Effects of anti-inflammatory drugs on lymphocytes

Raman and IR spectroscopic studies of fenamates--conformational differences in polymorphs of flufenamic acid, mefenamic acid and tolfenamic acid

Solid-state Raman and IR spectra of two polymorphic forms of each of three fenamates (flufenamic acid, mefenamic acid and tolfenamic acid) display subtle but highly reproducible differences. Many of these spectral differences can be ascribed to different conformations of these molecules, involving two of four possible orientations of one substituted benzene ring with respect to the other. Interpretation of the vibrational spectra in terms of conformational differences has been facilitated by DFT calculations at the B3LYP/cc-pVDZ level for each conformer. The calculated spectra are compared with the experimental spectra in order to identify the conformers present in two polymorphic forms in each case, and detailed band assignments are obtained from the DFT calculations.

Lymphatic transport of salicylates in dogs

1. Pharmacokinetic parameters were determined for acetylsalicylic acid (ASA) and salicylic acid (SA) in plasma and lymph following the intravenous or oral administration of a water-soluble preparation of lysine-acetylsalicylic acid to dogs. 2. By both routes of administration, ASA but not SA, tended to be deposited in lymph, as indicated by the ratio between the area under the concentration-time curve constructed for the parent compound and its metabolite in lymph and plasma. 3. A reduced conversion of ASA to SA by esterases in lymph, and lymphatic absorption of ASA following the oral administration might be factors responsible for the accumulation of the compound in the lymphatic system. 4. It is suggested that the lymphatic system might serve as a temporary reservoir compartment for ASA.

Correlation of disease activity and drug therapy with the autologous mixed lymphocyte reaction in rheumatoid arthritis

The response of peripheral blood lymphocytes (PBL) to autologous synovial fluid lymphocytes (SFL) from patients with rheumatoid arthritis and Reiter's syndrome was investigated in an autologous mixed lymphocyte reaction (AMLR). SFL were found to be poor responders but strong stimulators of autologous and allogeneic PBL compared with autologous PBL. The plastic-adherent (macrophage) cells from the SFL were found to be highly stimulatory to autologous PBL, particularly when the adherent cells were removed from the responding PBL. The stimulation of these PBL non-adherent cells by SFL adherent cells follows two main trends: either no stimulation, or higher stimulation than using unseparated SFL and PBL. Patients in the high stimulator group were taking non-steroidal anti-inflammatory drugs while those in the low responder group were taking, in addition, second-line drugs such as D-penicillamine or gold. Autologous serum was found to inhibit the AMLR and this is probably due to drug metabolites in patients' sera. Initial results show that the AMLR in individual patients is highly correlated, over time, with the erythrocyte sedimentation rate (ESR).

Macrophage-derived prostaglandin E modulation of the mixed-lymphocyte reaction: an anomaly of increased production and decreased T-cell susceptibility during tumor growth

One-way mixed-lymphocyte reactions (MLR) were used to assess macrophage (M phi)-derived factor-mediated modulation of normal and tumor-bearing host (TBH) T-cell immune responsiveness. Normal and TBH M psi culture supernatants contained the inhibitory substance prostaglandin E (PGE) in concentrations of 10(-8) to 10(-9) M, with TBH M phi supernatant containing approximately twice the amount of PGE as its normal counterpart. Normal and TBH MLR reactivity were both suppressed by the addition of normal host M phi supernatant. However, TBH T cells were less inhibited by TBH M phi supernatant (55%) as compared to normal host T cells (73%). Although dialyzed M phi supernatants were less inhibitory (17-19%) on normal host T-cell MLR reactivity, TBH T-cell responses were enhanced (20-46%). Indomethacin or eicosatetraynoic acid treatment of M phi reduced PGE levels in the supernatants and in general enhanced MLR reactivity. When PGE1 and PGE2 were titrated in the MLR, normal host T lymphocytes were more susceptible to inhibition than were TBH. Concentrations of PGE1 and PGE2 comparable to that found in normal host M phi supernatants caused approximately 38% inhibition whereas whole M phi supernatants decreased MLR reactivity by greater than 70%, suggesting that another factor(s) was necessary to account for the additional M phi-mediated suppression of lymphocyte function. Isoelectric focusing was used to fractionate normal host M phi supernatant. Two factors with isoelectric points in the pH ranges 7.0-8.5 and 4.5-5.0 were inhibitory in the MLR. An enhancing factor was also identified with an pI in the range of pH 6.0-7.0. These data suggest that TBH M phi-derived PGE production was increased over its normal counterpart, but that TBH T cells were less susceptible to its effect and an additional factor(s) was working in concert with PGE.

The effects of azathioprine and 6 MP on immunity

The thiopurines, azathioprine and 6 MP are potent inhibitors of both experimental and clinical immune responses. The primary pharmacological activities are mediated by competitive inhibition of enzymes concerned with de novo purine base synthesis; Immunosuppressive activities appear to result from cytotoxic activities directed against antigen-responsive lymphocytes; this inhibition is maximal when the treatment course coincides with the proliferative expansion phase of the response. By contrast, thiopurines are comparatively ineffective if used during an effector phase of an immune response. Furthermore, administration prior to antigenic challenge does not lead to immune inhibition; in fact, it may lead to augmentation of selected immune responses. Treatment with thiopurines does not result in acute lymphopenia; prolonged courses will cause a moderate decrease in circulating lymphocytes. The drug does not selectively deplete peripheral T or B cells but can acutely reduce K (killer) cells, which are effectors in ADCC responses. In addition, short-lived thymocytes and marrow lymphocytes are rapidly depleted by these anti-metabolites. Many in vitro functions of lymphocytes, from treated animals remain normal. Recent studies indicate that, in vitro, azathioprine is specifically able to bind murine T lymphocytes; this can be shown by their ability to inhibit their capacity to rosette with sheep erythrocytes. Azathioprine is also a potent inhibitor of mixed lymphocyte culture responses and can readily suppress the in vitro generation of cytotoxic T cells. These observations suggest that drugs exert preferential toxicities for murine T cells. B lymphocytes for mice appear to vary in their susceptibility for thiopurines. By contrast, the activity of human B cells can be readily suppressed with this drug whereas T helper function is comparatively resistant. In addition to immunosuppressive properties, thiopurines are capable of exerting anti-inflammatory activities, primarily by inhibiting the replication of hematopoietic precursors.

Aspirin and delayed type hypersensitivity

The effects of aspirin on delayed hypersensitivity were assessed in 40 healthy subjects who were randomly assigned to two equal groups. In a double-blind format, the individuals in one group were placed on 4 gm aspirin daily for 5 days, and individuals in the other group were given placebo. Lymphocyte proliferation was measured before and 72 hours after the initiation of drug, by using three mitogens and four antigens. The percentages of T and B lymphocytes were likewise measured before and during therapy. The subjects were skin tested with the same four antigens 72 hours after the initiation of drug, and the skin tests were read 48 hours later. No significant differences between the two groups were detected when skin tests, lymphocyte proliferation, and percentage of T lymphocytes were compared.

Effect of sodium salicylate on human and mouse granulopoiesis in vitro

Sodium salicylate inhibited generation of granulocyte and macrophage colonies when added to soft agar cultures of mouse or human bone marrow cells (CFUc) containing colony-stimulating factor (CSF). This effect was dose-dependent with over 90% inhibition at 48 mg%. The salicylate effect was not decreased with increasing concentrations of CSF, but inhibition was reversed when salicylate-treated CFUc were washed with drug-free medium before plating. CSF production was not inhibited by salicylate.

Effects of certain antirheumatic drugs on normal human peripheral blood lymphocytes. Inhibition of mitogen- and antigen-stimulated incorporation of tritiated thymidine

The effects of antirheumatic drugs on in vitro responses of normal human peripheral blood lymphocytes were examined and found to affect phytomitogen, antigen, and mixed lymphocyte responses. The drugs and concentrations (mumg/ml) at which 50% inhibition (ID50) of phytomitogen stimulation occurred were acetylsalicylic acid, 80; phenylbutazone, 150; indomethacin, 250; sodium aurothiomalate, 200; hydroxychloroquine, 75; D-penicillamine, 400; hydrocortisone, 50; naproxen, 350; and sodium meclofenamate, 175. Acetaminophen enhanced blastogenesis by 100% at 200 mug/ml, but was 50% inhibitory at 500 mug/ml. Other drugs had no effects. Numbers of viable cells in cultures with and without mitogens and drugs were generally similar at beginnings and ends of experiments. Stimulated cell cultures containing combinations of drugs exhibited greater inhibition than did cultures of individual drugs. Inhibition by drugs was greater when cells were cultured in medium alone than in medium with 20% plasma. Cells exposed overnight to phenylbutazone, indomethacin, sodium aurothiomalate, or sodium meclofenamate, then washed and stimulated, responded generally as well as did cells not exposed to drugs. Because some of these drugs exhibited effects at concentrations approaching therapeutic levels, these findings may be pertinent to clinical investigations of cellular immune responses of patients on drug therapy and to possible mechanisms of action for certain drugs.

Altered lymphocyte reactivity in rheumatoid arthritis

Blastogenic transformation of peripheral lymphocytes with phytohemagglutinin (PHA), conconavalin A (Con A), and pokeweed mitogen (PWM) was studied in 29 patients with rheumatoid arthritis (RA). The PHA response was depressed in a subgroup of RA patients with erosive disease. The Con A response was also depressed and paralleled the PHA response. The PWM response was not depressed. These results lend support to the hypothesis of a functional defect of cellular immunity in RA. It was shown that lymphocyte responsiveness to a single mitogen concentration is not an adequate assessment of the overall responsiveness of the lymphocytes tested.

Mixed leukocyte reaction in rheumatoid arthritis

The mixed leukocyte reaction (MLR) responses of 29 patients with classic rheumatoid arthritis (RA) were compared with those of 24 age- and sex-matched healthy controls. Pools of stimulating cells were selected to include the major cross-reacting HL-A specificities. In pooled human serum the MLR response of the RA lymphocytes was significantly enhanced relative to the response controls (P less than 0.05). In autologous serum there was suppression of the MLR response in patients with RA which correlated with disease activity. The data suggest the presence of an intrinsically enhanced cellular reactivity of RA lymphocytes suppressed by serologic factor(s). The mechanisms of this enhancement of suppression are discussed.

Suppression of lymphocyte transformation after aspirin ingestion

To learn whether in vitro blastogenesis of lymphocytes is affected by in vivo salicylate ingestion, blood samples were obtained from 19 normal volunteers before and after therapeutic doses of aspirin. Lymphocyte transformation studies performed on these blood samples showed marked and statistically significant suppression of blastogenesis. Maximum suppression was observed in blood samples obtained 12 hours after the last aspirin ingestion. As compared to controls, samples obtained at this time showed mean blastogenic responses to phytohemagglutinin and pokeweed mitogens of 49 and 56 per cent respectively. No correlation could be demonstrated between the plasma salicylic acid level and the degree of suppression of blastogenesis. Aspirin ingestion altered neither the proportions of circulating T and B cells nor the viability of lymphocytes in culture.

Lymphocyte transformation in malnourished children

In vitro lymphocyte stimulation with phytohaemagglutinin gave subnormal transformation values in children with protein-calorie malnutrition. It is suggested that impaired cell-mediated immunity may be one important mechanism for the susceptibility of malnourished children to infections. Lymphocyte transformation was also subnormal in children with measles and gastroenteritis but tended to be increased in pneumonia.

The effect of salicylate on the metabolism of normal and stimulated human lymphocytes in vitro

The effect of salicylate on the metabolism of peripheral blood lymphocytes in tissue culture was investigated. Lymphocytes incubated with sodium salicylate at a concentration of 30 mg/100 ml showed increased glucose consumption, lactic acid production, and oxygen consumption, evidence for uncoupling of oxidative phosphorylation. No decrease in cell number or viability (trypan blue dye exclusion) was noted in salicylate-treated cultures. Normal DNA, RNA, and total protein synthesis measured by radioisotope incorporation was depressed in the salicylate-treated cultures. Increased DNA synthesis after the addition of a mitogen (PHA) or antigen (PPD) to the culture was strikingly suppressed by salicylate. The degree of suppression was proportional to the concentration of salicylate used. The effect on RNA and protein synthesis in stimulated lymphocytes was much less pronounced. Acetylsalicylic acid was found to be as active as sodium salicylate in suppressing DNA synthesis, but the p-OH congener (p-OH benzoic acid) did not alter cell respiration, glycolysis, viability, or DNA synthesis. The salicylate effect was reversible as evidenced by return of cellular reactivity upon removal of the drug from the media.