Peptides, MAbs, Molecules, Mechanisms, and More: Taking a Stab at Cluster Headache.

BACKGROUND: Cluster headache is a highly disabling neurological disorder. PURPOSE: The purpose of this review is to highlight recent therapeutic advances in the treatment of cluster headache such as monoclonal antibodies as well as non-invasive vagus nerve stimulation, and examine future potential therapeutic targets. DISCUSSION: Several therapeutic agents currently in use may have underlying mechanisms important to cluster headache pathophysiology and have yet to be completely elucidated. The psychobiological aspects of cluster headache have a significant impact on patients, as well as pose limitations for treatment. Neuropeptides may play a role in underlying mechanisms in why cluster headache patients are frequent tobacco smokers. Alterations in the hypothalamic-pituitary-adrenal axis and neuroinflammation may play a role in suicidality. The circadian nature of cluster headache may generate the development of future treatment options. New understanding of mechanisms underlying post-traumatic headache may also provide insights into cluster headache pathophysiology. CONCLUSION: Molecular targets and neuromodulation advances have paved the way for a new generation of therapeutic agents in cluster headache. There are several other potential targets.

Headache in systemic lupus erythematosus: results from a prospective, international inception cohort study.

OBJECTIVE: To examine the frequency and characteristics of headaches and their association with global disease activity and health-related quality of life (HRQOL) in patients with systemic lupus erythematosus (SLE). METHODS: A disease inception cohort was assessed annually for headache (5 types) and 18 other neuropsychiatric (NP) events. Global disease activity scores (SLE Disease Activity Index 2000 [SLEDAI-2K]), damage scores (Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index [SDI]), and Short Form 36 (SF-36) mental and physical component summary scores were collected. Time to first headache and associations with SF-36 scores were analyzed using Cox proportional hazards and linear regression models with generalized estimating equations. RESULTS: Among the 1,732 SLE patients enrolled, 89.3% were female and 48.3% were white. The mean ± SD age was 34.6 ± 13.4 years, duration of disease was 5.6 ± 5.2 months, and length of followup was 3.8 ± 3.1 years. At enrollment, 17.8% of patients had headache (migraine [60.7%], tension [38.6%], intractable nonspecific [7.1%], cluster [2.6%], and intracranial hypertension [1.0%]). The prevalence of headache increased to 58% after 10 years. Only 1.5% of patients had lupus headache, as identified in the SLEDAI-2K. In addition, headache was associated with other NP events attributed to either SLE or non-SLE causes. There was no association of headache with SLEDAI-2K scores (without the lupus headache variable), SDI scores, use of corticosteroids, use of antimalarials, use of immunosuppressive medications, or specific autoantibodies. SF-36 mental component scores were lower in patients with headache compared with those without headache (mean ± SD 42.5 ± 12.2 versus 47.8 ± 11.3; P < 0.001), and similar differences in physical component scores were seen (38.0 ± 11.0 in those with headache versus 42.6 ± 11.4 in those without headache; P < 0.001). In 56.1% of patients, the headaches resolved over followup. CONCLUSION: Headache is frequent in SLE, but overall, it is not associated with global disease activity or specific autoantibodies. Although headaches are associated with a lower HRQOL, the majority of headaches resolve over time, independent of lupus-specific therapies.

Soluble interleukin-2 receptors increase during the active periods in cluster headache.

OBJECTIVE: To investigate whether cytokines are altered during the active period of cluster headache. BACKGROUND: Patients with cluster headache show activation of the hypothalamus in PET studies and via endocrinologic parameters. Data also suggest an inflammatory process occurs in cluster headache. A connection between the presumed inflammatory cause, an immunological activation, and the hypothalamus could be generated by certain cytokines. DESIGN AND METHODS: ELISA was used to determine the serum levels of soluble interleukin-2 receptors, interleukin-1, interleukin-6, and 2 soluble interleukin-6 receptors (sIL-6R and soluble gp130) in 18 patients with cluster headache (6 women and 12 men) during the cluster period and in 17 healthy controls who were headache-free (3 women and 14 men). RESULTS: Patients with cluster headache had significantly increased soluble interleukin-2 receptors (413.6+/-223 U/mL vs. 290.0+/-112 U/mL; P <.05) compared with controls. Serum levels of interleukin-1 (0.29+/-0.30 pg/mL vs. 0.13+/-0.13 pg/mL, n.s.), interleukin-6 (0.87+/-0.6 pg/mL vs. 0.91+/-0.7 pg/ml; n.s.), soluble interleukin-6 receptors (33,131+/-8,349 pg/mL vs. 35,063+/-7,606 pg/mL; n.s.), or soluble gp130 (289+/-59 pg/mL vs. 283+/-20 pg/mL; n.s.) did not differ between the 2 groups, although patients with cluster tended to have higher interleukin-1 values. CONCLUSIONS: Because elevated soluble interleukin-2 receptors indicate T cell activation, our findings suggest immune activation during cluster headache. Because interleukin-2 can activate the hypothalamus and stimulate the release of Corticotropin-releasing Factor (CRF), interleukin-2 could link a putative immunological cause of cluster headache with the observed hypothalamic activation. Systemic changes of interleukin-1 or the interleukin-6 system do not seem to play a role in cluster headache, as no alterations of serum levels were observed. Even so, unchanged serum levels do not exclude limited local production.

Putative neuroimmunological mechanisms in cluster headache. An integrated hypothesis.

During the last decade, numerous studies have been carried out to explore the function of the immune system in cluster headache and the release of reciprocal informational molecules from pain-sensitive structures. These neuroimmunological findings in cluster headache syndrome, although carefully considered, have varied from genetic aspects (HLA antigens) to functional activity of the immune system (NK cytotoxicity), and from study of the receptor expression of classical neurotransmitters of pain (5-HT, histamine) on immunocompetent cells, to the study of cytokines with a potent pro-inflammatory activity (interleukin-1). Other aspects considered have ranged from the study of the effectiveness of substances possessing a wellknown activity on the immune system (prednisone, lithium carbonate) in shortening cluster attacks to the 5-HT receptor expression changes observed on a peripheral substrate (monocytes) after the administration of sumatriptan. Although this was an exciting area of pioneering research, we have always interpreted our findings cautiously. In summary, we now believe that the neuroimmunological aspects of cluster headache can be proposed as an integrative model and that this immunological mechanism could improve our understanding of the pathogenic basis for this still obscure disease.

Effect of hyperbaric oxygen on the immunoreactivity to substance P in the nasal mucosa of cluster headache patients.

Exposure to hyperbaric oxygen has been shown to be effective in cluster headache, but the mechanism of the action is still not clear. Primary nociceptive neurons, containing neuropeptides such as substance P and particularly those innervating the nasal mucosa, could be involved in the pathogenesis of cluster headache. The present study evaluated the effect of an exposure to hyperbaric oxygen on the content of substance P in the nasal mucosa of patients affected by cluster headache. The results were compared with those observed in another group of cluster headache patients who underwent a placebo procedure. The samples of nasal mucosa were analyzed by immunocytochemical methods. A qualitative analysis of the slides was carried out by an operator under "blinded conditions". A marked decrease in the content of immunoreactivity for substance P was found in the patients exposed to hyperbaric oxygen. The decrease was statistically significant when compared with the findings of the placebo procedure. The results of the present study indicate that an influence on the content of peripheral neuropeptides could be involved in the mechanism of action of the beneficial effect of hyperbaric oxygen in cluster headache.

Serum interleukin-1 beta is increased in cluster headache.

We measured serum interleukin-1 beta (IL-1 beta) in 24 episodic cluster headache (CH) patients and 45 normal controls using a specific ELISA method. There was an increase in IL-1 beta in all CH patients compared to controls. IL-1 beta was further increased during the ictal phase of CH compared to patients between attacks and normal individuals. Between attacks, IL-1 beta was also significantly increased compared to controls. We suggest that these results represent an activation of the immune system in CH.

Is the unresponsiveness to sumatriptan in cluster headache related to an alteration in the 5-HT receptors?

It is well established that cluster headache shows impaired functions at the neuroimmunomodulatory system level. Defects in the expression of receptors for 5-HT, IL-1 and IL-2 have been found in these patients. Sumatriptan, an agonist activity for 5-HT1D receptor, truncates cluster headache attack in 74% of patients. Flow cytometric analysis of monocytes expressing 5-HT receptor in cluster headache patients showed different trends clearly correlated with the clinical response to sumatriptan. Our findings strongly support the concept that cluster headache patients which are non-responders to sumatriptan could present a block in their 5-HT receptor expression possibly due to specific autoantibodies for this receptor site.

Immunological alterations in cluster headache during remission and cluster period. Comparison with low back pain patients.

Cluster headache is a disorder of unknown origin. Some studies have focused their attention on neuroendocrine derangement, others on immunity. To probe central alterations in cluster headache (CH), immune parameters were investigated in cluster headache patients in comparison to low back pain patients and healthy controls. Increases in peripheral blood monocytes found in remission cluster headache patients may be attributable to chronic central nervous system (hypothalamic?) noradrenergic dysfunction or altered beta-endorphin. Alterations in NK+, CD3+ and CD4+ levels found in cluster period cluster headache and low back pain patients are probably pain or stress-related.

Anticardiolipin antibodies in cluster headache.

Antiphospholipid antibodies have occasionally been observed in migraine patients, but a recent study of a large series suggested the association was with other concurrent conditions, not specifically with migraine. We wondered about an association with other vascular headaches and measured anticardiolipin antibody levels in 20 cluster headache patients during the cluster period (three during an acute attack). Platelet counts were normal and VDRL negative in all patients. No elevated anticardiolipin antibody levels were found. There appears to be no important association between the presence of anticardiolipin antibodies and cluster headache, and we argue that there is no further rationale for seeking one.

New findings in cluster headache.

The clinical profile of cluster headache, in Italy better known as "Horton's histaminic headache" is described. The Author makes an inventory of all pathogenetic theories about this excruciating pain syndrome that strikes men more than women. On the basis of findings of the Author and his School over a ten-year period, there is a "periodic lack of immunitary oversee". The salient points of various stages of this study are: low frequency of HLA-B14 antigen with, in contrast, high frequency of the HLA-DR5 antigen of the major histocompatibility system. The HLA B18 antigen of the same major histocompatibility system has been found in patients who respond to lithium therapy. A lack of the HLA-B18 antigen has been found in cluster headache patients who are "non-responders" to lithium therapy. Low titers of antibody response in the pain free periods of these subjects, and high titers in the painful periods has also been found in the serum of cluster headache patients; the lack of alpha 1-antitrypsin in basal conditions; increase of IgE (PRIST) values in painful periods; high titers of C1qSp and KgBt circulating immuno-complexes. The cellular immunity studies of the patients showed an increase of the leukocyte subpopulations Leu7+ and Leu M3+. Besides, the natural killer function that contributes to the defense-mechanism against viral disease, was very low. High titers of anti-herpes simplex 1 and 2 viruses and anti-Epstein-Barr virus have been found in cluster headache patients and in a few observations of Burkitt's lymphoma with associated cluster headache, studied in Sahel area too.(ABSTRACT TRUNCATED AT 250 WORDS)

[Aspects of organ-specific autoimmunity in cluster headache]. / Aspetti autoimmunitari organo-specifici della cefalea a grappolo.

Fourty-eight cluster headache patients have been studied. Twenty-nine of them were affected also by rhythm cardiac abnormalities, and the other 19 by associated conjunctival hyperaemia. The presence of organ-specific autoantibodies was investigated by immunofluorescence. High titers of antibodies against cardiac antigenic determinants was found. The study of leukocyte subpopulations revealed a parallel increase in blood and in conjunctival mucosa of Leu7+ and LeuM3+ cells. These outcomes confirm the immunopathological theory of cluster headache.

Lymphokine-activated killer (LAK) cell phenomenon in cluster headache. "In vitro" activation by recombinant interleukin-2.

Previous studies showed that the Natural Killer (NK) activity of peripheral blood lymphocytes (PBL) from cluster headache (CH) patients is lower than that of controls. This decreased activity seems to be independent of the cluster period. beta-interferon has been shown to be more effective in increasing NK activity when incubated with PBL from CH patients, than with PBL from control donors. Lymphokine-Activated Killer (LAK) cells can be generated by incubation of human PBL in recombinant Interleukin-2 (rIL-2). This phenomenon was studied in 10 CH patients and 8 healthy volunteers. PBL were activated to LAK cells by "in vitro" incubation for 72 hours in Control Medium containing rIL-2 (1000 I.U./ml). A four hour Chromium 51 release was used to measure LAK Cell Killing of K562 target cells. The released radioactivity was measured in a gamma scintillation counter. The CH patients showed a marked increase of LAK generation compared to control subjects. This effect seems to be augmented during the cluster period.

[Immunological status of patients with painful syndromes in the face and head]. / Immunologicheskii status u bol'nykh s bolevymi sindromami v oblasti litsa i golovy.

As many as 145 patients with painful syndromes in the face and head underwent immunologic examination. They manifested certain changes in cellular and humoral immunity. An increase in the content of secretory IgA in the saliva and in the serum and a decrease of the concentration of IgM and IgG in the serum were detected in the majority of patients. In patients with NTN of mainly peripheral genesis and with Horton's syndrome, the concentration of IgE in the serum was significantly (P less than 0.01) elevated. The changes in the immunologic status, seen in patients after the treatment are discussed.

[Local and general humoral immunity in patients with migraine, Horton's syndrome and autonomic pain]. / Opredelenie mestnogo i obshchego gumoral'nogo immuniteta u bol'nykh s migreniami, sindrom Khortona i vegetalgiiami.

Patients with migraines, Horton syndrome and autonomic pains were subjected to immunological investigation that revealed different degrees of local and general immunity disorders: increase in blood serum IfA and salival IgAc concentrations. These changes are believed to be capable of serving as diagnostic and prognostic indices.