazard regression analysis.

RESULTS

There were a total of 2280 adult patients with ALF, including 56 % with renal dysfunction (defined as eGFR < 60 ml/min/1.73 m(2)) at listing. The highest proportion of patients with renal dysfunction was among those with ALF caused by hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome, fatty liver disease of pregnancy, heat stroke/hyperthermia, hepatitis A virus, and drug-induced liver injury due to acetaminophen APAP, phenytoin, trimethoprim-sulfamethoxazole, and macrolides. Despite the fact that 69 % (468/674) of patients with APAP-induced ALF listed as status 1/1A had renal dysfunction, only 0.9 % underwent simultaneous liver-kidney transplantation. Six-week survival probabilities in patients with ALF on the liver transplant waiting list were 71, 59, 56, 59, and 42 % with renal dysfunction stages of 1, 2, 3, 4, and 5, respectively. Multivariate analysis showed that after controlling for age, etiology of ALF, INR, total bilirubin, and region, the relative risk of death increased progressively as eGFR declined (P < 0.0001).

CONCLUSIONS

Among patients with ALF on the liver transplant waiting list, renal dysfunction was common (overall prevalence of 56 %). Most importantly, severe renal dysfunction was associated with significantly increased mortality.

Use of Antiepileptic Drugs in Patients with Chronic Kidney Disease and End Stage Renal Disease

Epilepsy is a disorder with an approximate worldwide prevalence of 1%. Due to complexities of metabolism, protein-binding, renal elimination, and other pharmacokinetic parameters, the dosing of antiepileptic drugs (AEDs) in patients with chronic kidney disease (CKD) or end stage renal disease (ESRD) deserves special attention. This is a review of the most commonly prescribed AEDs with special focus on their indication, pharmacokinetics, and unique considerations for use in patients with CKD and ESRD. A review of their renal toxicities is also included.

Graft-versus-host reactions: clues to the etiopathology of a spectrum of immunological diseases

Parental strain T lymphocytes injected into adult F, mice respond to allogeneic MHC antigens and so induce the symptoms of systemic graft v. host disease (GVHD). GVHD has two forms, stimulatory and suppressive, and in each there are pathological changes which resemble those seen in a variety of human disorders of immune regulation. In this article Ernst Gleichmann and his colleagues review the pathogenesis of these disorders and their induction by GVH reactions.

Use of Antiepileptic Drugs in Patients with Kidney Disease

The number of medications used to treat different types of seizures has increased over the last 10-15 years. Most of the newer antiepileptic drugs (AEDs) are likely to be unfamiliar to many nephrologists. For both the older and newer AEDs, basic pharmacokinetic information, recommendations for drug dosing in patients with reduced kidney function or who are on dialysis, and adverse renal and fluid-electrolyte effects are reviewed. Newer AEDs are less likely to have significant drug-drug interactions than older agents, but are more likely to need dosage adjustment in patients with reduced kidney function. The most common renal toxicities of these drugs include metabolic acidosis, hyponatremia, and nephrolithiasis; interstitial nephritis and other adverse effects are less common. Little is known about the clearance of most of the newer AEDs with high-efficiency hemodialyzers or with peritoneal dialysis. Monitoring of drug levels when available, careful clinical assessment of patients taking AEDs, and close collaboration with neurologists is essential to the management of patients taking AEDs.

Anticonvulsant hypersensitivity syndrome in children: incidence, prevention and management

Anticonvulsant hypersensitivity syndrome (AHS) is a rare, but potentially fatal, adverse reaction that occurs in patients, including children, who are treated with anticonvulsants. During metabolism of the anticonvulsant, toxic arene-oxide compounds are produced. AHS is associated with both cutaneous and systemic symptoms and is associated with multiorgan involvement. Liver damage, in particular, seems to be associated with fatal outcomes. The pathophysiology of AHS is still uncertain but it may be linked to a genetically determined inability to detoxify reactive drug metabolites. The prompt recognition of the first clinical signs of AHS, and the rapid withdrawal of the anticonvulsant, often avoids the progression of symptoms. Pharmacological treatment is essentially based on systemic corticosteroids in association with enteral nutrition, intravenous fluid augmentation, pain relief and ocular care. Intravenous immunoglobulins may also have a possible therapeutic role in some cases. Diagnostic tests, such as patch tests or in vitro assays, for AHS could help to identify patients at risk of developing the syndrome and could represent a first step of primary prevention when applied to relatives of patients.

Stevens-Johnson syndrome in a patient receiving anticonvulsant therapy during cranial irradiation

A 28-year-old female patient with a recent history of breast carcinoma was referred to our clinic with generalized necrotic skin eruptions and severe mucosal erosions, which developed right after the completion of cranial radiotherapy for brain metastases. She had been receiving prophylactic diphenylhydantoin treatment 100 mg three times daily during radiation therapy. The extensive involvement of the oral mucosa with conjunctivitis and synechiae of the eyelids, facial swelling, and extension of the rash over the trunk and shoulders with bullous detachment of less than 10% of the total body surface strongly suggested Stevens-Johnson syndrome caused by phenytoin treatment in our patient. There has been conflicting evidence on the role of radiotherapy in the increased risk of severe drug reactions. Although various authors have emphasized the augmented rate of severe mucocutaneous reactions caused by anticonvulsants given during radiotherapy and suggested discontinuing the prophylactic use of such drugs in patients with no history of seizures, others have argued in favor of prophylactic anticonvulsants. Given the high risk of seizures, reaching 20% in patients with brain tumors, and the low incidence of drug reactions, the suggestion of refraining from prophylactic anticonvulsants in the setting of primary or metastatic brain tumors is controversial.

Drug-induced acute interstitial nephritis

Acute interstitial nephritis (AIN) is a form of inflammatory renal disease affecting predominantly the tubules and the interstitium. Drugs, particularly beta-lactam antibiotics and non-steroidal anti-inflammatory drugs, are currently the most common causes. The pathogenesis of drug-induced AIN is complex but there is good clinical evidence for an immune-mediated reaction. Clinical findings may be variable depending on the drug involved and the individual response. Most patients recover from the acute renal failure; however, in older patients or in patients with pre-existing renal insufficiency the recovery of renal function may be incomplete.

Renal tubular dysfunction following treatment with anti-epileptic drugs

To evaluate renal side-effects of anti-epileptic medication in children, we performed a cross-sectional study of various aspects of renal function. We studied 59 patients from our outpatient clinic. They had been on anti-epileptic monotherapy for at least 3 months. None had a history of renal disease. Twenty-three healthy children of the same age group served as controls. After collecting 24-h urine samples, glomerular function was derived from creatinine clearance and from the excretion of albumin. Proximal tubular function was investigated by the urinary excretion of alpha 1-microglobulin and of the tubular enzymes N-acetyl-beta-D-glucosaminidase, alanine-amino-peptidase and fructose-1,6-di-phosphatase. Distal tubular function was examined by the 24-h excretion of Tamm-Horsfall protein. On treatment with carbamazepine (n = 27) and phenytoin (n = 8), the excretion of alpha 1-microglobulin was significantly increased, as compared with the healthy controls. On valproate (n = 20), ethosuximide (n = 9) and phenytoin (n = 8), therapies significantly increased excretion of N-acetyl-beta-D-glucosaminidase. This must be interpreted as an indication of a functional disturbance of the proximal tubulus. The other parameters, indicating function of the glomerulus, loop of Henle and distal tubules did not differ from normal.

CONCLUSION

Patients on anti-epileptic treatment with therapeutic drug levels may demonstrate minor signs of tubular dysfunction. These are probably insignificant from a clinical standpoint, but they should be considered in drug overdose.

Tubulointerstitial nephritis

Tubulointerstitial nephritis (TIN) describes a range of pathological processes that are at least partly responsible for the progression of renal disease of nearly all aetiologies. TIN is frequently the most important pathological manifestation of progressive glomerulonephritis, obstructive uropathy, reflux nephropathy and cystic diseases, although it may also present as a primary disease process associated with infection, drug use or other immunologically mediated disease. Recent clinical and laboratory research has increased our knowledge of tubulointerstitial structure, physiological function and tubulointerstitial response to injury. This review presents a classification of TIN in which acute and chronic tubulointerstitial diseases are recognized as forming a continuum. Primary TIN and TIN associated with glomerulonephritis, obstructive nephropathy and chronic progressive renal disease are discussed from both clinical and pathogenic aspects. It is argued that chronic TIN is a disease process in which inflammation is accompanied by a destructive tubulopathy and fibrogenesis. In acute TIN there is a cessation and reversal of this process. It is suggested that most forms of TIN have an immunological basis because of the presence of immune cell infiltrates, the occurrence of TIN in several immune diseases and immunological animal models of TIN. However, to date TIN has not been convincingly modified in patients by immune manipulation. Experimental evidence suggesting an important pathogenic role for proteinuria and antigenuria, and the renal tubule cell acting as an antigen-presenting cell is discussed.

A case of tubulo-interstitial nephritis with exfoliative dermatitis and hepatitis due to phenobarbital hypersensitivity

Severe exfoliative dermatitis and liver dysfunction developed in a 5-year-old girl 3 weeks after initiation of phenobarbital therapy. Liver function improved gradually after discontinuation of phenobarbital. During the convalescent stage an initially mild renal dysfunction was exacerbated by episodes of post-transfusion haemolysis. Liver biopsy revealed moderate parenchymal damage with subacute cellular infiltration. Renal biopsy demonstrated the cardinal findings of interstitial nephritis, excluding the possibility of acute tubular necrosis caused by haemolysis. Serial lymphocyte transformation studies and skin patch tests gave positive results for phenobarbital, supporting the view that these were unusual complications of phenobarbital hypersensitivity.

Familial occurrence of hypersensitivity to phenytoin

PURPOSE

Therapy with anticonvulsants such as phenytoin, phenobarbital, and carbamazepine can be complicated by severe hypersensitivity reactions. Previous work has suggested that the predisposition to such reactions is based on an inherited abnormality in the detoxification of reactive metabolites of the drugs. However, there are no reports of familial occurrence of the reactions in the literature. In the current study, we examined a family in which three siblings developed hypersensitivity reactions to phenytoin, confirming the inheritance of a predisposition to the reactions. Detoxification of reactive metabolites of the anticonvulsants was studied in cells from the patients and their siblings.

PATIENTS AND METHODS

Three siblings from a family of 12 siblings developed hypersensitivity reactions to phenytoin characterized by fever, rash, lymphadenopathy, and anicteric hepatitis. All recovered completely after discontinuation of treatment. One sibling tolerated phenobarbital without toxic sequelae. Peripheral blood mononuclear cells from the three patients and five additional siblings who had never taken anticonvulsants were exposed to oxidative metabolites of phenytoin, phenobarbital, and carbamazepine generated by a hepatic microsomal drug-metabolizing system in vitro. The toxicity of metabolites in the cells from the siblings was compared with that in cells from control subjects.

RESULTS

Cells from each of the patients who had experienced a hypersensitivity reaction exhibited increased toxicity from metabolites of phenytoin and carbamazepine, while the cellular response to metabolites of phenobarbital was within normal limits. Cells from four of the other siblings showed an abnormal response to phenytoin metabolites, while cells from the final sibling detoxified phenytoin metabolites normally.

CONCLUSION

Our observations on the patients confirm the inherited nature of phenytoin hypersensitivity reactions in vivo. In vitro studies demonstrated abnormal metabolite detoxification in the patients and several of their siblings. The detoxification defect included metabolites of phenytoin and carbamazepine but not of phenobarbital. A family history of a drug hypersensitivity reaction should alert physicians to the probability of a markedly increased risk of an adverse reaction in family members. In vitro assays to confirm adverse reaction risks may ultimately be able to provide individualized risk assessment for patients who must take anticonvulsants.

Phenytoin hypersensitivity syndrome: a case report

We report a life-threatening case of phenytoin hypersensitivity syndrome, a rare reaction primarily characterized by fever, skin eruptions, lymphadenopathy, eosinophilia, and hepatotoxicity. The reaction developed in a 27-year-old black man with surgically corrected tetralogy of Fallot who was treated with phenytoin for one month for exercise-induced sustained ventricular tachycardia. Phenytoin therapy was discontinued and the patient was treated with intravenous methylprednisolone; the therapy was later converted to oral prednisone. Clinical improvement was noted five days after admission and the patient was discharged on hospital day 14. This adverse reaction usually develops within six weeks of starting phenytoin therapy and may be fatal in up to 40 percent of the patients who develop hepatotoxicity. Early recognition of this relatively rare reaction is essential to prevent serious and potentially fatal complications.

Allergic nephropathy associated with ciprofloxacin

We report a case of ciprofloxacin-related allergic tubulointerstitial nephritis, which manifested as nonoliguric renal failure, eosinophilia, and eosinophiluria. Our patient responded to discontinuation of ciprofloxacin therapy and oral administration of a brief course of corticosteroids. Although rare, allergic tubulointerstitial nephritis apparently can be caused by ciprofloxacin therapy. Clinicians should be aware of this entity.

Acute tubulointerstitial nephritis

Acute tubulointerstitial nephritis (ATIN) is a common disorder characterized by a spectrum of clinical manifestations ranging from asymptomatic urinary abnormalities to acute oliguric renal failure. Tubular dysfunction out of proportion to the degree of renal failure is an important clue to the diagnosis. This review describes its pathogenesis, pathophysiology, diagnosis, differential diagnosis and therapy, emphasizing the drug-induced form of ATIN.

Anticonvulsant hypersensitivity syndrome. In vitro assessment of risk

Arene oxide metabolites of aromatic anticonvulsants (phenytoin, phenobarbital, and carbamazepine) may be involved in the pathogenesis of hypersensitivity reactions. We investigated 53 patients with clinical sensitivity to anticonvulsants by exposing their lymphocytes in vitro to drug metabolites generated by a murine hepatic microsomal system. The diagnosis of a hypersensitivity reaction was corroborated by in vitro rechallenge for each drug (phenytoin, n = 34; phenobarbital, n = 22; carbamazepine, n = 25) when cytotoxicity (% dead cells) exceeded 3 SD above the mean result for controls. Cross-reactivity among the drugs was noted. 7 out of 10 patients who had received all three anticonvulsants had adverse reactions to each. 40 out of 50 patients tested to all three drugs in vitro were positive to each. Adverse reactions were indistinguishable among anti-convulsants. Skin rash (87%), fever (94%), hepatitis (51%), and hematologic abnormalities (51%) were common clinical features of each drug. 62% of reactions involved more than two organs. Cells from patients' parents exhibited in vitro toxicity that was intermediate between values for controls and patients. In vitro testing can help diagnose hypersensitivity to anticonvulsants. Cells from patients may also be used for prospective individualization of therapy to decrease risk of adverse reaction. Cross-reactivity among the major anticonvulsants is common and should be considered before deciding on alternative therapy.

Cutaneous and immunologic reactions to phenytoin

Phenytoin (diphenylhydantoin; Dilantin) is a highly effective and widely prescribed anticonvulsant and antiarrhythmic agent. Since 1938 it has been invaluable in the treatment of grand mal and psychomotor epilepsy. Hydantoin derivatives have been used medicinally for more than a half-century. In recent years dermatologists have broadened the indications for phenytoin use to include recessive dystrophic epidermolysis bullosa, linear scleroderma, and pachyonychia congenita. In spite of widespread use and popularity, it is interesting that the frequency of complications relating to drug therapy remains low, relatively speaking. Nevertheless, a broad spectrum of cutaneous and immunologic reactions to phenytoin have been reported. These range from tissue proliferative syndromes (side effects), drug hypersensitivity syndromes (allergic effects), and a possible linkage with lymphoma (idiosyncratic effects). Therapeutic and toxic reactions to this commonly prescribed drug are comprehensively reviewed, analyzed, and summarized in this monograph.

Renal side effects of nonsteroidal antiinflammatory drugs: clinical relevance

Nonsteroidal antiinflammatory drugs (NSAIDs) induce a variety of renal side effects. We review their prevalence and clinical relevance, and identify the patients who are most at risk for these complications. NSAIDs induce hemodynamic renal failure in states of compromised renal perfusion and in the presence of a preexisting nephropathy. Association of triamterene and indomethacin is especially nephrotoxic and should be avoided. NSAIDs cause sodium retention and impair the natriuretic effect of diuretics: this side effect is clinically relevant in edema-forming states. Hyperkalemia induced by NSAIDs is harmful in case of renal failure and hypoaldosteronism. NSAIDs may induce an acute interstitial nephritis often associated with the nephrotic syndrome; the event is rare and unpredictable, and mainly propionic acid derivatives have been incriminated. NSAIDs are reported to attenuate the hypotensive effect of various drugs; further studies are warranted to better delineate the clinical relevance of this observation.

Ultrastructure of the kidney in acute interstitial nephritis

Fifteen percutaneous renal biopsies from patients with acute renal failure due to acute interstitial nephritis (AIN), in almost all cases due to drugs, were studied by electron microscopy. Differential counting of interstitial cells showed an average of 69% lymphocytes (small and large) and 11% macrophages. Plasma cells and eosinophils were comparatively rare. The infiltrate resembled that of acute rejection, suggesting a cellular hypersensitivity reaction. Proximal and distal tubules were severely affected focally. Migration of lymphocytes through the tubular basement membrane of otherwise well-preserved tubules was considered to be the first phase. Other tubules showed extreme thinning of the tubular basement membrane, with still intact cellular walls. Rupture of the tubular basement membrane and necrotic disintegration of tubular epithelial cells are probably late phenomena. The non-necrotic tubules displayed severe reduction of proximal brush border and proximal as well as distal tubular basolateral infoldings. Focal tubular disintegration leading to tubular block and/or backleak as well as decrease of proximal tubular sodium resorption leading to a decreased glomerular filtration (a mechanism probably also acting in ischemic acute renal failure) may all be factors responsible for the acute renal failure in AIN.

Pathogenesis of graft-versus-host reactions (GVHR) and GVH-like diseases

The graft-versus-host reaction (GVHR) in both mice and humans can lead to the development of a broad spectrum of clinical and pathological symptoms. These symptoms are strikingly similar to those of a number of diseases of proven or presumed immunological origin, such as systemic lupus erythematosus (SLE), other collagen vascular diseases, lymphoproliferative disease, and aplastic anemia. The purpose of our investigation was to describe the immunological and pathological events that take place in the course of graft-versus-host disease (GVHD) and to gain insight into the cellular mechanisms underlying these events. To this end, a model was employed in which nonirradiated F1 mice were used as recipients of parental lymphoid cells. By pathological manifestations, 2 basic forms of GVHD can be distinguished in such non-irradiated F1 recipients: One is acute GVHD which is often lethal. It is characterized by a variety of suppressive (hypoplastic) pathological symptoms, including a severe hypoplasia of the lymphohemopoietic system accompanied by aplastic anemia and hypogammaglobulinemia. The other basic form is characterized by stimulatory symptoms, such as persistent lymphoid hyperplasia, formation of autoantibodies, and development of pathological symptoms reminiscent of SLE and other collagen vascular diseases. The suppressive pathological graft-versus-host (GVH) symptoms are caused by T suppressor/killer (TS/K) cells of the donor which react towards allogeneic class-I-structures of the F1 recipient's major histocompatibility complex (MHC). The stimulatory pathological GVH symptoms, by contrast, are caused by donor T helper (TH) cells which react toward the recipient's allogeneic class-II-MHC structures. The possible implications of these observations for the pathogenesis of a number of GVH-like diseases in humans are discussed. The hypothesis is advanced that some of these GVH-like conditions, which arise either e causa ignota or after exposure to certain viruses or drugs, are caused by T lymphocytes reacting against self-MHC structures on lymphohemopoietic cells that were rendered "foreign". By analogy to GVHD, it is conceivable that the development of either stimulatory or suppressive GVH-like symptoms in individuals exposed to a given virus or sensitizing drug depends not on the etiologic agent per se, but on whether the predominant response is made by the individual's TH or TS@K cells. This, in turn, might depend on whether the agent becomes immunogenic in combination with class-II or class-I alloantigens.

Phenytoin hypersensitivity reaction presenting with toxic epidermal necrolysis and severe hepatitis. Report of a patient treated with corticosteroid "pulse therapy"

In this report we describe the successful outcome following the use of corticosteroid pulse therapy in a patient with a severe phenytoin hypersensitivity reaction presenting with toxic epidermal necrolysis and severe hepatitis. Steroid pulse therapy may be lifesaving in a severe dermatosis, such as toxic epidermal necrolysis.

Diphenylhydantoin-induced hypersensitivity reaction with interstitial nephritis

A 10-year-old black girl had an episode of diphenylhydantoin(DPH)-induced exfoliative dermatitis, lymphadenopathy, hepatitis, peripheral eosinophilia, and transient renal failure. The findings of specific lymphocyte sensitization of DPH, a clinically typical delayed hypersensitivity reaction, multinucleated histiocytes in the renal interstitium, and negative renal immunofluorescence studies for immune reactants indicate that the child's renal injury was at least partially cell-mediated.

Immunologic aspects of phenobarbital hypersensitivity

Seven patients with hypersensitivity reactions to phenobarbital are described. Clinical manifestations consisted of fever and pruritic skin rash, often associated with adenopathy and conjunctivitis. Reexposure to phenobarbital or other anticonvulsants resulted in redevelopment of symptoms. In vitro lymphocyte stimulation studies with anticonvulsant drugs suggested a cell-mediated hypersensitivity reaction to phenobarbital.

Universal cutaneous depigmentation following phenytoin-induced toxic epidermal necrolysis

A 10-year-old black girl with a severe hypersensitivity reaction to phenytoin is described. Adverse effects included interstitial nephritis, hepatitis, and toxic epidermal necrolysis. An apparently permanent sequela of universal cutaneous depigmentation developed. Although the presence of clear cells in the basal layer of the epidermis suggested that melanocytes might still be present, these clear cells were shown, by electron microscopy, to be Langerhans cells and not melanocytes. This patient demonstrates a unique outcome, not previously described in the literature.

Hodgkin's disease susceptibility: linkage to the HLA locus demonstrated by a new concordance method

The role of genetic susceptibility in the pathogenesis of Hodgkin's Disease has been considered relatively minor because of the rarity of familial disease, the absence of an identified pattern of inheritance, and the weakness of HLA associations in population studies. The availability of four prospectively ascertained HD families permitted reappraisal of the cosegregation of HLA and HD susceptibility by a new extended concordance analysis method. HLA haplotype concordance among patients was greater than that expected by chance alone for our four families (P less than 0.022) and also for these in combination with twelve informative families in the literature (P less than 0.0015). This study thus provides a new method, based on genotype concordance of affected relatives, for assessing linkage of HLA and disease susceptibility, and new evidence for the genetic control of susceptibility to HD. The model presented, as well as alternative and more complex models, points to the existence of an HD susceptibility gene in or near the HLA region, which, in the presence of a suitable etiologic agent or additional genetic susceptibility, leads to the induction of HD.

Drug-induced acute interstitial nephritis with granulomas

To shed more light on the immunopathogenesis of drug-induced acute interstitial nephritis, a combined histologic, immunopathologic, and ultrastructural study of renal biopsy specimens from nine patients with drug-induced renal disease was performed. None of the patients had pre-existing renal disease or evidence of sarcoidosis or tuberculosis. The principal drugs included a hydrochlorothiazide-triamterene combination (Dyazide), hydrochlorothiazide, fenoprofen, and furosemide and triamterene. Renal insufficiency developed approximately four to ten weeks after initiation of drug therapy. In all cases, withdrawal of the drug(s) with or without steroid therapy resulted in restoration of normal or near-normal renal function. Histologically, all biopsy specimens showed acute interstitial nephritis characterized by an intense but patchy mononuclear cell interstitial infiltrate consisting of lymphocytes, monocytes, and plasma cells, modest numbers of eosinophils, patchy tubular atrophy, interstitial edema, and normal glomeruli. All biopsy specimens contained interstitial (and, in two cases, perivascular) non-caseating granulomas, which were numerous in one case, moderate in four cases, and rare in the remainder. Direct immunofluorescence was negative for IgG, IgM, IgA, C1q, C4, and C3 along glomerular and tubular basement membranes. Immunoperoxidase staining for lysozyme (performed in three cases) demonstrated many positive cells in the infiltrate. In two cases in which granulomas were present in prepared sections, the epithelioid and multinucleated giant cells did not stain for lysozyme. Electron microscopy of the granulomas in two cases revealed that the epithelioid and giant cells had "secretory" features characteristic of hypersensitivity granulomas. These findings provide further evidence for the participation of cell-mediated immunity in the pathogenesis of at least some cases of drug-induced acute interstitial nephritis.