Inclusion Criteria:

• Must fulfill 1980 Preliminary Classification Criteria for systemic sclerosis of the American Rheumatism Association
• Diffuse cutaneous SSc, as evidenced by skin sclerosis proximal to the elbows or knees and absence of the anti-centromere autoantibody
• At least three years must have elapsed since the first non-Raynaud's manifestation
• Men and women of childbearing potential must use adequate birth control measures for the duration of the study and should continue such precautions for six months after receiving the last injection of AIMSPRO.
• Screening laboratory test results:

Hemoglobin > 8.5 g/dL WBC > 3.5 x 10^9/L Neutrophils > 1.5 x 10^9/L Platelets > 100 x 10^9/L SGOT (AST) and alkaline phosphatase levels must be within twice the upper limit of normal range for the laboratory conducting the test.

• Patient must be able to adhere to the study visit schedule and other protocol requirements
• Patient must be capable of giving informed consent and the consent must be obtained prior to any screening procedures
• No radiological evidence of malignancy, infection or (previous) tuberculosis in a chest radiograph performed within three months prior to the first injection of study drug

Exclusion Criteria:

• Women who are pregnant, nursing, or planning pregnancy within one and a half years after screening (i.e., approximately six months following last injection of study drug).
• Use of any investigational drug within one month prior to screening or within five half-lives of the investigational agent, whichever is longer.
• Use of a putative disease modifying drug (potential immunosuppressive drug) within one month of screening.
• Treatment with any therapeutic agent targeted at reducing TNF (e.g., infliximab, pentoxifylline, thalidomide, etanercept, etc.) within three months of screening.
• Previous administration of AIMSPRO.
• History of known allergy to animal proteins.
• Serious infections (such as pneumonia or pyelonephritis) in the previous three months. Less serious infections (such as acute upper respiratory tract infection [colds] or simple urinary tract infection) should be monitored to their conclusion or treated, as appropriate, prior to inclusion.
• Active hepatitis-B or hepatitis-C.
• Active tuberculosis.
• Patients with opportunistic infections, including but not limited to evidence of active cytomegalovirus, active Pneumocystis carinii, Aspergillosis, histoplasmosis or atypical mycobacterium infection, etc, within the previous six months.
• History of lymphoproliferative disease including lymphoma, or signs and symptoms suggestive of possible lymphoproliferative disease, such as lymphadenopathy of unusual size or location (such as nodes in the posterior triangle of the neck, infra-clavicular, epitrochlear, or periaortic areas), or splenomegaly.
• Known recent substance abuse (drug or alcohol).
• Poor tolerability of venepuncture or lack of adequate venous access for required blood sampling during the study period.
• Presence of a transplanted organ (with the exception of a corneal transplant > three months prior to screening).
• Patients receiving immunosuppressive therapy within one month of screening.
• Patients with malignancy within the past five years.
• Signs or symptoms of severe, progressive or uncontrolled renal, hepatic, haematologic, gastrointestinal, endocrine, pulmonary, cardiac or neurological disease (including demyelinating diseases such as multiple sclerosis).
• Patients who, within the past three months, have had either a myocardial infarction, uncontrolled congestive cardiac failure, unstable angina, uncontrolled systemic hypotension or uncontrolled systemic hypertension.
• Patients who have screening laboratory values which deviate 20% or more from the upper or lower limits of normal or which are considered to be clinically significant to the investigator.