Development and validation of a gene expression test to identify hard-to-heal chronic venous leg ulcers

Background

Chronic venous leg ulcers pose a significant burden to healthcare systems, and predicting wound healing is challenging. The aim of this study was to develop a genetic test to evaluate the propensity of a chronic ulcer to heal.

Methods

Sequential refinement and testing of a gene expression signature was conducted using three distinct cohorts of human wound tissue. The expression of candidate genes was screened using a cohort of acute and chronic wound tissue and normal skin with quantitative transcript analysis. Genes showing significant expression differences were combined and examined, using receiver operating characteristic (ROC) curve analysis, in a controlled prospective study of patients with venous leg ulcers. A refined gene signature was evaluated using a prospective, blinded study of consecutive patients with venous ulcers.

Results

The initial gene signature, comprising 25 genes, could identify the outcome (healing versus non-healing) of chronic venous leg ulcers (area under the curve (AUC) 0·84, 95 per cent c.i. 0·73 to 0·94). Subsequent refinement resulted in a final 14-gene signature (WD14), which performed equally well (AUC 0·88, 0·80 to 0·97). When examined in a prospective blinded study, the WD14 signature could also identify wounds likely to demonstrate signs of healing (AUC 0·73, 0·62 to 0·84).

Conclusion

A gene signature can identify people with chronic venous leg ulcers that are unlikely to heal.

Abstract P3-07-07: The pan-HER inhibitor, neratinib and wingless-type MMTVs (Wnt)/Wnt regulators in human breast cancer; a biological and clinical perspective

Background. Neratinib is an orally available tyrosine kinase inhibitor that irreversibly binds and inhibits EGFR, HER2 and HER4 receptor tyrosine kinases. Neratinib has been shown to have clinical activity in HER2-amplified or overexpressed breast cancers and those with HER2 mutations. However, there are indications that it may also work on other subtypes that are not strongly positive for the receptors. The present study first screened the effects of neratinib on a range of kinase targets and identified that the Wnt signalling components are key factors that allow neratinib to interact and targets. These targets were also validated in a cohort of human breast cancer.

Methods. Human breast cancer cohorts (n=124) were tested for the transcript expression of HER family including EGFR, HER2, HER3 and HER4 and a number of Wnt family members and the Wnt signalling regulators, ie. GSK3, Axin-1, Axin-2 and β-catenin. The expression patterns were analysed against the clinicopathological and survival status of the patients. Neratinib was tested on a panel of breast cancer cell lines including triple negative cells for the effects on cytoxicity, cell growth, matrix adhesiveness and cellular migration. Signalling kinase pathways were screened using an antibody based kinase array. The effect of neratinib on multiple protein kinases was tested on the cell models, together with other kinase inhibitors.

Results. Neratinib had an inhibitory effect on the cellular migration and cell-matrix adhesiveness of breast cancers at non-toxic concentrations, an effect more profound with MCF-7 and T47D cell lines than with BT20 and MDA MB-231 which are negative for the ER/EGFR/HER2 receptors. Of the multiple kinase inhibitors tested, neratinib was found to exert inhibition on cell function in synergy with the Wnt/β-catenin inhibitor (FK535) and GSK3 inhibitor (TWS119). The expression of the HER and Wnt family members, Wnt Inhibitory Factor-1 and Wnt regulators varied in mammary and breast cancer tissues and in their correlation with the clinicopathological factors. Of the aberrantly expressed receptors, Wnts and Wnt regulators, HER-2 and 4 were found to significantly correlate with Wnt10b (p<0.05), EGFR/HER1 was found significantly correlated with GSK3 (p<0.05) and HER-3 with Wnt5a (p<0.03). Furthermore, we identified that the integrated expression pattern of five of these factors, namely EGFR, HER2, HER4, Wnt5 and Wnt Inhibitory Factor-1 formed an expression signature that were significantly linked to the overall survival (survival time 148±3.7 vs 113.7 ±7.5 months for favourable and non-favourable pattern, respectively, p=0.002) and disease free survival (p=0.004) of the patients (median follow-up 120 months)

Conclusion. Neratinib, at non-toxic concentration levels, is a profound inhibitor of the migration and matrix adhesion of breast cancer cells, cell functions linked to the aggressiveness and metastasis of breast cancer cells. Its synergistic effects with the Wnt and GSK3 inhibitor, together with the prognostic value of the HER family/Wnt, indicate that the Wnt pathway together with the HER family forms a new molecular indicator and target when considering neratinib in the treatment patients with breast cancer.

Citation Format: Owen S, Ruge F, Lalani AS, Avogadri-Connors F, Bryce RP, Davies E, Jiang WG. The pan-HER inhibitor, neratinib and wingless-type MMTVs (Wnt)/Wnt regulators in human breast cancer; a biological and clinical perspective [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-07-07.

Abstract P4-05-03: Heat shock protein 27 (HSP27) and HER2 positively correlate in breast cancer and effect cell responsiveness to neratinib and cMET inhibitor

Background: Upregulation of heat shock protein-27 (HSP27), a key member of the HSP family, has been shown to confer resistance to chemotherapy and radiotherapy in solid tumours including breast cancer. Evidence is also emerging that HSP27 is linked to the metastatic spread of breast cancer and key cellular traits including cellular migration. Neratinib is an orally available tyrosine kinase inhibitor that irreversibly binds and inhibits EGFR, HER2 and HER4 receptor tyrosine kinases. cMET, the receptor for hepatocyte growth factor and target for cancer therapies, has been shown to be trans-phosphorylated by EGFR. In the current study, we evaluated HSP27 expression within a breast cancer cohort and its implications in cellular responsiveness to cMET inhibition and neratinib.

Methods: HSP27 transcript expression was analysed in our chemotherapy naïve breast cancer cohort (n=124) using quantitative PCR (qPCR) and compared to clinic-pathological information including long-term survival over a ten year follow up period. In addition, the correlation between HSP27 and HER2 expression was explored using Spearman Rank order. High-throughput cell migration analysis was performed using ECIS, on MCF-7 control and HSP27 siRNA knockdown cells in conjunction with neratinib and PHA 665752, a small molecule cMET inhibitor.

Results: In our primary breast cancer cohort, there were no significant associations between HSP27 transcript expression levels and tumour grade, TNM or estrogen receptor (ER) status. Combined survival expression analysis indicated that the worst patient prognosis was associated with high levels of both HER2 and HSP27 and high HER2 and low HSP27 whereas best patient prognosis was associated with low HER2 and low HSP27 expression. Knockdown of HSP27 in MCF7 cells brought about a reduction in cellular migration compared to the control. Additionally, this reduction was enhanced by the addition of neratinib, in a concentration dependent manner, and also cMET inhibition when individually treated. Furthermore, the greatest inhibitory effects on MCF-7 migration were seen following HSP27 knockdown and combined treatment with neratinib and PHA 665752.

Conclusions: Our current data suggests that HSP27 confers low sensitivity to drugs such as neratinib and PHA 665752, particularly in relation to cellular migration and hence potentially metastasis. Therefore, the targeting of HSP27, HER2 and cMET appear to act syngeristically to regulate cellular migration in vitro. Furthermore, clinically expression of HER2 and HSP27 may serve as a prognostic marker for breast cancer survival. Hence, combination therapies that target both HSP and HER2 pathways may provide new clinical opportunities for preventing breast cancer progression.

Citation Format: Owen S, Sanders AJ, Ruge F, Lalani AS, Avogadri-Connors F, Bryce RP, Jiang WG. Heat shock protein 27 (HSP27) and HER2 positively correlate in breast cancer and effect cell responsiveness to neratinib and cMET inhibitor [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-05-03.

Abstract P3-06-10: The impact of the Chinese medicine ShenLingLan on triple negative breast cancer, the metabolic and signalling pathways and clinical implications

Background. Triple negative breast cancer (TNBC) is a challenging both in the choice of therapies and clinical outcomes. In the present study, we investigated the potential prospect of a Chinese medicine formation, ShenLingLan, shown to have benefit to patients with cancer and able to influence the biological behaviour of cancer cells, on breast cancer cells in particular the differential response from TNBC and non-TNBC cells and, on the discovery that TNBC cells were particularly sensitive to the medicine, we went on to determine the signalling and mechanism of action.

Methods. A panel of three TNBC (MDA MB-231, BT20 and BT549) and a panel of three non-TNBC (MCF-7, ZR 75-1 and T47D) cells were used. A soluble extract from ShenLingLan, designated as SLDM, was utilised during this study. The proliferation, cellular migration and adhesiveness were tested using conventional and biophysical methods. Signalling profiling was conducted using a protein kinase array platform (Kinexustm). Metabolic profiling was conducted using the Seahorse platform. Expression of insulin receptor (IR) and insulin-like growth factor receptor (IGFR) gene transcripts (quantitative transcript analysis) and proteins (IHC) were conducted using a fresh breast cancer cohort and tissue array, respectively.

Results. SLDM had little effects on the growth of breast cancer cells. However, it had profound inhibitory effects on the migration of both TNBC and non-TNBC cells in a concentration dependent manner. Interestingly, TNBC cells were 5-20 times more sensitive than the non-TNBC cells in their migration and cell adhesion responses to SLDM. The protein array platform further revealed that, of the wide range of protein kinases, IR and IGRR1 were the most affected in that SLDM resulted in 25-50% reduction in the phosphorylation of IR and IR substrate in TNBC cells. SLDM also caused a contrasting response in IGFR1 phosphorylation in TNBC and non-TNBC cells. Metabolically, TNBC and non-TNBC cells responded to SLDM in very different fashions. For example, in TNBC cells SLDM resulted in a significant decrease in glycolytic activities, in particular that driven by insulin (30.2±12.2 pmol/min in control, 47.7±10 pmol/min with insulin and 35.4±4.2 pmol/min with insulin/SLDM, p=0.01). There is evidence that the mitochondria oxygen consumption (OCR) was also affected by SLDM in TNBC cells (p=0.01). These changes induced by SLDM were in clear contrast to non-TNBC cells which did not respond with significant reduction. Both TNBC and non-TNBC breast cancer tissues have higher IR staining than normal mammary tissues (p<0.001). TNBC tumours also demonstrated significantly more positive IR staining than the non-TNBC tumours (p=0.04).

Conclusion. ShenLingLan has a profound inhibitory effect on the migration and cell-matrix adhesion of TNBC cells, with marked effect on the metabolics of these cells. This effect connects with reduction of the IR and IGFR activation, mainly through the reduction in glycolysis. Together with the clinical implication of IR and IGFR in breast cancer, ShenLingLan has an important role in the treatment of breast cancer with an emphasis in TNBCs.

Citation Format: Jiang WG, Owen S, Ruge F, Gao Y, Wang H, Wei C, Wu Y, Davies E. The impact of the Chinese medicine ShenLingLan on triple negative breast cancer, the metabolic and signalling pathways and clinical implications [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-06-10.

Abstract P3-15-04: Signalling pathways targeted by the YangZheng Xiaoji extract and the therapeutic implications in human breast cancer

Background. Yangzheng Xiaoji is a formulation of Chinese medicine and has been used in the treatment of solid cancer as an adjuvant to chemotherapy by reducing the side effects to the patient. There has been evidence to show that the medicine has a direct biological role in cancer cells. In the present study, we sought to investigate the potential effects of the medicine on breast cancer cells and in particular aimed to identify the key targets and molecular pathways contributing to the anti-cancer effect of the medicine.

Methods. Human breast cancer cell lines (BT549, BT20, MDA MB-231, MCF-7 and ZR 75-1) with varying invasiveness and receptor status were used. The soluble extract of Yangzheng Xiaoji, namely DME25 was used in the study. The effects of DME25 on the growth, toxicity and cellular migration were assessed. Signalling kinase changes were screened using kinase antibody array based array technologies. Kinases were also validated using phosphorylation based protein blotting.

Results. Of the five breast cancer cell lines tested, Yangzheng Xiaoji extract DME25 showed little cytotoxicity over a broad range of concentrations. However, DME25 were able to markedly reduce the migration of the panel of breast cancer tested, without being toxic. Triple negative cells responded in a similar fashion with other cells. It was also noted that the adhesion of these cells were also inhibited by DME25. Using a protein kinase array, it was shown that a number of kinase complexes were inhibited by the medicine, notable ones including EGFR family kinases (reduced by 35%), Janus protein kinases (JAK) (by 57%), and Ras-related C3 botulinum toxin substrate (Rac1 or CDC42 GTPase) (by 49%) and Ribosomal protein S6 kinases (RSKs) (by 52%). Given the clinical significance of RSKs in human breast cancer, we further evaluated the role of RSK and RSK inhibitors in DME mediated cell functions and have demonstrated that both in triple negative breast cancer cells and receptor positive breast cancer cell lines, DME25 was able to synergistically enhance the effect of RSK2 inhibitor, SL1010-1, on the both the cellular migration and cell growth.

Conclusion. Yangzheng Xiaoji has a broad and direct effect on the migration of breast cancer, an effect unrelated to hormone receptor status and independent of cytotoxicity. The medicine appears to target kinase pathway, particularly for the RSK kinases, suggesting an important clinical implication in the treatment of breast cancer.

Citation Format: Jiang WG, Ye L, Owen S, Ruge F, Martin TA, Sanders AJ, Gao G, Wei C, Wu Y, Davies E. Signalling pathways targeted by the YangZheng Xiaoji extract and the therapeutic implications in human breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-15-04.

The clinical significance and impact of interleukin 15 on keratinocyte cell growth and migration

Chronic wounds represent a significant burden to health services and are associated with patient morbidity. Novel methods to diagnose and/or treat problematic wounds are needed. Interleukin (IL)-15 is a cytokine involved in a number of biological processes and disease states such as inflammation, healing and cancer progression. The current study explores the expression profile of IL-15 and IL-15 receptor α (IL-15Rα) in chronic wounds and its impact on keratinocytes. IL-15 and IL-15Rα expression were examined in healing and non-healing chronic wounds using qPCR and immunohistochemical analysis. The impact of recombinant IL-15 (rhIL-15) on human adult low calcium temperature (HaCaT) keratinocyte growth and migratory potential was further examined. IL-15 transcript expression was slightly, though non-significantly elevated in healing chronic wounds compared with non-healing chronic wounds. IL-15 protein staining was minimal in both subtypes of chronic wounds. By contrast, IL-15Rα transcript and protein expression were both observed to be enhanced in non-healing chronic wounds compared with healing chronic wounds. The treatment of HaCaT cells with rhIL-15 generally enhanced cell growth and promoted migration. Analysis with small molecule inhibitors suggested that the pro-migratory effect of rhIL-15 may be associated with ERK, AKT, PLCγ and FAK signalling. IL-15 may promote healing traits in keratinocytes and the differential expression of IL-15Rα is observed in chronic wounds. Together, this may imply a complex role for this interleukin in wound healing.

Reversal of Pathological Features of Graves' Orbitopathy by Activation of Forkhead Transcription Factors, FOXOs

CONTEXT

Graves' orbitopathy (GO) is a disfiguring/distressing, inflammatory autoimmune condition. This intractable problem is caused by expansion of the orbital contents around the eye by excessive fat generation (adipogenesis) and overproduction of extracellular matrix components, especially hyaluronan (HA) from preadipocytes/fibroblasts (PFs). Current immunosuppressive/antiinflammatory treatments are largely ineffective and have unpleasant side effects, and a better therapeutic strategy through understanding GO-associated pathological features is needed.

OBJECTIVE

Previously we identified depot-specific HA synthase 2 regulation (HAS2; major source of HA), which facilitates orbit-specific HA accumulation during adipogenesis, and targeting phosphatidylinositol-3-kinase/mechanistic target of rapamycin-complex-1 pathways blocked both pathological features. The current study revealed low expression levels of Forkhead box O (FOXOs; critical downstream effectors of phosphatidylinositol-3-kinase) in orbital PFs through adipogenesis compared with sc levels. We aimed to dissect the role of FOXOs in GO pathogenesis to identify nonimmunosuppressive targets for GO treatment.

DESIGN/SETTING/PARTICIPANTS

Human orbital and sc primary PFs were treated with small interfering RNA/chemical inhibitor (AS1842856) of FOXOs or FOXO enhancer trifluoperazine hydrochloride (TFP; Food and Drug Administration approved drug), in serum-free medium for 24 hours, or TFP treatment in adipogenic medium for 15 days.

MAIN OUTCOME MEASURES

Quantitative PCR was used to measure HAS2 transcripts and the terminal adipogenesis differentiation marker lipoprotein lipase. HA accumulation in the medium was measured by an ELISA.

RESULTS

Substantially increased or decreased HAS2/HA production was observed by inhibiting (small interfering RNA or chemical inhibitor) or enhancing (TFP) FOXO expression, respectively. TFP treatment is also sufficient to counteract thyrotropin receptor-activated HAS2/HA production and block adipogenesis in orbital PFs.

CONCLUSIONS

FOXOs play a crucial repressor role in the regulation of HAS2/HA production and adipogenesis in orbital PFs. Our data reveal for the first time that resetting GO-associated pathological features through drug-targeted activation of FOXOs could provide a feasible nonimmunosuppressive therapeutic strategy for GO.

Inflammatory-cell subpopulations in keloid scars

The aim of this study was to investigate the contribution of lymphocytes and macrophages to keloid scarring by morphologically characterising inflammatory cell subpopulations in keloid scars in comparison with normal skin. We took 3mm punch biopsies from the anterior forearms of eight normal healthy volunteers. Eight keloid scars were excised using an intralesional technique. All tissue was snap frozen in liquid nitrogen and serial sections were stained with a panel of anti-inflammatory cell monoclonal antibodies. The numbers of macrophages and lymphocytes and the proportions of the subpopulations were compared. Higher numbers of both macrophages and lymphocytes were found in keloid dermis (P=0.01 and P=0.02, respectively (Mann-Whitney U -test)). There was no significant increase in the expression of the lymphocyte-activation markers, CD25 and CD27. However, there was a significantly higher CD4(+):CD8(+)(Th:Ts) ratio (P= 0.046) in keloid tissue. This suggests that an imbalance in these inflammatory cell subpopulations may contribute to keloid scarring in man.

The role of lymphocytes in human dermal wound healing

BACKGROUND

Animal experimental data indicate a requirement for functionally active T lymphocytes to allow optimal healing of dermal wounds. Little evidence exists to confirm that this is the case in humans. Lymphocyte involvement in regulation of healing is probably mediated by release of secreted cytokines/growth factors, and we hypothesize that the cytokine profile requirement will be modulated as healing progresses.

OBJECTIVES

As this is likely to be reflected in lymphocyte subset changes over the course of normal healing, we investigated the immunophenotype of lymphocyte subpopulations during wound healing.

METHODS

Sequential biopsies were taken over 42 days from the margin of 12 wounds healing by secondary intention after pilonidal sinus excision. Serial biopsy sections were analysed by immunohistochemistry using lymphocyte-specific monoclonal antibodies, and lymphocytes were counted microscopically.

RESULTS

Within 42 days, the mean decrease in wound volume was 87.5%. This was accompanied by significant changes in the wound margin lymphocyte population. Total numbers (mean +/- SEM) of T lymphocytes decreased from 36.8 +/- 9.8 cells per field at inclusion in the study to 25.9 +/- 3.0 immediately prior to wound closure, with a concomitant increase in B lymphocytes from 1 +/- 0.4 to 9.5 +/- 3.6 cells per field. The CD4/CD8 T-lymphocyte ratio fell from an initial level of 3.6 +/- 0.3 to 2.1 +/- 0.3 (mean +/- SEM) prior to closure.

CONCLUSIONS

These data indicate that human wound-associated lymphocyte populations are modulated during healing; the increase in numbers of CD8+ T-suppressor lymphocytes is in accordance with previous animal data, indicating a role for these cells in downregulating healing as the wound closes. This study also documents an associated increase in B lymphocytes and healing of human wounds, with an as yet undefined role.

T lymphocytes and the lack of activated macrophages in wound margin biopsies from chronic leg ulcers

The objective of this study was to characterize the leucocyte infiltrate which accumulates at the margin of chronic wounds. These leucocytes are a rich source of cytokines and growth factors, and an inappropriate function of these cells may contribute to the maintenance of wound chronicity. The leucocyte populations were stained immunohistochemically with monoclonal antibodies specific for surface receptors which give an indication of cellular function. Wound margin biopsies taken from chronic leg ulcers exhibited a localized infiltrate of CD45+ leucocytes associated with vascularized tissue in the dermis adjacent to the wound margin. Lymphocytes were identified in highest numbers in this area and CD45RO+ T lymphocytes predominated over B lymphocytes, which were either absent or present in very low numbers. In the majority of chronic wounds examined, CD4+ T lymphocytes were present in greater numbers than CD8+ T lymphocytes with a mean (+/-SD) ratio of CD4+:CD8+ of 1.5 +/- 0.6. CD68+ macrophages were identified in all layers of the dermis at the chronic wound margin. In 60% of wounds examined, macrophages were negative for the activation associated markers CD16 (Fc gamma III receptor) and CD35 (C3b receptor). In those biopsies where CD16 and CD35 positive macrophages were observed these were preferentially located in the perivascular regions. These data indicate that as monocytes extravasate into chronic wound tissue they may be subjected to microenvironmental influences which either suppress or do not induce macrophage activation. Suppression of macrophage activation may lead to an inappropriate cytokine/growth factor secretion and contribute to the maintenance of wound chronicity.

Axon-glial relationships in the anterior medullary velum of the adult rat

The anterior medullary velum is a thin sheet of CNS tissue which roofs the rostral part of the IVth ventricle and contains fascicles of myelinated fibres which, in part, arise from the nucleus of the IVth cranial nerve. This study used histochemical, immunohistochemical, and intracellular dye-injection techniques to describe cellular interrelationships in the velum in whole-mounts and in sections. Rip antibody-stained whole mounts provided a unique description of both oligodendrocyte units (defined as an oligodendrocyte and the complement of myelinated internodal segments it forms), and consecutive myelin sheaths along the same axon. A broad range of unit morphologies was categorised into four arbitrary groups, according to classical criteria, which comprised small cells supporting the short, thin myelin sheaths of 15-30 small diameter axons (Type I), through intermediate types (II & III), to the largest cells forming the long, thick myelin sheaths of 1-3 large diameter axons. Rip antibody and ferric ion-ferrocyanide staining, together with intracellular dye injection, revealed oligodendrocyte process branching patterns and their mode of engagement of myelin sheaths, nodes of Ranvier, and the spatial disposition of the outer cytoplasmic rims of myelin sheaths. The latter formed a conspicuous spiral ridge on the exterior surface of myelin sheaths which connected with the paranodal loops at each heminode. Large bundles of axons decussated through the velum, the bulk of which were IVth nerve fibres which constituted the IVth nerve rootlet. The PNS/CNS transitional zone of the IVth nerve was located 0.25-0.50 mm along the root, where astrocytic end-feet defined an abrupt margin, convex towards the periphery, where the heminodes of central and peripheral myelin were apposed, and where the basal lamina tubes of the Schwann cell units were discontinued. The basal processes of ependymal cells lining the ventricular wall of the velum, passed between axon bundles before abutting on the basal lamina of the pia. Many of these processes branched and ran along the axonal bundles. A monolayer of microglia occupied a subependymal stratum in which the non-overlapping dendritic territories of each cell formed a regular mosaic throughout the velum without any obvious interaction with either axons or other glial cells. Astrocytes were also uniformly distributed; their fine processes made up a dense lattice amongst axons, often running parallel and within the fibre bundles; stouter ones had terminal end-feet which undercoated the basal lamina of both the glia limitans externa and the blood vessels in the velum.

In vitro allergenicity of cows' milk substitutes

There are numerous alternatives to cows' milk formula for allergic children. We have investigated the allergenicity of several of these using RAST and RAST inhibition on serum from 16 patients with a known history of cows' milk protein intolerance (CMPI) and 16 atopic controls. A RAST grade of > or = 3 for cows' milk was present in all those with CMPI, whilst all the controls gave RAST of < or = 1. Modified cows' milk formula, goats' infant formula, sheep and goats' milk produced similar results to cows' milk. Only two patients had RAST > or = 3 for soya milk and the soy/beef hydrolysate gave positive results in only three patients. One had positive RAST to Nutramigen and two to Pregestimil. Of the whey hydrolysates investigated, Pepti-junior gave seven positive RASTs whilst we were unable to bind Alfare to the sepharose in sufficient quantities to interpret the results which were negative in all cases. RAST inhibition data on pooled sera from the same patients agreed with the RAST results. The inhibition curves showed high inhibition with goats', sheep, modified cows' milk formula and the casein formula, AL110 (50%). Soy and soy/beef hydrolysate showed a much lower inhibition pattern. Casein hydrolysates showed low inhibition while the whey hydrolysate produced higher inhibition. We have shown that despite claims of low allergenicity, some of these alternative formulae are antigenically recognized in vitro by some cows' milk intolerant patients.