Immunologic studies in cimetidine-induced nephropathy and polymyositis

Toxic myopathies

Muscle tissue is highly sensitive to many substances. Early recognition of toxic myopathies is important, because they potentially are reversible on removal of the offending drug or toxin, with greater likelihood of complete resolution the sooner this is achieved. Clinical features range from mild muscle pain and cramps to severe weakness with rhabdomyolysis, renal failure, and even death. The pathogenic bases can be multifactorial. This article reviews some of the common toxic myopathies and their clinical presentation, histopathologic features, and possible underlying cellular mechanisms.

Iatrogenic and toxic myopathies

There has been increasing awareness of the adverse effects of therapeutic agents and exogenous toxins on the structure and function of muscle. The resulting clinical syndrome varies from one characterized by muscle pain to profound myalgia, paralysis, and myoglobinuria. Because toxic myopathies are potentially reversible, their prompt recognition may reduce their damaging effects or prevent a fatal outcome. Interest in the toxic myopathies, however, derives not only from their clinical importance but also from the fact that they serve as useful experimental models in muscle research. Morphological and biochemical studies have increased our understanding of the basic cellular mechanisms of myotoxicity. Toxins may produce, for instance, necrotizing, lysosomal-related, inflammatory, anti-microtubular, mitochondrial, hypokalemia-related, or protein synthesis-related muscle damage.

Nephrotoxicity and hepatotoxicity of histamine H2 receptor antagonists

The extensive use of selective histamine H2 receptor antagonists provides a unique opportunity to describe very rare adverse drug reactions. Although mild elevation of serum creatinine level following the administration of cimetidine is relatively common, acute interstitial nephritis (AIN) is a rare hypersensitivity reaction. There have been 25 published reports of AIN associated with H2 antagonist therapy and we also identified 16 cases from the Australian Adverse Drug Reaction Advisory Committee (ADRAC) database. AIN was reported most commonly following cimetidine administration. AIN was supported by renal biopsy in 28 patients and by rechallenge in 6. H2 antagonist-induced AIN was more commonly reported in men older than 50 years. In the majority of cases the onset was within 2 weeks of initiation of therapy (1 day to 11 months). The clinical manifestations were nonspecific including sterile pyuria, elevated erythrocyte sedimentation rate, fatigue, proteinuria and leucocytosis whereas rash, arthralgia and flank pain were rarely reported. There were 170 cases of hepatotoxicity following H2 antagonist administration reported to ADRAC. These were more common following ranitidine and included cholestatic, hepatocellular and mixed reactions. Hepatotoxicity was proven following liver biopsy in several cases published in the literature and in 15 cases reported to ADRAC. Hepatotoxicity recurred upon rechallenge in 6 cases. Generally, renal and hepatic adverse effects resolved quickly after cessation of H2 antagonist therapy and did not require specific treatment. Nephrotoxicity and hepatotoxicity following administration of an H2 antagonist is rare and a high index of suspicion is necessary for early detection. Now that many H2 antagonists are available over the counter, awareness of these conditions and early detection with cessation of H2 antagonist therapy would appear paramount.

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.

Toxic myopathies

Toxic myopathies may occur with a variety of prescribed medications, illicit drug abuse, or other toxins. The article discusses an overview of some of the compounds that may cause myopathy, the clinical and laboratory features, histology, mechanisms of action, and potential risk factors of myopathy. The ability to recognize these syndromes is essential to avoid unnecessary tests and to avoid delay in treatment, especially in critically ill patients or patients with other neuromuscular diseases.

Acute tubulointerstitial nephritis: phenotype of infiltrating cells and prognostic impact of tubulitis

The prognostic impact of tubulitis and the phenotype of the infiltrating cells in the tubules were studied in ten percutaneous renal biopsies from six patients with acute tubulointerstitial nephritis (ATIN). The inflammatory cell subsets in the tubules and interstitium (CD3+, CD4+, CD8+, CD20+, CD45RO+, CD56+, CD57+, CD68+ and TIA-1+ cells), the expression of vimentin and the proliferation-associated antigen Ki-67 by cortical tubular cells, and the grade of tubulitis, interstitial infiltration and fibrosis were analysed. Cytotoxic injury to tubular cells in the vicinity of tubular-wall-localized lymphocytes was studied ultrastructurally. ATIN was drug-induced in three patients, related to Legionella infection in two and idiopathic in one patient. Four patients recovered, one with reduced renal function. Two patients developed end-stage renal disease. CD8+ and CD4+ lymphocytes, and a smaller number of macrophages, infiltrated the tubules. The predominant lymphocyte subset in the tubules was the same as in the interstitium. Cytotoxic injury to tubular cells was not seen electron microscopically. The tubular cells exhibited increased proliferative activity and expressed vimentin, indicating non-specific tubular damage. The cell subset, the severity of tubulitis, and the tubular expression of vimentin were not related to outcome. The main prognostic factor was the severity of the interstitial fibrosis. Tubulitis in ATIN may be a harmless non-immune reaction, mediated by tubular expression of cytokines, together with adhesion and other molecules.

Granulomatous interstitial nephritis

Granulomatous interstitial nephritis is a rare condition whose pathogenesis is poorly understood. Of 203 renal biopsies performed between 1974 to 1994 in which interstitial nephritis was the predominant change, granulomata occurred in 12. The authors reviewed the records of these patients and performed immunopathologic and immunohistochemical studies in their biopsies to characterize the phenotype of infiltrating cells. The authors used markers for T cells, B cells, and macrophages, and determined whether they were activated through assessment of upregulation of HLA-DR molecules. Additionally, the authors attempted to delineate whether or not tubules contributed to giant cell formation through assessment of intermediate filament for keratins and macrophage markers in epithelioid cells. Drug (aspirin, gentamycin, or combination of drugs), infection (Echerichia coli or various organisms), and sarcoidosis accounted for granulomatous inflammation in three patients each, Wegener's granulomatosis and oxalosis resulting from intestinal bypass in one patient each, and in one patient the possible cause could not be determined. Except for biopsies of granulomatous inflammation resulting from infection, in which neutrophils predominated, in all other biopsies, T cells and macrophages made up most of the inflammatory cell infiltrate. HLA-DR was upregulated in mononuclear cells infiltrating the interstitium and was expressed in proximal tubular cells and endothelial cells in all but biopsies of patients with sarcoidosis. In no instance was there evidence that tubules contributed epithelial cells to giant cell formation. These findings are consistent with the notion that granulomatous interstitial nephritis is a cell-mediated form of tissue injury in which T cell-macrophage seem to play a major role.

Myositis associated with interleukin-2 therapy in a patient with metastatic renal cell carcinoma

BACKGROUND

Interleukin-2 (IL-2) has been used successfully in the treatment of some patients with metastatic renal cell carcinoma and melanoma, with a partial response rate of 15%-20%. It produces a well documented spectrum of side effects. Autoimmune diseases have been associated with IL-2 immunotherapy and the development of autoimmune thyroiditis may correlate with antitumor clinical response.

METHODS

A patient with metastatic renal cell carcinoma is described who developed a polymyositis-like myopathy after an autologous tumor vaccine and IL-2 therapy.

RESULTS

The patient had a delayed response for 15 months after developing this previously unreported toxicity.

CONCLUSIONS

To the authors' knowledge, this represents the first reported case of necrotizing myositis in association with IL-2 therapy. Subsequent continuous partial response of the advanced malignancy was observed for 15 months. In this case, IL-2 may have broken tolerance to both normal muscle cells and tumor cells.

Safety of acid-suppressing drugs

There is an extensive literature on the adverse effects of drugs that inhibit gastric acid secretion. This study presents a critical examination of interactions between antisecretory drugs and other compounds, the frequency of serious adverse effects relating to various body systems, the safety of antisecretory drugs in pregnancy, and longer-term safety data from postmarketing surveillance studies. While interactions with some other drugs, alcohol, and certain carcinogens are of potential concern, in practice clinically significant reactions appear to be rare if they occur at all. A small number of major side-effects have been documented, but they occur rarely, and postmarketing surveillance has not detected other longer-term sequelae. Safety of these drugs in pregnancy is not established, as data are so few. It is concluded that antisecretory agents, by comparison with most other classes of drugs, are remarkably well tolerated.

In vivo effect of omeprazole on HLA-DR expression and the monocyte-macrophage function in patients with duodenal ulcer disease

It is not known if omeprazole possesses any action on immune system. Therefore, we examined the effect of omeprazole on parameters of cellular immunity [T-cell subsets-CD3+, CD4+, CD(8+)- and HLA-DR expression on peripheral blood lymphocytes (PBLs)] and on function of peripheral blood monocyte-macrophages (PBMMs) [random migration (RM), directed migration (DM), phagocytosis index (P-I) and HLA-DR expression] in 13 duodenal ulcer patients before and during 3-mo omeprazole treatment. The number of T-cell subsets varied at pretreatment values (p > 0.05), whereas the percentage of HLA-DR positive PBLs increased significantly after 3-mo therapy (p < 0.001). On the other hand, all studied parameters concerning PBMMs (RM, DM, P-I and HLA-DR expression) increased significantly after 3-mo therapy (p < 0.001, p < 0.001, p < 0.003, p < 0.001, respectively vs. baseline values). In conclusion, omeprazole exerts an immunopotentiating effect on functions of PBMMs and may also influence T-cell function. These effects can be considered as an advantage of omeprazole in long-term treated patients with peptic ulcer disease.

Severe low back pain secondary to acute interstitial nephritis following administration of ranitidine

Acute interstitial nephritis is a disease characterized by renal inflammation and is thought to be secondary to a hypersensitivity reaction. Although the causes of acute interstitial nephritis are numerous, adverse reactions to many common drugs, particularly antibiotics and nonsteroidal anti-inflammatory agents, are important etiological factors. Acute interstitial nephritis has many clinical manifestations, most notably fever and rash. Flank pain is an uncommon presentation. A case of acute, severe, low-back pain and rash in a healthy woman found to be secondary to acute interstitial nephritis is reported. The etiology of acute interstitial nephritis in this patient's case is suspected to be ranitidine (Zantac; Glaxo Pharmaceuticals, Research Triangle Park, NC), which has not been previously associated with this syndrome.

Nuclear and mitochondrial changes of muscle fibers in AIDS after treatment with high doses of zidovudine

Zidovudine (formerly azidothymidine) is a potent inhibitor of the human immunodeficiency virus (HIV) reverse transcriptase and represents the first approved drug showing clinical efficacy in HIV-associated diseases. However, considerable toxicity causing macrocytic anemia, neutropenia, and myopathy has been reported, with severe mitochondrial alterations as a special feature of this myopathy. The mitochondrial changes are consistent with the fact that zidovudine acts as an inhibitor of the mitochondrial gamma-polymerase. Electron microscopically, we could confirm the presence of severely altered mitochondria in a 32-year-old male, who developed a necrotizing myopathy after daily administration of 1,000 mg zidovudine over a period of 15 months. In addition, there were even more severe nuclear changes that, for the most part, have not been documented electron microscopically in HIV-related myopathy either with or without zidovudine treatment, especially in non-necrotic and non-regenerating fibers. Since various in vitro studies have shown interference of zidovudine with nuclear DNA metabolism even in human cell lines, we assume that the nuclear changes that we observed are at least in part related to zidovudine treatment.

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.

The effect of cimetidine on lymphocyte subpopulations in vivo in experimental mice

The effects of cimetidine, an H2 receptor antagonist, on subpopulation of splenic lymphocytes were studied in mice. Cimetidine (50 mg/kg) was given to groups of mice by intraperitoneal injection. The splenic mononuclear cells from treated and control animals were evaluated for relative number of lymphocyte subpopulations (i.e. LYT1, LYT2, L3T4 and GAM cells) by flow cytometry. The percentages of LYT2 cells (suppressor equivalent) were significantly lower (5.5 vs 12.0%) in mice who were treated with cimetidine vs control animals. The percentages of L3T4 (helper equivalent) were not statistically different in any of the experimental groups.

Drug-induced myopathies

Myopathies are not an unusual complication of drug therapy. The major symptoms in drug-induced myopathies are proximal muscle weakness, increased muscle enzyme levels, electromyographic changes and histological lesions. Some drug-induced myopathies are associated with neuropathy. Drug-induced myopathies can be classified according to the presence or absence of muscular pain and associated neuropathy. Among painless myopathies, we can distinguish myopathies without neuropathy (corticosteroids), myopathies with neuropathy (colchicine, chloroquine and hydroxychloroquine) and myasthenic syndromes (D-penicillamine, antibiotics, beta-blockers). Among painful myopathies, the classification is similar: painful myopathies may or may not be associated with neuropathies. Painful myopathies include polymyositis (D-penicillamine, cimetidine, zidovudine) and other myopathies without polymyositis (clofibrate, statines, cyclosporin). Among the painful neuromyopathies, eosinophilia-myalgia syndrome is a recently described disorder associated with the use of L-tryptophan. Combinations of drugs (for example, a fibrate and a statine or cyclosporin and colchicine) can induce severe myopathies. If such drugs are used together a vigorous surveillance to detect any sign of myopathy is warranted. Instead of classifying drug-induced myopathies according to clinical features, a histological classification can be proposed. Many drugs can induce vacuolar myopathy (colchicine, chloroquine, amiodarone, cyclosporin, drugs causing hypokalaemia and lipid-lowering agents), some others cause a mitochondrial myopathy (zidovudine) or a necrotizing myopathy as seen with vincristine. Overall, several criteria for reporting drug-induced myopathy can be recommended: lack of pre-existent muscular symptoms, a free period between the beginning of the treatment and the appearance of symptoms, lack of another cause accounting for the myopathy, and complete or incomplete resolution after withdrawal of the treatment. Rechallenge of the treatment is not advisable because of the risk of a serious relapse. The exact mechanisms by which drugs cause myopathies are unknown. Some cases may be due to metabolic changes, whereas others may be immune mediated. Nevertheless, the aspect these conditions have in common is the regression of the myopathy with the discontinuation of the drug.

Polymyositis: a case history approach to the differential diagnosis and treatment

A wide range of conditions can mimic polymyositis. Thus, diagnosing this condition can be a challenge. Although no single criterion is diagnostic of polymyositis, the following criteria have been proposed and widely used: (1) symmetric proximal muscle weakness; (2) characteristic violaceous rash on the hands, elbows, and knees; (3) increased muscle enzymes in the serum; (4) characteristic electromyographic findings (insertional activity, fibrillation potentials, motor unit potentials of increased frequency and decreased duration, and normal conduction velocity in nerves); and (5) muscle biopsy specimen with characteristic inflammatory and myopathic changes. Although polymyositis primarily involves muscle, up to 20% of patients may have extramuscular problems. The main treatment for polymyositis is high-dose corticosteroids. In corticosteroid-resistant patients, methotrexate is often effective. In this report, case histories are presented to highlight the usefulness and the limitations of the common diagnostic criteria for polymyositis.

Interleukin-1 alpha, interleukin-2, and soluble interleukin-2 receptors in polymyositis

Cell-mediated immunity has been implicated in the pathogenesis of polymyositis (PM). We conducted a prospective study in which serum levels of soluble interleukin-2 receptors (IL-2R), IL-1 alpha, and IL-2 were correlated with creatine kinase (CK) levels and clinical disease activity. Cytokines and IL-2R were quantitated in 133 serum samples from 14 patients by use of an enzyme-linked immunosorbent assay. In patients with acute PM (9 patients), soluble IL-2R and IL-1 alpha levels were elevated initially, but declined rapidly with therapy. A significant linear relationship was found between soluble IL-2R levels and CK levels. IL-2 was initially detectable in only 3 patients, and it disappeared with therapy in all 3. The levels of cytokines and IL-2R were consistently normal in patients with inactive PM (2 patients). In patients with chronic PM (3 patients), the cytokines and soluble IL-2R levels were normal despite persistently abnormal CK levels and/or muscle weakness. Cellular IL-2R levels correlated positively with serum levels of soluble IL-2R. Our studies substantiate a pathogenic role for cellular immunity in PM, with the finding of activation of lymphocytes. The finding of increased levels of IL-1 alpha demonstrates for the first time that there is monocyte activation in PM. Persistent elevation of CK levels after normalization of the levels of cytokines and IL-2R may be prognostic of impending chronic disease. Serum soluble IL-2R appear to be a sensitive indicator of improvement or exacerbation of disease activity in patients with PM.

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.

Cimetidine: an immunomodulator

Suppressor T lymphocytes possess histamine2 (H2) receptors and contribute significantly to the function of the immune system. Experimentally, cimetidine, an H2-receptor antagonist, has been shown to enhance a variety of immunologic functions both in vivo and in vitro because of its inhibitory effects on suppressor-cell function. Successful tumor immunotherapy, as well as some protection from infection, has been reported in experimental animals. Patients receiving cimetidine have been shown to exhibit enhanced cell-mediated immunity as evaluated by increased response to skin-test antigens, restoration of sensitivity following development of acquired tolerance, and increased responses of lymphocytes to mitogen stimulation. Preliminary reports also indicate that cimetidine may offer therapeutic benefits for patients with Varicella zoster and Herpes simplex infections, as well as those suffering from mucocutaneous candidiasis and common variable hypogammaglobulinemia. These immunoregulatory effects are dose-related but are not always consistent. Because of its inhibitory effect on suppressor function, cimetidine treatment may be deleterious in patients with organ transplant and autoimmune disorders. Cimetidine should be used as an immunomodulator on an experimental basis only.

Drug-induced rheumatic syndromes. Diagnosis, clinical features and management

In order to avoid inappropriate therapy and prolonged morbidity, it is important to recognise when a patient's rheumatic complaints are due to drugs. However, this is often difficult because of the large number of drugs that have been implicated and the diversity of clinical presentations. Arthropathy may be seen with several different syndromes, including drug-induced lupus erythematosus (DILE), serum sickness and gout. The most widely reported of these is DILE, which usually develops after some months or even years of drug therapy. While many authors do not specifically require their presence for the diagnosis of DILE, antinuclear antibodies have been detected in the great majority of reported patients with DILE, whatever the causative drug. In contrast, patients who develop arthropathy soon after commencing a drug rarely have antinuclear antibodies and appear to be distinct from patients with DILE. Apart from arthropathy, a number of other syndromes that appear to have an immunological basis may be induced by drugs. Cutaneous vasculitis is not uncommon and drugs are frequently considered to be the aetiological factor. Whether drugs may cause larger vessel systemic vasculitis is less certain. Rarely, polymyositis and scleroderma-like syndromes have been associated with drug therapy. Corticosteroid-induced osteoporosis is a complication of all the corticosteroid preparations that are widely used at present. However, the development of deflazacort, a so-called 'bone-sparing' steroid, has raised the possibility that the effect of corticosteroids on bone may be separable, at least in part, from the other actions of these drugs. Data have been conflicting with regard to whether there is a 'safe' dose of corticosteroid. Similarly, it is unclear whether prophylactic therapy with agents such as calcium, fluoride and vitamin D is beneficial. Nonetheless, recent findings suggest that approaches will be developed to minimise the risk of osteoporosis in patients who require corticosteroids. There are a number of other ways in which drugs may affect bones. Osteomalacia is a well-known but uncommon complication of treatment with anticonvulsants and occasionally other drugs. The mechanism probably relates to the induction of hepatic enzymes and the consequent increased metabolism of vitamin D in patients with borderline levels initially. Osteosclerosis may also result from drug therapy; usually with fluoride or retinol (vitamin A) and its analogues. With continued research, the true spectrum of drug-induced rheumatic syndromes should become more clearly defined.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute interstitial nephritis: immunologic and clinical aspects

Acute interstitial nephritis is a common renal syndrome that may be associated with a variety of infections and drug therapies or may develop without an identified cause. Three cases are presented to illustrate the three types of acute interstitial nephritis--drug related, infection related, and idiopathic. Cell-mediated immune mechanisms seem to be more important than humorally mediated mechanisms in the pathogenesis of acute interstitial nephritis. Frequently, eosinophils are identified as a component of the interstitial cellular infiltrate, and eosinophiluria and eosinophilia have been claimed to be helpful in the diagnosis of acute interstitial nephritis, especially the drug-induced type. Neither eosinophiluria nor the presence of increased urinary levels of eosinophil major basic protein, however, is specific for the diagnosis of acute interstitial nephritis. Patients with drug-induced interstitial nephritis frequently have symptoms and signs suggestive of a hypersensitivity syndrome and rarely have more dramatic anaphylactic manifestations. Systemic glucocorticoids have been shown to be beneficial in this type of acute interstitial nephritis.

"Immunoregulatory effects of cimetidine: inhibition of suppressor cell effector function in vivo"

The effects of cimetidine upon suppressor cell effector function in a well-studied murine model of contact hypersensitivity were examined. Intravenous inoculation of BALB/c mice with DNP-coupled syngeneic spleen cells induced the production of DNP-specific suppressor cells which was demonstrated by a reduction in ear swelling after contact sensitization with 1-fluoro-2, 4-dinitrobenzene (DNFB) following transfer of spleen and lymph node cells to naive syngeneic recipients. Cimetidine treatment of mice who had also received suppressor cells eliminated the manifestation of suppressor cell activity as measured by the development of normal immunologic response following contact sensitization with DNFB. While all the groups receiving cimetidine showed restoration of delayed hypersensitivity, the maximum effect was seen when 50 mg/kg of cimetidine was administered on Day 5 (day of challenge). These results indicate that, in addition to its previously described inhibitory role in suppressor cell induction, cimetidine is also capable of inhibiting suppressor cell effector function. The involvement of histamine in both these processes in vivo is also suggested.

Lymphocyte subpopulations and lymphokine production in children with constitutional aplastic anemia

The expression of lymphocyte surface markers as well as the production of interleukin-2 (IL-2) and interferon-gamma (IFN) by mitogen-stimulated peripheral blood mononuclear cells (MNC) have been studied in five children with constitutional aplastic anemia. A significantly reduced T4/T8 ratio was found and two of five patients also had a reduced percentage of B cells. One patient had a high percentage of HLA-DR positive T8+ cells, very suggestive of a high degree of circulating activated T suppressor/cytotoxic cells. IL-2 production was reduced in two patients, whereas IFN production was only reduced in one of these. The abnormalities found correlate with the duration of the bone marrow failure. The patients with the longest duration of bone marrow failure also exhibited the lowest T4/T8 ratio. No spontaneous IFN production was detected in any of the patients. There was no clinical benefit or reversal of the immune abnormalities during and following treatment with cimetidine and cyclosporine A in two patients.

Dermatomyositis

Dermatomyositis and polymyositis are related disorders of unknown cause in which immunologic changes may be important. They sometimes overlap with other collagen vascular diseases, and not infrequently are associated with malignancy. The clinical features of the adult and juvenile forms of the disorder and the visceral manifestations of DM-PM are outlined, along with enzymatic, electromyographic, and histologic aids to diagnosis. While the cutaneous lesions often are resistant to treatment, systemic involvement may respond to corticosteroids or to immunosuppressive drugs. Treatment definitely alters the prognosis in cases not associated with malignancy.

Characterization of mononuclear cell subsets in renal cellular interstitial infiltrates

Indirect immunoperoxidase analysis using monoclonal antibodies (Mo Ab) was performed in 33 renal biopsies with interstitial cellular infiltration obtained from non-transplanted patients. We reviewed four acute interstitial nephritis (IN), three chronic IN, four granulomatous IN, four acute tubular necrosis, four vasculitis, seven primary glomerulonephritis and seven active lupus nephritis (LN). We used Mo Ab recognizing T and B cell markers [OKT3, OKT8, T4, B1, IOT14 (IL2 receptor)], HLA-DR related antigen (I2) and monocytes/macrophages (LeuM3). In all cases the interstitial cellular infiltrates were predominantly T cells, whereas the B cell population accounted for less than 20% of the infiltrate. LeuM3+ cells were present in 28 of 32 cases, usually in a lesser proportion than T cells. IOT14+ cells were exceptional. T4+/T8+ cells were clearly greater than one in three acute IN, three granulomatous IN, two LN and two vasculitis. The T8+ cell population predominated in one case of chronic IN related to a non-steroidal anti-inflammatory drug. In all the remaining cases T4+ and T8+ cells were equally present. Aberrant strong HLA-DR expression within tubular cells was noted in nine cases (4 LN) irrespective of the presence of tubular lesions. On the basis of the phenotypic analysis, our data do not support a specific pattern of the infiltrate in regard to a given etiology and thus cannot be used as a diagnostic tool. However, such analysis may aid in understanding the mechanisms of tissue injury.

Adverse reactions and interactions with H2-receptor antagonists

Histamine H2-receptor antagonists have been used in the treatment of gastrointestinal diseases for more than a decade and during this period have become one of the most commonly prescribed groups of drugs in the world. The deserved popularity of the H2-receptor antagonists reflects, in part, their therapeutic efficacy, which has revolutionised the treatment of peptic ulcer disease. An equally, or more, important reason for the widespread use of H2-receptor antagonists is their remarkably low toxicity. We have attempted, in this review, to present a detailed account of the minor and more serious adverse reactions, while emphasising the low incidence of the former and the rarity of the latter. The toxicology of the H2-receptor antagonists is discussed under two main headings: adverse effects; and drug interactions. The latter category is potentially the more significant, since the frequent use of therapy with multiple drugs may give rise to drug interactions, some of which are serious and may even be lethal. These drug interactions occur especially in the gastrointestinal tract, the liver and the kidneys. Thus, the absorption of other drugs may be altered because the H2-receptor antagonists inhibit gastric secretion--an effect illustrated by ketoconazole, the absorption of which is reduced when given in combination with cimetidine. Very important drug interactions are caused by inhibition of the hepatic microsomal enzyme cytochrome P450 by some of the H2-receptor antagonists. This effect appears to be related to the chemical structure of the individual H2-receptor antagonists and is not attributable to histamine H2-receptor blockade. For example, cimetidine is a powerful inhibitor of cytochrome P450, while the interaction of ranitidine with this system is weaker. Consequently, cimetidine reduces the metabolism of many drugs which are normally degraded by phase I reactions, leading to potentially toxic plasma concentrations of therapeutic agents such as some oral anticoagulants, beta-blockers, anticonvulsants, benzodiazepines and xanthines. Some of the H2-receptor antagonists are actively secreted by the renal tubules and may thus compete with other drugs for cationic tubular transport mechanisms, resulting in reduced urinary excretion and hence potentially toxic plasma concentrations. This type of drug interaction has been reported after administration of both cimetidine and ranitidine with procainamide or quinidine.(ABSTRACT TRUNCATED AT 400 WORDS)

Identification of the inflammatory cells in the central nervous system of patients with adrenoleukodystrophy

Adrenoleukodystrophy is a disorder of long-chain fatty acid metabolism associated with adrenal cortical insufficiency and central nervous system demyelination. The central nervous system disease is unusual in that it is abrupt in onset and accompanied by a considerable infiltration of mononuclear inflammatory cells. To determine the nature of these inflammatory cells, immunocytochemical staining was carried out on the mononuclear cells in the brain and cerebrospinal fluid of patients with adrenoleukodystrophy. Monoclonal antibodies to T lymphocytes (T11), the helper/inducer (T4) and cytotoxic/suppressor (T8) subsets of T lymphocytes, B lymphocytes (B1), and monocyte/macrophages (M1 or esterase) were used. Mononuclear cells in the perivascular cuffs of autopsy material from 4 patients were, on average, 59% T cells, 34% T4 cells, 16% T8 cells, 24% B cells, and 11% monocyte/macrophages. Cerebrospinal fluid from 8 of 10 patients had increased IgG concentrations. Mononuclear cells in the cerebrospinal fluid of 6 patients with active disease were, on average, 61% T cells, 40% T4 cells, 16% T8 cells, 3% B cells, and 18% monocyte/macrophages. This distribution of cells is similar to that found in the central nervous system during a cellular immune response and suggests the possibility that one component of this disease is immunologically mediated.

T-lymphocyte subsets in idiopathic dilated cardiomyopathy

Idiopathic dilated cardiomyopathy (IDC) is a common clinical problem in Africa. To determine if there is a defect of immune regulation in patients with IDC, the percentage of total T-cells (OKT3 positive), helper/inducer cells (OKT4 positive) and suppressor/cytotoxic cells (OKT8 positive) were measured using monoclonal antibodies in 20 patients with IDC and in 20 age-matched normal control subjects. The percentage of helper/inducer cells was significantly higher in the IDC patients (45 +/- 2% mean +/- standard error) than in the normal subjects (33 +/- 2%) and 8 of the 20 IDC patients had a helper/suppressor cell ratio (OKT4/OKT8) higher than the normal range. Of the 8 patients with this abnormality, 7 were studied within 3 months of the onset of their illness. Results suggest that an excessive immune reaction is part of the pathogenesis of IDC in Africans.

Inflammatory myopathies: Part 1

The inflammatory myopathies have diverse clinical and pathological features and multiple etiologies. Some are confined to a single muscle or group of muscles (e.g., orbital myositis and localized nodular myositis) while others are diffuse. Infective forms may be due to viral, bacterial, fungal, protozoal, or parasitic organisms. Viruses may cause acute self-limited forms of myositis and have been isolated from muscle in some cases of acute rhabdomyolysis and inclusion body myositis. They have also been implicated in some cases of congenital myopathy and in polymyositis and dermatomyositis, but there is no evidence of viral invasion of muscle in these conditions. In polymyositis and dermatomyositis there are derangements in humoral and cellular immune function, and recent evidence suggests an underlying disturbance of immunoregulation. The roles of genetic factors, drugs, and Toxoplasma infection have been under scrutiny. There is increasing recognition of immunological and pathological differences in polymyositis and juvenile and adult dermatomyositis, and in cases with associated connective tissue diseases, suggesting different underlying pathogenetic mechanisms. Inclusion body myositis, eosinophilic myositis, and granulomatous myositis can be separated from the other idiopathic inflammatory myopathies because of distinctive clinical and pathological features and this may also reflect different mechanisms of muscle injury. Recent developments in the treatment of the idiopathic inflammatory myopathies include the use of plasmapheresis and total-body irradiation in cases that are resistant to corticosteroids and immunosuppressive drugs.

Changes in the interleukin-1 and interleukin-2 generation in duodenal ulcer patients during cimetidine treatment

The effect of cimetidine treatment on the generation of interleukin-1 (IL-1) and interleukin-2 (IL-2) was studied in 11 duodenal ulcer patients. The results obtained were compared with those for untreated healthy subjects. The drug was administered intravenously in a dose of 200 mg four times a day for 8 days. The investigations were performed before, during and 1 wk after cimetidine therapy. IL-1 generation was determined by the ability of supernatants from 2-day cultured adherent cells stimulated by lipopolysaccharide to enhance proliferation of PHA-stimulated mice thymocytes. IL-2 generation was determined by the ability of supernatants from 2-day cultured, PHA-stimulated mononuclear cells to proliferate autologous 17-day cultured T cells. In all ulcer patients IL-1 generation diminished during cimetidine treatment (P less than 0.005). It continued to decrease in 4 subjects and increased in the other 7 ones following drug withdrawal. All the values were higher than those in healthy controls. IL-2 activity in ulcer patients was similar to that in healthy subjects and it increased significantly in all ulcer patients following the onset of the treatment (P less than 0.005) and decreased nearly to the initial values 1 wk after termination of the treatment (P less than 0.005). The present studies indicate that cimetidine, a selective histamine H2-receptor antagonist, deeply changes mechanisms of immunoregulation in patients with duodenal peptic ulcer.

Monoclonal antibody analysis of mononuclear cells in myopathies. I: Quantitation of subsets according to diagnosis and sites of accumulation and demonstration and counts of muscle fibers invaded by T cells

In 76 muscle specimens (normal controls, 9; Duchenne dystrophy, 11; scleroderma, 11; dermatomyositis, 13; polymyositis, 15; inclusion body myositis, 17), mononuclear cells were analyzed at perivascular, perimysial, and endomysial sites of accumulation. Monoclonal antibodies reactive for B cells, T cells, T cell subsets, killer (K) or natural killer (NK) cells, and the Ia antigen were used for cell typing. Macrophages were identified by the acid phosphatase reaction. Few extravascular mononuclear cells occurred in normal muscle. In all inflammatory myopathies, a mixed exudate of T cells, B cells, and macrophages was present. Mature K/NK cells were rare in all diseases. In dermatomyositis, polymyositis, and inclusion body myositis, there was a positive gradient for T cells, T8+ cells, and activated T cells and a negative gradient for B cells and T4+ cells between perivascular and endomysial sites. In scleroderma the predominant perimysial exudate consisted mostly of T cells and macrophages. The percentage of B cells at all sites, and the T4+/T cell ratio in the endomysium, were significantly higher in dermatomyositis than in the other diseases. In polymyositis and inclusion body myositis, the endomysial exudate contained a large number of T cells, T8+ cells, and activated T cells but only sparse B cells. T cells accompanied by macrophages focally surrounded and invaded nonnecrotic fibers in polymyositis and inclusion body myositis. Rare fibers in Duchenne dystrophy and a very few fibers in dermatomyositis and scleroderma were similarly affected. We infer that (1) T-B, T-T, and T-macrophage cooperativities are likely to exist in muscle in different myopathies; (2) T cell-mediated fiber injury plays a role in polymyositis and inclusion body myositis; (3) T cell-mediated fiber injury can also occur in inherited diseases, such as Duchenne dystrophy; and (4) a local humoral response may occur in muscle in dermatomyositis and possibly in polymyositis and inclusion body myositis.

Idiopathic acute interstitial nephritis: characterization of the infiltrating cells in the renal interstitium as T helper lymphocytes

A previously healthy 39-year-old man presented with acute renal failure. There was no history of exposure to drugs nor was there any infection. Renal biopsy revealed interstitial nephritis with extensive acute degenerative changes in the tubules and extensive interstitial infiltration with mononuclear cells and no eosinophils. Monoclonal antibody staining studies identified the cells in the renal interstitium to be a helper/inducer subset of T lymphocytes. We suggest that a delayed hypersensitivity mechanism played a pathogenetic role in this patient's idiopathic acute interstitial nephritis.

Captopril and immune regulation

We examined the in vitro effect of captopril (2.5 to 5 micrograms/ml) on the primary antibody response of human B cells. Captopril suppresses (by 50%) the specific anti-trinitrophenyl (TNP) response of unfractionated peripheral blood mononuclear cells (PBM) but not that of nonadherent PBM. The susceptibility to captopril suppression can be restored in the latter cell cultures by 10% adherent radioresistant cells. This suppression is independent of prostaglandins. In transfer experiments, cells preincubated with 5 micrograms/ml captopril suppress the antibody response of autologous nonadherent PBM. The inductive phase of this suppression requires both adherent cells and radiosensitive T cells. Once induced, the suppression can be transferred by isolated T effector cells. In vivo after a unique oral intake of captopril a moderate suppressor activity can be demonstrated in adherent cells from normal individuals. We conclude that captopril interferes with the immune regulation by inducing a suppressor circuit involving monocytes and a T8 suppressor effector lymphocyte.

Mononuclear cell subsets in human renal disease. Enumeration in tissue sections with monoclonal antibodies

Mononuclear inflammatory cells (MIC) in renal biopsies from 37 patients with renal disease were studied by avidin--biotin--immunoperoxidase complex (ABC) technique, utilizing monoclonal antibodies to cell surface antigens: T11 (total T), T4 (inducer/helper), T8 (suppressor/cytotoxic), B1 (B cells), M1 (monocytes), and Leu-7 (natural killer, NK cells). Renal MIC consisted mostly of T cells and monocytes. T cells were a predominating cell type in the renal interstitium of all patients studied (64-88% of MIC). The T4:T8 ratios ranged from 0.4 +/- 0.3 (mean +/- SEM) in interstitial nephritis to 2.5 +/- 0.9 in membranous glomerulonephritis. M1+ cells constituted from 10 to 62% of glomerular MIC and from 5 to 24% of interstitial MIC. Glomerular MIC were rare or absent in patients with IgA nephropathy (IgA N). These results support the concept that in situ interactions of T lymphocytes and monocytes may modulate the events leading to the development of human renal disease. The striking absence of glomerular MIC in IgA N could be related to persistence of immune deposits in the glomeruli of patients with this renal disorder.