VP1 test – American ME and CFS Society

Abstract:

Thirty-four patients with chronic fatigue syndrome (CFS) were compared with controls with DSM-III-R major depression on the Monospot and VP1 antigen tests.

There was no significant difference in the numbers initially VP1 positive in the groups (11/34 and 7/34 positive in the chronic fatigue and major depression group respectively). Four CFS but no depressed patients were Monospot positive initially. No patient was both Monospot and VP1 positive. Patients positive on the tests were offered a repeat 6 months later. Eight of the 11 VP1 positive patients in the CFS group were retested and four remained positive, but none of the four depressed patients retested remained positive. No patient retested remained Monospot positive.

The Monospot and VP1 tests appear to have little discriminating ability between these groups as screening tests and their predictive validity is unclear.

Source: Lynch SP, Seth RV, Main J. Monospot and VP1 tests in chronic fatigue syndrome and major depression. J R Soc Med. 1992 Sep;85(9):537-40. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1293640/ (Full article)

Abstract:

Myalgic Encephalomyelitis (ME) is a form of post viral fatigue syndrome resulting in myalgia and fluctuating fatiguability. Symptoms reflecting central nervous system dysfunction are common and include muscle weakness, headache, sensory disturbances, poor short term memory and impairment of concentration.

In view of the fact that sensory and cognitive disturbances are experienced by many patients objective evidence was sought with multi-modality sensory evoked potentials and auditory event-related cognitive potentials in a group of ME patients both with and without the enteroviral antigen, VP1 test positive.

The auditory brainstem, median nerve somatosensory and pattern reversal checkerboard visual potentials were normal for all 37 patients tested. In contrast to the sensory potentials significant differences in the mean latencies of the cognitive potential N2 and P3 were found. Reaction times were also significantly prolonged but the performance in terms of error was not significantly affected. No significant difference emerged in any of the parameters for the VP1 test. P3 was abnormal in latency or amplitude in 36% of the VP1 positive patients for the frequency discrimination task and 48% for the more difficult duration discrimination task.

The abnormalities indicate attentional deficits in some patients and slower speed of information processing in others. The prolonged latencies observed in these patients have not been observed in patients with depression in many other studies.

Source: Prasher D, Smith A, Findley L. Sensory and cognitive event-related potentials in myalgic encephalomyelitis. J Neurol Neurosurg Psychiatry. 1990 Mar;53(3):247-53. http://www.ncbi.nlm.nih.gov/pubmed/2324756

Note: You can read the full article here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1014138/