The thread that was mentioned has been archived because it was in a now defunct section of the forum.
Here are the abbreviations from that thread:
Commonly Used Abbreviations
ANN - Artificial Neural Network
AfME - Action for ME (a UK charity)
CAA - CFIDS Association of America
CBT - Cognitive Behavioral Therapy
CCC - Canadian Consensus Criteria.
CCD - Canadian Consensus Definition or Document
CDC (US) - Centers for Disease Control and Prevention
CFIDS - Chronic Fatigue and Immune Dysfunction Syndrome
CFS - Chronic Fatigue Syndrome
CFSAC - Chronic Fatigue Syndrome Advisory Committee
CMV - Cytomegalovirus
Cpn - Chlamydia Pneumoniae
CSF - Cerebrospinal Fluid
EBV - Epstein-Barr Virus
EFA - Essential Fatty Acids
EI - Environmental Illness
ERV - Endogenous retrovirus
ETA - edited to add
FDA - Food and Drug Administration (USA)
FM - Fibromyalgia
GET - Graded Exercise Therapy
GcMAF - Gc Macrophage Activating Factor
GP - General Practitioner
GWI - Gulf War Illness
H2S- Hydrogen Sulfide
HAART - Highly Active Antiretroviral Therapy
HCT - Hematocrit
HERX - herxheimer reaction
HERV - Human endogenous retrovirus
HHV-6 - Human Herpes Virus 6
HRV - Heart Rate Variability
IBS - Irritable bowel syndrome
IgG - Immunoglobulin G
IGM - Immunoglobulin M
IRIS - Immune Reconstitution Inflammatory Syndrome
LDN - Low Dose Naltrexone
LLMD - Lyme Literate Medical Doctor
MCS - Multi-Chemical Sensitivity
MEA - ME Association (a UK charity)
ME - Myalgic Encephalomyelitis
MRC (UK) - Medical Research Council
MSM - methylsulfonylmethane
NEID - Neuroendocrineimmune Disorders
NIH - National Institute of Health (USA)
NKC - Natural Killer Cells
NO - Nitric Oxide
NP - Nurse Practitioner
NT - Neural Therapy
OI - Orthostatic Intolerance
PCR - Polymerase Chain Reaction
PCP - Primary Care Physician
PEM - Post-exertional Malaise
POTS - Postural Orthostatic Tachycardia Syndrome
PR - Phoenix Rising
PWC - People with CFS
RAL - Raltegravir
RLS - Restless Leg Syndrome
Th17 - T helper 17 (Th17) cells
TMI - too much information
WPI - Whittemore Peterson Institute
XAND - x-associated neuro-immune disease
XMRV - xenotropic murine leukemia virus-related virus
Kina