R2R01: A long-acting single-chain peptide agonist of RXFP1 for renal and cardiovascular diseases

BACKGROUND

The therapeutic potential of relaxin for heart failure and renal disease in clinical trials is hampered by the short half-life of serelaxin. Optimization of fatty acid-acetylated single-chain peptide analogues of relaxin culminated in the design and synthesis of R2R01, a potent and selective RXFP1 agonist with subcutaneous bioavailability and extended half-life.

EXPERIMENTAL APPROACH

Cellular assays and pharmacological models of RXFP1 activation were used to validate the potency and selectivity of R2R01. Increased renal blood flow was used as a translational marker of R2R01 activity. Human mastocytes (LAD2 cells) were used to study potential pseudo-allergic reactions and CD4+ T-cells to study immunogenicity. The pharmacokinetics of R2R01 were characterized in rats and minipigs.

KEY RESULTS

In vitro, R2R01 had comparable potency and efficacy to relaxin as an agonist for human RXFP1. In vivo, subcutaneous administration of R2R01 increased heart rate and renal blood flow in normotensive and hypertensive rat and did not show evidence of tachyphylaxis. R2R01 also increased nipple length in rats, used as a chronic model of RXFP1 engagement. Pharmacokinetic studies showed that R2R01 has a significantly extended terminal half-life. The in vitro assays with LAD2 cells and CD4+ T-cells showed that R2R01 had low potential for pseudo-allergic and immunogenic reactions, respectively.

CONCLUSION AND IMPLICATIONS

R2R01 is a potent RXFP1 agonist with an extended half-life that increases renal blood flow in various settings including normotensive and hypertensive conditions. The preclinical efficacy and safety data supported clinical development of R2R01 as a potential new therapy for renal and cardiovascular diseases.

Fatty acid acylated peptide therapeutics: discovery of omega-n oxidation of the lipid chain as a novel metabolic pathway in preclinical species

We recently described C18 fatty acid acylated peptides as a new class of potent long-lasting single-chain RXFP1 agonists that displayed relaxin-like activities in vivo. Early pharmacokinetics and toxicological studies of these stearic acid acylated peptides revealed a relevant oxidative metabolism occurring in dog and minipig, and also seen at a lower extent in monkey and rat. Mass spectrometry combined to NMR spectroscopy studies revealed that the oxidation occurred, unexpectedly, on the stearic acid chain at ω-1, ω-2 and ω-3 positions. Structure-metabolism relationship studies on acylated analogues with different fatty acids lengths (C15-C20) showed that the extent of oxidation was higher with longer chains. The oxidized metabolites could be generated in vitro using liver microsomes and engineered bacterial CYPs. These systems were correlating poorly with in vivo metabolism observed across species; however, the results suggest that this biotransformation pathway might be catalyzed by some unknown CYP enzymes.

A five-year retrospective study on ascarid infections in dogs in southern Italy

INTRODUCTION

A 5-year retrospective analysis of ascarid infections (Toxocara canis and Toxascaris leonina) in dogs from southern Italy was performed to update the epidemiological scenario of these parasites and to identify the risk factors which may favour these infections in animals in this study area. A total of 8,149 dogs, referred to our labs for copromicroscopic analysis using the FLOTAC technique, was considered. A sub-sample of 500 faecal samples were analysed also with the Mini-FLOTAC technique. Of the overall dog samples analysed, 9,2 % (95 % CI = 8,6-9,8) resulted positive for T. canis while 0,5 % (95 % CI = 0,4-0,7) resulted positive for T. leonina. Co-infections with T. canis and T. leonina were found in 0,1 % of dogs (95 % CI = 0,0-0,1). The results obtained by the FLOTAC and Mini-FLOTAC examinations showed a nearly perfect k agreement (k = 0,99, P < 0,001) between these two techniques. Chi-square test showed positivity to T. canis and T. leonina significantly (P < 0,001) associated with dogs housed outdoor (i.e., that lived in garden or in kennel). Moreover, the positivity for T. canis was significantly associated (P < 0,001) also with age (i.e., puppies), as shown by the logistic regression. The decreasing overall prevalence both for T. canis and T. leonina during the years of monitoring, showed that, as suggested by the European Scientific Counsel Companion Animal Parasites, the regular diagnosis could contribute to an efficient control of these parasites.

Introduction of Non-natural Amino Acids Into T-Cell Epitopes to Mitigate Peptide-Specific T-Cell Responses

Non-natural modifications are widely introduced into peptides to improve their therapeutic efficacy, but their impact on immunogenicity remains largely unknown. As the CD4 T-cell response is a key factor in triggering immunogenicity, we investigated the effect of introducing D-amino acids (Daa), amino isobutyric acid (Aib), N-methylation, C_α-methylation, reduced amide, and peptoid bonds into an immunoprevalent T-cell epitope on binding to a set of HLA-DR molecules, recognition, and priming of human T cells. Modifications are differentially accepted at multiple positions, but are all tolerated in the flanking regions. Introduction of Aib and Daa in the binding core had the most deleterious effect on binding to HLA-DR molecules and T-cell activation. Their introduction at the positions close to the P1 anchor residue abolished T-cell priming, suggesting they might be sufficient to dampen peptide immunogenicity. Other modifications led to variable effects on binding to HLA-DR molecules and T-cell reactivity, but none exhibited an increased ability to stimulate T cells. Altogether, non-natural modifications appear generally to diminish binding to HLA-DR molecules and hence T-cell stimulation. These data might guide the design of therapeutic peptides to make them less immunogenic.

Identification of Potent and Long-Acting Single-Chain Peptide Mimetics of Human Relaxin-2 for Cardiovascular Diseases

The insulin-like peptide human relaxin-2 was identified as a hormone that, among other biological functions, mediates the hemodynamic changes occurring during pregnancy. Recombinant relaxin-2 (serelaxin) has shown beneficial effects in acute heart failure, but its full therapeutic potential has been hampered by its short half-life and the need for intravenous administration limiting its use to intensive care units. In this study, we report the development of long-acting potent single-chain relaxin peptide mimetics. Modifications in the B-chain of relaxin, such as the introduction of specific mutations and the trimming of the sequence to an optimal size, resulted in potent, structurally simplified peptide agonists of the relaxin receptor Relaxin Family Peptide Receptor 1 (RXFP1) (e.g., 54). Introduction of suitable spacers and fatty acids led to the identification of single-chain lipidated peptide agonists of RXFP1, with sub-nanomolar activity, high subcutaneous bioavailability, extended half-lives, and in vivo efficacy (e.g., 64).

Healthy Donors Exhibit a CD4 T Cell Repertoire Specific to the Immunogenic Human Hormone H2-Relaxin before Injection

H2-relaxin (RLN2) is a two-chain peptide hormone structurally related to insulin with a therapeutic potential in multiple indications. However, multiple injections of human RLN2 induced anti-RLN2 Abs in patients, hampering its clinical development. As T cell activation is required to produce Abs, we wondered whether T cells specific for RLN2 might be already present in the human blood before any injection. We therefore quantified the RLN2-specific T cell repertoire using PBMCs collected from healthy donors. CD4 T cells were stimulated in multiple replicates by weekly rounds of stimulation by dendritic cells loaded with RLN2, and their specificity was assessed by IFN-γ ELISPOT. The number of specific T cell lines was used to estimate the frequency of circulating T cells. In vitro T cell response was demonstrated in 18 of the 23 healthy donors, leading to the generation of 70 independent RLN2-specific T cell lines. The mean frequency of RLN2-specific CD4 T cells was similar to that of T cells specific for known immunogenic therapeutic proteins. Using overlapping peptides, we identified multiple T cell epitopes hosted in the N-terminal parts of the α- and β-chains and common to multiple donors, in agreement with their capacity to bind to multiple HLA-DR molecules. Our results provide important clues to the immunogenicity of RLN2 and highlight the weak central immune tolerance induced against this self-hormone.

Limited fibrosis accompanies triple-negative breast cancer metastasis in multiple model systems and is not a preventive target

The lysophosphatidic acid receptor 1 (LPAR1) is mechanistically implicated in both tumor metastasis and tissue fibrosis. Previously, metastasis was increased when fulminant fibrosis was first induced in mice, suggesting a direct connection between these processes. The current report examined the extent of metastasis-induced fibrosis in breast cancer model systems, and tested the metastasis preventive efficacy and fibrosis attenuation of antagonists for LPAR1 and Idiopathic Pulmonary Fibrosis (IPF) in breast and ovarian cancer models. Staining analysis demonstrated only focal, low-moderate levels of fibrosis in lungs from eleven metastasis model systems. Two orally available LPAR1 antagonists, SAR100842 and EPGN9878, significantly inhibited breast cancer motility to LPA in vitro. Both compounds were negative for metastasis prevention and failed to reduce fibrosis in the experimental MDA-MB-231T and spontaneous murine 4T1 in vivo breast cancer metastasis models. SAR100842 demonstrated only occasional reductions in invasive metastases in the SKOV3 and OVCAR5 ovarian cancer experimental metastasis models. Two approved drugs for IPF, nintedanib and pirfenidone, were investigated. Both were ineffective at preventing MDA-MB-231T metastasis, with no attenuation of fibrosis. In summary, metastasis-induced fibrosis is only a minor component of metastasis in untreated progressive breast cancer. LPAR1 antagonists, despite in vitro evidence of specificity and efficacy, were ineffective in vivo as oral agents, as were approved IPF drugs. The data argue against LPAR1 and fibrosis as monotherapy targets for metastasis prevention in triple-negative breast cancer and ovarian cancer.

Bradykinin-induced contractions of canine saphenous veins: mediation by B2 receptors and involvement of eicosanoids

1. Experiments were designed to determine the subtype of kinin-receptors mediating the contraction of venous smooth muscle to bradykinin and to investigate the involvement of metabolites of arachidonic acid in this response. 2. Bradykinin (10(-9) to 10(-6) M) caused concentration-dependent contractions of the canine isolated saphenous vein without endothelium, which were potentiated by indomethacin (10(-5) M, an inhibitor of cyclo-oxygenase). The concentration-response curve was biphasic, reaching an asymptote at 10(-8) M and a secondary maximal response at 10(-6) M. 3. Bradykinin (10(-8) M to 3 x 10(-6) M) caused a three fold stimulation in the release of the vasodilator prostaglandin E2 (PGE2) and a two fold stimulation of that of the vasodilator prostacyclin, measured by the production of 6-keto-PGF1 alpha (its stable breakdown product). 4. Under control conditions, nordihydroguaiaretic acid (NDGA, 10(-5) M), an inhibitor of lipoxygenase, did not affect the response to bradykinin. In the presence of indomethacin (10(-5) M), NDGA reduced contractions to bradykinin, suggesting the involvement of lipoxygenase metabolites in the potentiation evoked by the inhibitor of cyclo-oxygenase. 5. The selective B1 receptor agonist [des-Arg9]-bradykinin, in the concentration-range 10(-6) to 10(-5) M, induced contractions, which were abolished by the B2 receptor antagonist D-Arg-[Hyp3, Thi5, D-Tic7, Oic8]-bradykinin (Hoe 140; 10(-6) M). The selective B1 receptor antagonist [des-Arg9, Leu8]-bradykinin, (10(-7) to 10(-5) M) had no significant effect on bradykinin-induced contractions. 6. The B2 receptor antagonists Hoe 140 (10(-8) to 10(-6) M) and D-Arg [Hyp3, D-Phe7]-bradykinin (10(-7) to 10(-5) M) shifted the concentration-response curve to bradykinin to the right in a concentration-dependent manner. 7. These results indicate that, in the canine saphenous vein, bradykinin causes contraction by activating B2 receptors. This results in the production of metabolites of arachidonic acid, which play a key role in the contraction of canine saphenous venous smooth muscle.

Rilmenidine activates postjunctional alpha 1- and alpha 2-adrenoceptors in the canine saphenous vein

Experiments were performed to determine the subtypes of alpha-adrenoceptors involved in the contraction induced by rilmenidine in isolated canine cutaneous veins. Rings of saphenous vein (without endothelium) were suspended for the recording of isometric force in physiological salt solution. All experiments were performed in the presence of propranolol (to antagonize beta-adrenoceptors), cocaine (to inhibit neuronal uptake) and hydrocortisone (to inhibit extraneuronal uptake). In the presence of rauwolscine (an alpha 2-adrenergic blocker), rilmenidine caused concentration-dependent contractions which were inhibited by prazosin (nonselective alpha 1-antagonist) and by (+)niguldipine (selective alpha 1A-adrenergic antagonist), but not by (-)niguldipine. After treatment with phenoxybenzamine (to alkylate alpha 1-adrenoceptors), rilmenidine evoked contractions of the canine saphenous vein which were antagonized competitively by rauwolscine. The combination of rauwolscine and prazosin did not abolish contractions evoked by the highest concentrations of rilmenidine. Although binding experiments using 3H-idazoxan suggested the existence of a nonadrenergic binding site (around 20% of the total binding), contractile studies failed to demonstrate their involvement in the increases in tension evoked by rilmenidine. These experiments suggest that the contractions evoked by rilmenidine in isolated canine veins are mediated by both alpha 1A- and alpha 2-adrenoceptors.

Regulation of nitric oxide-like activity by prostanoids in smooth muscle of the canine saphenous vein

1. Organ bath experiments and measurements of prostanoids were performed to investigate the presence of nitric oxide synthase in venous smooth muscle and its interaction with cyclo-oxygenase. 2. In rings of canine saphenous vein without endothelium, the inhibitor of cyclo-oxygenase, indomethacin (10 microM), induced contraction. NG-nitro-L-arginine (100 microM) (L-NOARG), an inhibitor of nitric oxide synthase did not affect the tone of rings of canine saphenous vein when administered alone. However, in the presence of indomethacin L-NOARG (100 microM) induced further contraction. 3. Similar results were obtained in response to NG-monomethyl-L-arginine (L-NMMA)(300 microM or NG-nitro-L-arginine methylester (L-NAME)(100 microM). 4. When rings of canine saphenous vein without endothelium were contracted with phenylephrine (1 microM) instead of indomethacin, neither L-NOARG or L-NMMA induced further contraction. 5. When rings of canine saphenous vein without endothelium were contracted with noradrenaline (0.3 microM) in the presence of indomethacin (10 microM) plus L-NOARG (100 microM), a relaxation to L-arginine was observed. Transient relaxations to superoxide dismutase (150 u ml-1) were observed in all rings. 6. When rings of saphenous vein without endothelium were incubated with lipopolysaccharide (LPS) (100 micrograms ml-1) or interleukin-1 beta (10 u ml-1) the concentration-contraction curve to noradrenaline was not affected. 7. Rings without endothelium released prostaglandin E2 and prostaglandin I2, as measured by radioimmunoassay. The basal production was abolished by indomethacin and not affected by L-NOARG. 8. These results suggest that when cyclo-oxygenase is inhibited, a nitric oxide synthase activity is revealed in rings of canine saphenous vein without endothelium.

cGMP mediates the desensitization to bradykinin in isolated canine coronary arteries

The relaxation to bradykinin in canine coronary arteries is mediated by endothelium-derived nitric oxide (NO) and hyperpolarizing factor (EDHF). Desensitization to the kinin was induced by incubation of canine coronary arteries with endothelium with 10(-8) M bradykinin for 30 min. After washout, tissues were contracted with prostaglandin F2 alpha, and concentration-relaxation curves to bradykinin were obtained in control and desensitized arteries treated with indomethacin. After desensitization, there was a shift to the right of the concentration-relaxation curves to bradykinin. However, the elevation in guanosine 3',5'-cyclic monophosphate (cGMP) levels evoked by bradykinin was similar in both groups of tissues. The curves to bradykinin obtained in the presence of NG-nitro-L-arginine (an NO synthase inhibitor) were depressed, whereas those obtained in arteries contracted with potassium (to eliminate the EDHF-mediated relaxation) were not affected by the desensitization. Addition of NG-nitro-L-arginine, oxyhemoglobin, or methylene blue before the desensitization procedure preserved, whereas 3-morpholinosydnonimine (SIN-1, a donor of NO) and 8-bromoguanosine 3',5'-cyclic monophosphate impaired, the EDHF-mediated relaxation to bradykinin. Thus the selective impairment of the EDHF-dependent relaxation to bradykinin may be mediated by NO, acting mainly through increased production of cGMP.

Calmidazolium, a calmodulin inhibitor, inhibits endothelium-dependent relaxations resistant to nitro-L-arginine in the canine coronary artery

1. The role of calmodulin in endothelium-dependent relaxations in the canine coronary artery, was investigated by use of the inhibitor of calmodulin, calmidazolium. 2. The endothelium-dependent relaxations to adenosine diphosphate (ADP) and nebivolol, a beta-adrenoceptor antagonist, in control solution, and to bradykinin in high potassium solution (to inhibit endothelium-dependent hyperpolarization), were abolished by nitro-L-arginine (30 microM), an inhibitor of nitro oxide-synthase. Calmidazolium (10 microM) did not inhibit these relaxations. 3. Calmidazolium did not affect the endothelium-independent relaxations to SIN-1, an exogenous donor of nitric oxide (NO). 4. The relaxations to bradykinin and to the calcium ionophore A23187 in control solution were inhibited to a small extent by calmidazolium (10 microM). 5. Bradykinin and A23187 induced relaxations in the presence of nitro-L-arginine (30 microM) that were abolished by calmidazolium (10 microM) but not affected by glibenclamide (10 microM), an inhibitor of ATP-sensitive K+ channels. 6. The endothelium-independent relaxations to lemakalim, an ATP-sensitive K+ channel opener, were not affected by calmidazolium (10 microM) but were inhibited by glibenclamide (10 microM). 7. These results suggest that calmidazolium does not inhibit the endothelium-dependent relaxations due to endothelium-derived NO in the canine coronary artery but inhibits either the production of endothelium-derived hyperpolarizing factor (EDHF) from endothelial cells or its effects on vascular smooth muscle cells. Furthermore these results suggest that EDHF contributes to endothelium-dependent relaxations in the canine coronary artery.

Calmodulin antagonists inhibit endothelium-dependent hyperpolarization in the canine coronary artery

1. The effects of the calmodulin antagonists, calmidazolium and fendiline were investigated on endothelium-dependent hyperpolarization in the canine coronary artery. The membrane potential of vascular smooth muscle cells was measured with the microelectrode technique. 2. Smooth muscle cells of the canine coronary artery had a resting membrane potential of -50 mV. Bradykinin and the Ca(2+)-ionophore, A23187, induced concentration- and endothelium-dependent hyperpolarization. The hyperpolarization induced by a supramaximal concentration of bradykinin (10(-6) M) reached approximately 20 mV. 3. Calmidazolium (10(-5) M) and fendiline (10(-4) M) inhibited hyperpolarization induced by bradykinin and A23187. By contrast, calmidazolium did not affect the hyperpolarization induced by lemakalim, an opener of ATP-sensitive K(+)-channels. 4. These observations suggest that calmodulin is involved in the generation of endothelium-dependent membrane hyperpolarization of vascular smooth muscle.

Heterogeneous distribution of endothelium-dependent relaxations resistant to NG-nitro-L-arginine in rats

Endothelium-dependent relaxations that are resistant to inhibitors of nitric oxide synthase probably are mediated by endothelium-dependent hyperpolarization of the vascular smooth muscle. Experiments were performed to examine the distribution of this type of relaxation along the arterial tree of the rat by measuring changes in isometric force. Acetylcholine induced concentration- and endothelium-dependent relaxations in aortas and in pulmonary, common iliac, femoral, mesenteric, and renal arteries contracted with phenylephrine. In the presence of NG-nitro-L-arginine, the cumulative administration of acetylcholine induced relaxations only in the femoral, mesenteric, and renal arteries. The calcium ionophore A23187 relaxed mesenteric arteries contracted with phenylephrine in a concentration- and endothelium-dependent manner. The concentration-relaxation curve to A23187 was shifted to the right in the presence of NG-nitro-L-arginine. The maximal relaxations induced by lemakalim, a K+ channel opener, were smaller in those arteries that did not exhibit NG-nitro-L-arginine-resistant relaxations. These results suggest that NG-nitro-L-arginine-resistant relaxations are more frequently observed in smaller arteries. The arteries that exhibit NG-nitro-L-arginine-resistant relaxations may be more sensitive to an endothelium-derived substance that causes hyperpolarization of vascular smooth muscle cells.

Potentiation of endothelium-dependent relaxations to bradykinin by angiotensin I converting enzyme inhibitors in canine coronary artery involves both endothelium-derived relaxing and hyperpolarizing factors

Studies were designed to investigate the mechanisms underlying the augmentation by angiotensin I converting enzyme (ACE) inhibitors of the endothelium-dependent relaxations evoked by bradykinin. Isometric tension, tissue levels of cGMP, and transmembrane potential were measured in isolated canine coronary arteries as indications of the respective contribution of nitric oxide and endothelium-derived hyperpolarizing factor. In rings of coronary artery with endothelium, relaxations to bradykinin were potentiated by the ACE inhibitors cilazaprilat and perindoprilat. NG-Nitro-L-arginine (NLA), a nitric oxide synthase inhibitor, impaired relaxations to bradykinin. But the presence of ACE inhibitors partially restored this activity. Bradykinin stimulated the production of cGMP, and this was enhanced significantly by ACE inhibitors, indicating an augmented release of nitric oxide. NLA abolished the increase induced by bradykinin irrespective of the presence of ACE inhibitors. Electrophysiological studies revealed that bradykinin elicited an endothelium-dependent hyperpolarization of vascular smooth muscle that was insensitive to NLA and potentiated by ACE inhibitors. The bradykinin-induced hyperpolarization and NLA-resistant relaxations were transient and impaired by potassium depolarization. Thus, production of endothelium-derived hyperpolarizing factor may account for the NLA-resistant relaxations of canine coronary arteries. The relaxations induced by bradykinin were unaffected by the B1 kinin receptor antagonist des-Arg9,[Leu8]-bradykinin either in the absence or in the presence of NLA but were antagonized by the B2 kinin receptor antagonist D-Arg[Hyp3,D-Phe7]-bradykinin. Molecular exclusion chromatography of 125I-labeled [Tyr8]-bradykinin and its degradation products demonstrated that the breakdown of the kinin by isolated coronary arteries was prevented in the presence of perindoprilat.(ABSTRACT TRUNCATED AT 250 WORDS)

Decrease in enkephalinase A number in kidney membranes from hypercholesterolemic and hypertensive rats

The variation of enkephalinase A number on the hypertensive and hypercholesterolemia rats kidney membranes is studied using the [3H]-acetorphan, a potent inhibitor of enkephalinase A to label the protease in rat kidney. The binding of [3H]-acetorphan to kidney membrane determined in vitro with both equilibrium and kinetic methods is saturable and reversible involving a single class of sites with a dissociation constant of 4-5.3 nM. The [3H]-acetorphan binding capacity is identical, Bmax approximately 51 pmoles per mg of proteins, for kidney membranes from Sprague Dawley and Wistar Kyoto rats. In contrast, the enkephalinase A number is decreased in the pathological states studied: 20% for hypertensive rats and 50% for hypercholesterolemic rats. Such pharmacological results provide a great deal of information about the modification appeared in the metabolism of peptidic substrates of enkephalinase A in hypercholesterolemia and hypertension.

Indications for early surgery in cases of lumbar and dorsolumbar scoliosis: the role of vertebral rotation

There are very few objective criteria for the choice between conservative and surgical treatment of lumbar and dorsolumbar scoliosis ranging from 40 to 50 degrees. We reviewed the long-term results obtained in 76 patients treated with plaster braces because they had refused surgical treatment; in 56% of the cases a nearly 10 degree gain was maintained after the onset of treatment; all of the cases which showed improvement presented a reduction in the curve by at least half and rotation by at least one-third in tests in suspension or in bending, and this was maintained in plaster. In cases where the long-term results were poor, however, rotation did not change. In conclusion, of the many parameters examined, only a combined assessment of the reducibility of both the Cobb angle and of rotation provides a valid indication for the treatment of lumbar and dorsolumbar curves ranging from 40 to 50 degrees.

[Correlations between the prick test and aspecific bronchial reactivity in atopic patients]

Aspecific bronchial provocation test with Methacholine plays an outstanding role in the diagnostic routine of asthmatic disease, in order to accomplish a correct interpretation of the relation between A.B.I. and bronchial asthma. All researches give a special prominence to the bronchial reactivity distribution among the population, and point out that the distribution curve of response to aspecific challenge shows itself as an unimodal curve, since there is no clinic group (neither that one including subjects defined asthmatic from a clinic or anamnestic point of view) which clearly separates from the rest. A further important consideration indicates that a positive response to the test is not specific of bronchial asthmatic subjects, but it can also occur in patients affected with other pathologies such as chronic bronchitis, allergic rhinitis, and so on. Our study aimed, therefore, to evaluate the correlations occurring between skin sensitivity and aspecific bronchial reactivity in 5 groups of atopic patients (affected with: (1) asthma; (2) asthma + rhinitis; (3) asthma + rhinitis + conjunctivitis; (4) rhinitis + conjunctivitis; (5) rhinitis). In doing such correlations we also considered some other factors like sex, smoking habit, town or country provenance. Sensitiveness, specificity, and predicting value of Prick-test in comparison with Methacholine test have been analysed as well. The results so obtained show that no correlation occurs between Prick-test and Aspecific Bronchial Test in the groups of tested subjects. Test sensitiveness increases in the groups of patients affected with associated pathologies, and depends on factors like sex, smoking habit, town or country provenance.