Immune responses to Campylobacter and serum autoantibodies in patients with complex regional pain syndrome.

We hypothesised that some complex regional pain syndromes (CRPS) may have a postinfectious and/or autoimmune basis. Sera from 92 patients with CRPS and 92 controls were investigated for immunoreactivity to Campylobacter strains and to rodent tissues. Both IgA-antibodies to Campylobacter and tissue-specific reactivity were often present in patients with short disease duration (< or = 1.5 years). Patients with minimal preceding trauma had stronger nervous tissue-specific reactivity than other patients, regardless of disease duration. These results provide preliminary evidence for immune activation early in CRPS and, additionally, that patients with minimal trauma may comprise an autoimmune subgroup.

Intravenous immunoglobulin in the treatment of primary trigeminal neuralgia refractory to carbamazepine: a study protocol [ISRCTN33042138].

BACKGROUND: We have recently reported successful treatment of patients with chronic pain syndromes using human pooled intravenous immunoglobulin (IVIG) in a prospective, open-label cohort study. A randomised, placebo controlled, double blinded study is needed to confirm these results. We chose to study patients with carbamazepine resistant primary Trigeminal Neuralgia (rpTN), as these had responded particularly well to IVIG.A protocol involving the use of IVIG in rpTN is complex for three reasons: 1. The effect of IVIG does not follow simple dose-response rules; 2. The response pattern of patients to IVIG was variable and ranged between no effect at all and pain free remission between two weeks and >1 year; 3. TN is characterized by extremely severe pain, for which operative intervention is (if temporarily) helpful in most patients. DESIGN: A placebo controlled, parallel, add-on model was developed and the primary outcome variable defined as the length of time during which patients remain in the study. Study groups are compared using Kaplan-Maier survival analysis. Patients record their response to treatment ("severe, moderate, slight, no pain"). The study coordinator monitors pain diaries. Severe or moderate pain of three days duration will result in termination of the study for that patient. CONCLUSIONS: This study design utilizes a method of survival analysis and is novel in chronic pain research. It allows for both early departure from the study and voluntary crossover upon non-response. It may be applicable to the analysis of IVIG efficacy in other chronic pain syndromes.

Human pooled immunoglobulin in the treatment of chronic pain syndromes.

OBJECTIVE: To examine the use of intravenous immunoglobulin (i.v.i.g.) in chronic pain. DESIGN: A prospective multiple-dose, open-label cohort study in 130 consecutive patients who suffered from 12 chronic pain syndromes. The largest symptom groups were (number of patients): Fibromyalgia (48); Spinal pain (20); Complex regional pain syndrome (CRPS, 11); Peripheral neuropathic pain (12); and Atypical odontalgia or atypical facial pain (11). All patients had insufficient pain relief with established treatments. Pain relief was recorded using average pain intensity values as documented in standardized diaries. A specific treatment protocol was developed, and patients were enrolled over a 36-month period. RESULTS: Overall, 20% of patients had>70% pain relief and 27.7% of patients reported relief between 25% and 70%. Six patients (4.6%) had moderately increased pain levels for a duration of up to 9 weeks. Good relief, of more than 70%, was found in all major symptom groups. Patients with pain of short duration (<2 years) reported high relief rates (33.8% of patients in this group reported relief of >70%). No serious adverse events were reported. conclusions: i.v.i.g. may be effective in patients suffering from chronic pain. Controlled studies are needed to evaluate the efficacy of i.v.i.g. in these patients. Patients with a good response to i.v.i.g. may be models for the study of neuroimmune interactions in chronic pain.