The role of MMPs appear critical in IPF and probably in other categories of IIPs and ILDs.Doxycycline is a non specific MMPs inhibitor and has shown beneficial effects in IPF with demonstration of reduction in the MMPs level in BALF .Though not studied, it is likely that MMPs plays a significant role in other varieties of DPLDs-where administration of  doxycycline in similar fashion may have a therapeutic role

The proposed study will be a real world single arm prospective observational trial.  The selection criteria is not very strict as it prevails in existing practice of a physician in a developing country and the investigations will be done as far as possible to an extent the patient is willing or can afford to pay for in accordance with the prevailing circumstances.

Similarly, like a conventional trial there will be no fixed protocol for follow ups, though a regular requirement of review and monitoring will be suggested to each patient. Again, the volunteers will be requested to report for suspected adverse reaction, if any than looking such things on a stringent fashion as being done in a formal drug trial.

The evaluation process also will be far from ideal as is followed in a drug trial. However, it will be objective as far as possible in the available situation and the practice style.

All efforts will be exerted to extract the best possible information from the available records. The physician though not blinded will have full access into the record and power to modify the treatment as and when he or she feels it necessary. The etiological assessment and the severity evaluation will be done at the point of data collection only.